Marley Class 600 Cooling Tower User Manual
Contents
1. Marley Class 600 Cooling Tower User Manual 92 1317C aM Marley Tower Schematic AIR FLOW FAN FLOW CONTROL VALVE FLOW CONTROL VALVE DISTRIBUTION BASIN WATER INLET FILL AIR s 2 AIR FLOW FLOW DRIFT ELIMINATORS COLLECTION BASIN A Warning A Caution Note Contents Ge efaksudsezawaaaudewiaRa kawaii aaa A ai R ARR SAY EA 4 Bei re Stam Up wats tistics eda eters ida iii aid 4 Initial Starting Procedure 2 uuu 5 Routine Starting Procedure sss ana ata AAAA 6 paral gissen Danon nih iin Rania antes 6 Temperature Control and Energy Management sssssssessessrrsrssnrrirenssnrrrrensnrrrnrses 9 Mal tenahCe e sai a a tear a WE 10 CS AMIN g zus ERA z i ZE sc Rt A i nA Ed 12 Water Ireatme teuianececiwiwiaakat okna i RA ada EB AKP A 13 Seasonal Shutdown Instructions 2 uu esse ssania 17 Spare Pae eonan Z ats AAA aE AEAEE E AAA 18 PACCOSSOMMOS siasio aw A a wa aw A 18 Inspection and Maintenance Schedule susaea seen 19 Troublesho otiin Qe mezi akon dE SEN A AE wik WWE 20 Safo awa da ada aa e w zd sda Aa 21 Inspection Checklist e sieszie e za Z scenes Wa A RAZ AUE a 22 The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or to important information concerning the life of the product Indicates presence of a hazard which can cause severe personal injury death or2. 14 by the appropriate use of blowdown chemical treatment filtration cleaning etc Slime a gelatinous bacteria growth and algae a green or brown plant growth may grow in the cooling tower or heat exchangers Their presence can inter fere with cooling efficiencies Proprietary compounds are available from water treating companies for the control of slime and or algae however compounds which contain copper are not recommended The Langelier index calcium carbonate saturation index has proven to be an effective tool in predicting the aggressiveness of cooling tower water toward concrete The Langelier index relates the methyl orange alkalinity the calcium hardness the total solids the pH value and the temperature of the water From these values it is possible to calculate the index and predict the corrosive tendencies of the tower water toward concrete Maintaining a slightly positive Langelier index 0 0 1 0 provides excellent protection of concrete Data For Rapid Calculation of Saturation Index Saturation Index pH actual 9 3 A B C D A B c D Total Value Water Value Calcium Value M O Value Solids to Temp to Hardness to Alkalinity to ppm Apply CF Apply ppm Apply ppm Apply 50 300 0 1 32 34 2 6 10 11 0 6 10 11 1 0 400 1000 0 2 36 42 2 5 12 13 0 7 Dias 1 1 44 48 2 4 14 17 0 8 14 17 1 2 50 56 23 18 22 0 9 18 22 1 3 58 62 2 2 23 27 1 0 23 27 1 4 64 70 251 28
3. allowed to slow to low speed rpm or less before the low speed winding is energized When changing the direction of fan rotation allow a minimum of two minutes time delay before energizing the fan motor HOT WATER DISTRIBUTION SYSTEM Hot water from the process flows into open distribution basins situated above the banks of fill in each cell Meter ing orifices in the floor of these basins distribute water evenly over the fill If an Amertap condenser tube cleaning system is part of plant equipment care should be taken during operation to back wash the strainer section only after the sponge rubber cleaning balls are re moved from the system by trapping them in the collector If the balls are allowed to enter the cooling tower supply piping they can clog the plastic metering orifices Clogged orifices will cause unequal water distribution over the fill which will affect thermal performance Extensive clogging can leadto overflowing of the distribution basins and possible ice damage to towers installed in freezing climates The basins should be frequently checked for orifice clogging until such time as the operational sequence of the Amertap system as sures that no balls enter the cooling tower piping FILL Water leaving the distribution basin orifices is distributed uniformly over the fill plan area The water cascades downward through the fill maximizing water surface exposure to the air being moved by the fans mia DRIFT ELIMINATORS A
4. as variable frequency drives page 10 and other retrofittable control devices Please discuss your needs with your Marley representative Inspection and Maintenance Schedule General Recommendations More frequent inspection and mainte nance may be desirable Fan Motor Drive Shaft and Guards Geareducer Cold Water Basin Float Valve Control Valves Structural Members Casing and Louvers Fan Cylinder Stairs Ladders Walkway Doors Handrails Davits Derricks Hoists Inspect for clogging Check for unusual noise or vibration Inspect keys keyways and set screws 1 2 3 4 Make sure vents are open 5 Lubricate grease 6 Check oil seals 7 Check operating oil level 8 Check static oil level 9 Check oil for water and sludge 10 Change oil 11 Check fan blade tip clearance 12 Check water level 13 Check for leakage 14 Inspect general condition 15 Tighten loose bolts 16 Clean 17 Repaint 18 Rebalance 19 Completely open and close 20 Inspect repair for safe use 21 Inspect and repair before each use Drift Eliminators Fill Hot Water Basin Suction Screen U n wn niz u lt n wn D DINJI olololol s D DI Dln D DI Dll D daily W weekly M monthly Q quarterly S semi annually Y yearl
5. discolored water can result in staining of adjacent structures if foam is picked up by air being pulled through the tower and discharged out the fan cylinders Avoid operation of fans until the foaming is controlled AA Warning A Caution Seasonal Shutdown Instructions TOWER Drain all tower piping During shutdown clean the tower and make any necessary repairs Apply protective coating as required to all metal parts Particular attention should be given to mechanical equipment supports drive shaft and drive shaft guards Visually inspect for concrete deterioration See Warning note on page 12 regarding tower cleaning MECHANICAL EQUIPMENT Shutdown for less than 3 months Each month drain water condensate from the lowest point of the Geareducer and its oil system Check oil level and add oil if necessary Operate Geareducer to recoat all interior surfaces with oil Before start up drain water condensate and check oil level Add oil if necessary Refer to Geareducer Service Manual for maintenance and lubrication instructions Shutdown for 3 months or longer If the motors have space heaters operate mechanical equipment one hour each month Space heaters should be energized anytime motor is not operat ing If the motors do not have space heaters operate mechanical equipment one hour each week At start up operate mechanical equipment one hour or until oil is warm then shut the equipment down Drain the oil and refill wit
6. substantial property damage if ignored Indicates presence of a hazard which will or can cause personal injury or property damage if ignored Indicates special instructions on installation operation or main tenance which are important but not related to personal injury hazards A Caution General A cooling tower like any heat exchanger exchanges all heat imposed upon it from one fluid to another fluid For a cooling tower heat from the water is put into the air The plant process replenishes the heat to the water typically at another heat exchanger such as a condenser A cooling tower differs from many heat exchangers in that heat is transferred in two forms sensible and latent heat As heat is transferred from the water the air temperature increases sensible and the air s water content or humidity also increases latent As the heat load inlet air wet bulb temperature or airflow on a cooling tower changes the cooling tower will respond by finding a new equilibrium with the process The cooling tower will still dissipate all the heat from the process but at new water temperatures The cooling tower cold water temperature is the supply water temperature to the condenser and changes in the cold water temperature usually affect efficiency of the plant output Although the reduced cold water temperatures that result from maximum fan power utilization are usually beneficial to plant output the amount of fan power affects t
7. 34 dled 28 34 1 5 72 80 2 0 35 43 12 35 43 1 6 82 88 1 9 44 55 IES 44 55 eZ 90 98 1 8 56 69 1 4 56 69 1 8 100 110 Vet 70 87 12s 70 87 1 9 112 122 1 6 88 110 1 6 88 110 2 0 124 132 15 111 138 ls 111 138 25 134 146 1 4 139 174 1 8 139 174 2 2 148 160 le 175 220 1 9 175 220 2 3 162 178 12 230 270 2 0 230 270 2 4 280 340 2N 280 340 215 350 430 2 2 350 430 2 6 440 550 2 3 440 550 OMT 560 690 2 4 560 690 2 8 700 870 235 700 870 2 9 880 1000 2 6 880 1000 3 0 Based on Langelier formulas Larson Buswell residue temperature adjustments and arranged by Eskel Nordell mi 15 16 FOAMING Heavy foaming sometimes occurs when a new tower is put into operation This type of foaming generally subsides after a relatively short pe riod of operation Persistent foaming can be caused by the concentrations of certain combinations of dissolved solids or by contamination of the circulating water with foam causing compounds This type of foaming can sometimes be minimized by increasing the blowdown but in some cases foam depressant chemicals must be added to the system Foam depressants are available from a number of chemical companies WATER DISCOLORATION Woods contain some water soluble substances and these commonly discolor the circulating water on a new tower This dis coloration is not harmful to any of the components in the system and can be ignored However a combination of foaming and
8. Hz Volts F L Amps Frame SF Special Info Last Lubrication Date Grease Used Type Any Unusual Noise No Yes Action Required Any Unusual Vibration No Yes Action Required Any Unusual Heat Build up No Yes Action Required 23 SPX COOLING TECHNOLOGIES 7401 WEST 129 STREET OVERLAND PARK KANSAS 66213 UNITED STATES 913 664 7400 spxcooling ct spx com spxcooling com In the interest of technological progress all products are subject to design and or material change without notice 2009 SPX Cooling Technologies Inc Printed in USA Manual 92 1317C
9. adder Material Handrails Material Interior Walkway Material Cold Water Basin Material Water Distribution System Distribution Basin Material Inlet Pipe Material Inlet Manifold Material Flow Control Valves Size Nozzles Orifice Diameter Heat Transfer System Fill Drift Eliminators Louvers Use this space to list specific items needing attention 22 Inspection Checklist Condition 1 Good 2 Keep an eye onit 3 Needs immediate attention Mechanical Equipment 1 2 3 Comments Gear Drive Units Manufacturer Model Ratio Oil Level Full Add Immediately Low check again soon Oil Condition Good Contains Water Contains Metal Contains Sludge Oil Used Type Seals Backlash Fan Shaft Endplay Any Unusual Noises No Yes Action Required Drive Shafts Manufacturer Material Fans Manufacturer Fixed Pitch Adjustable Pitch Diameter Number of Blades Blade Material Hub Material Hub Cover Material Blade Assembly Hardware LUPA Tip Clearance min max Vibration Level Fan Cylinder Height Mech Eqpt Support Mat l Oil Fill and Drain Lines Oil Level Sight Glass Vibration Limit Switches Makeup Valves Other Components Motor Manufacturer Name Plate Data hp RPM Phase
10. d tighten if necessary Safety The tower has been designed to provide a safe working environment while either operating or shut down The ultimate responsibility for safety rests with the Operator and Owner When flow to the tower is shut off or when portions of the tower require maintenance temporary safety barricades may be required around openings Other safety precautions such as safety harnesses should be utilized where appropriate for compliance with OSHA regulations and standards and good safety practices See Warning page 12 Routine periodic maintenance must be performed on all personnel access and material handling accessories in ac cordance with the following schedule Ladders Stairways Walkways Handrails Covers Decks and Access Doors Davits Derricks and Hoists Inspect for General Condition Semi annually Semi annually Repair for Safe Use As Required As Required 21 Inspection Checklist Date Inspected Owner Owner s Tower Designation Inspected By Tower Manufacturer Process Served by Tower Design Conditions GPM Number of Fan Cells Condition 1 Good Structure Casing Material Structural Material Fan Deck Material Location Model No Serial No Operation Continuous Intermittent Seasonal F CW F WB F 2 Keep an eye on it 3 Needs immediate attention 12 3 Comments Stairway Material L
11. e fan Motor Runs Hot Wrong voltage or unbalanced voltage Check voltage and current of all three lines against nameplate values Overload Check fan blade pitch See Fan User Manual Check for drag in fan drive train as from damaged bearings Wrong motor RPM Check nameplate against power supply Check RPM of motor and gear ratio Bearings overgreased Remove grease reliefs Run motor up to speed to purge excessive grease Rotor rubs stator bore If not poor machining replace worn bearing Wrong lubricant in bearings Change to proper lubricant See motor manufacturer s instructions One phase open Stop motor and attempt to start it Motor will not start if single phased Check wiring controls and motor Poor ventilation Clean motor and check ventilation openings Allow ample ventilation around motor Winding fault Check with Ohmmeter Bent motor shaft Straighten or replace shaft Insufficient grease Remove plugs and regrease bearings Deterioration of grease or foreign Flush bearings and relubricate material in grease Bearings damaged Replace bearings Motor Does Not Come Up Incorrect fan blade pitch See Fan User Manual for blade pitching instructions because of line drop transformer terminals or reduce loads Increase wire size or reduce inertia Broken Rotor bars Look for cracks near the rings A new rotor may be required Have motor service person check motor 20 Troubleshooting Trouble Cause Remedy Wrong Rotation Mot
12. er without a heat load See caution page 6 Initial Starting Procedure 1 Fill the cold water basin and circulating water system to a level 1 2 13 mm below the overflow 2 Completely open all hot water flow control valves 3 Prime and start the circulating water pumps one at a time Increase the flow of circulating water gradually to design water rate to avoid surges or water hammer which could damage the distribution piping 4 When flow has stabilized at or near the design rate adjust water makeup to maintain the level that the water has pumped down to in the cold water basin See Cold Water Collecting Basin on page 8 This should coincide reasonably with the recommended operating water level indicated on the Marley project drawings 5 Adjust flow control valves to equalize the hot water depth in the distribu tion basins Adjust deepest water level basins first Lock valves in desired position with valve locking bar 6 Start the fan After 30 minutes operating time to permit Geareducer oil to come up to operating temperature check motor load with watt meter or take operating volt and ampere readings and calculate motor HP Refer to Marley Fan User Manual for instructions If it is necessary to pitch fans to pull correct contract horsepower measure results when circulating design water rate at design hot water temperature HP will change with air density LOCK OUT ALL ELECTRICAL SERVICE BEFORE ENTERING FAN AREA A Caution Rou
13. ety items items 19 and 20 in Table on page 19 Maintaining a record of this is especially important For a supply of check list forms contact your Marley sales representative HOT WATER DISTRIBUTION BASINS Metering orifices in the floor of the hot water basins may be cleaned without shutting down any part of the tower Remove dirt algae leaves etc which might get in these basins or orifices The metering orifices must be kept in place to assure proper water distribution Completely open and close flow control valves at least semi annually to remove any scale on the threads Before operating valve measure distance from valve stem guide to operating handle to assist in resetting the valve to the original operating position Grease the stainless steel stem to prevent scale forming Lubricate the valves at least semiannually with a lithium base NLGI No 2 consistency grease More frequent relubrication of valves and valve stems may be dictated by circulating water conditions COLD WATER COLLECTING BASIN Inspect collecting basin occasion ally for cracks leaks and spalling and repair if necessary Maintain a positive Langelier index in your circulating water See Water Treatment page 15 Minor leaks may appear in wood basins when starting with a dry basin but these generally disappear after the wood becomes soaked Keep cold water outlets clean and free of debris Makeup and circulating water controls must operate freely and maintain the des
14. h new oil Refer to Geareducer User Manual for instruction on changing oil Refer to Marley Downtime Instruction Manual for downtime of 6 months or longer Electric Motors Do not start motor without determining that there will be no inter ference with free rotation of the fan drive Refer to Marley Electric Motor Service Manual If shutdown period is longer than seasonal contact your Marley sales repre sentative for additional information 17 18 Spare Parts SPX manufactures and maintains a stock of common replacement parts for all cooling tower mechanical equipment Shipment of these parts are normally made within ten days after an order is received If emergency service is neces sary contact the local Marley sales representative for assistance To prevent prolonged shutdown periods in case of damage to the mechanical equipment it is suggested that the following parts be carried in the owner s stock One fan assembly One Geareducer assembly One driveshaft assembly e One motor Be sure to furnish the tower serial number when ordering parts Accessories Marley accessories are designed for improved maintenance access safety component handling and the general customizing of the tower to suit your process These accessories include stairways walkways externaland internal mechanical equipment removal systems derricks davits hot water basin covers for algae suppression motor control centers as well
15. he cost of running the cooling tower As these variables interact on a cooling tower the operator must find the proper trade off between these opposing forces These instructions will assist in obtaining efficient long life from Marley cooling equipment Direct questions concerning tower operation and maintenance to your Marley sales representative Always include your tower serial number when writing for information or ordering parts Look for this number on the nameplate on the tower endwall access door Before Start up SAFETY Temporary safety barricades should be placed around any exposed openings in the operating or non operating tower safety harnesses should be worn by personnel where appropriate and other safety precautions should be taken in compliance with OSHA regulations and standards CLEANING Remove any dirt and trash which has accumulated in the hot water distribution basins Clean any nozzles that are clogged Remove any sediment from the cold water basin sump and screens Use a water hose to flush cold water basins If you are restarting or recommissioning a previously used tower see Warning note on page 12 Note A Caution OPERATE WATER SYSTEM Complete steps 1 thru 4 under Initial Start ing Procedure below Circulate water over the tower continuously for several days before starting the mechanical equipment and putting the tower into continuous operation Do not circulate water over the tower in freezing weath
16. he surface soft and weak and in its more advanced stages the decayed wood can be easily removed This type of rot occurs primarily in the flooded areas of the tower Internal rot as the name implies occurs inside the wood members For this reason it is more difficult to detect than is soft rot Internal rot is most commonly found in the heavier members in the plenum areas of the tower One of the best methods of inspection for internal rotis sounding with hammer blows Members which have internal rot sound dead while non rotted members have a ring or live sound Areas which sound dead can be probed with a screwdriver or other pointed tool to verify the presence of internal rot The strength of a member with soft rot is not seriously affected However if internal rot is discovered the infected members should be replaced SPX has personnel on its staff experienced in all aspects of wood deterioration and preservative treatment In addition several Marley publications are avail able which give detailed information on the subject of wood deterioration and treatment Contact the nearest Marley sales representative for more information about wood inspection services and for copies of the publications Cooling Tower Cleaning Any evaporative type cooling tower must be thoroughly cleaned on a regular basis to minimize the growth of bacteria including Legionella Pneumophilla to avoid the risk of sickness or death Ser
17. ir leaving the fill passes through a bank of drift eliminators blanketing the entire height of the fill The purpose of these drift eliminators is to minimize the amount of water that is caused to exit the tower by the velocity of the moving airstream COLD WATER COLLECTING BASIN Water leaving the fill falls into the cold water basin that forms the base of the tower The normal water depth in a wood basin is 5 to 8 inches 127 to 203 mm while in a concrete basin the normal water level is 9 to 15 inches 229 to 381 mm below the curb Adjust the make up water supply to maintain this water level Maintain sufficient water depth to prevent cavitation WINTER OPERATION During periods of low temperature operation 35 to 40 F 2 to 4 C or below ice will form on the relatively dry parts of the tower that are in contact with the incoming air Primarily this includes the louvers and adjacent structural framing Ice forming characteristics on any given tower will vary depending on veloc ity and direction of wind circulating water rate and heat load Excessive ice formation may be controlled by regulating air and water flow through the tower by one or more of the following procedures 1 Shut the fan down This reduces the cooling rate to a minimum and in creases the quantity of warm water on the louvers to a maximum Except for extreme cold conditions or extended freezing conditions this procedure will normally control ice formation For au
18. ired water quantity in the system TOWER FRAMEWORK keep framework bolts tight Pay particular atten tion to bolts in the mechanical equipment supports Do not pull washers into the wood DRIVE SHAFT Check drive shaft alignment and condition of couplings every six months See the Drive Shaft Service Manual for correcting misalign ment balancing or replacing parts ELECTRIC MOTOR Lubricate and maintain each electric motor in accordance with the manufacturer s instructions If repair work is necessary contact the nearest representative of the motor manufacturer See Warranty Section of Marley Service Manual on Electric Motors FAN Inspect fan blade surfaces every six months For detailed maintenance information refer to Marley Fan Service Manual GEAREDUCER Make weekly and monthly oil checks Refer to the Geare ducer User Manual for detailed maintenance instructions PAINTING Periodically clean and if necessary recoat any chipped or dam aged paint to prevent corrosion mi 11 A Warning 12 COOLING TOWER WOOD DETERIORATION Cooling tower wood is pressure treated to help prevent decay However after several years of service some members may develop decay Routine inspections should be made to assure that decay is discovered before it is heavily advanced Decay is commonly of two very general types soft rot and internal rot Soft rot is easier to detect because it is almost always on the surface of wood members It makes t
19. of ice damaging the fan blades or cylinder Ice can also accumulate on fan blades and be thrown off damaging fan cylinder or blades Reverse opera tion of fans with adjacent fans not operating increases probability of icing The low discharge velocity of moist air from fan cylinders in which fans are not in operation can result in moisture laden air being pulled into the adjacent cylinder in which the fan is operating in reverse increasing this ice buildup Therefore fans each side of the one operating in reverse must be operated in forward rotation at full or half speed or all fans must be operated in reverse Allow at least a 10 minute delay between reverse operation and forward operation during subfreezing weather to permit ice to dissipate from fan blades and fan cylinders See Fan Drive Caution note on page 7 for fan speed change and reversing precautions Temperature Control and Energy Management The wet bulb temperature of the ambient air varies significantly on a daily basis and considerably from season to season As the wet bulb temperature reduces the tower becomes capable of producing colder and colder water or it becomes capable of producing a given cold water temperature at reduced airflow through the tower These characteristics are the opposing forces referred to under General on page 4 MAXIMIZING TOWER PERFORMANCE If your process is one which benefits from the coldest possible water that is if colder water allo
20. ooling of water The capacity of a tower to cool water to a given cold water temperature varies with the wet bulb temperature and the heat load on the tower As the wet bulb temperature drops the cold water temperature also drops However the cold water temperature does not drop as much as the wet bulb temperature Wet bulb temperature is the temperature indicated by the wet bulb thermometer of a psychrometer A tower does not control the heat load For a given heat load the quantity of water circulated determines the cooling range The hot and cold water tem peratures increase with higher heat loads Cooling range is the temperature A Caution A Caution difference between the hot water coming into the cooling tower and the cold water leaving the tower FAN DRIVE Air is caused to move through the tower by the operation of electric motor driven fans At full speed these fans are designed and pitched to move the amount of air required to accomplish the design thermal performance Proper utilization of these fans provides the operator a means by which to adjust the level of thermal performance to suit the requirements of the load See Temperature Control and Energy Management pages 9 and 10 If two speed motors are used allow a time delay of a minimum of 20 seconds after de energizing the high speed winding and before energizing the low speed winding Tremendous stresses are placed on driven machinery and motor unless the motor is
21. or Wrong sequence of phases Switch any two of the three motor leads Geareducer Noise Geareducer bearings If new see if noise disappears after one week of operation Drain flush and refill Geareducer See Geareducer Service Manual If still noisy replace Gears Correct tooth engagement Replace badly worn gears Replace gears with imperfect tooth spacing or form Unusual Fan Drive Loose bolts and cap screws Tighten all bolts and cap screws on all mechanical equipment Vibration and supports Unbalanced drive shaft or worn Make sure motor and Geareducer shafts are in proper couplings alignment and match marks properly matched Repair or replace worn couplings Rebalance drive shaft by adding or removing weights from balancing cap screws See Drive Shaft Service Manual Fan Make certain all blades are as far from center of fan as safety devices permit All blades must be pitched the same See Fan Service Manual Clean off deposit build up on blades Worn Geareducer bearings Check fan and pinion shaft endplay Replace bearings as necessary Unbalanced motor Disconnect load and operate motor If motor still vibrates rebalance rotor Bent Geareducer shaft Check fan and pinion shaft with dial indicator Replace if necessary Fan Noise Loose fan hub cover Tighten hub cover fasteners Blade rubbing inside of fan cylinder Adjust cylinder to provide blade tip clearance Loose bolts in blade clamps Check an
22. r losses by blowdown evaporation and drift The following table shows the minimum amount of blowdown percent of flow required to maintain different concen trations with various cooling ranges Number of Concentrations Cooling Range 15X 20X 2 5X 3 0X 4 0X 5 0X 6 0X 5 F 2 78 C 78 38 25 18 M 08 06 10 F 5 56 C 1 58 78 51 38 25 18 14 15 F 8 33 C 2 38 1 18 78 58 38 28 20 20 F 11 1190 3 18 1 58 1 05 78 51 38 30 25 F 13 89 C 3 98 1 98 1 32 98 64 48 38 Multipliers are based on drift of 0 02 of the circulating water rate EXAMPLE 7000 GPM 441 7 L s circulating rate 18 F 10 C cooling range To maintain 4 concentrations the required blowdown is 0 458 or 00458 times 7000 GPM 441 7 L s which is 32 1 GPM 2 02 L s If tower is operated at 4 concentrations circulating water will contain four times as much dissolved solid as the makeup water assuming none of the solids form scale or are otherwise removed from the system mi 13 Note Note 14 The use of corrosion and scale inhibitors is strongly recommended CHEMICAL TREATMENT In some cases chemical treatment of the cir culating water is not required if adequate blowdown is maintained In most cases however chemical treatment is required to prevent scale formation and corrosion Sulfuric acid or one of the polyphosphates is most generally used to control calcium ca
23. rbonate scale Various proprietary materials containing phosphates or other compounds are available for corrosion control When water treatment chemicals are required the services of reliable water treating companies should be obtained Preferred Cooling Tower Water Condition Limits For Standard Construction Materials pH Maximum Water Temperature Langelier Saturation Index M Alkalinity Silica Iron Manganese Oil and Grease Sulfides Ammonia Chlorine Organic Solvents Total Dissolved Solids 6 5 to 9 0 120 F 48 9 C 0 0 to 1 0 100 to 500 ppm as CaCOg 150 ppm as SiO 3 ppm 0 1 ppm 10 ppm for splash filled towers None allowed for film filled towers 1 ppm 50 ppm if copper alloys are presents 1 ppm free residual intermittently shock or 0 4 ppm continuously None allowed Over 5000 ppm can affect thermal perfor mance Calcium Cations Magnesium Sodium 800 ppm as CaCOg Depends of pH and Silica level No limit Chlorides Anions Sulfates Nitrates 750 ppm as NaCl 455 ppm as CI 800 ppm as CaCOg 300 ppm nutrient for bacteria Suspended Solids Splash Type Fill No specific limit Unless unusual water conditions have been anticipated and compensated for by the use of premium materials in the construction of the tower then it is the owner operator s responsibility to maintain water conditions within the limits tabled on page
24. s offer twice as many control steps with the added bonus that half speed which produces half of the normal airflow through the tower requires less than 20 of the full speed power requirement If your tower is equipped with a Marley Motor Control Center and or a Marley Smart System temperature controller please refer to the appropriate Owners Manuals Excessive fan cycling may shorten the motor s expected service life On fans 20 feet 6 meter diameter and smaller allow for 4 to 5 starts per hour On larger fans 2 or 3 starts per hour may be the limit On two speed motors each low speed start and each high speed start count as one start Variable frequency drives of course provide the ultimate in both tempera ture control and energy management and can be easily retrofitted to your system Please discuss this with your Marley representative If your tower is equipped with a Marley VFD drive please refer to the appropriate Owners Manual Unit Maintenance Well maintained equipment gives the best operating results and the least maintenance cost A regular inspection schedule is recommended to insure effective safe operation of the cooling tower Use the schedule on page 19 to obtain continuously good performance with the least tower maintenance See Inspection Checklist pages 22 and 23 in this manual Keep a continuous lubrication and maintenance record for each cooling tower Conduct regular inspection and repair of personnel saf
25. tine Starting Procedure After periods of routine shutdown the following restarting procedure should be followed 1 Start the circulating water pump s Increase the flow of circulating water gradually to design water rate to avoid surges or water hammer which could damage the distribution piping Circulating cold water over a tower in freezing weather will cause ice to form which may cause damage to the fill system Water should be bypassed until the heat load causes its temperature to rise above 70 F 21 C at which time it may be directed over the tower Also towers must not be operated with reduced water rate and or no heat load during freezing weather If a bypass is used do not modulate Bypass design must be reviewed by SPX 2 Start the fan s On multicell towers only as many fans should be started as are needed to produce the desired cold water temperature If the tower is equipped with two speed motors fans may be progressively started at half speed increasing to full speed as necessary to maintain the desired cold water temperature See Temperature Control and Energy Man agement pages 9 and 10 Operation TOWER PERFORMANCE keep the tower clean and the water distribution uniform to obtain continued maximum cooling capacity See Warning note page 12 Do not allow excessive deposits of scale or algae to build up on the fill or eliminators Keep the metering orifices free of debris to assure correct distribution and c
26. tomatic operation a timer switch can be provided to shut the fan down for a few minutes each hour 2 1If the tower has two speed motors operate the fan at half speed forward This reduces the cooling rate heat transfer and increases the quantity of warm water on the louvers 3 Under extended extreme cold conditions it may be necessary to operate the fan in reverse This forces warm air out through the louvers melting any accumulated ice Reversal may be at either full or half speed however full speed is recommended if adequate heat load is available Reverse opera tion of the fan should only be used to control ice not prevent it Reverse fan operation should not exceed 15 to 20 minutes Usually much less time than this is required to melt accumulated ice See Caution page 7 4 With no heat load on the circulating water icing cannot be controlled ef fectively by air control during freezing weather Towers must not be oper ated with reduced water rate and or no heat load during freezing weather If a bypass directly into the cold water basin is used all water must be bypassed Design of a bypass arrangement must include consideration of water impact effect on tower components A Caution Reverse operation of fans for prolonged periods during subfreezing weather can cause severe damage to fans and fan cylinders Ice can accumulate inside fan cylinders at fan blade plane of rotation and fan blade tips will eventually strike this ring
27. vice personnel must wear proper personal protective equipment Do NOT attempt any service unless the fan motor is locked out Operators of evaporative cooling equipment such as water cooling towers should follow maintenance programs which will reduce to an absolute minimum the opportunity for bacteriological contamination Public Health Service officials have recommended that good housekeeping procedures be followed such as regular inspections for concentrations of dirt scale and algae periodic flushing and cleaning and the following of a complete water treatment program including biocidal treatment Visual inspection should take place at least once a week during the operating season Periodic flushing and cleaning should be done at least twice a year Nozzles louvers drift eliminators and easily accessible fill surfaces should be flushed by use of a moderate pressure water nozzle being careful not to cause physical damage A reliable water treatment program should be installed and maintained Water Treatment BLOWDOWN Blowdown or bleed off is the continuous removal of a por tion of the water from the circulating system It is used to prevent dissolved solids from concentrating to the point where they will form scale The amount of blowdown required depends upon the cooling range design hot water temperature minus design cold water temperature and the composition of the makeup water water added to the system to compensate fo
28. ws you to produce more product or allows you to operate your system at significantly lower cost then continuous full speed operation of the fan s may be your best mode of operation In this mode of operation concern for the cold water temperature level would be limited to the potential for the tower to form ice during freezing weather See Caution page 6 and WINTER OPERATION pages 8 and 9 Although the 70 F 21 C cold water temperature indicated on page 6 is appropriate for cold weather start up and operation acceptable temperatures during full operation in spring summer and fall may be appreciably lower perhaps as low as 50 F 10 C or less Refer to your performance curves for expected tower cold water temperatures at varying flow rates ranges and wet bulb temperatures mib A Caution 10 MINIMIZING TOWER ENERGY USE Many processes gain no operating or production benefits from water temperatures below a certain level and for many that level may be only 10 F to 15 F 5 to 8 C below the design cold water temperature When a reducing ambient wet bulb permits the tower to reach that target cold water temperature level further reductions in the wet bulb temperature permit manipulation of fan speeds or operation to maintain that temperature level Single speed fans can be cycled on and off for cold water temperature con trol with the steps of control depending upon the number of fan cells in the tower Two speed motor
29. y R as required 19 Troubleshooting Trouble Cause Remedy Motor Will Not Start Power not available at motor terminals Check power at starter Correct any bad connections between the control apparatus and the motor e Check starter contacts and control circuit Reset overloads close contacts reset tripped switches or replace failed control switches If power is not on all leads at starter make sure overload and short circuit devices are in proper condition Wrong connections Check motor and control connections against wiring diagrams Low voltage Check nameplate voltage against power supply Check voltage at motor terminals Open circuit in motor winding Check stator windings for open circuits Motor or fan drive stuck Disconnect motor from load and check motor and Geareducer for cause of problem Rotor defectve Look for broken bars or rings Unusual Motor Noise Motor running single phase Stop motor and attempt to start it Motor will not start if single phased Check wiring controls and motor Motor leads connected incorrectly Check motor connections against wiring diagram on motor Ball bearings Check lubrication Replace bad bearings Electrical unbalance Check voltages and currents of all three lines Correct if required Air gap not uniform Check and correct bracket fits or bearing Rotor unbalance Rebalance Cooling fan hitting guard Reinstall or replac
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