A.O. Smith 101 User's Manual
Contents
1. eu ION TEINS ES rra cta Combustion Air Filter een Blower Compartment Burner Maintenance nn Condensate Removal System Venting Maintenance Heat Exchanger Preventive Maintenance Tube Cleaning Procedure REPLACEMENT PARTS LIMITED WARRANTY anne This design complies with the current edition of the ANSI Z21 13 low pressure boiler standard Compliance under this standard implies that when the boiler underwent test the gas manifold and control assembly provided on the boiler met safe lighting and other performance criteria Detailed installation diagrams are found in this manual These diagrams will serve to provide the installer a reference for the materials and methods of piping necessary It is essential that all water gas piping and wiring be installed as shown on the diagrams You should thoroughly read and understand this manual before installation and or operation of this boiler The factory warranty will be void if the boiler s have been improperly installed or operated AL 29 4C is a registered trademark of Allegheny Ludlum Corporation In addition to these instructio2. N MODULATING 7 IRI GAS SWITCH RETURN OPTIONAL p jat ists LOW GAS POWER OPTIONAL E CONTROL BOARD od LOW GAS RETURN OPTIONAL RIG y MC B 319 1 J5 E POWER VENTER AUDIBLE BLOCKED FLUE POWER BKN ALARM BLOCKED BLOCKED FLUE RETURN RIG FLUE SW BKW FLOW SWITCH POWER BKW FLOW SWITCH RETURN mi IRI GAS PROVER SW INLET INLET TEMPERATURE PROBE POWER BL LOW GAS TEMPERATURE INLET TEMPERATURE PROBE RETURN BL PROBE J8 N EXAMPLE 3 ON OFF INPUT SV MANUAL ECO POWER OPTIONAL EQYIPMENT OUTLET MANUAL ECO RETURN TEMPERATURE OUTLET TEMPERATURE PROBE POWER BK 24 VAC sa Fi J CIRCUIT PROBE ECO OUTLET TEMPERATURE PROBE RETURN BK 7 5 AMP DEDICATED SINGLE PHASE 115VAC RMS INPUT WITH A GROUNDED NEUTRAL LINE PER NEMA STANDARDS USING A 20 AMP CIRCUIT BREAKER FOR FIELD WIRED CONNECTIONS USE NO 10 AWG WIRES RATED FOR AT LEAST 194 DEG 90 DEG C s 5 L1 e W EXTERNAL gt ES JUNCTION BOX GND POWER OUTSIDE CABINET a PUMP CONTACT RELAY ON OFF MAIN POWER SWITCH IRI GAS VALVE RELAY POWER OPTIONAL IRI GAS VALVE RELAY RETURN OPTIONAL 24VAC POWER 120VAC HOT IRI GAS VALVE CONNECTOR RELAY OPTIONAL 24VAC RETURN GND GROUND 24VAC RET E 20 AMP INTERNAL WIRING SHOWN PUMP 24VAC HOT 120VAC
3. Fault Description section for list of soft and Auto Reset faults The pump remains on for the selected post circulate time to cycle the hot water out of the boiler The FCB is commanded to shut down and the Alarm output is turned on The green LED turns off and the red Service turns on and off flashes The only way to exit this state is for the user to press the Select key while the current error screen is displayed The fault is logged in the error history when the fault state is exited While the MCB is in the Heating mode the FCB moves from Idle to Pre Purge to Heat Igniter to Check for Flame and then to Heating The process waits in this state until the call for heat is satisfied the thermostat input is opened or a fault occurs When heat is satisfied the seguence continues to Post Purge and then back to Idle If three tries for ignition has been selected on the MCB dipswitch and flame is not detected at the appropriate time then the seguence moves to the Inter Purge state for 15 seconds and the FCB heat seguence is repeated If flame is still not detected after the third try the process declares a fault jumps out of seguence and goes to the error state Other types of faults detected at any time will also cause a jump to the error state Description of FCB control states Idle State When any error is declared during idle state The system 13 will remain in this state until the MCB request a heating cycle or a cold pu
4. GS GS gt 24VAC RETURN 24VAC RETURN DS1 GREEN LED 3 LINE POLARITY 18 CORRECT IF LIT FOR CLARITY XFMR FCB3 CCB FCB1 120VAC 120VAC 120VAC 120VAC HOT F5 F7 EARTH GROUND VFD an ino trad 120VAC 120VAC r i ve POWER DISTRIBUTION BOARD PDB THIS UNIT MAY HAVE ALL SOME OR NONE OF THE ABOVE OPTIONS w VB VW Variable Fire MODULE J20 or J21 ji Wiring Diagram F2 CIRCUIT 5 AMP HIGH ELOWER PROVER POWER BKW HIGH BLOWER PROVER RETURN YN HIGH BLOWER PROVER SW HIGH GAS PRESSURE SWITCH POWER OPTIONAL BKIW y HIGH GAS SW HIGH GAS PRESSURE SWITCH RETURN OPTIONAL RG OPTIONAL LOW BLOWER PROVER POWER BK W MO D U L ATI NG LOW BLOWER PROVER RETURN RIG LOW GAS SW splices CONTROL BOARD MCB o VALVE N H IGNITER HOT B IGNITER RTN Journ R FLAME SENSOR 1 FLAME SEHSOR SIGNAL R FLAME SENSOR 2 MODULATION KEY m m Ji LE jat VARIABLE FREQ AAA a DRIVE BLOWER MCB DIP SWITCH Sw2 FUNCTIONS SEE NOTES G Y 120 VAC WIRING LOW VOLTAGE WIRING FIELD INSTALLED COMMUNICATION CABLESSEE NOTES 120 VAC WIRING LOW VOLTAGE WIRING FIELD INSTALLED COMMUNICATION CABLES 120VAC HOT POSITION OFF FUNCTION 1 SPARE 2 YES HIGH GAS SWITCH 3 i 2 BLOWER SPEEDS 2 3 MCB DIP SWITCH Sw2 FUNCTIONS POSITION OFF FUNCTION 1 VB vw TYPE OF BOILER 2 3 1 IGNITION TRAILS WIRING LEGEND
5. necessary or incidental for any material and or permits reguired for installation of the replacement 4 LIMITATIONS ON IMPLIED WARRANTIES Implied warranties including any warranty of merchantability imposed on the sale of this boiler under state or provincial law are limited to one 1 year duration for the boiler or any of its parts Some states and provinces do not allow limitations on how long an implied warranty lasts so the above limitation may not apply to you 5 CLAIM PROCEDURE Any claim under this warranty should be initiated with the dealer who sold the boiler or with any other dealer handling the warrantor s products If this is not practicable the owner should contact U S Customers Canadian Customers A O Smith Corporation A O Smith Enterprises Ltd 500Tennessee Waltz Parkway P O Box 310 768 Erie Street Ashland City TN Stratford Ontario N5A 6T3 Telephone 800 527 1953 Telephone 800 265 8520 a The warrantor will only honor replacement with identical or similar parts thereof which are manufactured or distributed by the warrantor b Dealer replacements are made subject to in warranty validation by warrantor 6 DISCLAIMERS NO OTHER EXPRESS WARRANTY HAS BEEN OR WILL BE MADE ON BEHALF OF THE WARRANTOR WITH RESPECT TO THE MERCHANTABILITY OF THE BOILER OR THE INSTALLATION OPERATION REPAIR OR REPLACEMENT OF THE BOILER THE WARRANTOR SHALL NOT BE RESPONSIBLE FOR WATER DAMAGE LOSS OF USE OF THE UNIT INCONVENIENCE LOSS
6. parameters the control will return to step 5 and repeat the entire operating cycle Note Any fault detection during standby or running modes will halt the heating sequence and shift the system to the service mode where the detected fault will be displayed NOTE In standby and running modes the system constantly monitors the signals and the internal operation for faults Any detected fault will halt the heating sequence and shift the system to the service mode where the detected fault will be displayed TEMPERATURE SETPOINTS SYSTEM CONTROL ALGORITHM The boiler has a hysteresis type control which means that it will begin heating the water when the temperature sensed by the control probe inlet or tank falls below the operating setpoint minus the differential setpoint It will stop heating the water when the temperature rises to the operating setpoint UIM OPERATING PROCEDURES E O VE 25 100 FIRING RATE UIM USER INTERFACE MODULE 12 The UIM receives commands from the user and displays operational information to the user via an LCD liquid crystal display up to eleven LED s and five touch switches The LCD provides information to the user by the use of 10 menu activated screens Within each of the screens helpful information can be displayed by pressing the Help button The LED s visually inform the user about the mode the system is in The touch switches allow the user to control the operation of the sys
7. supplied with the boiler as shipped from the factory The installer must provide a filtering system in the air inlet to the boiler if dust dirt or construction dirt can be pulled into the boiler through the inlet air piping Periodically clean air filter per the manufacturer s instructions BLOWER COMPARTMENT The blower compartment should be cleaned annually to remove any dirt and lint that may have accumulated in the compartment 18 or on the blower and motor Buildups of dirt and lint on the blower and motor can create excessive loads on the motor resulting in higher that normal operating temperatures and possible shortened service life BURNER MAINTENANCE Qualified servicers should follow this procedure when the boiler s burner needs cleaning 1 Turn off the electrical power to the boiler and close the main manual gas shutoff valve s Allow the boiler parts to cool before disassembly Loosen the flange and separate the gas train from the manifold assembly Separate the burner from the blower adapter by first removing the four 4 bolts and subsequently the blower gaskets The blower should be free to move at this point FOR DIRECT VENT UNITS It is necessary to loosen and slide the rubber coupling on the blower adaptor in order to move the blower Loosen the seven bolts on the blower adapter at the base and move the burner ground wire Green aside Lift the blower adapter and remove the manifold assemb
8. that the over temperature is not being caused by improper setup or operation of the boiler Outlet temp is too high Flashing HARD Caused when the ECO a thermostat contacts in the Outlet probe are open when they should be closed Fault may be due to high outlet temperature bad switch contacts in the ECO or disconnected wiring Note The ECO can be checked by disconnecting the outlet probe from the MCB and reading the resistance across the two active pins on the connector at the end of the probe cable The value should be approximately 0 ohms when the temperature of the probe is less than 220 F Water level is too low Flashing HARD Caused by the Low Water Cut Out device not closing its feedback switch contacts when it should Check water line switch contacts wiring LWCO Gas pressure is too low Flashing HARD Caused by the Low Gas switch being open when it should be closed Check gas line switch contacts wiring Power vent not running Flashing HARD Caused by the Powered Vent device not closing its feedback switch contacts when it should Could also be caused by a problem with the relay output on the MCB Check output to powered vent switch contacts wiring Gas pressure too high Flashing HARD Caused by the High Gas switch being open when it should be closed Check gas line switch contacts wiring Inlet probe shorted or open Flashing HARD Caused when the thermistor in the probe or the wiring to the probe is shorted or disconnected Ch
9. the cause of the error on the display The operating programs for the system are stored in permanent memory inside the microcontrollers User selectable operating parameters and a history of detected faults are stored in rewritable memory in the microcontrollers A loss of power does not affect either of the memories INPUTS TO MCB TEMPERATURE SENSORS Temperature probes MCB outlet and either inlet or tank are reguired The MCB accepts analog temperature inputs from up to three sensors inlet outlet and remote ECO input MCB reguired The ECO energy cut off is a hi limit switch located inside the outlet probe It is a normally closed switch that opens if the probe is exposed to a temperature higher than the trip point Once tripped the control system needs to be manually reset Thermostat input MCB optional This input is set up to work with an externally connected thermostat that provides a contact closure If this input is closed and everything else is in the proper state a call for heat condition will be initiated These leads should be shorted together when a thermostat is not being used If it is desired that the thermostat control the temperature of the boiler the operating setpoint of the system should be set higher than the temperature that the thermostat is controlling This will allow the thermostat to control the boiler When the thermostat closes a call for heat will be generated until the thermostat d
10. water temperatures required for automatic dishwasher and laundry use can cause scald burns resulting in serious personal injury and or death The temperature at which injury occurs varies with the person s age and time of exposure The slower response time of children aged or disabled persons increases the hazards to them Never allow small 10 children to use a hot water tap or to draw their own bath water Never leave a child or disabled person unattended in a bathtub or shower The boiler should be located in an area that is inaccessible to the general public TABLE 1 Risk of Scalds Temperature Time to Produce 2nd amp 3rd Setting Degree Burns on Adult Skin Over 170 F 77 C Nearly instantaneous 160 F 71 C About 1 2 second SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF TURN OFF THE MAIN MANUAL GAS SHUTOFF VALVE TO THE APPLIANCE The operating temperature of the boiler must be maintained as follows e 120 F 49 C or higher inlet water temperature to the boiler e 20 F 11 C differential between the boiler s inlet and outlet e g 120 F 49 C inlet 140 F 60 C outlet minimum design temperatures If the inlet water temperature into the boiler is less than 120 F 49 adjustments on the water bypass are needed Please contact your A O Smith qualified service agent CONTROL SYSTEM The EMC modulation control system is a fully integrated state of the art electronic control s
11. 3 YES NO IRI GAS VALVE 4 TANK INLET CONTROLLING PROBE 5 YES NO POWERED VENT E YES NO LOW WATER CUTOFF 7 YES NO FIRING TYPE SEE NOTES 8 MODULATION MULTI STAGE 9 NOT USED 120 VAC WIRING 10 NOT USED LOW VOLTAGE WIRING COMMUNICATION CABLES Z 7 7 Z LILL LLLA BLOWER NOTE DRIVE IF ANY OF THE ORIGINAL WIRE SUPPLIED WITH THE APPLIANCE MUST BE REPLACED EQUIVALENT GAGE WIRE INSULATION TYPE 105 DEG C 600 VOLTS MUST BE USED CONNECT 212791 000 REV 3 VB VW 500 750 amp 1000 SCHEMATIC DIAGRAM LI 12 120VAC HOT NEUTRAL PUMP RELAY CONTACTS CIRCULATING PUMP VW UNITS ONLY VW UNITS ONLY G ON OFF SWITCH GROUND 20 AMP FUSE PDB F2 ADDITIONAL GAS VALVE ADDITIONAL RELAY OPTIONAL PUMP RELAY COIL CONTACTS OPTIONAL VW UNITS ONLY 15 AMP FUSE PDB F7 R wo ADDITIONAT RELAY E SCHEMATIC DIAGRAM LIGHTING amp OPERATION INSTRUCTIONS FOR MODELS VB VW 500 750 AND 1000 FOR YOUR SAFETY READ BEFORE OPERATING FIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY DAMAGE PER WARNING IF YOU DO NOT FOLLOW THESE INSTRUCTIONS EXACTLY A SONAL INJURY OR LOSS OF LIFE EQUIPPED WITH AN IGNITION DEVICE WHICH AUTOMATICALLY LIGHTS THE BURNER DO NOT TRY TO LIGHT THE BURNER BY HAND BEFORE LIGHTING SMELL ALL AROUND THE APPLIANCE AREA FOR GAS BE SURE TO SMELL NEXT TO THE FLOOR BECAUSE SOME GAS IS HEAVIER THAN AIR AND WILL SETTLE ON THE FLOOR WHAT TO DO IF YOU SMELL GAS DO NOT TRY TO LIGHT AN
12. A O Smith GAS FIRED POWER BURNER COPPER BOILERS FOR HYDRONIC HEATING AND HOT WATER SUPPLY e Installation Operation e Maintenance Limited Warranty WARNING If the information in this manual is not followed exactly a fire or explosion may result causing property damage personal injury or loss of life Do not store or use gasoline or other flammable vapors and liguids in the vicinity of this or any other appliance WHAT TO DO IF YOU SMELL GAS Do not try to light any appliance Do not touch any electrical switch do not use any phone in your building Immediately call your gas supplier from a neighbor s phone Follow the gas supplier s instructions If you cannot reach your gas supplier call the fire department Installation and service must be performed by a gualified installer service agency or the gas supplier A WARNING Read and understand this manual and all Warnings and Cautions within before installing and using this appliance Place these instructions adjacent to boiler and notify owner to keep for future reference PRINTED 0207 USER S MANUAL MODELS VB VW 500 750 AND 1000 SERIES 100 101 MC BEE SC RENTON WA STRATFORD ONTARIO VELDHOVEN THE NETHERLANDS NANJING CHINA www hotwater com email parts hotwater com 212801 000 A ALION Your safety and the safety of others is extremely important in the installation use and servicing of this boile
13. Auto Reset Check transformer output Should be over 24vac May be caused by excessive current drain or a faulty transformer Indicates a brown out reset occurred None Caused by a momentary dip in voltage on the MCB 5vdc power bus Contact factory Not considered a serious problem if it only occurs on very rare occasions Indicates a watchdog reset occurred None Caused when the micro executes the software in an improper way Contact factory Not considered a serious problem if it only occurs on very rare occasions FCB did not receive command from MCB Continuous SOFT Caused when communications between the MCB and the FCB are interrupted May occur when a surge of power on a nearby device i e arc welder creates an EMI burst Not a serious problem if it occurs rarely Water is not flowing Continuous SOFT Caused by the flow switch being open when it should be closed Check water lines pump flow switch contacts wiring Blower pressure is too low it they should have been closed Continuous SOFT Check blower switch contact wiring and for air leaks Flue is Blocked Continuous SOFT Caused by the blocked flue switch contacts being open when they should have been closed Check for flue blockage switch contacts wiring Outlet temp exceeded high limit setpoint Continuous Auto Reset Caused when the temperature of the outlet probe exceeds the high limit setpoint This is an internal software limit switch and not an actual device Check
14. OR DAMAGE TO PERSONAL PROPERTY OR OTHER CONSEQUENTIAL DAMAGE THE WARRANTOR SHALL NOT BE LIABLE BY VIRTUE OF THIS WARRANTY OR OTHERWISE FOR DAMAGE TO ANY PERSONS OR PROPERTY WHETHER DIRECT OR INDIRECT AND WHETHER ARISING IN CONTRACT OR TORT a Some states and provinces do not allow the exclusion or limitation of the incidental or conseguential damage so the above limitations or exclusions may not apply to you b This warranty gives you specific legal rights and you may also have other rights which vary from state to state or province to province Fill in the following for your own reference Keep it Registration is not a condition of warranty The model and serial number are found on the boiler s rating plate Owner Installation Address City and State Zip Code Date Installed Model No Serial No Dealer s Name Phone No Dealer s Address FILL IN WARRANTY AND KEEP FOR FUTURE REFERENCE 23 A O Smith Water Heaters 500 Tennessee Waltz Parkway Ashland City TN 37015 Phone 800 433 2545 www hotwater com E Mail parts hotwater com
15. Y APPLIANCE DO NOT TOUCH ANY ELECTRIC SWITCH DO NOT USE ANY PHONE IN YOUR BUILDING IMMEDIATELY CALL YOUR GAS SUPPLIER FROM A NEIGHBOR S PHONE FOLLOW THE GAS SUPPLIER S INSTRUCTIONS IF YOU CANNOT REACH YOUR GAS SUPPLIER CALL THE FIRE DEPARTMENT GAS FLOW FLAMMABLE A THIS APPLIANCE DOES NOT HAVE A PILOT IT 1 C USE ONLY YOUR HAND TO TURN THE MAIN MANUAL GAS VALVE NEVER USE TOOLS IF THE KNOB WILL NOT PUSH IN OR TURN BY HAND DON T TRY TO REPAIR IT CALL A QUALIFIED SERVICE TECHNICIAN FORCE OR ATTEMPTED REPAIR MAY RESULT IN A FIRE OR EXPLOSION DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN UNDER WATER IMMEDIATELY CALL A QUALIFIED SERVICE TECHNICIAN TO INSPECT THE APPLIANCE AND TO REPLACE ANY PART OF THE CONTROL SYSTEM AND ANY GAS CONTROL WHICH HAS BEEN UNDER WATER DONOT OPERATE APPLIANCE UNLESS UNIT IS FILLED WITH WATER AND WATER LINES ARE FULLY OPEN CLOSED OPERATING INSTRUCTIONS E W STOP READ THE SAFETY INFORMATION m BBOVFAONZHISIARE 6 OPEN MAIN VALVE TURN MAIN GAS VALVETO ON OR OPEN POSITJON THE VALVE IS IN THE ONZPOSIUON WBFN THE B 1 PRT E PTA PALA PAB SA PF T F ACAUTION should overheating occur or the gas supply fail to shut off turn off the gas supply at a location external to the boiler 1 e main manual gas shutoff valve Light the boiler in accordance with the instructions provided on the label affixed to the boiler s front d
16. area must be kept clear and free from combustible materials gasoline and other flammable vapors and liquids Any safety devices including low water cutoffs used in conjunction with this boiler should receive periodic every six months inspection to assure proper operation A low water cutoff device of the float type should be flushed every six months Periodic checks at least twice a year should be made for water leaks More frequent inspections may be necessary depending on water conditions The boiler mounted gas and electrical controls have been designed to give both dependable service and long life However malfunction can occur as with any piece of equipment It is therefore recommended that all components be checked periodically by a qualified serviceman for proper operation RELIEF VALVE The safety relief valve should be opened at least twice a year to check its working condition This will aid in assuring proper pressure relief protection Lift the lever at the top of the valve several times until the valve seats properly and operates freely DANG ER e Burn hazard Hot water discharge e Keep hands clear of drain valve discharge A WARNING Should overheating occur or the gas supply fail to shut off turn off the manual gas control valve to the appliance COMBUSTION AIR FILTER If the combustion air supply to the boiler contains dust dirt drywall dust etc a filter must be installed An air filter is not
17. cted plus a time stamp of when the error occurred The time stamp is based on the elapsed hours value at the time the error occurred It is displayed in hours and minutes This error remain displayed as long as it is still valid When cleared it is moved to the Error History Screen The system will automatically jump to this screen when an error is detected It will also go to this screen upon power up if an error was still valid when power was turned off NOTE Errors are cleared from this screen by pressing the select key Error History Screen This screen displays a list of the last 9 errors with time stamps that have occurred The last error to occur is displayed first Reload Defaults Screen From this screen the user can restore the factory default values for screen adjustable configurations by pressing the Select key The values restored are as follows VW Models Oper Setpnt Operating Setpoint 145 F 63 C Hi Limit High Limit Setpoint 210 F 99 C Hi Limit Dif High Limit Differential 20 F 11 VB Models Oper Setpnt Operating Setpoint 190 F 88 C Hi Limit High Limit Setpoint 230 F 110 Hi Limit Dif High Limit Differential 20 F 11 Both Models Tempert Units Temperature Units F Post Cir Secs Post Circulation pump delay 45 seconds Network Address Network Address none UIM Touch Switches Below the LCD display are five touch switches or keys that t
18. densate accumulates for this condition The transparent drain lines and condensate drain on the bottom of the vent collector should be visually inspected at one month intervals for blockage particularly in the areas of the loops in the lines which trap a small amount of condensate and the exit point of the vent collector drain Condensate in portions of the line other than the loop area indicates a blockage in the drain line Flush the lines with air or water and clear or replace the blocked portions of the line as necessary Note that areas of the drain line which include a sag or low spot in the line will also form a condensate trap which can be removed by levelling the tube and does not indicate a blocked system Inspect the metal vent drain and vent collector drain connectors at six month intervals Remove the hoses from the connections then check with a small wooden dowel or plastic rod passed up through the metal connection to insure the passage is clear using caution to not bend or damage the connector Call a gualified service agent to inspect and correct the problem if any obstructions are found in the connectors Replace all hoses and clamps immediately after inspection and before starting the boiler in accordance with the Lighting and Operating Instructions DO NOT OPERATE THE BOILER UNLESS ALL CONDENSATE DRAIN LINES ARE PROPERLY CONNECTED AND WORKING When a means to neutralize condensate has been installed you must also follow o
19. e Flammable Vapors severe burns instantly resulting in severe injury or death Children elderly and the T physically or mentally disabled WARNING are at highest risk for scald injury Explosion Hazard Feel water before bathing or NSA showering Temperature limiting Overheated water can cause valves are available E watertank explosion Read instruction manual for safe temperature setting e Properly sized temperature and pressure relief valve must be installed ADANGER Fire or Explosion Hazard Do not store or use gasoline or other flammable vapors and A WA RN liquids in the vicinity of this or any other appliance Breathing Hazard Carbon Monoxide Gas Avoid all ignition sources if you smell LP gas e Special consideration must be taken Do not expose boiler control to excessive gas pressure with installations above 6000 feet Use only gas shown on rating plate Please contact an AO Smith gualified service agent to obtain the proper Maintain reguired clearances to combustibles J E setup and instructions before lighting Keep ignition sources away from faucets after extended period of non use Failure to implement the proper setup will result in improper and inefficient gn operation of the appliance resulting in Anion production of increased levels of Rean runan Manda De DIE VOD carbon monoxide gas in excess of the installing using or servicing safe limits which could re
20. e wall horizontally vented gas fueled equipment does not provide the parts for venting the flue gases but identifies special venting systems the following requirements shall be satisfied by the manufacturer 1 The referenced special venting system instructions shall be included with the appliance or equipment installation instructions and 2 The special venting systems shall be Product Approved by the Board and the instructions for that system shall include a parts list and detailed installation instructions A copy of all installation instructions for all Product Approved side wall horizontally vented gas fueled equipment all venting instructions all parts lists for venting instructions and or all venting design instructions shall remain with the appliance or equipment at the completion of the installation CONNECTION DIAGRAM OUTSIDE CABINET FLOW PF je EXTERNAL JUNCTION Y 1 TANK TEMPERATURE PROBE POWER Y A TANK TEMPERATURE PROBE RETURN j J9 J20 or J21 Z Z Z Es a EXTERNAL THERMOSTAT RETURN POWERED VENT POWER OPTIONAL IGNITER POWERED VENT POWER SWITCH RETURN F2 j CIRCUIT OPTIONAL POWERED VENT GND OPTIONAL 5 AMP LOW WATER CUTOFF POWER OPTIONAL Ja LOW WATER CUTOFF SWITCH RETURN OPTIONAL LOW WATER CUTOFF GND OPTIONAL ALARM POWER OPTIONAL 317 m m un amp M ALARM GND OPTIONAL IRI GAS SWITCH POWER OPTIONAL fo Mah
21. eck the probe Note The thermistor and wiring can be checked by disconnecting the probe from the MCB and reading the resistance across the two active pins on the connector at the end of the probe cable The value should be approximately 10K ohms value will change slightly with changes in temperature Outlet probe shorted or open Flashing HARD Caused when the thermistor in the probe or the wiring is shorted or disconnected Check the probe Note the thermistor and wiring can be checked by disconnecting the probe from the MCB and reading the resistance across the two active pins on the connector at the end of the probe cable The value should be approximately 10K ohms value will change slightly with changes in temperature Tank Remote probe shorted or open Flashing HARD Caused when the thermistor in the probe or the wiring is shorted or disconnected Check the probe Note the thermistor and wiring can be checked by disconnecting the probe from the MCB and reading the resistance across the two active pins on the connector at the end of the probe cable The value should be approximately 10K ohms value will change slightly with changes in temperature Igniter current is too low Flashing HARD Caused by a low current draw problem with the igniter This may occurif the igniter is old damaged or disconnected and no longer draws the proper level of current This condition will affect the ability of the igniterto get hot enough to fire the gas pro
22. em operates with Silicon Carbide lgniters OPERATING SEOUENCE 1 The EMC modulation controller has four modes of operation Initialization Standby Running Modulation and Service The internal MCB micros control these modes through a seguence of steps or States which are further described in the UIM Operating Procedures section 2 When power 1 applied to the system it enters the initialization mode and the following automatic functions are performed e A O Smith opening screen is displayed system goes through a calibration indicated by the green running LED blinking and then staying on next the red service LED and yellow standby LEDs come on next the service and runnings LEDs blink ON and OFF e Stored values are recalled from memory e Configuration dipswitches are read e Pending faults are recalled Micros on all boards start running indicated by a flashing Yellow LED near each micro Input sensors are read 3 After initialization is complete approximately 10 seconds the system turns the green LED off and goes to the standby mode yellow Standby LED on unless a previously stored fault has been recalled which will send the system into the service model red Service LED on In standby mode the display shows the temperature screen and in fault mode the current error screen is displayed 4 The system then compares the temperature read from the controlling probe inlet or tank to the setpoint
23. ential AUTO HIGH LIMIT SETPOINT ADJUSTMENT PROCEDURE OUTLET TEMPERATURE PROBE The High Limit setpoint has a range of 90 F 32 C to 210 F 99 C for a VW and a range of 90 F 32 C to 235 F 113 C for a VB Use the following procedure to change the automatically resettable High Limit Setpoint 1 Press the MENU key 2 Scroll the gt with the DOWN key next to USER SETTING SCREEN 3 Press the SELECT key 4 Scroll the gt with the DOWN key until it is pointing to HIGH LIMIT SETPOINT 14 Press the SELECT KEY Use the UP and DOWN key to select the value you wish to enter Press the SELECT key to accept and store the new value High Limit Differential The outlet temperature must be below the automatic High Limit setpoint minus the High Limit Differential setpoint before a call for heat can be generated HIGH LIMIT DIFFERENTIAL SETPOINT ADJUSTMENT PROCEDURE The High Limit Differential Setpoint has a range of 1 F to 50 F for all models Use the following procedure to change the High Limit Differential Setpoint 1 Press the MENU key 2 Scrollthe gt with the down key next to USER SETTING SCREEN 3 Press the SELECT key 4 Scroll the gt with the DOWN key until it is pointing to HIGH LIMIT DIFFERENTIAL SETPOINT 5 Press the SELECT key 6 Use the UP or DOWN key to select the value you wish to enter 7 Press the SELECT key to accept and store the new value Operating Differential Setpoint
24. etermines that the reguired temperature has been reached AIRPRESSURE SENSORS OPEN CONDITION INDICATES FAULT Blocked Flue MCB reguired Normally closed switch that opens If the flue becomes blocked during operation Blower Prover MCB reguired Normally open switch that closes when the air pressure produced by the blower is above the set point GAS PRESSURE SENSORS OPEN CONDITION INDICATES FAULT Low Gas MCB reguired Normally closed switch that opens when the gas pressure falls below the trip level This input is enabled disabled by a dip switch on the MCB Hi Gas MCB required Normally closed switch that opens if the gas pressure exceeds a set value This input is enabled disabled by a dip switch on the MCB WATER LEVEL SENSOR OPEN CONDITION INDICATES FAULT Low Water Cut Off MCB optional Normally open switch that closes when water reaches preset level This input is enabled disabled by a dip switch on the MCB WATER FLOW SENSOR Flow MCB reguired Normally open switch that closes when flow exceeds a set value FLAME SENSOR Flame MCB reguired Returns a signal to the microprocessor if flame is detected on the burner the flame rod is missing or shorted the flame will not be detected OUTPUTS FROM MCB RELAY CONTACT OUTPUT Alarm MCB 24VAC optional Provides electrical power to operate an external alarm This can be an audio device i e Sonalert a visual device lamp or any o
25. f the National Fuel Gas Code as it relates to the installation of gas fired boilers The qualified installer must have a thorough understanding of this instruction manual Service Agency Aservice agency also must have ability equivalent to a licensed tradesman in the fields of plumbing air supply venting and gas supply including a thorough understanding of the requirements of the National Fuel Gas Code as it relates to the installation of gas fired boilers The service agency must also have a thorough understanding of this instruction manual and be able to perform repairs strictly in accordance with the service guidelines provided by the manufacturer Gas Supplier The Natural Gas or Propane Utility or service who supplies gas for utilization by the gas burning appliances within this application The gas supplier typically has responsibility for the inspection and code approval of gas piping up to and including the Natural Gas meter or Propane storage tank of a building Many gas suppliers also offer service and inspection of appliances within the building AWARNING A DANGER Read and understand this manual and all Warnings and Cautions within before installing and using this appliance e Do not store or use gasoline or other flammable vapors and liguids in the vicinity of this or any other appliance Place these instructions adjacent to boiler and notify owner to keep for future reference A N e E R Untempered hotwater can caus
26. ged Operating Setpoint This setpoint sets the base temperature for the control algorithm OPERATING SETPOINT ADJUSTMENT PROCEDURE The system has a standard programmable Operating Setpoint range of 70 F 21 C to 190 F 88 C for a VW and of 70 F 21 C to 220 F 104 C for a VB for either a Remote or inlet probe depending on selection The user can easily change the Operating Setpoint at any time by using the following procedure When any configuration or setpoint is changed and the Select key touched the new value is IMMEDIATELY saved to non volatile memory The factory default setting is 145 F 49 C 1 Press the MENU key 2 Scroll the gt with the DOWN key next to the USER SETTING SCREEN 3 Press the SELECT key 4 Scroll the gt with the DOWN key until it is pointing to OPERATING SETPOINT 5 Press the SELECT key 6 Use the UP or DOWN key to select the value you wish to enter 7 Press the SELECT key to accept and store the new value High Limit The outlet temperature probe contains both an ECO switch and a thermistor for temperature measurement The sensed outlet temperature is used for the automatically resettable High Limit setpoint If the sensed outlet temperature exceeds the High Limit setpoint a soft lockout condition will occur and the burner will be shut off This fault condition is automatically cleared when the temperature drops below the high limit setpoint minus the high limit differ
27. he operator uses to operate the system Menu Key Pressing this key activates the menu screen where the other screens can be accessed Select Key This key performs several functions Screens can be selected from the menu screen by pressing this key when the gt appears next to the screen desired On the User Settings screen items that appear next to a gt symbol can be selected with this key If a setpoint configuration item is selected the gt will then flash slowly to indicate that the item has been selected The Up and Down keys are then used to change its value From the Current Error Screen this key is used to reset the system from an error Up and Down Keys These keys are used to move upwards and downwards in screens to reach a desired item and to change setpoints and user settings They have an auto increment decrement feature for some of the configurations and values When you first press one of the keys and value changes by 1 count then wait 1 2 second and changes slowly until the key is released or if held for 3 or more seconds it will change the value quickly Help Key Pressing the Help key from any screen displays helpful information about that screen From the menu screen general help information is displayed as to how to use the user interface To return to the previous screen press the Help or Select keys or press Menu key to go to the menu screen If a small down arrow appears in the lower right ha
28. irculate The yellow LED is turned off and the green Running LED is turned on The green LED will remain on for all other states except the fault states Cold purging clears out any combustion gas that may be in the combustion chamber When purging is complete the system moves to the Heat State Heat Stage The system will command the FCB micros to start their heat seguence will be activated in order based on an algorithm that determines how much heat is needed The system will remain in this state until the heat reguest is satisfied the Tstat is opened or a fault occurs e Soft Fault State See Fault Description section for list of soft and Auto Reset faults The pump remains on for the selected post circulate time to cycle the hot water out of the boiler The FCB is commanded to shut down and the Alarm output is turned on The green LED turns off and the red Service turns on The MCB remains in this state until one of the following occurs e One hour passes automatic restart after one hour e If Communications error system will automatically restart if communications re establishes f user presses Select key while current error screen is displayed Hard reset If high limit error the outlet temperature drops below the high limit trip point minus the high limit differential outlet water temperature drops to safe level The fault is logged in the error history when the fault state is exited Hard Fault State See
29. ize GAS VENT DIRECTLY BELOW KEEP CLEAR OF ALL OBSTRUCTIONS INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled eguipment shall not approve the installation unless upon inspection the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR 5 08 2 a 1 through 4 EXEMPTIONS The following equipment is exempt from 248 CMR 5 08 2 a 1 through 4 1 The equipment listed in Chapter 10 entitled Equipment Not Required To Be Vented in the most current edition of NFPA 54 as adopted by the Board and 2 Product Approved side wall horizontally vented gas fueled eguipment installed in a room or structure separate from the dwelling building or structure used in whole or in part for residential purposes MANUFACTURER REQUIREMENTS GAS EQUIPMENT VENTING SYSTEM PROVIDED When the manufacturer of Product Approved side wall horizontally vented gas equipment provides a venting system design or venting system components with the equipment the instructions provided by the manufacturer for installation of the equipment and the venting system shall include 1 Detailed instructions for the installation of the venting system design or the venting system components and 2 A complete parts list for the venting system design or venting system MANUFACTURER REQUIREMENTS GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED When the manufacturer of a Product Approved sid
30. ly up from the 6 studs located on the cover plate and remove the burner gasket Remove any loose foreign material such as dust or lint with a vacuum Check all ports for blockage Dislodge any foreign material causing blockage Remove any soot or carbon deposits with a rag making sure to remove any lint left on the burner by vacuuming again Reverse the steps to reassemble the unit Restore electrical power and gas supply to the boiler Put the boiler back in operation by following the Lighting and Operating instructions in this manual e Check for gas leaks and proper boiler and vent operation CONDENSATE REMOVAL SYSTEM Due to the highly efficient operation of this unit condensate is formed during operation and must be removed by the condensate drain systems Inspect the condensate drains and tubes at least once a month and insure they will allow the free flow of condensate at all times The system must be inspected more frequently in cold weather if the drain system is located in an area such as along the floor where freezing temperatures are likely to occur The condensate drain system must be protected against freezing Contact a qualified service agent to inspect and correct the condition if freezing of the condensate lines is a problem The unit is equipped with a blocked flue switch which will shut the unit off if condensate is unable to drain and backs up in the unit A blocked flue error will appear when sufficient con
31. minutes the system will automatically clear the error and restart Auto Reset lockouts will monitor the cause of the fault and it the fault clears itself the system resets itself The following table shows the fault messages and some possible troubleshooting hints FAULT DISPLAYED Display Fail Comm Fail Stg Low AC Voltage Low 24VAC Brown Out Reset Timeout Reset FCB Comm Timeout No Flow Blower Prov Stg Blocked Flue High Limit ECO fault Low Water Low Gas Powered Vent High Gas Stg Inlet Probe Outlet Probe Tank Probe Igniter Stg Igniter Pwr Stg Igniter Hdwr Stg TROUBLESHOOTING IGNITION SYSTEM Fault Messages and Lockout Status stage number 1 2 3 or 4 DESCRIPTION RED LED LOCKOUT Communications with UIM interrupted Continuous Auto Reset Check communication cable to UIM Try moving to other Internal Communications connector on MCB Also check the connectors where the cable is plugged in for best connecting wires Communications with FCB interrupted Continuous Auto Reset Same as above Also try swapping FCB and UIM communications cables Line voltage less than 90 vac Continuous Auto Reset Check incoming power line for loss of voltage May also be caused by a power line brown out momentary loss of voltage Voltage from transformer less than 18 vac Continuous
32. nd corner then there is off screen content below what is displayed Press the down arrow to scroll down to this information After scrolling down an up arrow will appear in the upper right hand corner to indicate off screen content above what is displayed UIM LED s The three LED s to the right of the LCD indicate the status of the overall system The red LED indicates that a fault has been detected and the system has stopped running It is on continuously for soft faults and flashes for hard faults The Yellow LED indicates that the boiler is in a ready mode waiting for a call for heat command When on continuously the Green LED indicates that the system is in the heating mode If it is flashing it indicates that the UIM is in the initialization mode and the touch switches are being calibrated The VF boiler has a display on the UIM which is a scaled display indicating the current firing rate of the boiler 25 to 100 Fault Messages and Troubleshooting Guide The EMC 5000 modulation system does excessive self diagnostics and displays detected faults on the UIM display in an easy to read manner There are approximately 80 different faults that can be detected Some of the faults are caused by internal problems and some by external causes The faults create different types of system lockouts shut down Hard lockouts are serious problems that reguire the user to manually restart the system Soft lockouts can be reset by the user or after 60
33. ns the boiler s shall be installed in accordance with those installation regulations in force in the local area where the installation is to be made These shall be carefully followed in all cases Authorities having jurisdiction should be consulted before installations are made In the absence of local codes the installation must comply with the current editions as follows In the United States The National Fuel Gas Code ANSI Z223 1 NFPA 54 and the National Electric Code NFPA 70 INSTALLATION REOUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS For all side wall terminated horizontally vented power vent direct vent and power direct vent gas fueled water heaters installed in every dwelling building or structure used in whole or in part for residential purposes including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven 7 feet above finished grade in the area of the venting including but not limited to decks and porches the following reguirements shall be satisfied INSTALLATION OF CARBON MONOXIDE DETECTORS At the time of installation of the side wall horizontal vented gas fueled equipment the installing plumber or gasfitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back up is installed on the floor level where the gas equipment is to be installed In addition the installing plumber or gasfitter shall observe that a battery ope
34. of Mechanical Engineers must have been installed and fresh water used for filling and make up purposes a This warranty shall apply only when the boiler is used 1 with inlet water temperature 120 F 49 and above and outlet water temperatures not exceeding the maximum setting of its operative and or high limit control 2 at water pressure not exceeding the working pressure shown on the boiler 3 when filled with boiler water free to circulate at all times and with the heat exchanger free of damaging scale deposits 4 in a non corrosive and non contaminated atmosphere 5 in the United States its territories or possessions and Canada 6 at a water velocity flow rate not exceeding or below the boiler s designed rates 7 indoor installation only b Any accident to the boiler any misuse abuse including freezing or alteration of it any operation of it in a modified form or any attempt to repair leaks in the heat exchanger will void this warranty 3 SERVICE AND REPAIR EXPENSE Under this limited warranty the warrantor will provide only a replacement part The owner is responsible for all other costs Such costs may include but are not limited to a Labor charges for service removal repair or reinstallation of the component part b Shipping delivery handling and administrative charges for forwarding the replacement part from the nearest distributor and returning the claimed defective part to such distributor c All cost
35. on of gas Cause rapid ignition and carry over of flame across entire burner Give reasonably guiet operation during initial ignition operation and extinction Cause no excessive lifting of flame from burner ports If the preceding burner characteristics are not evident check for accumulation of lint or other foreign material that restricts or blocks the air openings to the burner or boiler To check burners Shutoff all gas and electricity to unit Allow unit to cool Remove main burners from unit Check that burner ports are free of foreign matter Clean burner with vacuum cleaner DO NOT distort burner ports Reinstall burners in unit Ensure that all the screws on the burner flange are tightened securely so that the gasket will provide a good seal Also check for good flow of combustion and ventilating air to the unit O O N After placing the boiler in operation check the ignition system safety shut off devices for proper operation To accomplish this with the main burner operating close the valve on the manifold Within four seconds the main burners should extinguish If this does not occur immediately discontinue gas supply by closing main manual shut off and call a gualified serviceman to correct the situation If the burners extinguish then light boiler in accordance with lighting and operating instructions A WARNING The flow of combustion air to the boiler must not be obstructed The boiler
36. oor on the inside WATER TEMPERATURE REGULATION A Untempered hot water can cause severe burns instantly resulting in severe injury or death Children elderly and the physically or mentally disabled are at highest risk for scald injury Feel water before bathing or showering Temperature limiting valves are available Read instruction manual for safe temperature setting HOT WATER CAN SCALD Boilers are intended to produce hot water Water heated to a temperature which will satisfy space heating clothes washing dish washing and other sanitizing needs can scald and permanently injure you upon contact Some people are more likely to be permanently injured by hot water than oth ers These include the elderly children the infirm or physically mentally disabled If anyone using hot water in your home fits into one of theses groups or if there is a local code or state law requiring a specific temperature water at the hot water tap then you must take special precautions In addition to using the low est possible temperature setting that satisfies your hot water needs a means such as a mixing valve shall be used at the hot water taps used by these people or at the hot water supply tank Mixing valves are available at plumbing supply or hardware stores Follow the manufacturer s instructions for installation of the valves Before changing the thermostat setting on the hot water system controller see Table 1 Hot
37. perating inspection and maintenance procedures specified by the manufacturer of the product Inspect the installed device to insure that it does not cause condensate to remain in the boiler or vent for any reason VENTING MAINTENANCE It is recommended that the intake and exhaust piping of the appliance be checked every 6 months for dust condensate leakage deterioration and carbon deposits A WARNING Do notusea nylon brush or other static creating material to clean dust and carbon deposits from heating surfaces and vent Such deposits are flammable and may be ignited by static electricity Use a metal brush to minimize the danger of explosion Qualified serviceman should follow this procedure when the boiler s intake and exhaust piping need cleaning 1 Turn off the electrical power and manual gas shut off e Allow boiler parts to cool before disassembly 2 Remove the vent pipe e Check parts and chimney for obstructions and clean as necessary 3 Remove burner from boiler and other metal parts as reguired to clean as necessary e Refer to parts list for disassembly aid 4 Clean and reinstall the parts removed in steps 2 and 3 e Be sure the vent pipe has a minimum upward pitch of 1 4 per foot 2cm m of length and is sealed as necessary 5 Restore electrical power and gas supply to boiler e Check for gas leaks and proper boiler and vent operation HEAT EXCHANGER PREVENTIVE MAINTENANCE In most water supply sys
38. perly Check the igniter and its associated wiring Improper power applied to the igniter circuit Flashing HARD Caused by improper line power being applied to the igniter circuitry Check line connections Paying particular attention to the earth ground connection Also check that line voltage does not exceed 132 VAC RMS Hardware problems with igniter circuit Flashing HARD 16 A N This is a pre mix burner system The flame is not supposed to be directly on the burner The flame should be just above the burner deck approximately 1 8 and blue in color see illustration NORMAL BURNER FLAME ABNORMAL BURNER FLAME BURNER FLAMES Visually check flame characteristics through the view port located on the top head of the boiler The Burner Flames illustration shows the normal flame condition These boilers are designed to give many years of efficient and satisfactory service when properly operated and maintained To assure continued good performance the following recommendations are made The area around the unit should be kept clean and free from lint and debris Sweeping the floor around the boiler should be done carefully This will reduce the dust and dirt which may enter the burner and heat exchanger causing improper combustion and sooting MAIN BURNER Check main burner every three months for proper flame characteristics The main burner should display the following characteristics Provide complete combusti
39. r Many safety related messages and instructions have been provided in this manual and on your own boiler to warn you and others of a potential injury hazard Read and obey all safety messages and instructions throughout this manual It is very important that the meaning of each safety message is understood by you and others who install use or service this boiler This is the safety alert symbol Itis used to alert you to potential personal injury hazards Obey all safety messages that follow this symbol to avoid possible injury or death DANGER indicates an imminently hazardous situation which if not avoided could resultin injury or death WARNING indicates a potentially hazardous A WARNING situation which if not avoided could result in injury or death CAUTION indicates a potentially hazardous ACAUTION situation which ifnotavoided may resultin minor or moderate injury CAUTION used without the safety alert CA TION symbol indicates a potentially hazardous U situation which if not avoided could result in property damage All safety messages will generally tell you about the type of hazard what can happen if you do not follow the safety message and how to avoid the risk of injury IMPORTANT DEFINITIONS Qualified Installer A qualified installer must have ability equivalent to a licensed tradesman in the fields of plumbing air supply venting and gas supply including a thorough understanding of the requirements o
40. rated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling building or structure served by the sidewall horizontal vented gas fueled eguipment It shall be the responsibility of the property owner to secure the services of gualified licensed professionals for the installation of hard wired carbon monoxide detectors In the event that the side wall horizontally vented gas fueled eguipment is installed in a crawl space or an attic the hard wired carbon monoxide detector with alarm and battery back up may be installed on the next adjacent floor level In the event that the reguirements of this subdivision can not be met at the time of completion of installation the owner shall have a period of thirty 30 days to comply with the above reguirements provided that during said thirty 30 day period a battery operated carbon monoxide detector with an alarm shall be installed APPROVED CARBON MONOXIDE DETECTORS Each carbon monoxide detector as reguired in accordance with the above provisions shall comply with NFPA 720 and be ANSI UL 2034 listed and CSA certified SIGNAGE A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight 8 feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment The sign shall read in print size no less than one half 1 2 inch in s
41. rge Pre Purge State The blower is turned on After 10 to 34 seconds 34 seconds for cold purging the system switches to the Heat Igniter State Heat Igniter State The sequence of operation is as follows The igniter relay is energized and the heat up period begins After 18 20 seconds If the igniter has reached a minimum of 2 8 amps the gas valve safety circuit is then activated If in this amount of time the igniter fails to reach a minimum amp draw of 2 8 amps the unit will re cycle up to 3 times before locking out on igniter hardware failure If the igniter does reach the minimum reguired amp draw of 2 8 amps the gas valve circuit is energized and the system advances to Flame Check status Check for Flame State The gas valve is turned on After 1 5 seconds the system checks that the gas valve relay is on If it is not the ignition trial is considered to have failed and the system advances to the Inter Purge state if any ignition trials remain otherwise an error is declared The flame sensor is checked If flame is detected the igniter is turned off The state machine then advances to the Heating State If after 5 seconds the flame is still not sensed then the Ignition trial is considered to have failed The state machine advances to Inter Purge if any ignition trials remain otherwise an error is declared Heating State The system remains in this state until the call for heat is cancelled or a fault occurs The
42. rs the inputs at these times ECO Blocked Flue Low Gas Hi Limit and Hi Gas at all times for a fault condition Tstat at all times for open closed conditions Flow for an on condition when the pump is on no check for off state Blower Prover when the Blower is on Igniter Current for an on condition approximately 18 seconds after the Igniter is turned on until the igniter is turned off and an off condition at all other times Flame for an on condition approximately 5 seconds after the gas valve is turned on until the valve is turned off and at all other times for an off condition Control Status Screen Displays the status that the MCB micros are in The MCB has 5 possible states and the FCB have 9 The normal MCB states seguence is to move from Idle to Pre Circulate when a call for heat Is initiated Once heat has been satisfied or the Thermostat is opened the seguence moves to Post Circulate and then back to Idle If a fault occurs at any time the process jumps out of seguence and goes directly to the appropriate Hard or Soft Fault state Description of MCB control states Idle The yellow Standby LED is turned on and the system waits for a heat reguest determined by the Thermostat or controlling probe inputs All outputs are off in this state except that if the Post Circulate time is set to continuous the pump will be on When the heat reguest is received the system moves to the Pre Circulate state e Pre C
43. s Each of the two stages has an independent Operating Differential setpoint Temperature Units Temperature can be displayed in either F or C units Post Circulate Delay Time The time circulation pump will stay on after the burner is turned off The time in seconds is adjustable with the following values 45 90 180 or continuous If the continuous value is selected the pump will remain on at all times and the post circulate state time will be set at 45 seconds Network Address This is a unique number assigned to this boiler to differentiate it from other boilers or water heater on the same A O Smith proprietary network A valid Network Address can be any number from 0 to 31 It is set by default to zero which is an invalid address The boiler will not communicate until it is changed to a valid and unique number This prevents two units from trying to respond to the same request from the PC or supervisory network device Configuration Settings Screen Displays the status of the dipswitches installed on all boards as described earlier Log amp System Info Screen Displays the following information Elapsed hours of operation Total time system has been powered up Number of running minutes Number of minutes system has been in the run mode kBtu rating of the boiler 0 to 5750kBtu in 10kBtu increments The software revision level of the MCB Current Error Screen Displays the last error that the system has dete
44. sult in serious personal injury or death Breathing carbon monoxide can cause brain damage or death Always read and understand instruction manual Fire Hazar CAUTION For protection against Improper installation and use may result risk of fire i in property damage Do not install boiler on Do notoperate boiler ifflood damaged carpeted floor Install in location with drainage e Fill boiler with water before operation Bealertforthermal expansion Do not operate boiler if flood damaged Refer to instruction manual for installation and service SAFE INSTALLATION USE AND SERVICE GENERAL SAFETY ee TABLE OP CONTENTS necio tecate condes Installation Requirements for the Commonwealth of Mass Aa erc PTT ie las Sonemalle usted ee Lighting and Operating Instructions Water Temperature Regulation Control Syste Operating Sequencoe salas Operating Procedures Operating Setpoint Adjustment Procedure TROUBLESHOOTING IGNITION SYSTEM Troubleshooting Gas Valve PREVENTATIVE MAINTENANCE
45. system returns to the Idle state if the call for heat is cancelled or satisfied and to the appropriate fault state if a fault occurs Inter Purge State The gas valve and the igniter are turned off The blower is on After approximately 15 seconds the system goes back to the Heating lgniter State Post Purge State The gas valve and the igniter are turned off The blower is then left on for approximately 25 seconds the system returns to the Idle state Error State The gas valve and the igniter are turned off The FCB micro tells the MCB micro which error has occurred The system waits in this state until the MCB sends a command to clear the error and the system returns to the idle state Cold Purge State Cold purge occurs when the MCB micro commands the blower to go on before lighting to clear the unit of residual gases This state normally lasts approximately 32 seconds but on a If the blower prover does not activate after 15 seconds This time allows the blower relay to activate the blower to come up to speed and the response from the blower prover to be filtered User Settings Screen Each setpoint or user setting has either a limited selection of values or a limited range of values The Up Down keys are used to change values After changing an item the Select key is pressed to accept the change or the Menu key is pressed to reject the change and restore the item to its original value The following setpoints can be chan
46. tem The operation of these parts is described in the following section UIM Screens On all screens a double vertical bar appears on the right side of the display each time a key is touched to indicate that a key has been activated On several screens an indicator gt appears on the left side of the display to indicate the active line The Up Down keys are used to move the indicator to the desired line and the Select key is pressed to select the line Also on most of the screens up down arrows appear on the right side of the screen to indicate that there is additional lines either above or below the displayed four lines Menu Screen Displayed when the user presses the Menu key This screen is the selection point for the other 9 screens Temperature Screen Displays the sensed temperatures of the Outlet Inlet and Tank probes Also displayed is the calculated Delta T Outlet minus Inlet for the system Shorted Short and disconnected probes are also displayed System Status Screen This screen is used to view the status of switch inputs and output states An asterisk is displayed next to the label when the status is True the description is fulfilled For example if water is flowing or detected by the flow sensor then an will appear in front of the Flow label i e Flow Another example would be the ECO switch If the outlet temperature is too high the display will show ECO The System monito
47. temperature If the temperature is less than the operating setpoint minus the differential temperature and the thermostat input is closed then a call for heat is established and the system shifts to the run mode green Running LED turns on The heating seguence begins by applying power to the pump After a few seconds the blower is turned on for 30 second pre purge period of combustion chamber The igniter is turned on After the igniter has reached a minimum of 2 8 amps the gas valve is energized to allow gas flow to burner After an additional one second the system checks the status of the flame through the flame rod sensor If the flame is not verified within 4 seconds the gas valve is immediately shut off followed by 15 second inter purge period then the system returns to step 7 if the Trial for Ignition dipswitch is set for three 3 tries If the dipswitch is set for one 1 trial the system will declare an error and boiler will reguire resetting the control The boiler will remain running until the set point is satisfied Once satisfied the blower will continue for 15 second post purge period Once set point has have been satisfied the boiler pump will continue to run for the programmed post circulate cycle The control now enters the idle state as displayed by the Standby LED The control will continue to monitor heat demand and state of other system devices Upon a drop of water temperature below the set
48. tems solids exist As the water is heated these tend to drop out depositing as scale or lime This scale must be removed before the heat exchanger tubes become blocked A CAUTION Lime accumulation can reduce the life of the equipment reduce efficiency and waste fuel Boiler failure due to lime or scale buildup voids the warranty 20 22 LIMITED WARRANTY A O Smith Corporation the warrantor extends the following LIMITED WARRANTY to the owner of this boiler 1 If within TEN years after initial installation of the boiler a heat exchanger or gas burner shall prove upon examination by the warrantor to be defective in material or workmanship the warrantor at his option will exchange or repair such part or portion This term is reduced to FIVE yearsif this boiler is used for water heating purposes other than hydronic space heating a This warranty is extended to the owner for all other parts or portion during the FIRST year following initial installation of this boiler b The warranty on the repair or replacement of the part or portion will be limited to the unexpired term of the original warranty 2 CONDITIONS AND EXCEPTIONS This warranty shall apply only when the boiler is installed in accordance with local plumbing and building codes ordinances and regulations the printed instructions provided with it and good industry practices In addition a pressure relief valve certified by C S A and approved by the American Society
49. ther device that will operate with the voltage and current level provided Pump MCB 120VAC reguired on systems that do not have an external pump Provides electrical power to directly operate a pump or the coil of an externally connected contactor Blower MCB 120 VAC required Variable speed blowers utilize the high blower output only Igniter MCB 120VAC reguired Provides power to operate the HSI igniters Gas Valve MCB 24VAC required Provides power to activate the gas valve The gas valve cannot be activated when the ECO contacts are open Low Water Cut Off MCB 24VAC optional Directly connected to the 24VAC line to provide power to operate an external LWCO device MCB AND PDB INDICATOR LAMPS AND FUSES A green LED is mounted on the PDB to indicate when line voltage is applied the PDB also contains a yellow and red LED and a test run jumper that are used during installation to verify proper power connections A red LED on the MCB is used to indicate when the 24VAC input fuse has blown Yellow LEDs are located near the microcontrollers on the MCB These LEDs are heartbeat indicators and blink approximately twice per second to indicate that the microcontrollers are running MCB JUMPERS The MCB has two jumpers JP1 on the MCB is used to terminate the external communications line It is normally left off and installed when the external cable is very long IGNITERS The EMC modulation syst
50. ystem It consists of sensors output devices a power switch a 24VAC transformer wiring and the following printed circuit boards Modulation Control Board MCB Power Distribution Board PDB User Interface Module UlM The MCB contains circuitry for both master control and flame control Dip switches on the MCB are used to configure the system The User Interface Module UIM communicates with the user through a set of touch pads and a 4 line 20 character LCD display The PDB provides connection points for input power the water pump and the transformer It also distributes power to the system and contains the system fuses The MCB also contains an external communications system to allow for connection to a PC a modem an EMS system or something similar Through this connection multiple boilers can also be linked together CAUTION The internal communications cables should never be connected to the external communications connectors and vice versa There are several microcontrollers used on the boards These control the temperature and ignition control functions for the boiler Inherent in the design are the normal operating seguences and safety features associated with a gas ignition control system The system continuously performs various diagnostic tests to verify proper appliance and control operation Should an unsafe condition occur the control will shut down the burner and display a red service light as well as indicate
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