Laars NEOTHERM NTV Page 8 Service Manual Download

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Service Manual - NeoTherm 500

Table of Contents (continued)

B15

Removing and Replacing the High and Low Gas

Pressure Switches ............................................................. 32

B16

Checking the Condensate Trap Water Level Switch ......... 35

B17

Testing the Condensate Trap Level Switch ....................... 36

B18

Removing and Replacing the Condensate Trap ................ 36

B19

Checking the Air Pressure Switch -

Blower Proving Switch ....................................................... 38

B20

Test Procedure for Air Pressure Switch ............................. 39

B21

Removing and Replacing the Air Pressure Switch ............ 39

B22

Checking the Blower .......................................................... 41

B23

Removing and Replacing the Blower ................................ 42

B24

High Stack Temperature Fault ........................................... 46

B25

Removing and Replacing the

Stack Temperature Limit Switch ........................................ 47

B26

Checking the System Sensor ............................................ 48

B27

Checking the DHW Sensor ................................................ 48

B28

Inlet Water Temperature Sensor ........................................ 49

B29

Removing and Replacing the

Inlet Water Temperature Sensor ........................................ 49

B30

Outlet Water Temperature Sensor ..................................... 50

B31

Removing and Replacing the

Outlet Water Temperature Sensor .................................... 50

B32

Testing the Temperature Sensors ...................................... 51

B33

Troubleshooting the Outdoor Reset System ..................... 52

B34

Servicing the Transformer ................................................. 52

B35

Removing and Replacing the Pressure Relief Valve ......... 54

B36

Ignitor Assembly ................................................................ 55

B37

Flame Sensor .................................................................... 56

B38

Pump Fault ........................................................................ 57

Summary of Contents for NEOTHERM NTV

Page 1: ...ocument 1292 Modulating Boiler Model NTH Sizes 399 850 MBTU h Water Heater Model NTV Sizes 399 850 MBTU h Every reference that you ll need to service the Commercial NEOTHERM Service Manual for NeoTher...

Page 2: ......

Page 3: ...ts in Section A The instructions in Section A will lead you to more detailed procedures in Section B Section C covers possible combustion problems and the combustion setup procedure For details on the...

Page 4: ...es several ways of locating information From the line at the top of the screen select Edit then Find Type in the item you want to find The PDF Reader will take you to the first occurrence of that item...

Page 5: ...dam age Improper installation and or operation will void the warranty Fire or Explosion Hazard Improper configuration can cause fuel buildup and explosion Improper user operation may result in death s...

Page 6: ...This appliance must be electrically grounded in accordance with these codes Hot Water This unit can produce water which is hotter than 125 F 52 C This can cause severe burns instantly or death from sc...

Page 7: ...ly Unit with Current User Interface 10 A10 Unit is Noisy 10 Section B Troubleshooting Procedures Sect Title Page B1 Quick Check of Components in the Safety Chain 11 B2 Troubleshooting the 24V AC Power...

Page 8: ...er 41 B23 Removing and Replacing the Blower 42 B24 High Stack Temperature Fault 46 B25 Removing and Replacing the Stack Temperature Limit Switch 47 B26 Checking the System Sensor 48 B27 Checking the D...

Page 9: ...m Control System Sect Title Page D1 Identifying the User Interface on Your Unit 73 D2 Using the Original White User Interface 74 D3 Reacting to Lockouts on the Original White User Interface 76 D4 Remo...

Page 10: ...Service Manual NeoTherm 500 viii...

Page 11: ...hite User Interface 7 A6 Unit is Running but Building is Still Cold 8 A7 Control Unit Says Run but Boiler is Not Firing 9 A8 Open Safety Chain Fault 63 9 A9 Unit Runs in High or Low Fire Only Current...

Page 12: ...Checking the Blower See Section B19 Checking the Air Pressure Switch Blower related problem Disconnect sensor for Outdoor Reset if used No System operates normally Yes See Section B33 Troubleshooting...

Page 13: ...See table of code numbers in Appendix Problem indication from controller Yes Code number supplied No See Section A4 Control Unit is in Standby Mode Controller stuck in Standby mode No Replace the SOL...

Page 14: ...condition the blower is running continuously but the display is completely blank If unit continues to operate normally temporary condition If breaker trips again See Section B2 Reset 24V breaker switc...

Page 15: ...weather shutdown is enabled Outdoor air temperature too warm Normal operating condition In certain situations the controller on this unit can go into Standby mode The Boiler pump is running so the uni...

Page 16: ...or Unit will not run for 20 min then automatically resets Controller reacting to a temporary problem No Units with original white user interface See Section A5 Changing Control Settings Change Not Com...

Page 17: ...the controller However if you do not press Done or OK the control ler will go into the Standby mode The setting for the DHW setpoint will remain at the old setting 180 because at this point the contro...

Page 18: ...s No Clear it Air inlet is blocked Clean Air intake inside unit is plugged Yes No Clean blow out Gas air mixture is correct but not enough gas air mixture is supplied Dirty fan Yes No Burner and or he...

Page 19: ...cked condensate drain Blocked exhaust vent High or low gas pressure Low water in system Problem with circulator pump Fault 63 is a bit like the Check Engine light in a car it indicates a problem but d...

Page 20: ...Noisy A10 On systems using the Current user interface To see if the unit is locked into high fire or low fire From the Home screen press i to go to the Info Install screen High light Test and press OK...

Page 21: ...the Outdoor Reset function is connected disconnect it at terminals 1 and 2 on TB 7 on the control board See Fig B1 1 Remember to re connect the sensor when you are done If the unit operates with the...

Page 22: ...ks are connected or jumpered out and the switches are closed allow ing the unit to fire when a call for heat arrives If you see 24V AC here this means that the following safety interlock switches are...

Page 23: ...n B16 Condensate Trap Level Switch 11 If you see 24V AC at J6 1 this means that all of the switches in the safety chain are satisfied The blower should run and then the pressure switch should close al...

Page 24: ...ough J2 on the control module See Fig B1 8 If power is available at J2 but the blower is not running go to Section B22 Checking the Blower If the blower is running and the unit does not fire go to Sec...

Page 25: ...V AC incoming voltage 120V AC at main power switch 3 7 on SW1 No Disconnect power Check for continuity through power switch SW1 Replace if necessary Disconnect power Check transformer see Section B34...

Page 26: ...C is present Yes See procedure B4 Checking the Low Water Cutoff Switch No Check for 24V AC between TB8 3 and TB4 1 24V AC is present Yes Check the optional external high limit switch 1 Check for actua...

Page 27: ...ith boiler attempting to run check for 24V AC across two leads on air pressure switch 24V AC is present switch open Yes See procedure B16 Checking Condensate Trap Level Switch No 12185 See procedure B...

Page 28: ...e Do not use Teflon tape on the threads This would interrupt the continuity Use pipe dope instead Check for water in boiler Yes Water present No Yes Check water supply water pressure and auto makeup v...

Page 29: ...1 The controller has two LED indicators Power red When lighted the control box has power Tripped yellow When lighted the controller has detected a low water condition The controller also has two switc...

Page 30: ...ront panel 2 Isolate the boiler Turn off the water shutoff valves located upstream and downstream of the unit 3 Drain the boiler 4 Unlock and open the front panels on the unit Turn the two wingnuts an...

Page 31: ...d wire Use the 5 16 socket to loosen both of these Remove the green ground wire from the left hand screw Twist the box slightly and pull it away from the backing plate 4 To reassemble reverse the proc...

Page 32: ...ntrol Other switches will reset auto matically Correct the cause of the problem and or replace the switch Checking the Flow Switch optional B7 B8 Warning Do not leave the room while unit is operating...

Page 33: ...ter to test the continu ity through the switch With no water flow and the paddles in the relaxed position standing upright the switch should be open Note There is a seal at the base of the paddle as s...

Page 34: ...sandpaper Pipe dope or Teflon tape Procedure 1 Turn off power to the system Use the main disconnect switch mounted above the front panel 2 Isolate the boiler Turn off the water shutoff valves located...

Page 35: ...artially block ing the flow The flowing water should hit the longer paddle first See Fig B10 1 9 Note the arrow and the word Flow on the large mounting nut This will help you to install the paddles in...

Page 36: ...arranged Fig B11 1 Gas shutoff valve typical B11 Tools and equipment required Small Phillips head screwdriver 1 3 8 and 5 16 sockets 4 mm Allen wrench Two medium sized pipe wrenches Gas resistant pip...

Page 37: ...ed this wire will go to the N C connection 7 On the left end of the assembly remove the four bolts which attach the gas assembly to the blower See Fig B11 4 The 5 16 socket will fit the head of each b...

Page 38: ...crew the large T nipple from the gas valve 12 Figure B11 7 shows the gas valve after it has been removed Notice the rubber washer be careful to install this correctly when mounting the new valve 13 To...

Page 39: ...the atmosphere 24V AC present switch open Yes Check gas supply Call gas company Gas pressure should be lower than 13 w c Check for 24V AC across the switch Reset the switch manually by pressing the b...

Page 40: ...present switch open Yes Check gas supply Call gas company Gas pressure should be greater than 3 w c Check for 24V AC across the switch Reset the switch manually by pressing the button WARNING Never ju...

Page 41: ...it is open Figure B14 1 shows the gas train Connect a test gauge to the inlet gas pressure tap The low pressure switch Honeywell p n C6097A is wired N O normally open and requires a manual re set You...

Page 42: ...et switch You will need to reset this switch if you disconnect an old switch or install a new switch The low pressure switch is set to trip below 3 w c water column The high pressure switch Honeywell...

Page 43: ...ight side of the machine yellow handle 4 Disconnect the wires to the gas pressure switch Remove the front cover on the gas switch by remov ing the two screws Before disconnecting the wires note the wa...

Page 44: ...ble reverse the procedure we have just described Use gas resistant pipe dope or Teflon tape on the threaded joints For both the high gas pressure and low gas pressure switch es check the setting on th...

Page 45: ...ch 24V AC present switch open No Yes See Section B3 Checking the Safety Chain Check for 24V AC across switch Test switch See Section B17 Replace if necessary See Section B18 Outlet blocked No Yes Flus...

Page 46: ...agna Therm unit is designed to operate in the condensing mode The combustion of natural gas produces a lot of water vapor In the NT unit this water vapor is condensed out of the exhaust gas inside the...

Page 47: ...the mounting screws then remove the right side panel 4 Disconnect the two wires from the top of the trap assembly 5 Notice the position of the Ty wrap then cut it 6 Use the water pump pliers to remove...

Page 48: ...ntake and exhaust vents Clean with a shop vac Dirty fan Yes No Test the air pressure switch See Section B20 Switch is OK No Replace switch Yes Problem with blower Yes See Section B22 Checking the Blow...

Page 49: ...continuity low Ohms switch closed Without pressure You should not see continuity high Ohms switch open 4 Disconnect the T Attach a manometer to the negative port on the blower When the fan starts you...

Page 50: ...e the pliers to release the hose clamps and re move the air hoses from the bottom of the switch Important During reassembly the hoses must be connected to the correct barbs on the switch Do not revers...

Page 51: ...s Check wiring harness Wires OK No Replace wire harness No Has call for heat At start of test unit should be ready to run Standby Blower runs Problem with temp sensor s System sensor Section B26 DHW s...

Page 52: ...lent Replacement gasket for front plate of heat ex changer Container for removed parts Procedure 1 Turn off power to the machine Use the main dis connect switch on the front of the machine just above...

Page 53: ...is to separate the front plate on the heat exchanger from the rest of the unit See Fig B23 5 Note the two large wires running to this assembly The spark wire and the flame sense wire look alike The u...

Page 54: ...ery time you clean the unit or remove the front cover of the heat exchanger 9 Once the assembly has been removed it looks like Fig B23 7 Remove the four 13mm screws that attach the blower to the assem...

Page 55: ...4 When attaching the front cover of the heat exchang er tighten the nuts in a cross pattern See Fig B23 10 If you tighten all of the nuts on one side first this might bend or distort the cover 15 Chec...

Page 56: ...k temperature limit to 190 F Actual stack temperature problem Check the continuity on the wires from the sensor to J9 4 J9 5 and J9 6 on the control module Wiring to sensor is correct Good connections...

Page 57: ...ch mounted above the front panel 2 The stack temperature limit switch is mounted in the far end of the heat exchanger assembly the end which is farthest from the operator control panel You should be a...

Page 58: ...g or is disconnected the display will present three dashes To check the sensor for accuracy see Section B32 The DHW sensor is mounted in the indirect hot water tank and provides the input for the DHW...

Page 59: ...re 1 Turn off power to the system Use the main disconnect switch mounted above the front panel 2 Isolate the boiler Turn off the water shutoff valves located upstream and downstream of the unit 3 Drai...

Page 60: ...or instructions on testing the assembly see Section B32 To reset the control system after the outlet sensor trips On a unit with the original white user interface Press the Reset button near the lower...

Page 61: ...r and water temperature high limit duplex sensor Stack sensor duplex sensor There are up to three more sensors mounted at remote locations System sensor DHW sensor if installed Sensor for Outdoor Rese...

Page 62: ...uit breaker to trip Yes Unit starts running Reconnect the sensor lead Is Outdoor Reset enabled on the controller Check programming Example Low boiler temp set to 130 heat setpoint set to 120 so unit n...

Page 63: ...oes not trip you can check for normal voltages 120V AC input Black wire on TB1 120V hot to white wire on TB2 neutral 24V AC output Blue wire on TB3 24V hot to yellow wire on TB4 common If the meter in...

Page 64: ...mounted on a pipe that extends up a few inches above the top panel of the NT unit 4 Disassemble and remove the drain pipe 5 Unscrew the valve from the vertical pipe using the two pipe wrenches 6 The r...

Page 65: ...120V power supply to the unit 2 Turn off all manual gas valves connecting the unit to the main gas supply line 3 Remove the front door of the unit to gain access to the ignitor assembly 4 Remove the t...

Page 66: ...4 The end of the flame rod should be 1 4 away from the burner See Fig B36 2 Cleaning or Replacement Procedure 1 Shut off the 120V power supply to the unit 2 Turn off all manual gas valves connecting...

Page 67: ...Control Input if the safety chain includes a flow switch The SOLA controller also can display error 51 Pump Fault No No Check for 120V at terminals 1 and 2 on TB5 Pump is getting power Disassemble an...

Page 68: ...58 Service Manual NeoTherm 500...

Page 69: ...th the gas and the flame produces CO2 carbon di oxide and H2 O water Carbon di oxide includes two oxygen atoms attached to every carbon atom When the burner cannot get enough air the flame is starved...

Page 70: ...Next button several times until you see Rate and 100 Press the Up arrow The NT unit is now forced into high fire for 5 minutes The CO2 readings should be between the values shown in Table C2 1 If the...

Page 71: ...e CO2 is within the range identified For the low fire adjustment turning the screw clockwise CW makes the mixture richer 3 Repeat steps 2 and 3 to confirm that the CO2 readings are within the re quire...

Page 72: ...gh fire for 5 minutes then return to normal operation How to get there From the Home screen press I to go to Info Install Choose Test then go to Forced Rate Select Set High Fire then select Start Test...

Page 73: ...makes the mixture richer 3 You might have to go back and forth between high fire and low fire several times before the CO2 readings are correct in both cases Repeat steps 2 and 3 and continue to adjus...

Page 74: ...figures in Table Cannot reach Gas inlet pressure OK Yes No Gas supply problem Check with gas company Interior of burner is clean No Clean burner and heat exchanger See Section C5 Can reach Combustion...

Page 75: ...anger Because of the way the air gas channel is attached to the blower the simplest way to do this is to remove the whole air gas chan nel blower gas valve assembly This will require you to disconnect...

Page 76: ...embly to the blower See Fig C5 3 The 5 16 socket will fit the head of each bolt Use the 3 8 socket on the nut on the other end 5 Behind the gas valve locate the black rubber air intake hose Loosen the...

Page 77: ...hanger from the rest of the unit See Fig C5 6 Note the two large wires running to this as sembly The spark wire and the flame sense wire look alike The unit will not run if you reverse these wires Bef...

Page 78: ...every time you clean the unit or remove the front cover of the heat exchanger 9 Fig C5 8 shows how the assembly looks after it has been removed Note The white ceramic refractory material on the inside...

Page 79: ...wer Shown with front cover for heat exchanger removed Cleaning the Burner and Heat Exchanger continued C5 cont 12 Now you can pull the burner out of the hole in the front plate for the heat exchanger...

Page 80: ...e the protective coating The sensor will work but only for a short time The best way to clean the flame sensor is to use a dollar bill as shown in Fig C5 10 The paper used in the bill is just abrasive...

Page 81: ...Stainless steel coils dirty C5 cont The heat exchanger in Fig C5 11 is new so it is clean Figure C5 12 is a photo of a dirty heat exchanger Normally you will find a heat exchanger that looks like thi...

Page 82: ...ng er tighten the nuts in a cross pattern See Fig C5 16 If you tighten all of the nuts on one side first this might bend or distort the cover 4 The gas valve includes a rubber washer See Fig C5 17 Be...

Page 83: ...produced with two different types of user interfaces as shown below Notice that Laars has been using the same control module through out the SOLA controller but the user interfaces were changed in 20...

Page 84: ...d Table D2 1 User Mode Menu Structure The interface records the last lockout and alert codes but these are erased if the interface is reset or power to the NeoTherm unit is turned off We will explain...

Page 85: ...t cycle minutes of delay between startups Table D2 2 Setup Mode Parameters Using the Original White User Interface continued Diagnostic Menu Diagnostic Mode allows you to see any alerts or lock outs T...

Page 86: ...rily indicate a problem Here is the procedure used to recover from a Lockout The Lockout indication will appear in the lower left hand corner of the dis play and the lockout code will flash in the cen...

Page 87: ...l 3 Disconnect all of the wiring connections to the control module The connectors are keyed so that they can only be inserted one way Be careful not to bend the wires sharply or pull them out of the c...

Page 88: ...l ler Up Down Arrow buttons Use these to go to the choice you want to select in the display area then press the round OK button Left Right Arrow buttons Use these to go to the choice you want to selec...

Page 89: ...n your system The central section shows some additional operating and setup information In this case this area lists the boiler name boiler state current demand and the current password level the acce...

Page 90: ...lockouts and alarms Display Setup You can use this option to adjust the contrast of the display or change the items which appear at the top of the Home display Table D5 2 Functions on Info Install Me...

Page 91: ...is 1 min ute The numbers near the left edge of the screen show the allowable range for this value In this case the time can be set anywhere between 1 minute and 15 minutes In this example we will chan...

Page 92: ...be changed by a trained techni cian who enters a password These include setup and parameter changes made when the system is installed and some diagnostic and troubleshooting functions The installer l...

Page 93: ...Diagnostics to check the status of the sensors and the digital inputs and outputs The system also records a history of lockouts and alarms Analog Sensors You can use this display to check on operating...

Page 94: ...rect delayed or waiting for a response This does not necessarily indicate a problem If a problem occurs while the system is starting up the system will declare a Hold A brief explanation of the cause...

Page 95: ...connected Swing the panel up and place it face down on the cloth Ribbon cable connectors X01 12 pin X07 8 pin 4 Disconnect the two wiring connectors 8 pin connector X07 12 pin connector X01 Each conn...

Page 96: ...herm unit because the Honeywell SOLA control ler is the most complicated part it s tempting to assume that the controller is causing the problem Usually the problem is caused by an input a sensor or s...

Page 97: ...d all of the existing control settings if pos sible This will allow you to re enter the settings after you install the new controller Record the current settings for temperature set points outdoor res...

Page 98: ...emove the control push the lower ends of the left side clips and swing the left side of the control toward you Green connector mounted in far right position J2 J1 CP10 J10 CP9 J9 CP8A J8 CP8B J8 J6 CP...

Page 99: ...ation mode and safety parameters need verification and a device needs reset to complete verification 2 Configuration ended without verification re enter configuration verify safety parameters and rese...

Page 100: ...Internal fault 1 Reset module 2 If fault repeats replace module 18 Internal fault Safety relay test failed due to feedback not on L Internal fault 1 Reset module 2 If fault repeats replace module 19...

Page 101: ...ult repeats replace module 32 46 Internal fault Safety key 0 through 14 L Internal fault 1 Reset module 2 If fault repeats replace module 47 Flame rod to ground leakage H Check flame rod See Section B...

Page 102: ...ace the module 64 PII Pre Ignition Interlock off H or L 1 Check wiring and correct any faults 2 Check preignition interlock switches to assure proper functioning 3 Check the valve operation 4 Reset an...

Page 103: ...r fault H 1 Check wiring and correct any possible errors See Section B28 2 Replace the Inlet sensor 3 If previous steps are correct and fault persists re place the module 92 Outlet sensor fault H 1 Ch...

Page 104: ...ny errors 2 Make sure that the flame detector is wired to the cor rect terminal 3 Make sure the flame and ground wires are protected from stray noise pickup 4 Reset and sequence the module if code rea...

Page 105: ...al hardware test Not a lockout 111 Flame current lower than weak threshold H Hold time of recycle and hold option Will not be a lockout fault Hold only Internal hardware test Not a lockout 113 Flame c...

Page 106: ...he VFD s Variable speed Fan Drive ability to change speeds 3 Change the VFD 4 If the fault persists replace the module 137 ILK Interlock failed to close H 1 Check wiring and correct any possible short...

Page 107: ...n switch J6 terminal 3 and its connections Make sure the switch is working correctly and is not jumpered or welded 4 Reset and sequence the relay module 5 If the fault persists replace the relay modul...

Page 108: ...ltage across the switch Supply voltage should be present If not the block intake switch is defective and needs replacing 5 If the fault persists replace the relay module 165 Block intake off L 1 Check...

Page 109: ...onse setting L 1 Return to configuration mode and recheck selected parameters reverify and reset module 2 If fault repeats verify electrical grounding 3 If fault repeats replace module 189 Invalid fla...

Page 110: ...le 201 Invalid lightoff rate proving setting L 1 Return to configuration mode and recheck selected parameters reverify and reset module 2 If fault repeats verify electrical grounding 3 If fault repeat...

Page 111: ...peats replace module 215 Invalid purge rate proving setting L 1 Return to configuration mode and recheck selected parameters reverify and reset module 2 If fault repeats verify electrical grounding 3...

Page 112: ...ical grounding 3 If fault repeats replace module 226 Invalid outlet high limit setpoint setting L 1 Return to configuration mode and recheck selected parameters reverify and reset module 2 If fault re...

Page 113: ...d recheck selected parameters reverify and reset module 2 If fault repeats verify electrical grounding 3 If fault repeats replace module 237 Invalid DHW Domestic Hot Water connec tor type setting L 1...

Page 114: ...rmittent spark can be seen 6 The controller waits through a trial for ignition period of four seconds The direct spark ignition switches to constant spark for three sec onds during which time the gas...

Page 115: ...105 Service Manual NeoTherm 500 Appendix 3 Wiring Diagram App3...

Page 116: ...106 Service Manual NeoTherm 500...

Page 117: ......

Page 118: ...ax 800 559 1583 Headquarters 20 Industrial Way Rochester NH 03867 603 335 6300 Fax 603 335 3355 1869 Sismet Road Mississauga Ontario Canada L4W 1W8 905 238 0100 Fax 905 366 0130 www Laars com Litho in...

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