Laars NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manu User Manual

Document 1291Modulating Boiler Model NTHSizes 080–285 MBTU/hWater Heater Model NTVSizes 150–285 MBTU/hEvery reference that you’ll need, to service t

Service Manual NeoTherm 80 - NeoTherm 285viii

90Service Manual NeoTherm 80 - NeoTherm 285Code Description L or H Procedure159 Main valve off L 1. Check the main valve terminal wiring and correct a

91Service Manual NeoTherm 80 - NeoTherm 285Code Description L or H Procedure178 Safety relay on at safe start check L Internal fault.1. Reset module.2

92Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure196 Invalid ignition source setting L

93Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure210 Invalid postpurge time setting L 1

94Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure221 Uncongured DHW (Domestic Hot Wate

95Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure232 Invalid pressure sensor type setti

96Service Manual NeoTherm 80 - NeoTherm 285Appendix 2 - Ignition and Firing SequenceApp2This is the basic operating sequence of the appliance whether

97Service Manual NeoTherm 80 - NeoTherm 285Appendix 3 - Wiring DiagramApp3

98Service Manual NeoTherm 80 - NeoTherm 285

1Service Manual NeoTherm 80 - NeoTherm 285A1Troubleshooting - Start HereFor troubleshooting instructions, see these sections:Section Symptom PageA2

Customer Service and Product Support: 800.900.9276 • Fax 800.559.1583Headquarters: 20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.3

2Service Manual NeoTherm 80 - NeoTherm 285Unit Will Not Fire - Blower is Not RunningA2NoYesCheck 120V AC electrical power.Display is lit?See Section B

3Service Manual NeoTherm 80 - NeoTherm 285Unit Will Not Fire - Blower is Not RunningA2cont.Check programming in controller -temperature settings, outd

4Service Manual NeoTherm 80 - NeoTherm 285Blower Runs Continuously, No DisplayA3In this condition, the blower is running continuously, but the display

5Service Manual NeoTherm 80 - NeoTherm 285Control Unit is in “Standby” ModeIn certain situations, the controller on this unit can go into “Standby” mo

6Service Manual NeoTherm 80 - NeoTherm 285A4cont.Control Unit is in “Standby” Mode (continued)Example:High flue temperature tripsHigh Stack Temp. Sens

7Service Manual NeoTherm 80 - NeoTherm 285Changing Control Settings, Change Not CompleteOriginal (White) InterfaceNeoTherm units were produced using t

8Service Manual NeoTherm 80 - NeoTherm 285Unit is Running, But Building is Still ColdA6YesNoClear itAir inlet isblocked?CleanAir intakeinside unit isp

9Service Manual NeoTherm 80 - NeoTherm 285Control Unit Says “Run,” But Boiler is Not FiringIn this condition, the panel is lighted, so you know the un

10Service Manual NeoTherm 80 - NeoTherm 285Short-Cycling - Fault #61There are several conditions that can cause short-cycling, and some of them can be

11Service Manual NeoTherm 80 - NeoTherm 285Quick Check of Components in the Safety Interlock ChainThis procedure gives you a quick way of checking the

12Service Manual NeoTherm 80 - NeoTherm 285Quick Check of Components in the Safety Interlock Chain - continued6. If this unit is set up to use a sepa

13Service Manual NeoTherm 80 - NeoTherm 28510. Check for 24V AC between terminals 1 and 2 of J8 on the control module. See Fig. B1-6. If 24V AC is

14Service Manual NeoTherm 80 - NeoTherm 285Quick Check of Components in the Safety Interlock Chain - continuedB1cont.Fig. B1-8 - Control voltage for

15Service Manual NeoTherm 80 - NeoTherm 285Troubleshooting the 24V AC Power Supply24V ACbetween TB3and TB4?YesNo24V AC supply is OK120V ACto NT unit?N

16Service Manual NeoTherm 80 - NeoTherm 285Checking the Safety InterlocksB324V AC ispresent?(all switches closed)YesNoSafety interlock chain is OKChec

17Service Manual NeoTherm 80 - NeoTherm 285Checking the Safety Interlocks - continuedB3cont.24V AC ispresent?(other safety switches closed)YesNoCheck

18Service Manual NeoTherm 80 - NeoTherm 285Checking the Low Water Cutoff Switch (option)Control resets?YesNoCheck for continuity frombase of switch to

19Service Manual NeoTherm 80 - NeoTherm 285Checking the Low Water Cutoff Switch (continued)Controller for Low Water CutoffThe low water cutoff switch

Service Manual NeoTherm 80 - NeoTherm 285How to Use This ManualiHow to Use the Troubleshooting InformationThis manual is divided into ve main section

20Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Low Water Cutoff SwitchThe low water cutoff switch is designed to shut down the

21Service Manual NeoTherm 80 - NeoTherm 285Procedure - Replacing the control box1. To remove the cover, remove the two sheet metal screws on the side

22Service Manual NeoTherm 80 - NeoTherm 285High Water Temperature Limit Switch (optional)Laars does not provide this switch. It is installed only whe

23Service Manual NeoTherm 80 - NeoTherm 285Testing the Flow SwitchThe ow switch uses a set of paddles to sense water owing through the system. See

24Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Flow SwitchThe switch assembly includes two parts: a set of paddles that extend

25Service Manual NeoTherm 80 - NeoTherm 285Fig. B10-3 - Wiring connections inside switch boxRemoving and Replacing the Flow Switch (continued)5. Now

26Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Gas ValveThe modulating gas valve consists of a valve body that controls the on/

27Service Manual NeoTherm 80 - NeoTherm 2854. Unplug the wires running to the gas valve. The connector is keyed, and can only be plugged in one way.

28Service Manual NeoTherm 80 - NeoTherm 2859. Now you can remove the air/gas channel and blower assembly from the machine. Remove the ve #25 Torx-h

29Service Manual NeoTherm 80 - NeoTherm 28511. Now you can remove the gas valve. There are four 4mm socket-head cap screws. Fig. B11-9 shows the g

Service Manual NeoTherm 80 - NeoTherm 285iiFinding Information in this PDF FileThis manual includes a lot of detailed information, but none of this is

30Service Manual NeoTherm 80 - NeoTherm 285Checking the Condensate Trap Level SwitchB1224V AC present?(switch open)NoYesSee Section B3 -“Checking the

31Service Manual NeoTherm 80 - NeoTherm 285Testing the Condensate Trap Level SwitchFig. B13-1 - Small condensate trap assembly (typical)Some operatin

32Service Manual NeoTherm 80 - NeoTherm 285Tools and equipment required:* 1/4” socket• Small diagonal cutters or knife• Water-pump pliers• 11” Ty-

33Service Manual NeoTherm 80 - NeoTherm 285Checking the Air Pressure Switch - Blower Proving SwitchExhaust ventblocked?YesNoClear the vents.Check the

34Service Manual NeoTherm 80 - NeoTherm 285Test Procedure for Air Pressure Switch1. The switch is located behind the front panel. Dis-connect the tw

35Service Manual NeoTherm 80 - NeoTherm 285Procedure - Removing or replacing the switch1. Turn off power to the machine. Use the main disconnect swi

36Service Manual NeoTherm 80 - NeoTherm 285Checking the BlowerB18YesBlower goesto full speed?Replace the SOLA controllerSee Section D8, D9.Unplug J2.

37Service Manual NeoTherm 80 - NeoTherm 285The easiest way to remove the blower is to remove the air/gas channel and blower as an assembly, then separ

38Service Manual NeoTherm 80 - NeoTherm 2854. Unplug the wires running to the gas valve. The connector is keyed, and can only be plugged in one way.

39Service Manual NeoTherm 80 - NeoTherm 285Remove these screwsFig. B19-7 - Removing the air/gas channel and attached blowerRemoving and Replacing the

Service Manual NeoTherm 80 - NeoTherm 285iiiSafety NotesPlease read this section before beginning any troubleshooting procedures. DANGERIf the inform

40Service Manual NeoTherm 80 - NeoTherm 285High Stack Temperature FaultB20YesNoCorrect this immediately.Blocked exhaust outlet?Dirty heat exchanger?If

41Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Stack Temperature Limit SwitchThe stack temperature limit switch will shut down

42Service Manual NeoTherm 80 - NeoTherm 285Checking the System SensorB22Checking the DHW SensorB23The System sensor is mounted in the circulating loop

43Service Manual NeoTherm 80 - NeoTherm 285Inlet Water Temperature SensorA typical installation for the inlet water temperature sensor is shown in Fig

44Service Manual NeoTherm 80 - NeoTherm 285Fig. B26-1 - Outlet water temperature sensor (typical)The outlet water temperature switch allows the contr

45Service Manual NeoTherm 80 - NeoTherm 2854. The outlet water temperature sensor is mounted in the shoulder of the heat exchanger assembly, just abo

46Service Manual NeoTherm 80 - NeoTherm 285Troubleshooting the Outdoor Reset SystemServicing the TransformerFig. B30-1 - Transformer installation (ty

47Service Manual NeoTherm 80 - NeoTherm 285Tools and equipment required:• Volt-Ohmmeter• Phillipsheadscrewdriver(size#1)• Deepsocketfortrans

48Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Pressure Relief ValveIf the system pressure exceeds the relief valve setting, th

49Service Manual NeoTherm 80 - NeoTherm 285Ignitor AssemblyThe ignitor assembly is a two-rod system that con-sists of a ground rod and a spark rod.Adj

Service Manual NeoTherm 80 - NeoTherm 285Electrical Shock HazardElectrical shock can cause severe injury, death or property damage. Only a professiona

50Service Manual NeoTherm 80 - NeoTherm 285The ame sensor is a single-rod system, and is mounted in the front cover of the heat exchanger. Over time

51Service Manual NeoTherm 80 - NeoTherm 285B34Pump FaultA problem with the circulator pump could appear as a #79 error (Outlet High Limit). It could

52Service Manual NeoTherm 80 - NeoTherm 285

53Service Manual NeoTherm 80 - NeoTherm 285Possible Combustion ProblemsAbout Correct CombustionWhen the unit is ring, the gas valve must always suppl

54Service Manual NeoTherm 80 - NeoTherm 285Combustion Adjustment Procedure - Units with Original (White) User Interface WARNING Improper adjustme

55Service Manual NeoTherm 80 - NeoTherm 2852. Once you have completed the high re combustion test, measure the CO2/O2 in the ue products at Low Fir

56Service Manual NeoTherm 80 - NeoTherm 285Combustion Adjustment Procedure - Units with Current User Interface WARNINGImproper adjustment of the h

57Service Manual NeoTherm 80 - NeoTherm 2852. Next, measure the CO2 and O2 in the ue products at low re. The NeoTherm can be forced to remain in lo

58Service Manual NeoTherm 80 - NeoTherm 285Troubleshooting Combustion ProblemsDuring adjiustment,can reach targetfigures in Table?Cannot reachGas inle

59Service Manual NeoTherm 80 - NeoTherm 285Cleaning the Burner and Heat ExchangerThe buildup of black carbon soot on the external surfaces of the heat

Service Manual NeoTherm 80 - NeoTherm 285Table of ContentsSection A - Troubleshooting - Start HereSect. Title ...

60Service Manual NeoTherm 80 - NeoTherm 285Disassembly Procedure:1. Turn off power to the machine. Use the main discon-nect switch on the front of th

61Service Manual NeoTherm 80 - NeoTherm 2858. The gas inlet pipe (black pipe) runs to the underside of the gas valve. It is attached by four 3mm soc

62Service Manual NeoTherm 80 - NeoTherm 28511. Note the two large wires running to this assembly. The spark wire and the ame sense wire look alike.

63Service Manual NeoTherm 80 - NeoTherm 28515. Figure C5-11 shows the inside of the heat exchanger. Black carbon soot can build up on the coils as a

64Service Manual NeoTherm 80 - NeoTherm 2852. Clean the heat exchanger by brushing away any soot with the toilet brush, and collecting the dust using

65Service Manual NeoTherm 80 - NeoTherm 285Identifying the User Interface on Your UnitThere are two main parts to the control system on a NeoTherm uni

66Service Manual NeoTherm 80 - NeoTherm 285Using the Original (White) User InterfaceThisinterfacewasusedonallNeoThermmodelsproducedthrough20

67Service Manual NeoTherm 80 - NeoTherm 285Setup ModeTogototheSetupMode,pressandholdtheUpandDownbuttonsatthesametimeforaboutthree

68Service Manual NeoTherm 80 - NeoTherm 285Using the Original (White) User Interface - continuedNormallyyouwillwanttodothe“highre”setuprst

69Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Original (White) User InterfacePleasecheckthetroubleshootinginstructionsin

Service Manual NeoTherm 80 - NeoTherm 285Table of Contents (continued)B15 Checking the Air Pressure Switch - Blower Proving Switch ...

70Service Manual NeoTherm 80 - NeoTherm 285Using the Current User InterfaceThisinterfaceisusedonallNeoThermmodelsproducedsince2012.Thetable

71Service Manual NeoTherm 80 - NeoTherm 285Home DisplayWhentheboilerisoperatingnormally,thecontrollerwilldisplaytheHomedisplay.SeeFig.

72Service Manual NeoTherm 80 - NeoTherm 285QuickStart Thismenugivesyouaneasywaytocheckorchangethemostcommonset-tings on the unit:•CHs

73Service Manual NeoTherm 80 - NeoTherm 285Youwillnoticethatthesystemdidnotaskyouforapassword,sothisisoneofthevaluesthatcanbech

74Service Manual NeoTherm 80 - NeoTherm 285Entering a Password or NameThe system uses a different type of screen to enter a password or name. If you

75Service Manual NeoTherm 80 - NeoTherm 285Fig. D5-8 - Enable/ disable screenFig. D5-9 – Changing LCD contrastTurning a Function On and OffSomeoft

76Service Manual NeoTherm 80 - NeoTherm 285Reacting to Lockouts on the Current User InterfaceThesystemrespondstothreekindsoftroubleindica-tion

77Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the Current User InterfaceFig. D7-1 - Current user interfaceTools and equipment re

78Service Manual NeoTherm 80 - NeoTherm 2857. Placethenewcircuitboardinpositionandreplacethe screws.8. Pluginthetworibboncableconnect

79Service Manual NeoTherm 80 - NeoTherm 285Removing and Replacing the SOLA ControllerAlloftheNTunitsusetheSOLAcontroller.Thisprocedureexpl

Service Manual NeoTherm 80 - NeoTherm 285Table of Contents (continued)Section D - Using the NeoTherm Control SystemSect. Title PageD1 Identifying th

80Service Manual NeoTherm 80 - NeoTherm 285 Ontherightsideofthecontroller(readingtoptobottom): • DisconnectconnectorCP6fromJ6 • Dis

81Service Manual NeoTherm 80 - NeoTherm 285App1Appendix 1 - Error CodesThis table includes a listing of the faults that might be generated by the cont

82Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)App1cont.Code Description L or H Procedure11 Internal fault:Invalid bur

83Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure26 Internal fault:Static ame rippleH

84Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure53 AC input phases reversed L 1. Check

85Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure79 Outlet high limit H or L 1. Check w

86Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure97 Internal fault: A2D mismatch. L Int

87Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure108 Flame lost in run L 1. Check main

88Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)CodeDescription L or H Procedure129 Fan speed failed during preignition

89Service Manual NeoTherm 80 - NeoTherm 285Appendix 1 - Error Codes (continued)Code Description L or H Procedure153 Combustion pressure off H or L 1.