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Form 155.21 - Johnson Controls

1. 5 lt X lt WY CHILLED WATER 8 8 N 4 TOWER WATER O S 152 a N Q WATER 1014630 JOHNSON CONTROLS 155 21 1 510 MODEL 10E3 9 2 13 40 9 13 40 0 0099 0007 0006 0002 0001 008 009 009 007 002 0099 0007 0006 0002 0001 008 009 005 007 002 CHILLED WATER GPM CHILLED WATER 554 4 14 0057 0007 0006 0002 0057 0007 0006 0002 TOWER WATER GPM TOWER WATER
2. 50 TOWER WATER 40 30 gt lt 2012 2 10 8 D 6 5 4 3 2 OO GPM HOT WATER 1200 LD14629 59 PTX Chart MODEL YIA 803 FORM 155 21 1 510 MODEL 8 1 PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER 80 60 40 30 gt 20 4 10 lt 7 5 3 2 1 wo 5 gt 5 N 5 A GPM CHILLED WATER 70 50 30 gt 20 2 9 N E 52 10 gt COs 4 4082 3 92 2 2 56 1 5 2 GPM TOWER WATER 50 40 30 x 20 O lt 10 2 8 4 6 5 4 3 2 Notes on 63 WATER FIG 26 CONT D PRESSURE DROP CURVES 60 PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER 80 60 40 30 20 ano 40 30 20
3. 4 AUTOMATIC DE CRYSTALLIZATION PIPE WATER 906 0 gt 55000000050 14REFRIGERANT VALVE PURGE DRUM CONDENSER nae FLUSH LINE REFRIGERANT LEVEL VALVE SOLUTION PUMP SOLUTION HEAT EXCHANGER REFRIGERANT 4 3 PUMP EDUCTOR Note Orifices may differ between various models 1004768 FIGURE 13 AUTOMATIC DECRYSTALLIZATION FEATURE HOT WATER UNITS amp STEAM UNITS WITH ADC CONTROL JOHNSON CONTROLS 25 Purging and Non condensables FORM 155 21 1 510 THIS PAGE INTENTIONALLY LEFT BLANK 26 JOHNSON CONTROLS 155 21 1 510 SECTION 3 PURGING AND NON CONDENSABLES NON CONDENSABLES It is necessary to purge absorption chillers due to the potential for the systems to collect non condensable gases Non condensables if allowed to accumulate will reduce the absorption unit s performance and may cause corrosion within the unit It could be speculated that over ninety percent of all capacity related complaints on IsoFlow units involve the presence of non condensables A non condensable is defined as a gaseous substance that cannot be liquefied or condensed at the pressure and temperature surrounding it Non condensables appear in two forms in absorption units 1 Internally generated non condensables are formed as a by
4. X 2 2 9 152 N CHILLED WATER N TOWER WATER 22 x ag 1014576 53 5 gt 9 0091 0001 008 N 00 0001 008 gt 9 Q 5 5 1 5 4 5 0 5 1 0665 006 4 ONIA Bha oos 25 68 IN W lt ve ToN oN 5 6 002 008 gt 00 8 4 00 002 06 2g FF 259 S 3 R 899 1 JYNSSJYd YALVM YALVM 1 0091 0001 005 lt 000 008 2 00 009 006 5 os 5 008 gt 52 E 0
5. 11 Controls and 11 CONTROL DESCRIPTIONS 11 Components the Control Center 11 Components of Power 11 Components External to the Control Center 12 CONTROL SEQUENCE i 13 SYSTEM OPERATION 19 19 CAPACITY CONTRO 20 19 Maximum Load Limits at Reduced Condensing Water Temperatures 19 Solution and Refrigerant Interchange During Operation 19 Anti FreeZe 22 Chilled Water Control Stability 22 042 24 22 Stabilizer Refrigerant Solenoid 2500 22 Capacity Control Valve 22 Automatic Decrystallization Control 22 DISCUSSION OF SUB SYSTEM 22 Automatic Decrystallization Feature 22 Basic Automatic Decrystallization Piping Circuit Model All Sizes 22 FIUSH 23 Combination of Basi
6. CHILLED WATER 600 GPM 100 200 1014579 JOHNSON CONTROLS 155 21 1 510 MODEL 4C1 MODEL 5C2 60 40 Sff 30 20 5 2 X 10 lt 7 5 5 5 3 2 5888888 08 8 CHILLED WATER CHILLED WATER 65 65 40 25 40 30 30 20 20 t a a 5 10 10 7 7 5 5 12 12 24 2 2 4 3 2 2 1 1 S S RBB GPM GPM TOWER WATER TOWER WATER 40 30 12 x 20 m 10 a 5 8 12 6 4 5 2 5 3 0 2 Q 52552 55552 Notes 63 HOT HOT WATER LD14580 FIG 26 PRESSURE DROP C
7. ONT AN N 14 40 39 33 N 14 40 0011 0001 008 004 009 009 007 002 0011 009 007 002 WATER WATER 1014631 63 FIG 26 CONT D PRESSURE DROP CURVES 61 JOHNSON CONTROLS 155 21 1 510 MODEL 1322 MODEL 12 1 0004 0009 0007 0006 0002 5 1 55 0004 0009 0007 0006 0002 65 13 40 0 2 YALVM 14 0 NOY N 15 0009 0005 0007 0006 0002 9 Sh 9 N N 134 40 9 13 40
8. 43 23 5 aa gadis 45 FIGURE 24 aed ad ie 48 FIGURE 25 SPECIFIC GRAVITY 49 FIGURE 26 PRESSURE DROP 53 28 5 50 EQUIVALENTS aniria a 73 FIGURE 29 VACUUM UNITS OF 5 73 6 JOHNSON CONTROLS 155 21 1 510 SECTION 1 GENERAL This manual contains instructions and information required by the operator for proper operation and pre ventative maintenance of the YORK IsoFlow Absorption Liquid Chillers Included in this instruction are discussions of the basic principles of operation of Lithtum Bromide Absorption Systems and descriptions of the functional operation of major components and sub systems Instructions relat ed to the controls and normal operating sequence of the various modifications of the IsoFlow units can be found in YIA Control Panel Operation Manual Form 155 21 Installation Manual Form 155 21 N1 JOHNSON CONTROLS Procedures and checks to be conducted by the operator are described extensively for all areas of operation These involve the Pre Start modes of units normal operation of units and operation
9. 5 55 9 002 006 2 11112 9 00 00 06 YALVM 14 YALVM 14 1 1014577 JOHNSON CONTROLS GPM HOT WATER See Notes on page 63 FIG 26 CONT D PRESSURE DROP CURVES 54 155 21 1 510 MODEL 281 MODEL 382 60 49 lt lt 2 30 n 20 X Q 10 Kis 7 5 gt 5 7 0 3 2 1 CHILLED WATER 60 lt lt 5 5 5 a 8 TA 14 LO Q TOWER WATER TOWER WATER 40 40 30 30 20 20 lt lt O 10 42 10 6 6 2 5 8
10. N GPM TOWER WATER 02 Kis N 2 GPM HOT WATER LD14628 JOHNSON CONTROLS PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER See Notes on page 63 FIG 26 CONT D PRESSURE DROP CURVES JOHNSON CONTROLS MODEL 701 60 40 2 O 30 SA 20 45 10 7 5 3 2 1 ooo 70 4200 50 30 20 BRANO 40 TOWER WATER 30 20 200 300 8606 WATER 1000 1200 PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER FORM 155 21 1 510 702 60 40 30 Ae 20 2 10 lt 7 5 3 2 1 Q CHILLED WATER 70 50 25 30 wee 20 2 po lt 19 Q 5 aw 2 4 gt 3 2 24 1
11. 4 y O 4 5 5 22 3 5 3 0 2 2 oc oa 1 1 0 N N Notes on 63 WATER WATER 1014578 FIG 26 CONT D PRESSURE DROP CURVES JOHNSON CONTROLS 55 PTX Chart MODEL YIA 3B3 FORM 155 21 1 510 MODEL 484 FIG 26 CONT D PRESSURE DROP CURVES 56 60 12 40 o 2 20 9 10 7 or 5 5 3 2 1 2 2 no 0 Q GPM TOWER WATER 40 30 20 lt o 45 2 Vv 10 QA 9 6 X 5 a 4 3 2 See Notes on 63 PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER 60 40 30 20 AN 47 9 2 ar
12. 5 TOWER 9 02920202050 050 02050 0 0 0 0 05950205050 WATER 00000 0 050 INLET 2 5 09 57 D 2 PURGE SYSTEM RT3 517 12 28 Suction Bypass Line ADC Flush Line VRQ 1 1 2 VR11 x Absorber Return 3SOL Unloader SOL PUMP 1 1 amp 1A2 512 Units Only 520 X vsi3 518 A vs19 Orifices may differ between various models PT2 is for Steam units only May differ between various models O Not Installed on Models 5C3 6C4 12F1 13F2 amp 14F3 A Not Installed on Models 7D1 7D2 8D3 9E2 10E3 amp 14F3 LD13806 FIGURE 5 BASIC FLOW DIAGRAM 18 JOHNSON CONTROLS SYSTEM OPERATION Based On Standard Steam Units Model YIA The cycle diagram for Model YIA Steam Hot Water operated systems is shown in FIGURE 5 The follow ing discussion will describe the absorption system operation generally in reference to this particular configuration Liquid usually water for air conditioning applications or process applications is chilled as it passes through the evaporator tubes by giving up heat to refrigerant flowing over the outside of the tubes This heat causes refrigerant to evaporate since it is at a pressure with a corresponding boiling temperature lower than the leav ing chilled water temperature For example water is chilled from 54 F to 44 F 12 C to 6 6 C w
13. Oan na 36 SHAFT SEAL REPLACEMENT a 36 REPAIRING OIL LEAK Sins 36 Location Cause and 36 Repairing Technique 36 DRIVE PROBLEMS 36 39 INTRODUCTION 39 TROUBLESHOOTING 39 Pump Tripping 39 Pump Tripping Thermal Protection 39 Unusual 1 0 4 0000000000 000000000 39 39 Section STEAM AND WATER QUALITY CONTROL 41 E E A eae aa E 41 STEAM CONDENSATE HOT WATER QUALITY 41 TUBE CLEANING 42 Section UNIT OPERATING 43 EINER A E 43 START UP NORMAL 43 OPERATING 44 General
14. CONTROL VALVE HOT WATER OR STEAM GENERATOR OUTLET LD13806E FIGURE 10 CONDENSER Condensed refrigerant flows by gravity and pressure differential through an orifice or expansion device to the evaporator This refrigerant plus that recirculated by the refrigerant pump is distributed over the evapo rator tubes to complete the refrigerant cycle Capacity of the unit is automatically controlled from the temperature of the chilled water leaving the evapo rator The steam or hot water control valve meters the steam or hot water flow to the generator Refer to FIGURE 5 for complete cycle diagram CAPACITY CONTROL The YIA control panel controls the capacity of the unit by throttling the control valve which in turn regulates heat into the generator section of the unit In prior YIA chiller controls sensors monitored incom ing Cooling Tower Water Temperature CTWT Valve positions were controlled based on predetermined reduced temperatures see Form 155 16 OM1 This feature was kept the unit design solution concentrations in balance so the unit would not crystallize over dilute or inhibit refrigerant vaporization at reduced CTWT temperatures The capacity control logic in the OptiView panel is dif ferent from prior YIA absorption panel logic There are three sub control mechanisms interacting constantly 20 FORM 155 21 1 510 1 Leaving Chilled Liquid Temperature Control
15. 42 09 42 80 43 50 44 19 44 88 45 55 46 22 46 88 47 54 48 18 48 82 49 45 50 07 50 68 51 29 51 89 52 48 53 06 53 64 54 21 54 77 55 32 55 86 56 40 56 93 57 45 57 97 58 47 58 97 59 46 59 94 60 42 60 88 61 34 61 80 62 24 62 68 63 10 63 52 63 94 64 34 CRYSTALLIZATION AREA LD14221 FIGURE 25 SPECIFIC GRAVITY CONCENTRATION JOHNSON CONTROLS 49 PTX Chart Power failures result in the unit pumps stopping com pletely Without the pumps inducing flow through the various sections of the unit concentrated solution be comes trapped in the generator section and the solution to solution heat exchanger If this concentrated solution is allowed to cool down to a low enough temperature it may turn to a slushy liquid and eventually to a solid substance The potential for a YORK IsoFlow Chiller to crystal lize during a power interruption is directly related to the following 1 The concentration of the solution in the solution heat exchanger is very important The higher the concentration at the time of power failure the more likely the unit is to crystallize a The higher the load the higher the concentra tion b A unit w
16. HT1 1014498 REFRRIGERANT LEVEL SWITCH REFFRIGERANT PUMP CUTOUT SWITCH HIGH PRESSURE CUTOUT SWITCH HIGH TEMP CUTOUT SWITCH GENERATOR PRESSURE TRANSDUCER STEAM SUPPLY PRESSURE TRANSDUCER STEAM UNITS ONLY TEMPERATURE SENSOR LEAVING CHILLED WATER TEMPERATURE SENSOR AUTO DECRYSTALLIZATION TEMPERATURE SENSOR STRONG SOLUTION TEMPERATURE SENSOR LEAVING TOWER WATER TEMPERATURE SENSOR ENTERING TOWER WATER TEMPERATURE SENSOR ENTERING CHILLED WATER TEMPERATURE SENSOR STEAM HOT WATER SUPPLY REFIGERANT TEMPERATURE SENSOR REFRIGERANT TEMP LEAVING THE CONDENSER STRONG SOLUTION TEMP LEAVING HEAT EX STABILIZER REFRIGERANT SOLENOID FOR DECRYSTALLIZATION REFRIGERANT LEVEL SOLENOID UNLOADING STEAM CONDENSATE DRAIN SOLENOID VALVE NOT SHOWN NOT APPLICABLE ON ALL UNITS PURGE TANK SOLENOID PURGE PUMP SOLENOID LOW REFRIGERANT TEMPERATURE CUTOUT SWITCH FIGURE 4 SYSTEM CONTROL COMPONENT LOCATIONS 16 JOHNSON CONTROLS FORM 155 21 1 510 6501 5 SIGHT GLASSES LD14570 LEFT END OF UNIT RT6 RT1 1014569 RIGHT END OF UNIT FIGURE 4 CONT D SYSTEM CONTROL COMPONENT LOCATIONS JOHNSON CONTROLS 17 Absorption System Operation FORM 155 21 1 510 PTI HP1 CONCENTRATED CONDENSER lt RT4 SOLUTION LiBr TOWER WATER
17. flow for a portion of the return pipe from A to B Below some point B a solid liquid level is established and solid liquid exists from B through the heat exchanger 2 and return pipe 3 If the solution concentration from the generator is excessively high solution crystals will start to build on the shell side of the heat exchanger This will restrict the flow through the normal system of return piping described above and the established solution level B will rise in the return pipe 1 This will continue to rise until an elevation in the pipe C is reached JOHNSON CONTROLS At this point emergency solution return pipe is vided This return pipe 9 with connection entering the return piping at 8 is used This return pipe 9 has a trapped section of pipe 10 riser portion 11 and pipe sections 12 and 13 leading to the absorber The heat exchanger is bypassed in the operational use of this emergency return system of piping Its operation is completely automatic It should be noted that as crystallization proceeds it is not necessary for the solution to back up into the gen erator itself to engage the use of the ADC It is desirable to bring the device into operation before an extreme condition of crystallization ocurs Connection 8 enters the normal return piping at a level appreciably below the normal generator operating level 17 Since this enters the return piping at a point where there
18. LCHLT Control 2 Strong Solution Concentration Control SSC Control 3 Limited load by warning conditions With the introduction of the RT10 sensor the OptiView panel is now capable of continuous monitoring of the strong solution temperature in the most critical location where it would most likely begin to crystallize The logic then analize the three control mechanisms and chooses the lowest limit to ensure trouble free opera tion Listed below is a brief description of each control mechanism Leaving Chilled Liquid Temperature LCHLT Control The goal of the LCHLT control is to match the leaving chilled liquid temperature with leaving chilled liquid temperature setpoint It calculates an error value current leaving chilled liquid temp minus the leaving chilled liquid temperature setpoint and a rate value leaving chilled liquid temperature from the current sample minus the leaving chilled liquid temperature from the previous sample and returns an opening valve variation This variation is added to the current valve opening value Strong Solution Concentration SSC Control The goal of the SSC control is to avoid solution concen trations that can crystallize It calculates an error value current strong solution concentration strong solution concentration limit and a rate value Strong solution concentration from the current sample strong solution concentration from the previous sample and returns an opening valve v
19. The evaporator consists of a single or multi pass tube bundle a refrigerant pan and a refrigerant spray header assembly The liquid to be chilled usually water flows through the tubes to be cooled by vaporization of the liquid refrigerant water condensed in the condenser The liquid refrigerant is pumped through the sprays and flows down over the outside surface of the evaporator tubes Absorption System Operation FORM 155 21 1 510 MODEL STANDARD STEAM CYCLE DIAGRAM HP1 KEY PTI CONCENTRATED 1 55 RI4 SOLUTION LiBr X T TOWER WATER VR40 888 98 ourler 09 959 INTERMEDIATE 90 090 08 SOLUTION LiBr 59 989 96 vP10 CHILLED LIQUID 96 09 RT9 TOWER 5 PURGE CONTROL VALVE TANK REFRIGERANT LIQUID a LOW TEMPERATURE BY 2 REFRIGERANT LIQUID a PURGE 2 Places ty GENERATOR GAS VAPOR 1777 VENT ves Anti Freeze Line 2 2 lt CHILLED 20000009000000
20. eal 44 Performance Data and 44 JOHNSON CONTROLS 5 Introduction FORM 155 21 1 510 Section PTX 47 READING THE PTA CHART ee 47 CRYSTAL iaaii 47 REFRIGERANT 47 50 2 53 Section 10 PREVENTATIVE MAINTENANCE 2 2 2 2 21 4 65 CLEANING AND MAINTAINING THE TUBES WITHIN THE 8 65 65 BRUSH CLEANING OF 65 TROUBLESHOOTING TABLE b 66 PREVENTATIVE MAINTENANCE 67 APPENDIX Glossary 69 LIST OF FIGURES FIGURE 1 COMPLETE CYCLE 10 FIGURE 2 TYPICAL POWER PANEL 60 HZ NEMA 1 STANDARD UNIT POWER PANEL SHOWN 12 FIGURE 3 MODEL YIA ABSORPTION UNIT 15 FIGURE 4 SYSTEM CONTROL COMPONENT 16 FIGURE 5 BASIC FLOW 18 6 EVAPORA
21. faces to help reduce corrosion rates Micropanel The brains of the unit The micropanel is the elec tronic control panel which instructs the entire unit on when and how to run Integrated into the logic of the micropanel are sensors to measure key temperatures and pressures which are then used to monitor real time conditions Model Number A series of abbreviations or designations used to iden tify IsoFlow units Molybdate Lithium Molybdate Li MoO the current corrosion inhibitor used for YORK s absorption units By chem ically slowing down the natural tendency of steel to oxidize or corrode the inhibitor is supplied in solution with the Lithium Bromide also refer to Inhibitor Non Condensables A gaseous substance that cannot be liquified or condensed at the pressure and temperature surround ing it The presence of non condensables in the unit can cause severe performance problems Non condensables appear in two forms in the unit 1 Internally generated non condensables are formed as a by product of corrosion 2 Air may be drawn into a unit via leaks Non condensables that collect in the absorber section of the unit low side blanket the heat transfer tubes and raise the internal pressure thus reducing the absorber s ability to capture the refrigerant vapor Non condensables that collect in the condenser high side blanket the condenser tubes thus reducing the condenser s capacity It should b
22. ing full load conditions refrigerant should be observed dripping out of this hole Ifrefrigerant is observed to shooting out of this hole that means the level is above the hole Any tendency to over concentrate the solution further will cause the refrigerant to rise and overflow from the sides of the pan FIGURE 12 is a depiction of what to look for SAWTOOTH REFERENCE 12 AUXILIARY ea DRAIN PAN AUXILIARY DRAIN PAN EVAPORATOR PAN LD14572 FIGURE 12 EVAPORATOR AUXILIARY DRAIN PAN 21 Absorption System Operation ANTI FREEZE LINE For sustained operation at low loads and low condens ing water temperature the concentration of lithium bromide by weight in the refrigerant circuit may approach 35 40 With conditions such as these the pressures in the lower shell are reduced The pure water refrigerant entering the evaporator from the con denser would at these times be below the freezing point of water 32 F 0 C by as much as 12 and could cause ice to hang up in the refrigerant conden sate lines from the condenser after the orifices To prevent this a small amount of refrigerant actually very dilute solution now in the refrigerant circuit is routed from the discharge of the refrigerant pump to mix with the pure water refrigerant about to enter the evaporator from the condenser This line is identified on the cycle diagram FIGURE 5 as the antifreeze line
23. F 71 1 C the OptiView panel will ener gize the 2SOL stabilizer solenoid valve to allow refrigerant to flow from the discharge of the refrig erant pump into the STS thus diluting the solu tion Depending on the operational conditions of the unit the ADC cycle may go through certain steps to help reduce the solution concentration These steps are Normal Limited Primary and Secondary ADC cycles Measures to Prevent Crystallization Good practices to help prevent crystallization should always be employed These include 1 Insulating the solution to solution heat exchanger generator solution outlet box and all interconnect ing piping 2 Tower water absorber cooling water must be controlled to prevent rapid fluctuations in tem perature 3 Keep the absorber condenser and evaporator tubes clean 4 Do not allow non condensables to accumulate in the unit Proper purging techniques and solution chemistry control will greatly reduce the likelihood of crystallization 5 Be sure the refrigerant charge is adjusted so that refrigerant spill will occur if solution concentrations exceed the norm Refrigerant may need to be adjust ed after several years of operation due to the amount of refrigerant vapor removed during purging 51 PTX Chart PRESSURE DROP CURVES FIGURE 26 shows the pressure drops for the chilled water condenser water and the hot water in relation ship to the rate of flow in GPM The absorber con
24. denser includes 1 2 PSI pressure drop through the cross over line For construction of the cross over line see YORK Form 155 21 N1 The data shown are for pressure taps on the water boxes near the inlet and outlet nozzles If pressure gauges are used to deter mine pressure drop they should be calibrated so that maximum efficiency is obtained Also a correction for static head difference must be made if the gauges are not located at the same elevation or level The conver sion from PSI to ft of water is 2 31 ft for 1 PSI 52 FORM 155 21 1 510 JOHNSON CONTROLS PRESSURE DROP CURVES MODEL 1 1 FORM 155 21 1 510 MODEL 1A2 70 50 lt 30 lt gt 20 ox lt 10 12 F 5 0 2 1 CHILLED WATER PRESSURE DROP FT WATER re PRESSURE DROP FT WATER WATER See Notes page 63 FIGURE 26 PRESSURE DROP CURVES JOHNSON CONTROLS PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER 70 50 30 20 10
25. off cycle since the solution temperature will eventu ally equal the surrounding ambient temperature All units employ some sort of dilution cycle which fulfills this requirement As long as the unit is allowed to dilute itself during an orderly shutdown sequence the unit should be able to sit idle at fairly low plant room ambient temperatures for extended periods of time without any threat of crystallization Typically after a dilution cycle the average solution concentra tion within the chiller will be below 45 lithium bromide by weight Although the crystallization line on FIGURE 24 does not extend that far it can be seen that the solution at 45 concentration will have no tendency to crystallize at normal ambient tempera tures Why Does Crystallization Occur Probably the most common reason for crystallization is due to power failures If a chiller is running at full load and power is interrupted for a sufficient length of time the concentrated solution in the high side of the unit will eventually cool down Since no dilution cycle was performed the solution concentration in some areas of the unit may still be relatively high If the temperature of this concentrated solution 18 allowed to fall low enough the solution will reach its crystalliza tion point Plant room temperature insulation quality and the solution concentration all play a part in the determination of how long it will take before the unit will crystallize
26. position This is necessary to provide proper dilution of the solution thus protect ing against crystallization during shutdown and to avoid freezing up the evaporator tubes during unit oper ation including the dilution cycle operation during which refrigeration effect still occurs START UP NORMAL This start up covers units that have previously been started NOTE See Form 155 21 1 Control Panel Operation Manual for detailed instruction on how to operate the OptiView control panel 1 If the chiller has been idle for a long period of time such as at the first start up of the cooling season it will be necessary to check the internal pressure of the unit to ensure a smooth start up and possibily perform a purge from the absorber section JOHNSON CONTROLS 2 Refer to the chart in FIGURE 22 to compare the saturation pressure within the unit to the equiva lent plant room temperature If the measured internal unit pressure is within the shaded area of the chart the start up may continue If not purge the unit until the internal unit pressure reaches the shaded area of the chart 3 Open the main shut off valves in condensing water chilled water and steam or hot water sup ply lines to the system 4 Close all disconnect switches to the control panel the cooling water pump chilled water pump and tower fans 5 Place the condensing water pump chilled water pump and tower fan switches in the Automa
27. 47 gt lt 155 21 1 510 ose Ove oee 609 LXLd ZL SSl WHOS 062 080 042 3 1 5 022 0 2 NOILVZITIVLSAYD 092 ose Ove oez 002 061 081 09 08 ZS E UNG 000721 You 68 6 suenb 1601 166 5 14927 swb qI OCH UL LEZ 19 BH 96072 189 184 BH u L 184 76610 666 0 1 0001 26 62 09 659 0 esd 9691 896 8 09 4 914 20 4 D Op 81 X 0p 0 lt 4 o 4 UOISJBAUOD 05 ANVdWO9 51081 09 5 1014221 FIGURE 24 PTX CHART JOHNSON CONTROLS 48 155 21 1 510 155 17 1 609 SPECIFIC GRAVITY CONCENTRATION TABLES AQUEOUS LiBr SOLUTIONS Refrigerant Table LiBr Weight Temperature F 38 44 Solution Tables Temperature F 39 19 39 93 40 66 41 38
28. 9 0082 0002 0001 WATER 008 002 009 006 007 0082 0002 1014630 63 FIG 26 CONT D PRESSURE DROP CURVES JOHNSON CONTROLS 62 MODEL 14F3 80 x 60 40 52 30 z 45 20 a 9 10 7 or 5 3 or 1 WO CHILLED WATER lt LL 2 0 0 A _ TOWER WATER 60 50 40 30 20 10 6 2 5 9 4 3 2 ye N N GPM HOT WATER Notes on 63 1014633 FIG 26 CONT D PRESSURE DROP CURVES JOHNSON CONTROLS FORM 155 21 1 510 Pressure drop curves include 1 psi pressure drop for cross over line Pressure drop curve for the condenser water circuit only is shown as a dotted line For total tower water pressure drop through the chiller use the appropriate solid line For example a chiller with a 2 Pa
29. A portion of the refrigerant is vaporized by steam or hot water flowing through the generator tubes thus con centrating the solution see FIGURE 9 STEAM OR HOT WATER CONTROL VALVE HOT WATER lt OR STEAM GENERATOR OUTLET LD13806D FIGURE 9 GENERATOR Concentrated solution flows by gravity and pressure dif ferential through the heat exchanger where it is cooled regeneratively by cooler dilute solution The heat exchanger has thus improved the efficiency of the sys tem by reducing the amount of steam or hot water required to heat the dilute solution in the generator and the amount of concentrated solution cooling required in the absorber An intermediate solution consisting of a mixture of cooled concentrated solution from the generator heat exchanger with dilute solution from the bottom of the absorber is recirculated over the absorber tubes by the solution pump with the aid of the eductor to complete the solution cycle see FIGURE 7 19 Absorption System Operation Refrigerant vapor released from the dilute solution in the generator is condensed on the condenser tubes by giving up its heat of condensation to condensing water passing through the tubes This condensing water is the same water that was used to cool the absorber see FIGURE 9 5 A OUTLET 5
30. Chilled Water Control Stability Operation of an absorption system without the tower water bypass valve control used to maintain a given cooling water temperature to a unit requires certain control measures within the unit to maintain acceptable stability of operation The effect of rapidly changing tower water temperature such as occurs when tower fans cycle off and on would affect the unit capacity control This causes steam valve opening and closing tendencies to cut out on refrigerant low temperature thermostat if provisions are not made to offset these tendencies Stabilizer Refrigerant Solenoid 2SOL YIA units are equipped with a control stabilizer arrangement This control operates the refrigerant valve 2SOL to permit immediate transfer of refrigerant to the generator drain line for immediate control of refrig erant temperature This causes dilution of the solution and hence reduction of absorption and refrigeration effect This type of action required when cooling water temperature fluctuates corrects the low temperature condition permits refrigeration effect to continue and prevents unloading of the cooling tower 22 FORM 155 21 1 510 DISCUSSION OF SUBSYSTEM OPERATION Automatic Decrystallization ADC The likelihood of solution crystallizing increases as the concentration increases and or the temperature decreas es This could happen in the shell side of the heat exchanger and could extend to the piping a
31. DIAGRAM YIA FIELD CONTROL MODIFICATIONS 155 21 W2 WIRING DIAGRAM YIA FIELD CONNECTIONS 155 21 W3 APPLICATION DATA CHILLER MATERIALS FOR VARIOUS WATER QUALITIES 160 00 AD5 NOMENCLATURE YIA ST 1A1 46 5 _ LEVEL VOLTAGE or ONIY Std Tubes UNIT SIZE 17 208 3 60 Special Tubes 14 3 22 5 00210 3 50 HW Hot Water paon W 575 3 YORK IsoFlow Absorption Chiller JOHNSON CONTROLS 155 21 1 510 5 Section 1 INTRODUCTION ecset 7 GENERAL E T 7 Section ABSORPTION SYSTEM 9 GENERAL 9 9 9 0 9 9 DESCRIPTION OF MAJOR COMPONENTS AND SUB SYSTEMG 9 General Condenser Shell 9 Evaporator Absorber Shell 9 Solution PUMP 11 Refrigerant PUN P s 11 induced 11 aai
32. Note Some orifices may differ between various models FIGURE 1 COMPLETE CYCLE DIAGRAM 10 JOHNSON CONTROLS The absorber consists of single multi pass tube bundle the absorber spray header assembly and the lower part of the shell which serves as a solution stor age pan Tower water is circulated through the absorber tubes to cool the lithium bromide solution being sprayed over the outside of the tubes This aids the absorption process Solution Pump The unit has one solution pump mounted under the lower shell This pump transfers dilute solution to the generator from the absorber and with the aid of an eductor pumps mixed intermediate solution to the absorber sprays Refrigerant Pump All units have one refrigerant pump mounted beneath the lower shell to recirculate refrigerant to the evapora tor sprays and over the evaporator tubes Heat Exchanger The heat exchanger is mounted under the lower shell to improve system efficiency by transferring heat from the warm concentrated solution low water content to the relatively cool dilute solution high water content on its way to the generator This assists both the generator in heating and the absorber in cooling the dilute and concentrated solutions respectively Purge System YORK absorption systems are designed and manufac tured for extreme leak tightness to ensure against infiltration of non condensables into the high vacuum system Leakage of air into the s
33. Operation Form 155 21 01 COMPONENTS IN POWER PANEL see FIGURE 2 1SW Service Disconnect Switch This is a non fused service disconnect switch The incoming power lines from the customer supplied fused disconnect switch or circuit breaker should be connected to terminals L1 L2 and L3 of this switch 1T Transformer This is a step down transformer that reduces the unit s incoming power primary down to the required control voltage of 120 115 1 50 60 secondary 1FU 2FU 3FU Control Fuses These are used on all 60 Hz standard NEMA 1 units 1FU and 2FU are on the primary side of the 1T trans former The amperage rating of these fuses depends on the unit s voltage The 3FU fuse is always a 10 amp fuse and is on one leg of the secondary coil of the 1T transformer It is used for the control panel voltage 1CB Circuit Breaker This takes the place of 1FU and 2FU on 60 Hz NEMA 4 units and 50 HZ 380 volts units 2CB Circuit Breaker This takes the place of 3FU on 60 Hz NEMA 4 units and 50 Hz 380 volts units 11 Absorption System Operation FORM 155 21 OM1 510 1M Starter Contactor for Solution Pump MTH1 and MTH2 Motor Thermostats This is used on all units These are used on all units with Buffalo Pumps These Klixon type thermostats are imbedded in the motor 2M Starter Contactor for Refrigerant Pump windings and will open when the motor internal tem This is used on all units perature reach
34. STRIP 2 01 0312 2 61 3100 WASHER 3 1 2 2 1 7 8 2 01 0316 41 2363 WASHER 41 0929 2 35 3800 2 02 5708 SCREW 1041 12051058 SPECIFICATIONS Free Air Displacement 160 5 6 Guaranteed Partial Pressure AR 0 1 Pump Rotational Speed 525 Number of Stages eee ee 2 Oil Capacity 2 1 4 Net Weight Pump Only 82 Net Weight Mounted Pump lbs 112 Shipping Weight Mounted Pump 125 FIGURE 20 MODEL 1402 VACUUM PUMP FOR YORK JOHNSON CONTROLS 37 Buffalo Pumps FORM 155 21 1 510 THIS PAGE INTENTIONALLY LEFT BLANK 38 JOHNSON CONTROLS 155 21 1 510 SECTION 6 BUFFALO PUMPS INTRODUCTION The Buffalo pumps used on YORK IsoFlow chillers are single suction single stage hermetically sealed centrifugal pumps designed for zero leakage Totally Closed Liquid Cooled TCLC applications The pumps employ a unique spring loaded conical bearing design that allows for long life between overhauls The pump bearings are cooled a
35. circuit to the refrigerant circuit under a controlled basis The amount of lithium bromide transferred is kept to a mini mum by introducing this lithium bromide only when the refrigerant level in the refrigerant circuit is at a minimum operational level This is done by opening the 3SOL unloader solenoid valve only when IF level switch opens and the chilled liquid temperature is 2 F from setpoint This criterion will avoid 3SOL openings at unit start up when the refrigerant levels are inherently low As the unit load increases the contaminated refrigerant will clean up naturally as the refrigerant vaporization rate increases JOHNSON CONTROLS FORM 155 21 1 510 Refrigerant Overflow An auxiliary refrigerant overflow pan is located near the left end tube sheet and can be viewed through the two evaporator sight glasses To aid in viewing this internal component use a focused beam flashlight to shine through one of the two sight glasses see FIGURE 4 while looking through the other Since the amount of refrigerant in the refrigerant circuit is at a maximum at 100 capacity overflow would normally start to take place at this condition or slightly above The evaporator sight glasses allow the techni cian a visual means to track the refrigerant level in the evaporator pan A 3 16 weep hole is drilled near the top of the evaporator pan just in front of the auxiliary refrigerant overflow At the correct refrigerant level dur
36. except if cooling water is used in an air washer The lines to the purge drum and its coil must be acid cleaned when the cool ing circuit is cleaned BRUSH CLEANING OF TUBES Tube fouling consisting of dirt and sludge can usually be removed by brushing the tubes To do this drain the water sides of the circuit to be cleaned cooling water or chilled water remove the heads and thoroughly clean each tube with a soft bristle bronze brush DO NOT USE A STEEL BRISTLE BRUSH A steel brush may damage the tubes Improved results can be obtained by admitting water into the tube during the cleaning process This can be done by mounting the brush on a suitable length of 1 8 pipe with a few small holes at the brush end and connecting the other end to the water supply by means of a hose 65 Preventive Maintenance Tubes FORM 155 21 1 510 TROUBLESHOOTING TABLE SYMPTOM POSSIBLE CAUSE CORRECTIVE ACTION 1 ABSORPTION UNIT A Power supply and unit fuses Replace if necessary WILL NOT START B Flow switches open Check chilled water and cooling tower pumps C Starter overloads open Push reset buttons of both starters D Motor coolant float switch open Contact local district office for service 2 UNIT CYCLING OR Air in water piping causing varying Purge air from the water piping ERRATIC CHILLED water flow to the unit RIE Control valve functioning Check actuator and linkage Adjust if necessary
37. scale is identified in any of the tube bundles it will be necessary to remove this scale to prevent operational and or corrosion problems 42 FORM 155 21 1 510 build up of scale on tubes cause a wide range of problems including Reduced chilling capacity High solution concentration Crystallization Pitting and corrosion of tubes Reduced efficiency The first step in trying to clean scales from tubes is to brush clean them Only soft nylon brushes should be used as damage to the copper or CuNi tubes will result if harder brushes such as steel are used If the brush cleaning is unsuccessful in removing all the scale from the tubes it will be necessary to chem ically clean them An experienced and reputable con tractor should be consulted If the chemical cleaning is not performed properly extensive tube damage may result JOHNSON CONTROLS 155 21 1 510 SECTION 8 UNIT OPERATING PROCEDURES GENERAL For complete details on installation and how to set up the companion parameters that control the YIA absorp tion units refer to Form 155 21 N1 It is recommended that Automatic switches be used for con trol of the condensing water pump the chilled water pump and the tower fan motor However the chilled water pump and the condensing water pump must always be operating when the unit is in operation and are thus pre ferred in the Automatic
38. shipped loose with the unit for field installation See Form 155 21 N1 IsoFlow Installation Manual for details on installing this valve and applicability 1 High Pressure Cutout Switch This digital safety switch is located off the top of the condenser shell and is hardwired directly into the control panel It is factory preset to trip the unit when the unit internal pressure reaches 710 mm Hg Abs It will automatically reset itself when the units pres sure reduces to 40 mm Hg Abs 1 High Temperature Cutout Switch This digital safety switch is located on the control panel side of the generator shell with an accompany ing thermistor inserted into an adjacent thermowell It is hardwired directly into the control panel and fac tory set to trip the unit when the generator shell skin temperature reaches 330 F 165 6 C It has a manual reset push button and an amber light on the control to indicate it is functioning 13 Absorption System Operation LRT Low Refrigerant Temperature Cutout Switch This digital safety switch is located on the opposite side of the refrigerant outlet box from 1F float switch It has an attached thermistor which is inserted into a thermowell that is located on the refrigerant line leading out of the bottom of the refrigerant outlet box The switch protects the unit from freezing refrigerant It is factory preset to trip at 34 F 1 1 C It will auto matically reset when
39. the gas drawn from the intake port is compressed to the pressure necessary to expel it past the exhaust valve Condensation takes place when the ratio between the initial pressure and the end pressure of the compression is high that is when the mixture of vapor and gas drawn from the intake port is com pressed from a low pressure to a high pressure By adding air through the gas ballast valve to the mixture of vapor and gas being compressed the pressure required for delivery past the exhaust valve is reached with a considerably smaller reduction of volume of the mixture Depending upon the amount of air added condensation of the vapor is either entirely avoided or substantially reduced OIL LEVEL DETERMINATION The amount of oil suitable for efficient and satisfac tory performance should be determined after the pump has reached its operating temperature Initially the pump should be filled with fresh oil while the pump is idle Fill the pump through the pump discharge port until the oil level falls halfway up the oil level win dow If after a short period of operation the level should fall it is likely the result of oil entering some of the interior pockets of the pump If the oil level rises this means oil has drained into the pump cavity while idle To correct this shut off the pump then drain oil down to proper level 33 Purge Pump Operation If a gurgling sound occurs additional oil may need to be added Mechanical
40. treatment Improperly treated or maintained steam condensate or hot water will result in decreased efficiency high operating costs and pre mature failure due to steam condensate or hot water side corrosion Steam Condensate or hot water samples should be collected and analyzed on at least a monthly basis by the treatment specialist A quarterly review with the treatment supplier should address the conditions of the steam systems and develop action plans based on these analyses A third party consulting company can help oversee the treatment programs in order to properly protect the physical plant and avoid costly downtime 41 Unit Operating Procedures It is equally important that the owner operator of the equipment performs an inspection of the generator tubes at the frequencies recommended in the Tube Bundle Section of the Preventive Maintenance Schedule located in this manual In addition to peri odic cleaning with tube brushes tubes must be inspected for wear and corrosion Tube failures usu ally occur due to corrosion erosion and fatigue due to thermal stress Eddy current analysis and visual inspection by boroscope of all tubes are invaluable preventative maintenance methods These provide a quick method of determining steam generator tube condition at a reasonable cost Your local YORK Service Representative will be more than happy to supply any or all of these services TUBE CLEANING If during an inspection
41. within the absorber while the unit is running ADVAGuard 750 YORK s newest Inhibitor An inorganic inhibitor pro viding excellent corrosion protection to the unit s internal steel and copper surfaces Also see Inhibitor Alcohol 2 Ethylhexanol A liquid added to an absorption chiller to enhance the heat and mass transfer in the Absorber It is an octyl alcohol whose chemical name is 2 Ethyl 1 Hexanol 8 18 with a molecular weight of 130 2 a boiling point of 364 3 F 184 6 C and a flash point of 177 8 F 81 C 760 mmHg Having a colorless clear appearance it has a somewhat pungent odor By adding 2 Ethylhexanol to the absorption cycle overall unit performance increases by 5 15 In addition cycle temperatures pressures and concentrations tend to decrease with the addition of 2 Ethylhexanol Automatic De crystallization ADC Pipe The ADC pipe is a U shaped line coming off the gen erator solution outlet box and terminating in the absorber shell During normal unit operation this line has no flow in it If crystallization were to occur it would normally be in the strong solution side of the heat exchanger This blockage would back up solution into the generator and into the automatic de crystalli zation pipe Once the hot solution goes into the ADC pipe it bypasses the heat exchanger and goes directly into the absorber shell thus heating the solution in the absorber shell The heated solution in the absorber
42. 0000000000 WATER 000000000000000000000000 OUTLET 000000000000000000000000 7 2 000000000000000000000000 000000000000000000000 8 000000000000000000000000 CHILLED 5 000000000000000000000 900000000000000000000000 WATER 000000000000000000000000 9 EVAPORATOR ETET e VP 2 g 8 273 Press 8 gt 8 lt 90950090000595952 9090959595059 0 00009526050 8 995959595950505050595059505950595050505059505 2 0 020202050 0 0 0 0 05020 0 0 0 05050505060 O 0 0 0 0 0 0 0 6 0 0 0 0 0 0750 5 9505090905050505900509050905099505090905090 5 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a 9 0505059505950505950595050 959505050505959 WATER 92920 95059590959020909007 220 INLET 3 7501 2 VR10 817 62891 Suction Bypass Line VR8 ADC Flush Line VR9 1 1 2 BUMP Absorber Return 5 SOL PUMP 1 1 8 1 2 12 Units Only vs20 lt vs13 VS18 819 9 Orifices may differ between various models PT2 is for Steam units only May differ between various models O Not Installed on Models 5C3 6C4 12F1 13F2 amp 14F3 A Not Installed on Models 7D1 7D2 8D3 9E2 10E3 amp 14F3 1004763
43. 990 1 DILUTE SOLUTION VR40 09 OUTLET 80 696 68 89 Ses 68 68 696 69 m CHILLED LIQUID WATER la STEAM OR HOT WATER CONTROL VALVE REFRIGERANT LIQUID LOW TEMPERATURE RT7 WATER REFRIGERANT LIQUID HIGH TEMPERATURE lt STEAM DILUTE PURGE LIQUID 2 2 Places GAS VAPOR 1 Anti Freeze Line CHILLED 00000000000000000000000 OUTLET 000000000000005000000000 3 h 0000000000 000000 000000000000 CHILLED 0000000000000000000 WATER 600000000000000000000000 1 7777777777777777777 20020 9220 1 2 RT8 8 8 55525555 2 2 5 15255555225 25255 2525222 2233 2 z S 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 09 0502050 0 0 0 0 050 050 00 0205050505060
44. BER PD zje BSORBER FLOW OND amp ABS 5 gt CONDENSER FLOW 2 2 2 2 PSIG CONDENSATE TEMP F FLOW MEASURED 7 GENERATOR i fel REFRIGERANT TEMPERATURE erom conoensen 0 9 0 4 5 A4 amp 4 0 14 2 SOLUTION TEMPERATURE Remarks 22 FASS FASS ABSORBER 2 2 ORDER ADDRESS FROM ABSORBER TO GENERATOR 2 9 a 8 lt a 3 14 2 2 4 4 gt 2 4 lt lt 4 2 PRL 22 KR 5 5 99 SOLUTION CONCENTRATION of 549 5 22220222 RELATIVE CIRCULATION 203 15 5 2 HA He 7145 7531 FIGURE 23 OPERATING DATA SHEET gt d D gt lt 1004771 JOHNSON CONTROLS 45 PTX Chart FORM 155 21 OM1 510 THIS PAGE INTENTIONALLY LEFT BLANK 46 JOHNSON CONTROLS 155 21 1 510 SECTION 9 PTX CHART READIN
45. G THE PTX CHART The PTX chart Pressure Temperature and Concentration chart shown in FIGURE 24 is an invaluable tool when it comes to absorption cooling It can be used for almost every kind of troubleshooting situation plotting solution cycles through each heat exchanger and determining if air is within the sys tem However for this exercise the PTX chart will be explained only for determining the concentration of solution samples Taking solution samples must only be done by a trained and qualified Johnson Controls Field Service Representative Determining the Solution Concentration The PTX chart FIGURE 24 shows pressure in mm Hg absolute horizontal lines temperature in degrees fahrenheit vertical lines and Solution Concentration in percentages diagonal lines The amount of water necessary to make the compound turn into a fluid is represented by the area to the left of the crystallization zone on the PTX Chart at the corresponding tempera ture The Crystallization Area is the right half of the chart In reading the PTX chart two of three pieces of infor mation are required With these two pieces of data the third data point can be obtained The temperature is the easiest to obtain and the pressure can be obtained via the unit gauges Use caution when using the unit mounted vacuum gauge for checking the internal unit pressure do NOT under any circumstances let air into the unit when checking the pressur
46. OLS Pump Tripping on Thermal Protection If the winding temperature thermostat is tripping the pump allow the thermostat to reset Exercise caution as the motor housing skin temperature may be in excess of 300 F 148 9 C when the winding tempera ture thermostat trips Although rare if the thermostat will not reset in a reasonable period of time it may be defective If this is the case temporarily bypass the thermostat and run the pump Check the motor hous ing temperature with an infrared thermometer The average outside skin temperature of a solution pump motor housing is 190 F 87 8 C at stable operating conditions 100 F 37 8 C suction temperature Refrigerant pumps run cooler than this Check to be sure that the pump is not running dry periodically or that either the suction discharge isolation valves are closed Check to see that the pump is not pumping abnormally high temperature liquid for some reason If no problems related to flow through the pump are found the internal coolant passages may be blocked Pump disassembly will be required Contact your local YORK Factory Service office for details Unusual Noise Vibration Pumps will make some noise during normal operation If pump is experiencing cavitation the noise and vibration will be more severe Abnormal sounds and vibration may be due to foreign material trapped in the coolant circuit and rubbing between the stator and rotor Noise may also be a result of extre
47. SINGLE STAGE YIA ABSORPTION CHILLERS WITH OPTIVIEW CONTROL CENTER LS OPERATION AND MAINTENANCE Form 155 21 OM1 510 YIA MOD D SINGLE STAGE STEAM HOT WATER WITH OPTIVIEW CONTROL CENTER LD14498 1A1 through 14F3 155 21 1 510 READ BEFORE PROCEEDING GENERAL SAFETY GUIDELINES This equipment is a relatively complicated apparatus During installation operation maintenance or service individuals may be exposed to certain components or conditions including but not limited to refrigerants oils materials under pressure rotating components and both high and low voltage Each of these items has the potential if misused or handled improperly to cause bodily injury or death It is the obligation and responsi bility of operating service personnel to identify and recognize these inherent hazards protect themselves and proceed safely in completing their tasks Failure to comply with any of these requirements could result in serious damage to the equipment and the property in which it is situated as well as severe personal injury or death to themselves and people at the site This document is intended for use by owner authorized operating service personnel It is expected that this individual possesses independent training that will enable them to perform their assigned tasks properly and safely It is essential that prior to performing any task on this equipment this individu
48. Solution Returns to Absorber Level in Outlet Pipe will Vary with Purge Tank Pressure Swirling Action in Outer Annulus and Spillover into Inner Chamber Separates Non Condensables from Solution 0 9 0 00 Weak Solution with Entrained Non Condensables From Purge Eductor 6 1005090 17 5 VALVES Some special valves have been added to the YIA auto purge system All of the valves are designed to be reli able and leak free There are several special purpose valves used such as the check valve and the automatic purge valves Please note all valves have been given a designation number for identification purposes The following is a description of each individual valve and its functional purpose Not all valves may be used on some models 30 FORM 155 21 1 510 VP1 This manual valve is used for initial purging of the unit at unit commissioning When open it will pull non condensables out of the absorber evaporator shell from a higher location than It is connected in series just before valve VP4 on the purge tree end both valves will need to be open for manual purging Note on larger units this valve maybe stand alone VP2 This manual diaphragm valve is used to remove non condensables from the purge tank It must be always ope
49. TOR 19 19 FIGURE 8 SOLUTION 19 FIGURE 9 GENERATOR tie tia 19 FIGURE 10 20 FIGURE 11 SOLUTION AND REFRIGERANT LEVEL VARIATION WITH LOAD 22 2 422221 21 FIGURE 12 EVAPORATOR AUX 21 FIGURE 13 AUTOMATIC DECRYSTALLIZATION 25 FIGURE 14 YIA PURGE SYSTEM 28 FIGURE 15 PURGE TANK N 29 FIGURE 16 PURGE doen 29 FIGURE 17 30 FIGURE 18 THE COMPLETE ISOFLOW PURGE 5 32 FIGURE 19 PURGE PUMP PIPING AND VALVES NORMAL 2 4 4 33 FIGURE 20 MODEL 1402 VACUUM PUMP 37 FIGURE 21 FLOW OF REFRIGERANT WATER OR LITHIUM BROMIDE THROUGH 40 FIGURE 22 ACCEPTABLE INTERNAL UNIT
50. URVES JOHNSON CONTROLS 57 PTX Chart MODEL 5C3 MODEL 155 21 1 510 6 4 FIG 26 CONT D PRESSURE DROP CURVES 58 60 H 40 5 30 20 5 10 7 Y 5 5 3 Y 2 1 2 2 Q CHILLED WATER 65 40 30 20 LL 10 7 5 4 3 ty 2 1 oS 29 ON AN GPM TOWER WATER 40 30 th 20 2 T 10 8 J 5 5 9 4 Y 3 2 5 O 5 63 PRESSURE DROP FT WATER PRESSURE DROP FT WATER PRESSURE DROP FT WATER 60 40 30 20 70 50 30 20 BRANO 50 40 30 20 ZT ype 2 7 2 A 7 Loe 27 4
51. Units that provide year round cooling Once every four months and as required due to excess purge requirements Units that provide only seasonal cooling Once at the beginning of the cooling season once in the middle and as needed due to excess purge requirements 2 Units should be leak tested when excessive purging is required Note The solution chemistry should always be checked and adjusted as necessary prior to performing a leak test 3 frequent rebuilds will be required if solids and or dissolved copper is present in the solution 4 Perform every 2 3 years or as required Check average skin temper atures of pumps YORK Johnson Controls Qualified Service Technician Operator 68 JOHNSON CONTROLS 155 21 1 510 GLOSSARY TERMS Absorber The concentrated solution coming back from the gen erator is pumped to a solution spray header where it is sprayed over the tubes in the absorber Refrigerant vapor is absorbed into the solution and the solution is thus diluted This diluted solution is collected at the bottom of the absorber where it is again pumped to the generator Auto De crystallization ADC Flush Line The ADC line runs between the solution pump dis charge and the ADCline When the solution pump runs weak solution is constantly supplied to the ADC line This keeps the ADC line from crystallizing due to it being exposed to the low pressures generated
52. al functions related to general performance of the system Information and guides are given pertaining to care and general mainte nance of the unit A glossary of terms has been included in the back of this manual Review these definitions in order to be familiar with the concepts found throughout this manual Absorption System Operation FORM 155 21 1 510 THIS PAGE INTENTIONALLY LEFT BLANK 8 JOHNSON CONTROLS 155 21 1 510 SECTION 2 ABSORPTION SYSTEM OPERATION GENERAL INFORMATION The principle of refrigeration is the exchange of heat and in absorption liquid chilling there are four basic heat exchange surfaces the evaporator the absorber the generator and the condenser refer to FIGURE 1 In absorption chilling the refrigerant is water like any refrigeration system absorption chilling uses evapora tion and condensation to remove heat To maintain effective evaporation and condensation absorption chilling employs two shells which operate at different controlled vacuums The lower shell Evaporator and Absorber has an inter nal absolute pressure of about one one hundredth that of the outside atmosphere or six millimeters of mer cury a relatively high vacuum The vacuum allows water the refrigerant to boil at a temperature below that of the liquid being chilled Thus chilled liquid entering the evaporator can be cooled for air condition ing or process cooling applications Eva
53. al shall have read and understood this document and any referenced materials This individual shall also be familiar with and comply with all applicable governmental stan dards and regulations pertaining to the task in ques tion SAFETY SYMBOLS The following symbols are used in this document to alert the reader to areas of potential hazard DANGER indicates an imminently hazardous situation which if not avoided will result in death or seri ous injury DANGER WARNING indicates a potentially hazardous situation which if not avoided could result in death or seri ous injury WARNING WARNING VE CAUTION identifies a hazard which could lead to damage to the machine damage to other equipment and or environmental pollution Usually an instruction will be given together with a brief explanation CAUTION NOTE is used to highlight additional information which may be helpful to you NOTE External wiring unless specified as an optional connection in the manufacturer s product line is NOT to be connected inside the micro panel cabinet Devices such as relays switch es transducers and controls may NOT be installed inside the micro panel NO external wiring is allowed to be run through the micro panel All wiring must be in accordance with 5 published specifications and must be performed ONLY by qualified Johnson Controls personnel Johnson Controls will not be responsible for damages problems r
54. anel Service manual 155 21 1 for additional detail on this valve and how it operates JOHNSON CONTROLS FORM 155 21 1 510 3SOL Refrigerant Level Solenoid Valve Unloader Valve The function of 3SOL is to transfer solution to the refrigerant circuit of the machine Normally this is not a desired condition However is some situations it is used effectively to allow the unit to stay on line make it run more stabwle and keep the pumps from cavitating Please refer to the OptiView Service Manual Form 155 21 M1 for additional details on this valve and how it operates 4SOL Automatic Shut Off Valve not shown This valve is a customer supplied and installed valve It ensures 100 shut off during a cycling safety shut down or a power failure It works in conjunction with the 6SOL steam condensate drain solenoid valve For additional details on this valve if installed refer to Installation Manual Form 155 21 N1 5SOL Purge Solenoid Valve This valve is no longer used with units that have Welsh vacuum pumps installed from the factory 6SOL Steam Condensate Drain Solenoid Valve if applicable This valve is located on the condensate outlet box of the generator shell opposite the steam inlet It is a normally closed NC valve and is energized at all times during unit operation The function of this valve is to stop all steam flow through the generator when the unit is off or during a power failure This valve is
55. ariation this variation is added to the current valve opening value Load Limited By Warning Conditions The control valve can also be under certain limitations depending upon unit operating conditions These limits will take precedence over the LCHLT and SSC controls Unit pull down limit soft shutdown or ramp down remote max load limit warnings caused by refrigerant temp is less than 35 5 F 1 9 C warnings caused by generator pressure is greater than 517 mm Hg Abs JOHNSON CONTROLS Limiting Capacity by Mixing Solution and Refrigerant The YIA is capable of obtaining low load conditions with low cooling tower water temperatures Achievement of low capacity at low cooling water temperatures involves reduction of concentration in the solution circuit thus water removed from the refrigerant circuit is added to the solution circuit for dilution This happens while the unit is operating at low loads REFRIGERANT LEVEL REFRIGERANT BLOWDOWN EVAPORATOR SIGHT GLASSES EVAP PAN ABSORBER COIL pind SOLUTION LEVEL SOLUTION SIGHT GLASS 25 LOAD EVAP PAN EVAPORATOR REFRIGERANT SIGHT GLASSES LEVEL REFRIGERANT BLOWDOWN OVERFLOW 029 0 99 090000 ABSORBER COIL SOLUTION LEVEL SOLUTION SIGHT GLASS 100 LOAD 1004766 FIGURE 11 SOLUTION AND REFRIGERANT LEVEL VARIATION WITH LOAD By diverting lithium bromide from the solution
56. astage and contamination of the solution and refrigerant if through wall pitting occurs For additional various water qualities see Chiller Materials Application Guide YORK Form 160 00 05 YORK IsoFlow Absorption Chillers can only deliv er design output and efficiency if they are properly operated and maintained One of the most important elements of proper maintenance is the cleanliness of the tubes to prevent fouling scaling and corrosion during daily operations and shutdowns It is the responsibility of the owner operator of this equipment to engage the services of an experienced and reputable water treatment specialist for both the initial charging of the system and its continuous monitoring and treatment Improperly treated or main tained water will result in decreased efficiency high operating costs and premature failure due to waterside corrosion For water treatment programs to be acceptable they must protect all exposed metal i e carbon steel cop per and brass from corrosive attack The use of corro sion inhibitors must be effective at low concentrations must not cause deposits on the metal surfaces and must remain effective under a broad range of pH tem perature water quality and heat flux Furthermore the inhibitor package must prevent scale formation and disperse deposits while having a minimal environ mental impact when discharged Water samples should be collected and analyzed on at least a monthly
57. ately two weeks there is a strong indication that either a leak is develop ing or there is a problem with the solution chemistry or both Therefore if a unit is manually purged it is important to keep track of the purging history If the unit 15 equipped with SmartPurge the micro processor keeps track of the purging frequency and alerts you if it has become excessive When to purge the purge tank The old philosophy of purging an absorption unit was to have the equipment room operator manually purge the unit once per day whether it was necessary or not In addition to purging from the purge tank most opera tors preferred to purge from the absorber with the purge pump for a given period of time Although some users may still prefer this method it should not be necessary providing the unit is in good health Since the YIA unit s internal purge system is automati cally and continuously while the unit is operational moving non condensables from critical areas of the unit such as the absorber or condenser to the purge tank it is only necessary to monitor the purge tank pressure and evacuate it periodically It should not be necessary to purge the absorber with the purge pump on a properly operating unit Although the purge tank can adequately maintain 100 mm Hg pressure autopurge will evacuate the tank if the pressure exceeds 80 mm Hg The purge tank will be evacuated until the tank pressure is reduced to 30 mm Hg It is r
58. basis by the water treatment specialist A quarterly review with the treatment supplier should address the conditions of the water systems and devel op action plans based on these analyses A third party water consulting company can help oversee the water treatment programs in order to properly protect the physical plant and avoid costly downtime JOHNSON CONTROLS It is equally important that the owner operator of the equipment performs tube cleaning and inspection of the absorber condenser and evaporator waterside tubes at the frequencies recommended in the Tube Bundle Section of the Preventive Maintenance Schedule located in this manual In addition to periodic cleaning with tube brushes tubes must be inspected for wear and corrosion Tube failures usually occur due to corrosion erosion and fatigue due to thermal stress Eddy current analysis and visual inspection by boroscope of all tubes are invaluable preventative maintenance methods These provide a quick method of determining waterside tube condition at a reasonable cost STEAM CONDENSATE OR HOT WATER QUALITY YORK IsoFlow units use corrosion resistant CuNi tubes in the generator As with the waterside of the system it is the responsi bility of the owner operator of this equipment to engage the services of an experienced and reputable steam condensate or hot water treatment specialist for both the initial charging of the system and its continu ous monitoring and
59. bles from the purge tank JOHNSON CONTROLS VP8 This check valve is located between the purge pump and oil trap It is a flapper type check valve which must be installed horizontally with the hinge marking up and the free flow arrow pointing towards the purge pump Its purpose is to provide added protection from air enter ing if the purge valve were open during an unattended power failure situation It works best at high pressure differentials Note this valve is a maintenance item and may malfunction with extended or severe usage It is located so that it can be taken apart and cleaned with kerosene or similar degreaser The stamped hinge hex end will unscrew right handed threads from the body of the valve to access the flapper assembly Oil Separator The oil separator is located in the suction line of the purge pump It is constructed so that oil from the vacuum pump cannot get drawn into the unit should a power failure occur during purging The separator is sized to hold twice the volume of the purge pump oil charge The oil separator also serves as a trap in the unlikely event that solution gets drawn into the purge piping and helps prevent contamination of the purge pump Absolute Pressure Gauge This gauge is important for reading the very low pressure in the absorber section of the unit or the vacuum pump The gauge is no longer a manometer type gauge that contains mercury It is a dial type non mercury abs
60. c ADC Piping Circuit and ADC Control Feature 23 2SOL Refrigerant Valve 23 PURGING AND 27 teint 27 INTERNAL PURGING WHILE UNIT IS 27 PURGE COMPONENT SS 27 JOHNSON CONTROLS 155 21 1 510 Section PURGE PUMP 24 02 33 GENERAL 33 33 Types Lubricants 33 PURGE PUMP PIPING AND OPERATING 33 The Principle of Gas 33 OIL 33 Section EJ PURGE PUMP MAINTENANCE 35 VACUUM 35 Pressure 35 35 CHANGES AND OIL LEVELS 35 Draining The 35 Fl shing he PUMP 2 45 22 35 Refilling The
61. e See the Purging section of this manual for the correct method to check the unit pressures Looking at the PTX chart follow the vertical tempera ture line and the horizontal pressure line to where the two intersect The closest diagonal line to this inter section would be the correct solution concentration As the concentration of lithium bromide increases reducing water content the solution becomes more viscous When all water is removed the solution returns back to its natural state as a solid JOHNSON CONTROLS CRYSTALLIZATION All absorption chillers that use lithtum bromide and water as the solution refrigerant pair are subject to crystallization This is due to the fact that some areas of the unit operate with solution liquid concentration levels that are only possible at higher than the normal ambient temperature surrounding the unit For exam ple the solution concentration in the generator of a single stage absorption unit is typically 64 3 lithium bromide by weight Referring to FIGURE 24 64 3 solution will begin to crystallize at 110 F 43 3 C Since the solution temperature in the generator nor mally is higher than 200 F 93 3 C at most load conditions no crystallization will occur as long as the higher solution temperatures are maintained Special measures do have to be taken before the unit is shut down so that the solution is sufficiently diluted in all areas of the unit to prevent crystallization during the
62. e emulsi fies with the oil which is recirculated and subjected to re evaporation during the normal cycle of pump activ ity thus reducing the ultimate vacuum attainable Some foreign particles and vapors may form sludges with the oil impair sealing and lubrication and cause eventual seizure Although the gas ballast valve is helpful in removing vapors especially water it is not equally effective on all foreign substances therefore periodic oil changes are necessary to maintain effi cient operation The required frequency of changes will vary with the particular system The oil should be changed when it looks dirty cloudy milky or when the pump is not capable of pulling below 2mmHg Abs OIL CHANGES AND OIL LEVEL Draining the Pump An oil change is most easily accomplished when the pump is warm and the oil is less viscous Use a clear plastic container large enough for the oil in the par ticular pump Stop the pump and open the drain valve Thoroughly drain the pump by tipping the pump slightly if this is possible The small residue remaining in the pump may be forced out by hand rotating the pump pulley with the exhaust port par JOHNSON CONTROLS tially closed and the intake port open Closing the exhaust port completely under these conditions will create excessive pressure at the drain valve which may cause the oil being drained to splatter Flushing the Pump This procedure should be performed whenever the performanc
63. e noted that the only non condensable that is not self generated by the chemistry inside the unit is nitrogen Air is over 70 nitrogen an air leak is the only external source of nitrogen All other non con densables are generated by various chemical reactions that occur internally for many different reasons 71 Glossary of Terms Oil Trap The oil trap is located between the purge pump suction connection and the unit It is designed so it will hold one complete oil charge of the vacuum pump In the event air was to get into the unit through the vacuum pump the low pressure in the absorber would induce the oil onto the system Therefore the oil trap is used as a safety measure to protect the absorption unit from the oil Orifice A restriction in a liquid line for the purpose of reduc ing the internal diameter of the line Usually created by a blank piece of metal with a small hole drilled into it to create a pressure differential when a liquid passes through it Pass Baffle A division plate or plates baffles inserted into a water box to create chambers which force the water to pass through different portions of the tube bundle called passes Although the pressure drop increases with each pass the tradeoff for heat transfer optimiza tion and nozzle locations are justified Power Panel The power panel serves as single point wiring loca tion for the unit s incoming power wiring It houses all the unit pump contactor
64. e of the pump is poor and changing the oil didn t correct this shortcoming 1 Check the oil level a Ifthe oil level is well above the fill mark this can indicate the pump has ingested lithium bromide solution Go to step 2 b Ifthe oil level is even with the fill mark and you do NOT suspect lithium bromide solu tion has been ingested accidentally by the pump run the pump for 15 minutes and allow the pump oil to warm up before going to step 2 2 Turn off the motor for the vacuum pump Drain the oil into a clear plastic container Look for water settling to the bottom of the container In some cases an emulsion of oil and water can be seen between the oil and the water If water is noticed perform steps 3 through 5 several times until the oil comes out clear The oil drained from the pump is from the oil case only There may be water or other contaminants in the pumping mechanism To be sure all contaminants have been removed the pump mechanism needs to flushed 3 Make sure the belt guard is installed before pro ceeding further Attach a short hose to the drain valve which runs into a clear plastic container Secure the hose end in the container so that it does not blow around during the next step 4 Flushing the pump is carried out by adding a cup of new DUOSEAL oil through the exhaust OUT port while the pump is turned on for 15 20 seconds While adding the pump oil the exhaust OUT port is blocked b
65. ecommended that units without autopurge be purged the same way 31 Purge Pump Operation PURGE TANK X 2 4 gt lt VACUUM GAUGE O PT3 D gt lt 7501 8501 OIL ABSORBER TRAP NON COND FROM ABSORBER TEST HOSE BALLAST PURGE PUMP TO SOLUTION PUMP SUCTION FIGURE 18 THE COMPLETE ISOFLOW PURGE SYSTEM 32 FORM 155 21 1 510 10 4 SOLUTION PUMP DISCHARGE VENT TO ABSORBER GAS SEPARATOR LD14575 JOHNSON CONTROLS 155 21 1 510 SECTION 4 PURGE PUMP OPERATION GENERAL As previously discussed each machine is equipped with a vacuum pump refer to FIGURE 19 which is designed to remove non condensables from various areas of the machine The following issues should be kept in mind whenever operating a YORK Vacuum Pump Cleanliness Take every precaution to prevent foreign particles from entering the pump A fine mesh screen is pro vided for this purpose in the intake passage of all YORK Vacuum Pumps Types of Lubricants All YORK mechanical vacuum pumps are tested with DUOSEAL oil and shipped with a full charge to pre vent unnecessary contamination DUOSEAL oil has been especially prepared and 18 ideally suited for use in mechanical vacuum pumps because of its desirable viscosity low vapor pressure and chemical stability The vacuum guarantee on all YORK vacuum pumps applie
66. es 300 F 150 C to 392 F 200 C depending on pump type The thermostats will auto 3M Starter Contactor for Purge Pump matically reset when the motor windings cool down This is used on all units 27 F 15 C from the trip point 10L thru Overloads Each starter contactor is accompanied by a heater ele ment overload with resetting capability The designa tion number of the overload matches the designation number of the starter contactor POWER SERVICE TRANSFORMER DISCONNECT SWITCH 1FU 2FU 3FU lt GROUND LD14568 FIGURE 2 TYPICAL POWER PANEL 60 HZ NEMA 1 STANDARD UNIT POWER PANEL SHOWN 12 JOHNSON CONTROLS CONTROL COMPONENTS EXTERNAL THE CONTROL CENTER see FIGURE 3 Hermetic Motor Thermostats not shown The Solution and Refrigerant pump motors are cooled by the circulating fluid In the case of inadequate cool ing each motor has an internal motor protector of the Klixon type imbedded in the motor windings to pro tect the motor from damage if overheating occurs Refer to Section 6 for additional details Refrigerant Level Float Switch This level switch is located in separate chamber on the side of the refrigerant outlet box Its function is to determine if a refrigerant level is present or not If the refrigerant level is not present either from a low chiller load or low tower water temperature it could cause the refrigerant
67. esult ing from improper connections to the controls or application of improper control signals Failure to follow this will void the manufacturer s warranty and cause serious damage to property or injury to persons JOHNSON CONTROLS 155 21 1 510 OF THIS DOCUMENT In complying with YORK Johnson Controls policy for continuous product improvement the information contained in this document is subject to change with out notice While Johnson Controls makes no com mitment to update or provide current information automatically to the manual owner that information if applicable can be obtained by contacting the near est YORK Johnson Controls Service Office It is the responsibility of operating service personnel as to the applicability of these documents to the equip ment in question If there is any question in the mind of operating service personnel as to the applicability of these documents then prior to working on the equip ment they should verify with the owner whether the equipment has been modified and if current literature is available ASSOCIATED LITERATURE DESCRIPTION OPERATION YIA UNIT 155 21 OM1 INSTALLATION YIA UNIT 155 21 N1 SERVICE OPTIVIEW CONTROL CENTER 155 21 M1 RENEWAL PARTS YIA OPTIVIEW CONTROL CENTER 155 21 RP1 RENEWAL PARTS YIA UNIT 155 21 RP2 WIRING DIAGRAM UNIT 155 21 W1 WIRING
68. f the unit The Magnetite lyer not the inhibitor helps reduce corrosion rates in the unit YORK s current inhibitor is ADVAGuard 750 Insulation Units should be insulated in the field according to the installation manual Insulation should be installed for a variety of reasons 1 Decreases the heat loss through the walls of the vessel to its surroundings thus increasing the effi ciency of the machine 2 Helps reduce the potential of crystallization in the event of a power failure 3 protection for operating personnel in high temperature areas 4 Eliminates condensation on low temperature areas of the machine IsoFlow Our trademark name for a single stage absorption unit Isolation Valve One isolation valve is located at each Buffalo Pump inlet and outlet It is a positive sealing butterfly type valve mounted between standard ANSI flanges Each valve incorporates an EPDM liner on the valve face to act as a sealing surface When closed the valves will isolate the unit vacuum from the pump area to offer ease of serviceability when working on the pumps JOHNSON CONTROLS FORM 155 21 1 510 Lithium Bromide Lithium bromide or LiBr is a solid salt chemical compound of lithium and bromine When mixed with water it becomes a liquid solution Its extreme hygro scopic character makes LiBr useful as a desiccant in absorption chiller systems Magnetite An iron oxide layer formed on the internal unit sur
69. from cavitation and eventual over heating For more details on the operation of these floats see Mod D Operation YORK Form 155 21 Ol Generator This component of the absorption system heats diluted lithium bromide solution coming from the absorber shell The generator can receive its heat source from either hot water of 266 F 130 C and 300 PSIG or steam up to 337 F 169 C and 17 PSIG As the solution is heated refrigerant vapor is boiled off and rises to the condenser The resulting concentrated lithium bromide solution flows back to the absorber sprays measure of volumetric flow rate Gallons Minute JOHNSON CONTROLS This is also sometimes called an energy balance It is based on the physics principle conservation of ener gy which states that the energy that is put into a cycle is equal to the energy coming out of the cycle e g Heat in Heat out The above equation is used to mathematically prove within a cerain tolerance 5 that the energy we put into the machine or cycle is coming out of the cycle If this is proven then we know our measure ments used to compute unit capacity are correct Hot Water Valve The capacity control valve that regulates the amount of hot water to the generator hot water units only Inhibitor A chemical used to help form a magnetite layer to minimize or inhibit the corrosion on the internal steel surface area o
70. ge pump with out the belt guard place On units with SmartPurge be aware that the purge pump starts and stops automatically CAUTION 7SOL 1 FIGURE 14 YIAPURGE SYSTEM 28 FORM 155 21 OM1 510 The purge pump is factory mounted bracket system on the YIA units The purge pump is used to 1 Remove stored non condensables from the purge tank 2 Manually purge the absorber The purge pump will go through a warm up period when started This will help keep the oil free of refrigerant Although occasionally some of the non condensable gases produced are unpleasant in odor the normal quantities are very small If venting the purge exhaust is required it can be done by running the purge piping outdoors or into a scrubbing unit of some type Common sense should prevail in the piping design in venting the purge pump out doors Total pressure drop of vent piping must not exceed 5 psig PT3 EDUCTOR 8SOL OIL TRAP VP8 PURGE PUMP GAS SEPARATOR LD14573 JOHNSON CONTROLS Explosion Warning Never install isolation valve on the discharge of the pump or in the vent line Closing this valve while the pump is operating could result in an explosion The purge pump should be operated with the gas ballast open to prevent refrigerant vapor from condensing in the oil Close the purge pump gas ballast when performing a bubble leak test procedure Leave the gas ballast
71. h IsoFlow absorption units operate at less than atmospheric pressure a vacuum if certain safe ties fail and or incorrect valves are closed the unit could experience higher pressures in certain cham bers Therefore a pressure relief apparatus a rupture disk is added only to hot water units Sight Glass A leak tight port hole used to visually inspect liquid levels within the unit A threaded design with a quartz glass window is presently being used Solution A mixture of deionized water with a certain by weight of dissolved lithium bromide LiBr Corrosion inhibitors are also added to the solution to reduce the internal corrosion rates in the unit Solution Heat Exchanger A counterflow solution to solution heat exchanger A component that exchanges heat between two streams of lithium bromide solution The hotter the solution being supplied to the generator is the less heat that needs to be added thus improving efficiency Likewise the cooler the solution is going to the absorber the less heat that needs to be removed by the cooling towers Therefore the heat exchanger pre heats the solution going to the generator and cools the solution going to the absorber JOHNSON CONTROLS Solution Pump A hermetically sealed centrifugal pump located under the absorber It receives diluted lithium bromide solu tion from the absorber shell and circulates it through a heat exchanger and up to the generator The discharge of thi
72. ing refrig erant vapor Condenser The refrigerant vapor rises to the condenser and is condensed by the cooler tower water running through the condenser tubes The liquid refrigerant flows back to the lower shell and is once again sprayed over the evaporator The refrigerant cycle has been completed Now the concentrated lithium bromide solution flows from the generator back to the absorber in the lower shell ready to absorb more refrigerant Its cycle has also been completed DESCRIPTION OF MAJOR COMPONENTS AND SUB SYSTEMS YORK IsoFlow Absorption Chillers consist of the fol lowing major components and sub systems Generator Condenser Shell Assembly This is the upper of two cylindrical shells and it con tains two tube bundles the generator and the condens er The generator is a single pass flooded tube bundle when operated with steam and may be a one or two pass flooded tube bundle when operated with hot water The steam or hot water flowing through the tube bundle boils the water vapor from the solution that surrounds the outside surface of the generator tubes The condens er section of this shell assembly consists of a single pass tube bundle through which cooling water is circu lated condensing the water vapor boiled off in the generator and a condenser pan to collect the water Evaporator Absorber Shell Assembly This is the lower shell assembly and it also contains two sections the evaporator and the absorber
73. is open sewer flow there is no flow of solution down the ADC pipe during normal operation It is necessary that this automatic decrystallization pipe contain a liquid trap Otherwise there would be unwanted flow of vapor from the top shell to the lower shell due to the difference in pressures between the two shells ADC Flush Line To provide a liquid trap a small capacity flush line is provided 14 to supply a small GPM flow of dilute solution into the trapped portion of the decrystallization pipe It is desirable that the riser portion of this trap be sufficiently high to take care of any extreme condition in top shell pressure such as with unusually high con densing water temperature and degree of condenser fouling Consequently a riser portion is extended up into the exterior pipe 12 This pipe 11 inside the pipe 12 is an extension of the trapped section of the pipe 10 This flow of flush solution through the trap also serves the purpose of sweeping out the small amount of water condensate that tends to be absorbed into the dilute solution at the liquid vapor interface JOHNSON CONTROLS FORM 155 21 1 510 There is a simple way to tell whether the solution flow from the generator is by normal return methods through the heat exchanger or whether the automatic decrystal lization pipe is being used If the trapped section of pipe 10 or pipe 13 is hot to the touch such as that nor mally experienced a
74. is water first passes through the Absorber and then to the Condenser Typical tempera tures are entering the Absorber at 85 F leaving the Absorber entering the Condenser i e crossover at 92 F 33 3 C and leaving the Condenser at 95 F 35 C Some external means of removing this heat is necessary Typically a cooling tower is used for this application Crystallization Under certain conditions lithium bromide solution may increase in viscosity and become slush like or even so lidify The likelihood of solution crystallizing increases as the concentration increases and or the temperature decreases For reference here are some points where 69 Glossary of Terms the liquid solution of lithium bromide will crystallize assuming a saturation condition 240 F 115 C 70 207 F 97 C 69 182 F 83 C 68 158 F 70 C 67 138 F 59 C 66 120 F 49 C 65 Typically crystallization occurs where the heated high concentrated solution leaves the generator and passes through the heat exchanger This is where the solution is at its highest concentration that meets the lowest temperature Under normal running conditions crystallization is not a problem Extreme cold ambient temperatures power failures and unit air leakage are the typical causes for crystallization Dilution Cycle Intentionally running the solution refrigerant tower water and chilled water pumps after
75. ith dirty tubes or non condensables will be more susceptible due to higher con centrations in the solution heat exchanger c Overfiring the unit will tend to over concen trate the strong solution and make it more susceptible for crystallization 2 A decrease of the solution temperature The ambi ent temperature of the machine room and the amount of thermal insulation on the solution to solution heat exchanger will also determine the likelihood of crystallization Improper or inade quate thermal insulation on the hot sections of the unit will allow heat loss to progress rapidly and therefore shorten the amount of time before the concentrated solution cools down to its crystalli zation temperature Outside air dampers remain open during a power failure may allow the plant room to cool down quickly which will has ten crystallization 3 The duration of the power interruption is very important Although it is very difficult to quantify the acceptable time before crystallization occurs it is doubtful that harmful crystallization will occur if the power interruption is less than fifteen minutes Power interruptions lasting thirty min utes or longer have been experienced during full load operation of some machines with no prob lems Although a more rare occurrence units can also crys tallize during operation Two of the chief causes of crystallization during operation are non condensables in the absorber and rapidly fluctua
76. ith the evaporator at 6 3 mmHg absolute pressure which cor relates to a 40 F 4 4 C boiling point refer to FIGURE 6 CHILLED WATER OUTLET RT6 CHILLED WATER INLET lt LD13806A FIGURE 6 EVAPORATOR Refrigerant vapor in the evaporator is attracted and absorbed by intermediate lithium bromide solution flowing over the outside of the absorber tubes thus diluting the solution Heat generated in the process heat of absorption is removed by condensing water from a cooling tower or other source flowing through the absorber tubes see FIGURE 7 2 5 TOWER WATER INLET LD13806A FIGURE 7 ABSORBER JOHNSON CONTROLS FORM 155 21 1 510 Relatively dilute solution from the bottom of the absorber is pumped by the solution pump through the heat exchanger where it is regeneratively heated by hot concentrated solution draining from the generator The solution then travels up to the generator see FIGURE 8 350 SOL PUMP 520 813 1013806 FIGURE 8 SOLUTION PUMP Generator tubes are submerged in lithium bromide solution which enters the generator in a dilute condition at one end and leaves concentrated at the opposite end
77. ld be thoroughly cleaned of all previous gasket material and the mating surfaces cleaned of any nicks DRIVE PROBLEMS When troubleshooting drive problems or checking belt tension always shut off and lock out power at the main disconnect switch If for any reason the pump will not operate turn off and lock out the power at the main circuit breaker or disconnect Check the overload assembly and electri cal connections Remove the guard cover followed by the belt Re establish power to the pump If the motor operates properly try hand rotating the pump in the proper direction with the pump intake port open If both turn freely then replace the belt and check the belt tension The tension should be sufficient to drive the pump without visible slippage Any greater ten sion will cause noise and possible damage to the bear ings of both the motor and pump Make certain that both pulley grooves are clean and free from oil The pulleys must be fastened securely on their respective shafts and in parallel alignment Re install the belt guard and check for proper operation and amperage Replace or re build any defective components JOHNSON CONTROLS 155 21 1 510 GAS BALLAST PORT 1 4 NPT FEMALE CONNECTION 1005105 gt 1 13 16 INTAKE NIPPLE ACCEPTS 5 8 3 4 10 3 4 20 THREAD 1 20 THREAD STD MOTOR 1 2 12 5 8 41 0669
78. me bearing wear Pump disassembly is required Pump Overhaul The expected time span between Buffalo Pump over hauls on a properly maintained JsoFlow unit should be between 50 000 and 60 000 hours Pumps installed on units running with high amounts of suspended sol ids or high amounts of dissolved copper in the solution will suffer shorter lives It is therefore recommended to install a solution filtration kit on the unit to remove the suspended solids and or perform a copper removal procedure as indicated on the solution chemistry report Contact your local YORK Factory Service office for details 39 gt 5 5 72 155 21 1 510 9015001 2222222222222222222222722222222227222 77727 22 2 22 2 SA FIGURE 21 FLOW OF REFRIGERANT WATER OR LITHIUM BROMIDE THROUGH PUMP JOHNSON CONTROLS 40 155 21 1 510 SECTION 7 STEAM AND WATER QUALITY CONTROL WATERSIDE GENERAL INFORMATION The absorber condenser and evaporator water must be free of corrosive elements or inhibited to prevent attack of the waterside tubing Impurities and dis solved solids can cause scaling that reduces heat exchanger efficiency and causes corrosion of tubes Corrosion in turn can result in more serious prob lems such as metal w
79. mote optimum shell side coefficients of heat transfer This additive is charged into the unit upon initial start up and rarely does more Hexanol have to be added The effect of Hexanol addi tive on unit performance appears later in this section The design load rating for the YIA 6C4 unit used for the data simulation is as follows JOHNSON CONTROLS 155 21 1 510 100 Design Load 517 9 Tons Valve Inlet Steam Pressure 12PSIG Condenser Water Flow 1870 GPM 299 F Entering Condenser Water Temp 85 F Normal Installation Ambient Pressure 29 5 Hg Chilled Water Flow 1243 GPM 14 5 PSIA Chilled Water Range 54 F to 44 F Steam Source 15PSIG 300 F Passes Chiller Condenser Absorber 2 1 1 Assume steam condensate is flashed at atmospheric Fouling Factor for Absorber pressure before it is weighed for test data purposes Condenser and Evaporator 0005 Steam Pressure at Generator 9 2 PSIG Steam Flow 9478 b hr SCALE FACTORS CHILLER 2005 10095 1 60005 ABSORBER CONDENSER 000 007 58078 3 7772 9 72 22 CHILLED WATER ENTERING TEMPERATURE F 57 9 7 5 9 2 57 77 2 LEAVING TEMPERATURE Y 3 PRESSURE PSI 15 6 15 6 5 6 A 3 7263 7242 CONDENSING WATER ABSORBER SNS TEST TESTER CONDENSER miata ROM CONDENSER BSOR
80. n when in the auto purge mode VP4 This valve is used to manually purge the absorber section of the unit It is connected to the internal absorber purge header system located below the tube bundle When open the purge pump will pull the non condensables from the absorber It is always in the closed position for auto purging 7SOL Purge Tank Pressure Valve This solenoid valve is only supplied on units with the auto purge feature The Optiview panel will control the opening and closing of this valve in auto or manual purge mode It only opens when the pressure from PT3 is proven to be 15 mm Hg absolute or less When this valve is open non condensables from the purge tank are allowed to be purged out 8SOL Purge Pump Pressure Valve This motorized ball valve is only supplied on units with the auto purge feature The Optiview panel will control the opening and closing of this valve in auto or manual purge mode After the purge pump is started and completed the warm up period 8SOL will open A 60 second timer is started to allow this valve to open completely If the pressure as monitored at PT3 is not at or below 15 mmHg absolute after the 60 seconds has expired an additional 60 timer will commence If the pressure is still above 15 mmHg absolute after the second 60 seconds has expired 8SOL will close and a purge pump failure will be displayed 8SOL and 7SOL are connected in series in order for 8SOL to be open to purge the non condensa
81. nd lubricated by the pumping fluid refrigerant water or lithium bromide solution The pumping liquid also carries away heat generated by the motor Do not run the pump dry Even momentary operation without the pump and motor casing filled with liquid will damage pump bearings FIGURE 21 shows a cutaway view of a single ended pump The arrows indicates the cooling circuit through the pump TROUBLESHOOTING Pump Tripping on Overloads Check voltage supply on all three phases to be sure it is correct for the pump motor in question Check over load for proper amperage setting Pump Motor FLA loose wires or poor connections that generate heat and trip the overload If no problems found shut off all power to the unit and lock out tag out all discon nects Check the motor connections to be sure the pump is wired correctly Using a megohm meter check the pump motor windings for shorts or grounds If motor problems are found motor replacement will be neces sary Contact your local YORK Factory Service office for details If no problems are found during this pro cedure reconnect the motor Apply power to the unit and run the pump while watching the operating amps If high amps are encountered the problem may be mechanical such as bearing seizure Pump inspection will be necessary If the overload continues to trip but the motor amperage is within the allowable range the overload is defective JOHNSON CONTR
82. nd the educ tor causing stoppage of flow and producing a noisy condition The automatic decrystallization feature is available on all YORK IsoFlow Absorption Systems All models are equipped with this basic ADC piping circuit plus the ADC control feature The automatic decrystallization aids for trouble free operation of the unit While the ADC piping circuit will not completely eliminate the possibility of crystalliza tion requiring service assistance it will greatly reduce the likelihood A mild temporary crystallization may occur in rather extreme condensing water temperature variations and can be automatically managed without loss of refrigeration or special attention from the opera tor Still more positive measures attacking the major factors in solution crystallization are taken in models where the ADC controls are utilized Direct dilution of the solution with refrigerant and reducing the heat input to the generator when the tendency to crystallize is automatically detected are both affected by ADC con trols arranged to continue in effect until the tendency to crystallize disappears ADC Piping Circuit in Detail Referring to FIGURE 13 the normal return solution flow from the generator is via the return pipe 1 through the heat exchanger 2 and then through the eductor suction pipe 3 to the eductor 4 During normal operation the flow of solution in the return pipe 1 is accomplished by a condition of open sewer
83. nerator is cooled and condensed in the condenser and supplied to the evaporator Here it is immediately exposed to a much lower pressure which causes some immediate flashing boiling Most of the refrigerant cools to the satura tion temperature and remains in liquid form It is then pumped and sprayed over the Evaporator tube bundle As the refrigerant passes over the outer surface of the tubes it evaporates i e flashes or boils due to the low pressure approximately 5 5 6 5 mmHg which is equivalent to a saturation temperature of 36 41 F 2 2 5 C The refrigerant vapor is then immediately drawn through the eliminator towards the absorber This vacuum is caused by the hygroscopic action the affin ity lithium bromide has for the refrigerant vapor Evaporator Sprays A series of spray nozzles that evenly distribute refrig erant from the refrigerant pump discharge to the evaporator section tubes Level Switch 1F 3F There are two level switches that sense liquid levels on the IsoFlow units Both are located in the refriger ant circuit Switch 1F is at the side of the evaporator refrigerant outlet box and senses the level in the box At low levels in this box the 1F switch will open causing the micropanel to initiate corrective proce dures to keep the unit from running out of refriger ant Level switch 3F is located just before the inlet of the Buffalo refrigerant pump It s main purpose is to keep the Buffalo pump
84. nt present in solution Consequently the refrigerant quantity in the evaporator pan will increase and begin to spill over into the absorber section This spilling will act to reduce the solution concentra tion and thus lower the chances of crystallizing 2 The OptiView logic constantly monitors the tem peratures from the refrigerant leaving the condenser section at RT9 and strong solution temperature at RT3 From these two temperatures the logic will calculate the solution concentration as it leaves the generator section When the solution concentration reaches 65 5 the control status field will display High Concentration Control in Effect This control algorithm will reduce the control valve opening to keep the solution concentration at a safe level while maintaining the highest level of unit operation under the present conditions JOHNSON CONTROLS FORM 155 21 1 510 3 The third type of crystallization prevention is through the Automatic Decrystallization Cycle ADC Essentially when crystallization starts to occur a blockage usually forms in the strong solu tion side of the solution to solution heat exchanger STS and the solution starts to back up into the generator As solution starts to fill the generator outlet box it will begin to exit through the ADC line Sensor RT2 attached to the side of the ADC line senses the temperature rise in this line due to the high temperature solution flowing through it At 160
85. ntroller and or fan fluctuating rapidly thermostats as necessary H ADC circuit malfunction Check sensor and 2SOL refrigerant solenoid for proper operation Steam pressure too high Check setting of pressure reducing valve if used Adjust steam valve to reduce maximum opening 4 PURGE PUMP INCA A Contaminated oil Change oil as recommended PABLE OF PULLING B Ballast valve cracked or scored Repair with kit listed in Renewal Parts list BELOW 1MM Malfunctioning pump Repair or replace 5 PURGE PUMP OIL A Faulty shaft seal rubber Repair with kit in Renewal Parts manual LEAKAGE 66 JOHNSON CONTROLS FORM 155 21 OM1 510 PREVENTATIVE MAINTENANCE SCHEDULE Maintenance Interval Months unless otherwise indicated Preventative Maintenance Component See Operation Below Solution Chemistry Analysis Add inhibitors as needed 1 Record Operational Data Data Form Leak Test Unit Check Electrical Connections Replace Sight Glasses or Glass Gaskets Check For Proper Solution Levels Check For Proper Refrigerant Levels Check For proper Concentration of Octyl Alcohol Check Unit Level and or Pitch Check solenoids for bypass LRT Low Refrigerant Temperature Cutout Switch Unit Safety Controls Chilled Water Flow Switch Performance Condenser Water Flow Test Switch 1 High Temperature Cutout Switch Accuracy check of thermis tors and
86. olute gauge that will meet todays standards for prohibiting mercury in the work environments The gauge reads in Torr which is the same as mmHg absolute However due to the extreme sensitivity of this gauge the upper most range is 40 Torr Unlike the manometer gauge it will not read purge tank pressure Care should be taken to prevent lithium bromide solution from contaminating the gauge Contamination will cause inaccuracies in the pressure reading and may damage the internal working components The gauge will ship loose for field installation in the purge tree It is highly recom mended to install an isolation valve between the gauge and the purge tree for when the gauge is not in use JOHNSON CONTROLS FORM 155 21 1 510 Purging Frequency The purge tank evacuation frequency will be dependent on several factors such as unit size operational parame ters running time solution chemistry and of course leak tightness of the unit Some units may only need to have their purge tank evacuated a few times per year Others may require more frequent evacuation Although very frequent purge tank evacuation is a matter of concern a change in the frequency is also an indicator of a unit problem For instance a unit may routinely accumulate 80 mm Hg of pressure in the purge tank over 200 hours of operation approximately one month If all of the sudden the purge tank accumulates 80 mm Hg pressure in 100 hours of operation approxim
87. ork Pennsylvania USA 17405 1592 Tele 800 861 1001 Subject to change without notice Printed in USA Copyright by Johnson Controls 2010 www york com ALL RIGHTS RESERVED Form 155 21 OM1 510 New Release
88. performance including sampling of the unit fluids requires the services of a Johnson Controls Field Service Representative He will take samples of the refrigerant the lithium bro mide charge and the cooling water as well as a com plete set of operating data He can assist in a complete performance analysis and report on the condition of the unit Samples can be analyzed and a complete report obtained on the chemical content and pH levels The investment by the customer in the cost of these services is nominal compared to the cost of the unit and the ultimate cost of repairs or increased operating costs should the unit be inadequately maintained Inadvertent introduction of air into the unit by the operator or the existence of leaks are to be avoided at all times to ensure a long life of the unit The proper method of taking samples is straight forward but requires special training so that conclusions reached concerning the condition of the unit the solution chemistry and the cooling water are valid 44 FORM 155 21 OM1 510 For greatest accuracy of the data taken on operating units calibrated 1 5 F increment thermometers should be used particularly for measuring temperatures of chilled water and cooling water Calibrated test type pressure gauges and manometers also contribute to the attainment of accurate data Accurate flow meters for water and steam condensate flow with a subcooler complete the instrumentation requirement
89. porator Refrigerant enters the top of the lower shell and is sprayed over the evaporator tube bundle Heat from the liquid being chilled evaporates the refrigerant Absorber The refrigerant vapor then migrates to the bottom half of the lower shell Here the vapor is absorbed by a lithium bromide solution Lithium bromide solution is basically nothing more than salt water However lithi um bromide is a salt with an especially strong attraction for water The mixture of lithium bromide and the refrigerant vapor called the dilute solution now collects in the bottom of the lower shell Generator The dilute solution is then pumped through the heat exchanger where it is preheated by hot concentrated solution from the generator The heat exchanger improves the efficiency of the cycle by reducing the amount of steam or hot water required to heat the dilute solution in the generator The dilute solution then continues to the upper shell containing the Generator and Condenser where the absolute pressure is approximately one tenth that of the outside atmosphere or seventy millimeters of mercury The dilute solution flows over the generator tubes and is heated by steam or hot water passing through the JOHNSON CONTROLS interior of the tubes The amount of heat input from the steam or hot water is controlled by a motorized valve and is in response to the required cooling load The hot generator tubes boil the dilute solution releas
90. product of corrosion 2 Air may be drawn into a unit via leaks Non condensables that collect in the absorber section of the unit blanket the heat transfer tubes and reduce the absorber s ability to capture the refrigerant vapor Non condensables that collect in the high side of the unit end up in the condenser where they blanket the condenser tubes reducing the condenser s capacity Full load capacity will be prevented by high condens ing pressure NON CONDENSABLE QUANTITIES An absorption unit s general health can be determined by both the quantity and quality of non condensables it produces A properly maintained YORK IsoFlow unit will produce very few non condensables the fewer the better small amount of internally generated gases will always be present and should be considered normal Air leaks no matter how small will almost always cause noticeable increases in the amount of non condensables a unit produces JOHNSON CONTROLS Since it is important to correct any air leaks as soon as possible it is essential to develop a disciplined method of purging a unit so that any abnormalities can be dis covered quickly On SmartPurge equipped units the purge tank is automatically evacuated only when nec essary and the frequency of evacuation is continuously monitored by the OptiView control panel CONTINUOUS INTERNAL PURGING WHILE UNIT IS OPERATING The purge system is designed to automatically and con tinuo
91. properly not closing Check max rate setting normal 1 0 C Low temperature thermostat Check cutout setting using 1 5 F thermometer not cutting out at correct setting 39 F If not working properly contact temperature settings local district office D Fluctuating steam pressure or Correct supply source hot water temperature E Cooling water temp cycling Readjust settings improper tower fan setting 3 UNIT NOT MAKING Air in unit CAPACITY a Improper purging See Purge System Operation section for proper procedure for purging b Purge pump malfunctioning See Purge Pump Maintenance section for servicing information c Leak in unit Contact local district office for service B Cooling Tower water GPM Set to correct quantity using design pressure drop below design for your unit C Insufficient steam to the Check supply Readjust steam valve and regulating generator flange valves if necessary D Condensate backup into Check steam trap float and or valves generator tubes E Tube fouling excessive See Preventive Maintenance section for proper method of cleaning tubes F Crystallization a Air in unit See Purge System Operation section for proper procedure for purging b Improper dilution cycle Check float operation Check dilution time operation See that condenser water and chilled water pumps run until completion of dilution cycle G Cooling tower water temperature Readjust setting or replace co
92. pump to cavitate overheat or make the unit cycle on and off In these cases the unloader solenoid valve 3SOL will open to allow solution to mix with refrigerant This mixing will cause the refrigerant level to increase to satisfy the pump needs and sustain unit operation 3F Refrigerant Pump Cutout Float Switch This level switch is located in a separate chamber just below the refrigerant outlet box on the vertical section of pipe leading to the pump Like the 3F switch it monitors the refrigerant level to determine if a level 15 present or not If no level is detected the control logic will shutdown the refrigerant pump after some pro grammable refrigerant pump parameters are met Flow Switches not shown Units fabricated at the release of this document will be equipped with factory supplied and mounted analog thermal type flow sensors in the outlet nozzle of the evaporator and condenser sections These devices will be wired into the control panel so no further installa tion process is necessary 1SOL Motor Coolant Solenoid Valve These are not used on units with Buffalo Pumps 2SOL Stabilizer Refrigerant Solenoid Valve The function of 2SOL is to supply refrigerant to the generators solution outlet line to reduce the solution concentration There are certain conditions in which this valve will open automatically during unit opera tion This valve can also be opened manually to facilitate service procedures Refer to Control P
93. pumps will gurgle in varying degrees under four conditions of performance 1 when operating at high pressure as in the beginning cycles of evacuation of the purge drum 2 when the oil level in the pump reservoir is lower than required 34 FORM 155 21 OM1 510 3 when a large leak is present in the system and 4 when the gas ballast is open Best performance of a mechanical pump is generally obtained after sufficient time has been allowed for the pump to come to operat ing temperature JOHNSON CONTROLS 155 21 1 510 SECTION 5 PURGE PUMP MAINTENANCE VACUUM PROBLEMS Pressure Determinations A simple test for the condition of a mechanical pump is a determination of its ultimate pressure capability This can be accomplished by attaching a gauge direct ly to the pump The gauge may be any suitable type provided consideration is given to the limitations of the gauge being used The pump must be capable of pulling a vacuum of at least 2 mmHg absolute If the pressure is unusually high the pump may be badly contaminated low on oil or malfunctioning On the other hand if the pressure is only slightly higher than the guaranteed pressure of the pump an oil change may be all that is required Oil Contamination The most common cause of a loss in efficiency in a mechanical pump is contamination of oil It is caused by condensation of water and alcohol vapors and by foreign particles The undesirable condensat
94. rd layer of mineral deposit which precipitates out of the water and forms a hard coating on the inside surfaces of the tubes This coating is often invisible but always highly resis tant to heat transfer The most common types of scale found within the tubes are calcium carbonate calcium sulphate and silica although other scales do form depending upon local water conditions Since scale is usually invisible when tubes are wet it is better to blow the water out of the tubes and allow the tubes to thoroughly dry before checking for scale After the tubes have thoroughly dried calcium scale will usually show up as a white coating inside the tube silica scale may not show up at all but the scale can usually be flaked off of the inside of the tube with a small knife JOHNSON CONTROLS The only positive method of identifying a scale is a chemical analysis although an analysis of the water used in a specific system will indicate the type of scale which may be expected to form Although other good commercial cleaning agents are available for removing a specific scale factory experience shows with commercial inhibited hydrochloric muriatic acid to be a good cleaning agent for most scales When it becomes necessary to clean condenser tubes the absorber tubes should also be cleaned If the chilled water system is kept clean during installation and is filled with clean water it should not be neces sary to clean the evaporator tubes
95. s and overloads as well as fuses and terminal lugs for ease of serviceability A transformer is included to reduce the incoming unit voltage to the required control voltage to the micro panel Pressure Drop The amount of pressure decrease experienced between two locations Often referred to when describing the drop in pressure found while passing water through the tubes in a chiller Typically measured in PSI or FtH 0 Purge Pump An external pump connected to the purge system of the unit This pump is used to evacuate non condens ables from the unit Purging A process by which non condensables present in a unit are removed through the use of a vacuum pump Refrigerant Deionized water is used as the refrigerant 72 FORM 155 21 1 510 Refrigerant Anti Freeze Line This line runs between the outlet of the refrigerant pump and the refrigerant condensate line s coming down off the condenser When the refrigerant pump is operating a constant supply of refrigerant is mixed with the refrigerant coming from the condenser to keep it from freezing during low loads and low con denser water temperatures Refrigerant Pump A hermetically sealed centrifugal pump located down stream of the evaporator outlet box This pump receives liquid refrigerant from the evaporator and discharges it back up to the evaporator sprays It con tinues to re circulate the refrigerant while the chiller is operational Rupture Disk Althoug
96. s converted back to pressure The eductor outlet will be at a pressure between the high pressure inlet and the low pressure inlet see FIGURE 16 Pressurized Solution Flow from Solution Pump Discharge Induced Flow of Saturated Water Vapor containing Non Condensables from Condenser Low Pressure Area Created Around The Jet of Solution That is Forced Through the Eductor Nozzle Eductor Outlet Should be 10 F 5 6 C Warmer than Solution Inlet When Working Properly Solution Containing Non Condensables to Gas Separator 10050900 FIGURE 16 PURGE EDUCTOR FIGURE 15 YIA PURGE TANK JOHNSON CONTROLS LD1457C4 29 Purging and Non condensables GAS SEPARATOR The gas separator is where the non condensables are removed from the solution flowing out of the purge eductor FIGURE 16 Solution mixed with non condensable gases flows into the side of the separator where it enters an annulus between the inner chamber and the outer wall of the separator The swirling and overflowing action induced by the inner chamber causes the non condensables to rise up and accumulate near the top of the separator The solution outlet pipe extends down into the inner chamber where solution with no non condensables is present The non condensables accumulating near the top of the gas separator pass upward through the non condensable outlet pipe into the purge tank Non Condensables to Purge Tank Weak
97. s for the attainment of an accurate heat balance This instru mentation is not normally available in the field However it can be obtained by special arrangements Nevertheless a measure of the trend of system perfor mance can be obtained by the systematic measure ment of data taken with instrumentation normally available in the field In all cases however any analy sis is only as good as the degree of accuracy of the data taken A steady state of operating conditions with all readings taken as simultaneously as possible assists in obtaining valid data All thermometers and pressure measuring devices should be calibrated so that readings are corrected to the true values Insulation placed around the pipe and the outside well will improve the accuracy and validity of readings With the assumption that all data taken are accurate and valid the following method of analysis for system performance is recommended Performance Data and Calculations Refer to the sample operating data sheet in FIGURE 23 This data is simulated by a computer for a YIA 6C4 unit with nominal passes The assumed operating condition is 80 of the design load rating with assumed fouling factors of 0005 001 and 0015 in the absorber and condenser but with 0005 in the evaporator tubes The effect of fouling on all readings is readily apparent This data also assumes that the 2 Ethyl 1 Hexanol additive is present in the unit at the proper concentration to pro
98. s only when DUOSEAL oil is used PURGE PUMP PIPING AND OPERATING VALVES The purge pump piping and valves illustrated in FIGURE 15 is installed at the factory and can be used for several functions During normal operation both the gas ballast and the leak rate test valve must be open at all times The Principle of Gas Ballast The Effects of Unwanted Vapor Systems which contain undesirable vapors cause difficulty from both the standpoint of attaining desirable pressures as well as contamination of the lubricating medium A vapor is defined as the gaseous form of any substance which is usually a liquid or a solid Refrigerant water and alcohol vapors are two of the most common vapors encountered in absorption chillers When such vapors exist in a system the vapors or mixtures of gas and vapor are subject to condensation within the pump This precipitated liquid may dissolve or become emul sified with the oil This emulsion is recirculated to the chambers of the pump where it is again volatized causing increased pressure within the system JOHNSON CONTROLS Bubble Test Hose Leak Rate Test Valve Open Gas Ballast Oil Drain 1006051 FIGURE 19 PURGE PUMP PIPING AND VALVES NORMAL OPERATION The Presence and Removal of Condensate Condensation takes place particularly in the compres sion stroke of the second stage of a two stage pump The compression stroke is that portion of the cycle during which
99. s pump operates above atmospheric pressure The pump is cooled by the solution it is pumping Specific Gravity S G The ratio of the mass of a liquid to the mass of an equal volume of distilled water at 39 F 3 8 Steam Valve The capacity control valve which regulates the amount of steam to the unit Steam units only Tube Sheet End Sheet The book ends of the mainshell The tube sheets are located at each of the axial ends of the unit where the tubes are rolled and waterboxes are mounted Tube Support A smaller gauge steel sheet identical in tube hole lay out to the tube sheet but used internally to provide support and rigidity for the bundle of tubes Vacuum When the pressure within a vessel is less than standard atmospheric pressure 14 7 PSIA or 0 PSIG The term vacuum usually refers to any pressure below atmospheric pressure The degree of vacuum can be expressed in many ways but most commonly as in this manual it is measured in inches of mercury or millimeters of mercury Atmosphere at 32 F mmHg Inches Hg abs PSIA 29 92 14 696 14 25 20 1005113 FIGURE 28 PRESSURE EQUIVALENTS JOHNSON CONTROLS FORM 155 21 1 510 One atmosphere is equal to 760 millimeters of mercury absolute Torr 29 92 inches of mercury absolute or 14 7 pounds per square inch absolute see FIGURE 29 When vacuum is measured relative to atmospheric pressure and toward absolute zero the negati
100. solution concentration remains constant as it passes through the solution to solution heat exchanger If it is cooled below 140 F 60 C at any point in the route crystallization will begin The cool solution leaving the absorber is the solution to solution heat exchanger s medium that cools the concentrated solution leaving the generator as it passes on the shell side of the solution to solution heat exchanger This relatively cool solu tion temperature is the determining factor of whether crystallization occurs Tower water inlet temperature will greatly affect the leaving solution temperature of the absorber If the tower water temperature is lower than design or is allowed to fluctuate in a downward trend fairly rapidly the potential exists to over cool the concentrated solution in the solution to solution heat exchanger resulting in crystallization To further compound this type of situation if the ab sorber is not performing well due to the presence of non condensables the amount of solution flowing to the generator will be less than normal since there is less refrigerant in it Since the unit is attempting to make design capacity the firing rate will be sufficient to raise the solution concentration higher than the design 5 JOHNSON CONTROLS This will result in even higher solution concentrations leaving the generator The temperature of the solution leaving the absorber will also be lower than normal due to the amount of s
101. ss absorber and a 1 Pass condenser use the ABS COND 2 1 curve 63 Preventive Maintenance Tubes FORM 155 21 1 510 THIS PAGE INTENTIONALLY LEFT BLANK 64 JOHNSON CONTROLS 155 21 1 510 SECTION 10 PREVENTATIVE MAINTENANCE TUBES CLEANING AND MAINTAINING THE TUBES WITHIN THE SHELLS Tubes The necessity for tube cleaning will be indicated by a drop in capacity or other symptoms The frequency of cleaning will vary as influenced by local water charac teristics atmosphere contamination operating condi tions etc In many major cities reliable commercial organiza tions are now available which offer a specialized ser vice of cleaning water sides of pressure vessels These organizations will analyze the type of dirt or scale to be removed and then use the proper cleaning solution for the specific job Tube fouling is commonly due to deposits of two types of elements 1 Dirt rust or sludge which is carried from some other part of the system into the tubes This mate rial does not usually build up to coat the entire tube surface but lies in the bottom of the tubes When this accumulation of sludge is great enough water flow through the tubes will be restricted and the heat transfer surface will be reduced This type of tube fouling is easily visible and can be removed by a thorough brushing with a soft bristle bronze brush as outlined under Brush Cleaning of Tubes 2 Scale is a ha
102. t is not necessary to apply any sealant to the gasket Tighten the mounting screws uniformly and refill the pump with DUOSEAL oil Follow instructions included in repair kit REPAIRING OIL LEAKS Location Cause and Effect Oil leaks may develop wherever two mating faces are sealed with a gasket Such seams may fail as the result of deterioration of the gasket material loosening of the screws caused by temperature variations or improper care as the result of previous reassembly Typical gasketed seams in a mechanical pump are located at the oil level window the shaft seal the oil drain and the mating faces of such mechanical sur faces as the intake chamber cover The importance of a gasketed seam is determined principally by its func tion If it is a vacuum seal the ultimate performance of the pump is dependent upon it If it is an oil seal the pump may be operated satisfactorily for some time 36 FORM 155 21 1 510 without loss of function Eventually of course a great loss of oil may cause harmful damage Repairing Technique An oil seam may be sealed by any of several methods When an O ring is employed the surfaces of the O ring and its groove should be wiped clean If the O ring is not badly deformed or scratched it may be reused by sealing with a slight film of vacuum oil or vacuum grease Thin composition gaskets are gener ally used for large irregularly shaped areas A replace ment joint of this type shou
103. t pipe 1 then the solution is return ing by means of the automatic decrystallization pipe If it is cold to the touch corresponding to normal tempera ture of dilute solution or slightly above then there is no return flow through the automatic decrystallization pipe Combination of Basic ADC Piping Circuit and ADC Control Feature see FIGURE 13 As hot concentrated solution backs up and overflows into the emergency solution return line 9 the tempera ture of the pipe increases and the ADC sensor item 18 attached to the pipe senses this temperature At a tem perature of approximately 160 F the ADC sensor 18 starts a control panel timer which signals the capacity control valve 23 to close to 50 for a minimum of 10 minutes During the first 2 minutes 2SOL 16 is ener gized to permit refrigerant to be pumped into the return pipe 1 via connection 15 The cycle will be repeated every 10 minutes until line 8 cools to approximately 150 F or lower At this point crystallization has been nor mal circulation of solution from the generator will pro ceed It must be noted that the ADC operation will continue for at least 10 minutes regardless of a shutdown or subse quent restart 2SOL Refrigerant Valve Blowdown Manual operation of the refrigerant valve 2SOL may be selected by using the manual pump key on the System Screen when in service access level When this valve is energized refrigerant will flow through
104. the line into the shell side of the heat exchanger and ultimately into the absorber shell thus transferring refrigerant back into the solution side of the system 23 Absorption System Operation ITEM NO 24 OMAN OA 8 ON gt LEGEND TO FIGURE 13 DESCRIPTION SOLUTION RETURN PIPE SOLUTION HEAT EXCHANGER EDUCTOR SUCTION EDUCTOR SOLUTION PUMP SUCTION SOLUTION PUMP DISCHARGE GENERATOR SUPPLY LINE A D C PIPE OVERFLOW CONNECTION A D C PIPE A D C PIPE TRAPPED SECTION A D C PIPE RISER SECTION A D C OVERFLOW JACKET ITEM NO 13 14 15 16 17 18 19 FORM 155 21 1 510 DESCRIPTION A D C OVERFLOW DUMP LINE A D C FLUSH LINE REFRIGERANT VALVE CONNECTION REFRIGERANT VALVE 2SOL SOLUTION LEVEL IN GENERATOR A D C THERMOSTAT RT2 CAPACITY CONTROL VALVE START OF OPEN SEWER FLOW TOP OF SOLID LIQUID LEVEL A D C SOLUTION OVERFLOW POINT JOHNSON CONTROLS 155 21 1 510 DILUTE SOLUTION BR INTERMEDIATE SOLUTION U REFRIGERANT 2 STEAM WATER KN amm nguo CONTROL VALVE CONDENSER GENERATOR WATER 4 STEAM 5 231 7 O
105. the temperature difference increases 4 F 14 FORM 155 21 OM1 510 Control Valve not shown This valve is used to control the amount of heat energy steam or hot water that enters the generator section of the unit It receives a control signal from the Control Panel to open or close to control the Leaving Chilled Water Temperature LCHLT to the Leaving Chilled Water Temperature Setpoint If the heat source is steam the maximum inlet temperature is 337 F 169 C If the heat source is hot water the maximum inlet temperature is 266 F 130 C JOHNSON CONTROLS 155 21 1 510 0067011 4 HOLIMS JANVd TOULNOO HOLIMS 100109 131100 YOlWYWdaS lt 519 1 915 NOILVZITIVLSANOSG INVYS9 110 NOILN10S OLNV 1 YOLVYANAD NOILN10S a 1 YOLVYANAD HOLIMS ASIA LLH 1 YOLVYANSS dWAL HOIH 1 201 LNANOdWOD FIGURE 3 MODEL YIAABSORPTION UNIT FRONT VIEW 15 JOHNSON CONTROLS Absorption System Operation FORM 155 21 OM1 510 8501 7501
106. the unit has been shut down to allow the concentrated solution to become more dilute Essentially the cycle continues without the addition of heat thus slowly diluting the solution to concentration levels where it is more dif ficult to crystallize Note The dilution cycle is dependent upon many factors Please see the micropanel instructions for details Eductor An eductor is a liquid powered jet pump Jet pumps have no moving parts and use a high pressure stream of liquid to pass through a nozzle causing a portion of of a low pressure stream coming into the side of the pump to combine with the nozzle stream This causes a reduction in pressure at the low pressure inlet and induces the rest of the low pressure inlet substance to flow into the body of the pump On IsoFlow units an eductor is used in place of a centrifugal pump to induce strong concentrated solu tion exiting the generator outlet box to combine with weak concentrated solution exiting the solution pump discharge before going to the absorber spray header Evaporator The section of a chiller that is responsible for remov ing the heat from the chilled water circuit thus cool ing the chilled water used to cool a building a manu facturing process or whatever application it is intend ed Typically the chilled water is cooled from 54 F to 44 F 12 C to 6 6 C In an absorption chiller the 70 FORM 155 21 1 510 pure refrigerant generated in the ge
107. then heats up the crystallized heat exchanger from the opposite side of the tubes and causes the crystallized lithium bromide to dissolve back into solution JOHNSON CONTROLS Blowdown While running the unit refrigerant is intentionally dumped into the absorber shell section by opening 2SOL stabilizer solenoid valve A refrigerant blow down will further dilute the solution in the absorber shell A blowdown is required before taking a solution sample for analysis to separate the alcohol from the refrigerant and to hasten the refrigerant clean up procedure C O P Coefficient of performance A means of comparing the performance of a chiller as the ratio of the cooling output divided by the heat input Concentration The percent by weight of lithium bromide present in solution New solution is sent with a concentration of 53 if the inhibitor is ADVAGuard 750 55 if the inhibitor is molybdate 54 if Chromate 53 if Nitrate Condensate Condensed steam leaving the unit Condenser Vapor produced by the generator enters the condenser and is cooled and condensed back into a liquid by the tower water flowing through the inside of the con denser tubes The condensed vapor liquid drips down into a collection pan located at the bottom of the con denser From there it flows out of the pan through an orifice and into the evaporator Condenser Tower Water The external water loop which is used to remove heat from the unit Th
108. tic position If manual operation is required for spe cial considerations refer to the NOTE under General 50 Q lt 10 or 5 D or 1 40 60 80 100 120 PLANT ROOM TEMPERATURE F 1006021 FIGURE 22 ACCEPTABLE INTERNAL UNIT PRESSURES 43 Unit Operating Procedures OPERATING DATA General A complete set of data on operating temperatures and pressures should be recorded for the unit regularly The purpose is to permit early recognition of an abnor mal condition or trend that requires corrective mainte nance before serious damage occurs to the unit Daily observation of the unit is useful to disclose any sudden changes Record these changes on FORM 155 16 F2 All measurements that are recorded should be taken as simultaneously as possible with a steady load and a steady cooling tower water temperature near the design conditions A progressive gradual deterioration in unit performance is an indication that scaling is occurring that there is a gradual buildup of inerts or that there is a malfunction of controls It is mandatory that all performance analyses be based on date and taken on units that are free of leaks Otherwise the lithium bromide concentrations and the steam pres sure and steam flow requirements for a given load as well as a complete set of operating temperatures will be abnormal A thorough check of system
109. ting tower water temperatures 50 FORM 155 21 1 510 Non condensables in the Absorber Non condensables in the absorber result in less refriger ant being absorbed by the solution The solution never gets as diluted as it should It leaves the absorber and is heated in the generator If the unit s heat input is at or near full load the leaving solution concentration may exceed the level at which it can remain liquid when pass ing through the solution to solution heat exchanger For example the normal concentration of solution leaving the absorber at full load is between 58 and 59 3 If there are non condensables present in the absorber the solution concentration may exceed 61 Since the unit is attempting to operate at full load the firing rate will be sufficient to raise the solution concentration in the generator by at least the same amount as when the absorber solution was normal which was approximately 5 Raising the solution concentration by 5 would result in 66 solution leaving the generator Referring to the PTX chart in FIGURE 24 it can be seen that the crystallization temperature for 66 solution is approximately 140 F 60 C Since the generator tem perature is higher than 140 F 60 C the solution will be okay while it is still in the generator The problem occurs when this over concentrated solution passes through the solution to solution heat exchanger on its way back to the absorber sprays This
110. transducers Instrumentation Accuracy check of Condenser Pressure Gauge if applicable Inspection pump bearing and seal wear Rebuild as required Inspection of pump contac Solution and tors and overloads Refrigerant Pumps Check operating amperage of pumps Check electrical connec tions to pumps Check performance of pumps pressures etc T YORK Johnson Controls Qualified Service Technician O Operator JOHNSON CONTROLS 67 Preventive Maintenance Tubes FORM 155 21 1 510 PREVENTATIVE MAINTENANCE SCHEDULE CONT D Maintenance Interval Months unless otherwise indicated Preventative Maintenance Component Operation Solution Refrigerant Pumps Inspection of belt replace or tighten as needed Check operating amperage of pump Check electrical connec tions to pump Purge Pump Inspection of pump contac tor and overload Change oil Determine ultimate vacuum of pump Build or replace pump Rebuild Purge Diaphragm Purge Valves System Accuracy check of Vacuum Gauge Clean tubes in absorber condenser evaporator and Tube Bundles hot water heat exchanger where applicable Eddy current Inspection for wear of steam valve Rebuild or replace as needed Check for proper steam Steam valve Steam fired modulation Units Only Inpect steam system piping and components for leaks Inspect for design steam entering conditions NOTES 1
111. ubcooling that will be present as result of the lack of mass transfer taking place This will result in a greater potential for over cooling the concentrated solution in the solution to solution heat exchanger Fluctuating Tower Water Temperature Rapidly fluctuating tower water temperature can also cause crystallization The reasons are essentially the same as described in the previous example Rapidly falling tower water temperature will cause the leaving solution temperature from the absorber to drop quickly This cool solution may over cool the concentrated solu tion leaving the generator as it passes on the shell side of the solution to solution heat exchanger This can happen at normal generator solution concentrations although the problem would be compounded if there were already abnormally high solution concentrations in the generator Unit Features That Help Prevent Crystallization During operation the chiller has some inherent fea tures that will help prevent crystallization from occur ring They are as follows 1 When the refrigerant charge is adjusted properly at full load conditions the level of refrigerant in the evaporator pan will be near the top of the pan but not spilling over If the absorber section begins to malfunction due to a loss of mass transfer rate of refrigerant being absorbed into the solution either by tube fouling or presence of non condensables the concentration will increase i e less refrigera
112. usly remove non condensables from the absorber section of a unit and store them in an area called a purge tank Here they can be manually or automatically evacu ated by the unit purge pump The transport of the non condensables to the purge tank is a continuous process accomplished without the use of any moving parts The purge tank must be evacuated by the unit purge pump This can be done either manually or automati cally depending if the unit is equipped with Smart Purge or not SmartPurge monitors the purge tank pressure and evacuates the purge tank when the tank pressure reaches 80 mm Hg absolute The automatic purge system stops evacuating the purge tank when its pressure is reduced to 30 mm Hg PURGE COMPONENTS Several devices combine to provide the functional purge system Many of the components can be found on the purge tree The purge tree is a series of piping and valves connected together and located on the control panel side of the unit see FIGURE 14 The valves are manifolded together for convenience so that nearly all purge opera tions can be performed from one location 27 Purging and Non condensables PURGE PUMP Each unit is equipped with a purge pump which is essen tially a vacuum pump specially modified to work well in lithium bromide service YIA units have a 5 6 cfm belt driven two stage rotary vane type vacuum pump The purge pump exhausts the unit non condensables Do not operate the pur
113. valve in the open position except when performing a leak test See the Pumps section of this manual for further purge pump maintenance information PURGE TANK The purge tank is a long round tank located on the up per shell The purge tank is essentially a storage container where non condensables are kept until they can be pumped out of the unit by the purge pump The stored non con densables are pumped into the purge tank by the purge eductor system Non condensables stored in the purge tank do not affect the unit performance The purge tank is kept separate from the rest of the unit by a liquid U trap seal Due to the liquid seal height the purge tank can safely hold at least 100 mm Hg absolute of pressure without fear of the non condensables venting into the absorber PT4 VP2 FORM 155 21 OM1 510 PURGE EDUCTOR The purge eductor FIGURE 16 is a liquid powered jet pump ejector Jet pumps have no moving parts and use a high pressure stream of liquid solution from the solution pump discharge line passing through a nozzle to cause a portion of a low pressure stream condenser refrigerant vapor and non condensables coming into the side of the pump to combine with the nozzle stream This causes a reduction in pressure at the low pressure inlet and induces the rest of the low pressure inlet substance to flow into the body of the pump In the diffuser section of the pump some of the velocity of the combined liquid flow i
114. ve sign is used to indicate that it is a negative gauge pres sure value When vacuum is considered in the other direction i e from absolute zero the term absolute or abs is used see FIGURE 29 From FIGURE 28 we can see that a pressure reading of 300 Torr is the same as 11 8 in Hg abs and 5 8 PSI abs Water Box A structure designed to contain the water both entering and exiting the unit by using nozzles to restrict the water into a contained area The nozzle directs the water into the waterbox where pressure builds up forcing the water through the tubes As the water exits the tubes on the opposite end it is restricted by the waterbox on the other side of the tube bundle Again pressure builds up and the water is either forced by a pass baffle back through another section of the tube bundle or directly out of the outlet nozzle YIA YORK IsoFlow Chiller ABSOLUTE UNITS GAUGE UNITS Measured From Absolute Zero Measured From Atmospheric Pressure PSIA PSIG TORR Hg 147 mm Abs 0 _ inHg ATMOSPHERIC PRESSURE 760 29 92 0 PSIG 14 7 PSIA INCREASING VACUUM DECREASING VACUUM 0 0 0 Absolute Zero Pressure Perfect Vacuum 1005114 FIGURE 29 VACUUM UNITS OF MEASUREMENT 73 14 5 155 21 1 510 JOHNSON CONTROLS 155 21 1 510 5 JOHNSON CONTROLS 75 ul YORK BY JOHNSON CONTROLS P O Box 1592 Y
115. y the palm of your hand Look for water coming out of the drain hose Turn off the pump 35 Purge Pump Operation 5 Repeat step 4 until only clean oil comes out of the drain hose 6 Fill the pump through the exhaust port with 2 25 quarts of DUOSEAL vacuum pump oil 7 Plug the intake IN port with a rubber stopper Turn the pump on and run the pump for 10 min utes Close the gas ballast valve Refilling the Pump Refill the pump by pouring new DUOSEAL oil into the exhaust port Fill to the indicated level and start the pump with the intake closed A gurgling noise is normal when high pressure air is drawn through the pump It should disappear quickly as the pressure within the pump is reduced If gurgling continues with gas ballast closed add sufficient additional oil through the exhaust port until gurgling ceases SHAFT SEAL REPLACEMENT To replace the shaft seal of a pump drain the oil and remove the pump pulley and key Remove the screws securing the old seal and pry it loose with a screw driver or similar wedge being careful not to mar the surface of the pump body against which the seal fits Discard the seal and its gasket inspect all surfaces and repair any damages with a fine abrasive stone Wipe all sealing areas clean and place a film of DUOSEAL oil on both the shaft and the inside bore of the new shaft seal Using a new gasket carefully slide the new seal into position and center it on the shaft I
116. ystem will deteriorate the refrigeration capability of the unit as the absolute pressure in the unit rises and corrosion problems could develop The purge system provides a means for ridding the unit of any such accumulation of non condensables The system consists of a purge header arrangement in the bottom absorber section a purge eductor gas separator purge storage tank associated piping connections wir ing solenoid valves transducers and purge pump The control logic provides for automatic and continuous purging of non condensables from the unit The logic will monitor track and display non condensables purg ing trends The system allows for manually purging of non condensables directly from the unit or the purge tank JOHNSON CONTROLS FORM 155 21 1 510 Controls and Wiring An electronic control system is provided with each absorption unit to permit automatic or manual control of the system Provisions are made for the following 1 Automatic capacity control involving electronic controls for steam or hot water valves 2 Safety controls involving flow switches float switches low refrigerant temperature cut out motor overloads and protective thermostats 3 Special control features to provide for steam econ omy and for prevention of crystallization 4 Functional controls which permit operation over a wide range of condenser water temperatures COMPONENTS IN THE CONTROL CENTER See IsoFlow Control Panel

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