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Takagi T-H3J-DV, Service Handbook

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12     •        On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models

ERROR CODE

GREEN LED ON 

COMPUTER BOARD

SYMPTOM OR ISSUE

TROUBLESHOOTING PROCEDURE (PAGE NUMBER)

321

Two Flashes

Inlet thermistor failure

Code 311, 321, 331 or 341: Thermistor Failure, p. 16.  

331

Two Flashes

Outlet thermistor failure  

(540 model only)

Code 311, 321, 331 or 341: Thermistor Failure, p. 16.  

341

Two Flashes

Exhaust thermistor 

failure 

(indoor models only)

Code 311, 321, 331 or 341: Thermistor Failure, p. 16.  

391

Two Flashes

Air-fuel ratio rod failure

Code 391: Air-Fuel Ratio Rod Failure, p. 17

.

441

Two Flashes

Flow Sensor Failure 

(Easy-Link or Multi-Link 

System)

Code 441: Flow Sensor Failure (Easy-Link or Multi-Link 

System Only), p. 17.

510

Six Flashes

Abnormal main gas 

solenoid valve (MV)

Code 510: Abnormal Main Gas Solenoid Valve (MV), p. 

17

.

551

Six Flashes

Abnormal gas solenoid 

valve (SV1, SV2, and/

or SV3)

Code 551: Abnormal Solenoid Gas Valve (SV1, SV2, and/

or SV3), p. 18

.

611

Four Flashes

Fan motor fault

Code 611: Abnormal Fan Motor, p. 18

.

651

Four Flashes

Flow adjustment valve 

fault (Easy-Link or Multi-

Link System)

Code 651: Flow Adjustment Valve Fault (Easy-Link or 

Multi-Link System only), p. 18

.

661

Four Flashes

Bypass valve fault  

Code 661: Bypass valve fault 

 

(540 (T-H3) model only), p. 19

.

701

One Flash

Computer board fault

Code 701: Computer Board Fault / Proportional Gas 

Valve Fault, p. 19

.

711

One Flash

Gas solenoid valve drive 

circuit failure

Code 711: High Limit Switch / Overheat Cutoff Fuse 

Circuit is Compromised, p. 19

.

721

Six Flashes

False flame detection

Code 721: False Flame Detection, p. 20

.

741

N/A

Miscommunication 

between water heater 

and remote controller

Code 741: Remote Control Problem, p. 20

.

751

N/A

Miscommunication 

between water heater 

and temperature 

controller (Indoor 

model only)

Code 751: Temperature Controller Problem, p. 20

.

761

N/A

Miscommunication 

between units in an 

Easy-Link or Multi-Link 

system.  (540/T-H3 Only) 

Code 761: Communication Error in Easy-Link or Multi-

Link System, p. 20.

Summary of Contents for T-H3J-DV

Page 1: ...door T H3J DV 240 Outdoor T H3J OS 340 Indoor T H3S DV 340 Outdoor T H3S OS 540 Indoor T H3 DV 540 Outdoor T H3 OS THIS SERVICE HANDBOOK IS FOR USE BY QUALIFIED SERVICE PROFESSIONALS ONLY IF YOU NEED...

Page 2: ...nition Failure Flame Loss 14 Code 311 321 331 or 341 Thermistor Failure 16 Code 391 Air Fuel Ratio Rod Failure 17 Code 441 Flow Sensor Failure Easy Link or Multi Link System Only 17 Code 510 Abnormal...

Page 3: ...ion Components 39 Easy Link Connections with Previous Models 540 T H3 Only 43 DIP Switch Setting on the 540 T H3 Computer Board 43 Temperature Settings 44 Diagnostic Mode 45 Individual Unit 45 Multipl...

Page 4: ...7 NAT 2 4 0 60 LP 3 2 0 80 NAT 2 8 0 70 LP 3 2 0 80 NAT 2 9 0 72 Min inch W C kPa LP 0 6 0 15 NAT 0 7 0 17 LP 0 7 0 17 NAT 0 7 0 17 LP 0 6 0 15 NAT 0 7 0 17 LP 0 7 0 17 NAT 0 7 0 17 LP 0 6 0 15 NAT 0...

Page 5: ...d order Here is how to use this manual First refer to the Installation Manual as the primary source of information Refer to it along side this manual throughout the troubleshooting process Before trou...

Page 6: ...odels only Figure 1 The purpose of this diagram is to illustrate tankless water heater design concepts and may not be accurate to the unit s physical description Operation 10 The proportional gas valv...

Page 7: ...heater must sense water flow to initialize operations Water flowing through the heater backwards will not activate the flow sensor A dirty inlet filter A dirty inlet filter can either prevent water fr...

Page 8: ...The gas line may be sized improperly The gas supply pressure may be too low This may be caused by a malfunctioning gas supply regulator so check to see if the regulator is working properly See Check g...

Page 9: ...t per hour This number must be less than the maximum ratings shown on the gas meter s rating plate If the maximum energy input of all appliances exceeds the maximum rating of the gas meter consult you...

Page 10: ...w on the display points toward IN Refer to error code indicator in Figure 3 p 11 Check that the gas line is open and is purged of air page 33 Are the hot and cold water connections to the water heater...

Page 11: ...21 Three Flashes Ignition failure Loss of flame Code 111 or 121 Ignition Failure Flame Loss p 14 311 Two Flashes Outlet thermistor failure 240 340 models Heat Exchanger Thermistor Failure 540 models C...

Page 12: ...SV3 Code 551 Abnormal Solenoid Gas Valve SV1 SV2 and or SV3 p 18 611 Four Flashes Fan motor fault Code 611 Abnormal Fan Motor p 18 651 Four Flashes Flow adjustment valve fault Easy Link or Multi Link...

Page 13: ...Models 13 ERROR CODE GREEN LED ON COMPUTER BOARD SYMPTOM OR ISSUE TROUBLESHOOTING PROCEDURE PAGE NUMBER 941 Five Flashes Abnormal exhaust temperature Indoor model only Code 941 Abnormal Exhaust Temper...

Page 14: ...was not able to establish a flame after three failed ignition attempts code 121 These codes can appear due to a component in the heater or due to an external cause such as no gas supply Also these co...

Page 15: ...dy and in place while a weak spark will jump around 5 1 If no spark or a weak spark is observed check the purple igniter wire connections at both the igniter and at the computer board Unplug and recon...

Page 16: ...ire connections are secure and free of burns or cuts 4 Check the thermistor s resistance value See Table 4 for a list of normal resistance values 5 Clean the thermistor as follows a Drain the unit of...

Page 17: ...ly is turned on 3 Check the flow sensor control valve wires to see if they are broken or disconnected Refer to Figure 41 p 49 or Figure 42 p 50 4 Verify the flow rate using the water heater s controll...

Page 18: ...re that there are no contaminants inside the water heater cabinet Correct any issues that are found 3 Visually check for breakages in the fan motor wiring or burn marks on the computer board PCB Repai...

Page 19: ...tlet thermistor as follows 3 1 Push the on off button on the temperature controller or remote controller so the orange STAND BY LED turns off 3 2 Run water through the heater 3 3 Check the reading of...

Page 20: ...onnected to the remote controller properly 4 Power surges can cause this fault If frequent power surges occur install adequate surge protection to prevent nuisance faults 5 Check the voltage across th...

Page 21: ...re to any or all safety procedures specifically in regards to electrical and gas safety 1 Check the rating plate to verify that the gas type of the water heater matches the gas type applied to the uni...

Page 22: ...ill become gas rich and trigger the 101 or 991 code To check and clean the fan see Cleaning the Combustion Components page 39 To check and clean the burner refer to Cleaning the Combustion Components...

Page 23: ...tion of the exhaust temperature control Enable Disable Default DEFAULT No 3 OFF No 4 OFF No 5 OFF OFF ON 1 2 3 4 5 6 7 8 9 10 Propane OFF ON 1 2 3 4 5 6 7 8 9 10 Natural Gas OFF ON 1 2 3 4 5 6 7 8 9 1...

Page 24: ...control This switch is for a specialized purpose only Enable Disable Default 7 N A Do not change switch position N A N A Default 8 Deactivation of the freeze protection ring system Enable Disable Defa...

Page 25: ...T H3 Model Computer Board Figure 11 No Functions ON position OFF position 1 Parent Child setting for Easy Link Systems Parent Child Default 2 3 4 FM FM and Input Fan motor speed is increased automati...

Page 26: ...eed change No 3 No 4 No 5 0 to 2 000 ft 0 DEFAULT OFF OFF OFF N A N A 2 000 to 3 000 ft 1 OFF ON OFF N A 6 3 000 to 5 000 ft 2 ON ON OFF 6 10 3 OFF OFF ON 9 14 5 000 to 7 500 ft 4 ON OFF ON 12 18 5 OF...

Page 27: ...OFF OFF N A 7 Elevation Level DIP switch settings Output reduction Fan motor speed change No 3 No 4 No 5 0 to 2 000 ft 0 DEFAULT OFF OFF OFF N A N A 1 OFF ON OFF N A 6 2 000 to 4 000 ft 2 OFF OFF ON...

Page 28: ...lower bank See Figure 14 Figure 14 Lower bank of DIP switches 540 T H3 Elevation Level DIP switch settings Output reduction Fan motor speed change No 2 No 3 No 4 0 to 2 000 ft 0 DEFAULT OFF OFF OFF N...

Page 29: ...motor speed change No 2 No 3 No 4 0 to 2 000 ft 0 DEFAULT OFF OFF OFF N A N A 1 OFF ON OFF N A 6 2 000 to 4 000 ft 2 OFF OFF ON 9 14 4 000 to 6 000 ft 3 ON OFF ON 12 18 Special function ON OFF OFF N...

Page 30: ...Switch BL Gas Propor Valve W R BL BL BL BL P BK BK W BK BK Outlet thermistor Inlet thermistor Surge box Hi limit switch for exhaust Exhaust thermistor W W W W BK W BL R BK Temperature controller Heat...

Page 31: ...Y BL Gas Propor Valve R Y O BL W FM IG Igniter rod P P exchanger Heat thermistor Inlet thermistor Outlet thermistor Temperature remote controller optional accessory Parent 1 2 Flow Sensor Flow Adjust...

Page 32: ...in port then open their valves to drain the water 6 3 Go to step 8 7 Place a bucket or pan under the water filter drain plug to catch the water when it drains Figure 17 You may also drain the water to...

Page 33: ...ulation ensure that they are turned off 2 Turn on hot water at one fixture in the structure Make sure that it is located at the highest point possible If possible use the hot side of a two handle fixt...

Page 34: ...king the Manifold Gas Pressure 1 Verify that the gas supply pressure is within the correct operating range when the heater fires at maximum combustion Incorrect gas supply pressure will affect the gas...

Page 35: ...rify proper operation Adjusting Minimum Manifold Pressure WARNING Complete the following procedure ONLY if you have been instructed to do so by the Technical Service Department See WARNING text at the...

Page 36: ...ll display flow if the flow sensor is working properly 2 Remove the flow sensor as described in Flow Sensor Control Valve Removal and Installation page 51 3 Blow into the inlet of the flow sensor Watc...

Page 37: ...inside of the burner Use 100 grit sandpaper or other suitable abrasive Be sure to remove any oxidation or contaminates 5 2 Clean the portion of the air fuel ratio rod that extends to the inside of the...

Page 38: ...alves C D 5 Pour the white vinegar 3 gallons into the five gallon bucket 6 Connect one hose to the transfer pump s discharge outlet Connect its opposite end to the service connection at the cold water...

Page 39: ...the computer board 2 Remove the computer board from the water heater according to the following steps See also Figure 41 p 49 or Figure 42 p 50 2 1 INDOOR MODELS ONLY Unplug the wire connectors for t...

Page 40: ...from the manifold plate assembly 5 8 Inspect the gaskets on the manifold plate for any tears If compromised replace with part number 100074229 item 113 and or 100074230 item 114 See p 73 5 9 Inspect t...

Page 41: ...ter from the burner with compressed air 7 5 Inspect the gasket Minor surface tears are acceptable If the gasket shows major separations replace the gasket before the unit is returned to service 8 Clea...

Page 42: ...connectstothe gasproportionalvalveisnotlabeled withanumber Ithastwowires red andwhite Seeschematicsonpages 30or31 NOTICE If necessary refer to the exploded assembly views which start on page 71 Inspec...

Page 43: ...ect Easy Link connections Temperature remote controller 9008172005 TM RE40 540 T H3 Previous model Previous model Previous model Case 1 Temperature remote controller 9007603005 TM RE30 Previous model...

Page 44: ...mperature remote controller 100112155 TM RE30 See Figure 37 page 43 The 520 T H2 or 710 T M32 can be connected with temperature remote controller 9007603005 TM RE30 but they cannot be connected with t...

Page 45: ...ostic mode press and hold the HOT and COLD buttons simultaneously for at least five seconds NOTE You may exit diagnostic mode by pressing the ON OFF button Also if left alone the display will exit dia...

Page 46: ...umber Figure 40 shows that mode number 6 is selected See Table 18 page 47 for a list of mode numbers and their meanings Figure 40 Whole diagnostic mode Unit no Mode no Information This example shows t...

Page 47: ...current rotation 0 to 720 minutes After 720 the next rotation occurs Air Fuel ratio rod current 0 to 999 A 8 ON OFF cycles during current rotation 0 to 100 cycles After 100 the next rotation occurs Fl...

Page 48: ...SERVICE PROCEDURES 48 On Demand Water Heater Service Handbook for 240 340 540 Condensing Models This page is left blank to preserve facing pages...

Page 49: ...Screw Secures the Computer Board Assembly Fuse Box Computer Board PCB High Limit Switch Exhaust Exhaust Thermistor See also Component Diagrams Item Numbers which starts on page 71 Air Fuel Ratio Rod...

Page 50: ...eat Exchanger Igniter Rod Wire Connection Secondary Heat Exchanger Over heat Cutoff Fuse OHCF Flame Rod AFR Wire Connections This Screw Secures the Computer Board Assembly Fuse Box Computer Board PCB...

Page 51: ...ems 460 461 page 74 6 2 Pull the cold connection tube item 466 page 74 from the outlet of the flow sensor control valve then lift the valve off the inlet connection You may have to twist the valve off...

Page 52: ...gure 42 p 50 2 1 INDOOR MODELS ONLY Unplug the wire connectors for the exhaust high limit switch item 472 p 74 and the exhaust thermistor item 718 p 74 See also Figure 41 page 49 2 2 Disconnect these...

Page 53: ...item 113 and or 100074230 item 114 See p 73 5 9 Inspect the o ring item 151 p 73 and gas inlet ring item 119 p 73 at the gas connection for cuts or breaks If damaged replace with part number 100074242...

Page 54: ...If you removed the white connectors from the solenoids reconnect them Match the printed number on the wire to the corresponding number that is stamped on the solenoid body See Figure 46 For example if...

Page 55: ...onnections in the figure noted above 9 INDOOR MODELS Connect the wires from the temperature controller item 722 page 71 to the computer board The correct receptacle is shown in one of these schematics...

Page 56: ...472 p 74 and the exhaust thermistor item 718 p 74 See also Figure 41 page 49 2 2 Disconnect these wires from the front of the burner Flame rod wire orange See Figure 41 p 49 or Figure 42 p 50 center o...

Page 57: ...s or breaks If damaged replace with part number 100074242 item 151 and or 100074526 item 119 Gas Valve Manifold Plate Installation 6 Install the gas valve manifold assembly See item 102 p 73 6 1 Attac...

Page 58: ...ction in the figure noted above Insert the connector from the power supply cable to its port on the fuse box See Fuse Box in the figure noted above Reinstall the flame rod AFR wires See Flame Rod AFR...

Page 59: ...MAINTENANCE On Demand Water Heater Service Handbook for 240 340 540 Condensing Models 59 MAINTENANCE This page is left blank to preserve facing pages...

Page 60: ...easier 1 Shut the unit down as follows 1 1 Shut Off power and gas supply as follows 1 1 1 Shut off Power by disconnecting the power cord or shutting off the power disconnect 1 1 2 Shut off the gas sup...

Page 61: ...ave a 540 model with a bypass valve you must remove an additional fastener See item 458 at connection point A two places page 74 5 2 Pull the cold connection tube item 466 page 74 from the outlet of t...

Page 62: ...Figure 41 p 49 9 5 Disconnect the air tube off the left side of the gas valve Figure 57 See also Clear Plastic Tube in Figure 41 p 49 Manifold Screws DO NOT remove the screws indicated by the white cr...

Page 63: ...High Limit Switch wires clip the zip tie to separate them Figure 60 NOTICE Do not cut nick or damage the wires when clipping the zip tie 11 Remove the burner from the combustion chamber 11 1 Remove tw...

Page 64: ...out of the copper pipe 12 6 INDOOR MODELS Disconnect the venting from the exhaust flue 12 7 IF you have a 540 model disconnect the bypass valve wiring as follows Heat Exchanger Thermistor 540 Models O...

Page 65: ...2 Remove the following items from the primary heat exchanger and INSTALL THEM IN THE SAME LOCATIONS ON THE NEW PRIMARY HEAT EXCHANGER High limit switch on the left side item 412 page 74 Over heat Cut...

Page 66: ...st on a flange on the inside of the case INDOOR MODELS Make sure that the flue gasket item 154 page 74 is on the inside of the case 5 Insertandhandtightenthree 3 screwsasshowninFigure63 page 64 Thiswi...

Page 67: ...p See item 462 on page 74 11 Attachthetopofthecondensate draintubetotheportonthebottom ofthesecondaryheatexchanger See Item416onpage74 12 Install the fan with the air inlet facing toward the front as...

Page 68: ...tabs at the connection Hand tighten only See Brass Screw Securing Gas Valve in Figure 41 p 49 13 5 Attach the air tube from the bottom of the combustion chamber to the port on the left side of the gas...

Page 69: ...it by hand tightening both mounting screws 20 Reconnect the freeze protection heater wiring Connect each male female pair of connectors that have YELLOW wires When you finish you will have reconnected...

Page 70: ...ns inside the cabinet Locate the two unsecured ground wires green Secure them with screws as shown in Figure 72 Locate the plug and receptacle with blue wires Plug them together at the left hand side...

Page 71: ...Models 71 COMPONENT DIAGRAMS ITEM NUMBERS Indoor model Outdoor model Case assembly 052 052 003 007 002 050 006 704 005 052 702 704 008 052 050 052 717 702 713 004 002 001 001 004 Temperature remote c...

Page 72: ...MPONENT DIAGRAMS ITEM NUMBERS CONT Computer board assembly Surge box assembly 540 T H3 model 240 T H3J and 340 T H3S model 710 701 713 103 709 402 707 708 714 721 407 408 701 714 403 715 721 707 722 7...

Page 73: ...assembly 101 104 115 106 107 108 110 109 111 712 112 062 053 053 709 053 401 103 105 065 054 113 114 102 708 119 151 118 055 051 150 057 055 063 117 053 116 062 121 714 719 707 711 117 540 T H3 model...

Page 74: ...ssembly D A E 459 454 411 412 058 F 413 452 450 414 451 414 418 416 009 C 453 468 468 052 455 463 455 469 052 463 462 467 064 462 462 473 466 466 415 451 465 418 414 464 471 064 D 472 153 152 053 718...

Page 75: ...ord assembly 007 N A EK161 Back guard panel 008 N A EK160 Chamber fixing plate 009 100074203 EKH23 Condensate drain port 050 N A EW000 Truss screw M4x12 w washer SUS410 051 N A EW001 Truss screw M4x10...

Page 76: ...230 EKK2K Manifold gasket B 115 100074217 EKK0G Burner holder gasket 116 100074227 EKK2D Pressure port 117 N A EX019 Combustion chamber tube 118 100074616 EK117 Gas inlet 119 100074526 EX00D Gas inlet...

Page 77: ...333 Overheat cut off fuse 414 100074682 EK209 Pipe heater 415 100074683 EK210 Inlet heater for Indoor model 100074684 EK211 Inlet heater for Outdoor model 416 100074685 EK231 Drain tube 417 100074629...

Page 78: ...00076100 EK280 Surge box 704 100074601 EK146 120 VAC wire for Indoor model 100074697 EK143 120 VAC wire for Outdoor model 706 100074326 EKK4V 120 VAC Power ON OFF switch 707 100074649 EK189 Remote con...

Page 79: ...340 540 Condensing Models 79 COMPONENT ITEM NUMBERS CONT Item Part Description 240 340 and 540 models T H3J T H3S and T H3 models 723 N A EK178 Fixing plate 724 100112572 TM RE40 Temperature remote c...

Page 80: ...80 On Demand Water Heater Service Handbook for 240 340 540 Condensing Models Copyright 2016 A O Smith Corporation All rights reserved...

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