A.O. Smith T-H3J-DV Service Manual
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A.O. Smith T-H3J-DV Service Manual

On-demand water heater
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240 (T-H3J), 340 (T-H3S)
and 540 (T-H3) Models
On-Demand Water Heater
Service Manual
A.O. Smith Water Products
Company
500 Tennessee Waltz Parkway
Ashland City, TN 37015
Toll Free: 1-877-737-2840

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Summary of Contents for A.O. Smith T-H3J-DV

  • Page 1 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) Models On-Demand Water Heater Service Manual A.O. Smith Water Products Company 500 Tennessee Waltz Parkway Ashland City, TN 37015 Toll Free: 1-877-737-2840...

  • Page 2: Table Of Contents

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Table of Contents   1. Specifications........................  2. Exterior view........................  3. Interior view........................  4. List of main components in the interior view..............5. Schematic diagram......................6.

  • Page 3: Specifications

    240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 1. Specifications Model Indoor Outdoor Indoor Outdoor Indoor Outdoor (T-H3J-DV) (T-H3J-OS) (T-H3S-DV) (T-H3S-OS) (T-H3-DV) (T-H3-OS) inch H 22.4 x W 17.7 x D 10.7 Dimensions 570 (H) x 450 (W) x 272 (D) Weight lbs.

  • Page 4: Exterior View

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 2. Exterior view Direct Vnet Indoor models Side view Front view 17-3/4" (450 mm) 7" (180 mm) 4" (101 mm) 11-1/4" (285 mm) 4" (102 mm) 4" (102 mm) 5-3/4"...

  • Page 5: Top View

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Outdoor models Front view Side view 17-3/4" (450 mm) 7" (180 mm) 11-1/4" (285 mm) 4-1/2" (114 mm) 11" (281 mm) 10-3/4" (272 mm) 1/2" (13 mm) HOT 4-3/4"...

  • Page 6: Interior View

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 3. Interior view 240 Indoor (T-H3J-DV) 340 Indoor (T-H3S-DV) AC120V Page...
  • Page 7 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 240 Outdoor (T-H3J-OS) 340 Outdoor (T-H3S-OS) AC120V Page...
  • Page 8 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 540 Indoor (T-H3-DV) AC120V Page...
  • Page 9 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 540 Outdoor (T-H3-OS) AC120V Page...

  • Page 10: List Of Main Components In The Interior View

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 4. List of main components in the interior view Items# in Part # Description components 240, 340 and T-H3J, T-H3S and diagram 540 models T-H3 models Indoor EK159 models Case assembly...
  • Page 11 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Items# in Part # Description components 240, 340 and T-H3J, T-H3S and diagram 540 models T-H3 models Indoor 319143-443 EK109 models Fan motor Outdoor 319143-043 EKK25 models Indoor Freeze 319143-496...
  • Page 12 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Items# in Part # Description components 240, 340 and T-H3J, T-H3S and diagram 540 models T-H3 models Manifold port Gas inlet port 319143-525 EK198 Indoor (240/340 models) (T-H3J/T-H3S models) 319143-527 models...

  • Page 13: Schematic Diagram

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 5. Schematic diagram The diagram below refers to both the Direct Vent Indoor models and Outdoor models. Direct Vent Indoor models only Hi-limit switch for exhaust Intake port Exhaust Exhaust thermistor Secondary heat exchanger...

  • Page 14: Wiring Diagram

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 6. Wiring diagram 240 (T-H3J) models / 340 (T-H3S) models W: WHITE BK: BLACK LB: LIGHT BLUE R: RED BL: BLUE Y: YELLOW G: GREEN O: ORANGE BR: BROWN P: PURPLE 240/340 Outdoor...
  • Page 15 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 540 (T-H3) models W: WHITE BK: BLACK LB: LIGHT BLUE R: RED BL: BLUE Y: YELLOW G: GREEN O: ORANGE BR: BROWN P: PURPLE 540 Outdoor 540 Direct Vent Indoor Heater Heater Heater...

  • Page 16: Wiring Diagram Checkpoints For Diagnosis

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 7. Wiring diagram check points for diagnosis The table below applies to both the the Direct Vent Indoor models and Outdoor models. Check- Part and Description Color of wires Normal range point 120V Power supply...
  • Page 17 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Check- Part and Description Color of wires Normal range point Remote controller White – Black 11 to 25 VDC Red - Blue 132 to 192 VDC Fan motor Yellow - Blue 13 to 17 VDC Orange - Blue...

  • Page 18: A) Resistance Values Of The Temperature Thermistors

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 8. (A) Resistance values of the temperature thermistors The the Direct Vent Indoor models and Outdoor models use the same thermistors. Resisitance values at different temperatures °F Temperature °C Resistance...

  • Page 19: B) Resistance Values Of The Temperature Exhaust Thermistors

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 8. (B) Resistance values of the temperature exhaust thermistor Only the Direct Vent Indoor models are equipped with the exhaust thermistor. Resisitance values at different temperatures °F Temperature °C Resistance...

  • Page 20: Operational Flow Chart

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 9. Operational flow chart The diagram below refers to both the Direct Vent Indoor models and Outdoor models. Power supply ON FAV&BV open Operation SW ON Remove cause Opeartion lamp OFF Operation stop Pre-check...

  • Page 21: Component Specifications

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10. Component specifications   10-1. Burners.........................   10-2. Gas manifold........................   10-3. Fan motor........................  10-4. Gas valve assembly...................... 10-5. Flame rod........................10-6. AFR rod......................... 10-7. Heat exchanger......................10-8.

  • Page 22: Burners

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-1. Burners Part # • 319143-514 (EK192) Unit Part# #101 There are 2 types of burners in the burner assembly: the gas-rich burner stabilizes the flames within the combustion chamber and the air-rich burner produces more heat in the combustion chamber.

  • Page 23: Gas Manifold

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-2. Gas manifold • 319143-515 (EK181) : Propane Included Part # Unit Part# • 319143-516 (EK182) : Natural gas in #102 1. The manifold distributes gas from the gas valves to the burners. The manifold has two types of the nozzles: one type for gas-rich burners (16 nozzles) and the other for air-rich burners (15 nozzles) Function...

  • Page 24: Fan Motor

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-3. Fan motor • 319143-443 (EK109) : Direct Vent Indoor model Part # Unit Part# #103 • 319143-043 (EKK25) : Outdoor model To provide combustion air into the combustion chamber and to exhaust Function flue gas.

  • Page 25: Gas Valve Assembly

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-4. Gas valve assembly • 319143-515 (EK181) : Propane Included in Part# Unit Part# • 319143-516 (EK182) : Natural gas #102 Opens and closes the gas pathways of the water heater (main and solenoid gas valves) Function Modulates the gas flow from the gas inlet (proportional gas valve)

  • Page 26: Flame Rod

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-5. Flame rod Part # • 319143-517 (EK193) Unit Part# #108 Function To detect flames while the water heater is in operation. 1. Unable to detect flames when flames actually do occur. Failure events 2.

  • Page 27: Afr Rod

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-6. AFR rod Part # • 319143-517 (EK193) Unit Part# #108 Checks flame conditions during combustion. Function When AFR rod detects unexpected flame conditions, the computer of the water heater makes adjustments in the fan motor speed to compensate.

  • Page 28: Heat Exchanger

    Color / Number of wires Checkpoint NOTE: Pictures are on the following page Part # Model 319143-525 EK198 240 Indoor (T-H3J-DV) / 340 (T-H3S-DV) 319143-526 EK199 240 Outdoor (T-H3J-OS) / 340 (T-H3S-OS) 319143-527 EK200 540 Indoor (T-H3-DV) 319143-528...
  • Page 29 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-7. Heat exchanger The heat exchanger of the 240 (T-H3J) and 340 (T-H3S) models have the “77” mark, and 540 (T-H3) models have the "P77" mark as shown below. 240, 340 Indoor (T-H3J, T-H3S-DV) 240, 340 Outdoor (T-H3J, T-H3S-OS) 11"...

  • Page 30: Secondary Heat Exchanger

    Inspect for soot buildup inside the secondary heat exchanger. Color / Number of wires Checkpoint NOTE: Pictures are on the following page Part # Model 319143-525 EK198 240 Indoor (T-H3J-DV) / 340 (T-H3S-DV) 319143-526 EK199 240 Outdoor (T-H3J-OS) / 340 (T-H3S-OS) 319143-527 EK200 540 Indoor (T-H3-DV) 319143-528...
  • Page 31 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-8. Secondary heat exchanger The heat exchanger of the 240 (T-H3J) and 340 (T-H3S) models have the “77” mark, and 540 (T-H3) models have the "P77" mark as shown below. 240, 340 Indoor (T-H3J, T-H3S-DV) 240, 340 Outdoor (T-H3J, T-H3S-OS) 11"...

  • Page 32: Flow Adjustment Valve

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-9. Flow adjustment valve Part# • 319143-463 (EK129) Unit Part# #402 Function Controls water flow to properly control the output hot water temperature. 1. Water leakage from valve. Failure events 2.

  • Page 33: Flow Sensor

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-10. Flow sensor Part# • 319143-463 (EK129) Unit Part# #402 Detects and measures water flow rate using a spinning impeller and Function magnetic pick-up. Failure events Unable to detect or measure any water flow rate. Ignition sequence does not start (water heater will not initiate any Effects on the water heater operation)

  • Page 34: Bypass Valve

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-11. Bypass valve (540 (T-H3) models only) • 319143-464 (EKD58) Part # Unit Part# #403 540 (T-H3) models only 1. Mixes hot water from the heat exchanger with cold water from the water inlet in order to modulate and control the water heater’s outlet water temperature.

  • Page 35: Thermistors

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-12. Thermistors #407 (Inlet) Unit Part # *See the table below #408 (Outlet ) Part# #411 (Heat exchanger) Function Measures cold/hot water temperatures in the water heater. Failure events Unable to properly measure water temperatures within the water heater.
  • Page 36 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-12. Thermistors 240 (T-H3J) and 340 (T-H3S) models Part# 319143-214 (EKK4J) (Inlet thermistor) 42 Part# 319143-529 (EK207) (Outlet thermistor) 113 540 (T-H3) models Black Part# 319143-465 (EK137) (Inlet thermistor) 42 Blue Part# 319143-190 (EKK1A)

  • Page 37: Exhaust Thermistors

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-13. Exhaust thermistor Part# • 319143-131 (EKH6E) Unit Part# #718 Function Measures the exhaust temperatures in the secondary heat exchanger. Failure events Unable to measure exhaust temperature in the exhaust chamber properly. If the thermistors fail open or short, error code appears before starting Effects on the water heater operation.

  • Page 38: Hi-Limit Switch

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-14. Hi-limit switch • 319143-228 (EM212) 240 (T-H3J) /340 (T-H3S) models Part# Unit Part# #412 • 319143-095 (EKN34) 540 (T-H3) models -Based on bi-metal thermal expansion. -Detects excessively high water temperature in pipes of the heat exchanger. -After detection, communication between the computer board and gas Function valves are severed, shutting down the water heater instantly.
  • Page 39 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-14. Hi-limit switch After the hi-limit switch was working, refer to the following procedure. 1. Turn off the controller. 2. Open a hot water tap and lower the temperature of the heat exchanger. 3.

  • Page 40: Hi-Limit Switch For Exhaust

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-15. Hi-limit switch for exhaust Part# • 319143-104 (EKH6G) Unit Part# #472 -Based on bi-metal thermal expansion. -Detects excess temperature (more than 151˚F or 66˚C) of exhaust gas in Function the exhaust chamber.

  • Page 41: Overheat Cutoff Fuse

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-16. Overheat cut off fuse Part# • 319143-149 (EK333) Unit Part# #413 -The overheat cutoff fuse contains solder with a melting point of 430 ˚F (221 ˚C). -Detects excessive temperatures within the water heater, especially around the heat exchanger and combustion chamber.

  • Page 42: Freeze Protection Heaters

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-17. Freeze protection heaters • 319143-531 (EK209) #414 • 319143-532 (EK210) : Indoor #415 Part# • 319143-533 (EK211) : Outdoor Unit Part# • 319143-468 (EK105) #417 • 319143-535 (EK217) #464 Prevents the heat exchanger, water valves, and water pipes within the water heater from freezing.

  • Page 43: Computer Board

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-18. Computer board • 319143-543 (EK186): 240 (T-H3J) models Part# • 319143-544 (EK175): 340 (T-H3S) models Unit Part# #701 • 319143-545 (EK176): 540 (T-H3) models Function Controls the functions of most of the parts in the water heater. Failure events Malfunctioning computer -A component(s) may not operate within the water heater.

  • Page 44: Igniter

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-19. Igniter Part # • 319143-479 (EK153) Unit Part# #711 -To ignite the gas/air mixtures when the water heater is ready to burn gas on its burner surface. Function -The output voltage of the igniter is more than 14 kVDC.

  • Page 45: Freeze Protection Thermostat

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-20. Freeze protection thermostat • 319143-496 (EK184): Indoor Part# Unit Part# #713 • 319143-497 (EK185): Outdoor Temperature detecting device which prevents the pipes within the water heater from freezing. When this device detects temperatures below 36.5 ˚F Function (2.5 ˚C) inside the water r heater, power is supplied to the electric heaters to prevent the water heater from freezing.

  • Page 46: Surge Box

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 10-21. Surge box Part# Unit Part# #121 • 319143-522 (EK163) Protects the unit from high voltage and/or high electric current caused by lightning. There are 2 types of surge absorbers in the water heater. Surge absorber Function A is activated by voltage higher than 220 V, the other one is activated by voltage higher than 680 V.

  • Page 47: Fault Analysis & Specifications

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 11. Fault Analysis & Specifications Remarks: 1. Proper range of values of voltage & resistance shown below. 2. Please refer to the wiring diagram for checkpoint positions. 3.
  • Page 48 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Check Natural of Fault Diagnosis point 1 Check whether the flow rate is high enough to keep the water heater running. 2 Check if there is a recirculation system installed and check also if the •...
  • Page 49 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Check Natural of Fault Diagnosis point 6 Fault of PCB in the water heater No voltage flow adjustment valve • Fluctuation of hot Normal: 7.0 to 16 VDC between (red-black) water temperature 7 Flow adjustment valve fault Normal: 0.09 to 0.2 kΩ...
  • Page 50 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Ignition failure Turn off the power or water supply Diagnosis Check point 1 Check gas supply and inlet gas pressure (Refer to section 1) 2 Check the igniter (Refer to section 10-19) Visual inspection: connection/breakage of wires and/or observed weak spark.
  • Page 51 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Loss of flame Turn off the power or water supply Diagnosis Check point 1 Check gas supply and pressure (Refer to section 1) 2 PCB fault  [1] No voltage to gas main solenoid valve (MV) Normal: 93 to 120 VDC between COM (blue) &...
  • Page 52 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Disconnected/short-circuited inlet thermistor Turn off the power or water supply Diagnosis Check point 1 Inlet thermistor fault (Refer to section 10-12) Visual inspection: connection/breakage of wires and/or debris on thermistor.
  • Page 53 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Flow sensor failure (Only Easy-link system) Turn off the power or water supply Diagnosis Check point 1 Flow sensor fault (Refer to section 10-10) Visual inspection: connection/breakage of wires and/or debris on impeller.
  • Page 54 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Fan motor fault Turn off the power or water supply Diagnosis Check point 1 PCB and fan motor fault (Refer to section 10-3 & 10-18) Visual inspection of fan motor: connection/breakage of wires or dust buildup (causing electrical shortage) Normal: 132 to 192 VDC between red &...
  • Page 55 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method 1 PCB fault (701 error code)  [1] Fault of preparation for the outlet thermistor Turn off the power or water supply operation.
  • Page 56 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Miscommunication between water heater and When computer detects temperature controller (Direct Vent Indoor proper connections between the models only) water heater and the temperature controller, "751"...
  • Page 57 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Error Code Malfunction description Cancellation method Abnormal exhaust temperature Turn off the power or water supply (Direct Vent Indoor models only) Diagnosis Check point 1 Check how long the water heater has been installed and in use. 2 Check the vent length.

  • Page 58: Controls And Settings

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12. Controls and settings 12-1. Diagnosis using the temperature controller and temperature remote controller..59 12-2. Verifying functionality of computer board..............63 12-3. Displaying error code history, Clearing error code history memory, and Display patterns for error codes....................64 12-4.

  • Page 59: Diagnosis Using The Temperature Controller And Temperature Remote Controller

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-1. Diagnosis using the temperature controller and temperature remote controller   TEMPERATURE CONTROLLER and TEMPERATU REREMOTE CONTROLLER The illustration below shows an example of the controllers. The exact display may differ from examples. Temperature controller Temperature remote controller Display for Temperature...
  • Page 60 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 < For multiple units in an Easy-Link system >   1. Press and hold the "HOT" and "COLD" buttons simultaneously for at least 5 seconds to enter “Diagnostics Mode”.
  • Page 61 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Description of mode numbers in “Diagnostics Mode” Mode # Whole multi-unit system information (#0) Unit information (#1 to #4) Total system flow rate 0 to 999 (GPM) Total operation time 0 to 999 (x 100 hours) BTU requirement for...
  • Page 62 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Mode # Whole multi-unit system information (#0) Unit information (#1 to #4) Bypass valve 0 to 999 (x 10 steps) position** closed position = 0 Ratio of hot water and 0 to 999 (%) cold water** EEPROM Initialization...

  • Page 63: Verifying Functionality Of Computer Board

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-2. Verifying functionality of computer board A. How to check if the computer board works properly Check the power ON-OFF switch of the water heater. AC120V The factory setting is ON position. Power ON-OFF switch Temperature remote controller...

  • Page 64: Displaying Error Code History, Clearing Error Code History Memory And Display Patterns For Error Codes

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-3. Displaying error code history, Clearing error code history memory and Display patterns for error codes Displaying error code history Check the mode #11 to 13 of "Diagnostic Mode" of the controller.

  • Page 65: Clearing The "101" And "991" Error Code

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-4. Clearing the “101” and “991” error code The “101” and “991” error codes signify imperfect (abnormal) combustion, caused by insufficient intake air and/or obstructions in the exhaust. A.

  • Page 66: Afr Rod Function

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-5. AFR rod function <Function> The AFR rod checks flame conditions during combustion. When the AFR rod detects unexpected flame conditions, the computer board of the water heater adjusts the fan motor speed to ensure that air and fuel are always at a proper mixture ratio, minimizing emissions.

  • Page 67: Dipswitch Settings

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-6. DIPswitch settings 240 (T-H3J) and 340 (T-H3S) models The 240 (T-H3J) /340 (T-H3S) Indoor shares the computer Computer board board with the 240 (T-H3J) /340 (T-H3S) Outdoor. The DIPswitches have certain special functions as shown on the following table and generally should not need adjustment.
  • Page 68 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 The 540 Indoor (T-H3-DV) shares the computer board with the 540 Outdoor 540 (T-H3) models (T-H3-OS). There are two banks of DIPswitches computer board Upper bank of (upper and lower bank) on the computer board.
  • Page 69 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 The lower bank of DIPswitches Functions ON position OFF position Parent/Child setting for Easy-Link systems Parent Child (Default) FM+, FM- and Input- (FM speed is increased automatically. See section 12-13) DEFAULT ON 1 2 3 4 5 6 No.2: OFF...

  • Page 70: Assigning Unit Numbers In The Easy-Link System Only 540 (T-H3) Models

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-7. Assigning unit numbers in the Easy-link system Only 540 (T-H3) models 540 (T-H3) models computer board A. How to display the unit number    Press the “Increase” button on the computer board of child unit.

  • Page 71: A) On/Off Conditions: Overview

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-8. (A) ON/OFF conditions: Overview The following table shows the ON/OFF conditions of the water heater. ON / OFF Conditions The BTU requirement is more than 29,800 BTU/h Inlet water temperature is lower 5.4 °F than the set temperature and BTU requirement is more than 14,880 BTU/h Conditions needed...

  • Page 72: B) On/Off Conditions: Btu Requirements

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-8. (B) ON/OFF conditions: BTU requirements A. Calculating the ON/OFF conditions of the water heater    "Condition needed to turn the water heater ON" – T ) × GPM × 500 > 14,880 "Condition needed to turn the water heater OFF"...

  • Page 73: Multi-Unit System On/Off Conditions Only 540 (T-H3) Models

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-9. Multi-unit system ON/OFF conditions Only 540 (T-H3) models In an Easy-Link system, the amount of 540 (T-H3) models called on to activate depends on the FLOW RATE and the SET TEMPERATURE.

  • Page 74: Operation Time For Unit Rotation Only 540 (T-H3) Models

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-10. Operation time for unit rotation Only 540 (T-H3) models The unit that turns on first is whichever unit the 540 (T-H3) models decides is the primary unit. The priority unit will rotate when it reaches 100 ON/OFF cycles or after 12 hours of operation.

  • Page 75: Individual Unit Operation In Easy-Link System While Parent Unit Is Under Abnormal Conditions (Individual Operation Mode) Only 540 (T-H3) Models

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-11. Individual unit operation in easy-link system while parent unit is under abnormal conditions (Individual operation mode) Only 540 (T-H3) models In an easy-link system, if a parent unit undergoes abnormal conditions, the 540 (T-H3) models can operate as individual units.

  • Page 76: Easy-Link Connections With Previous Models

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-12. Easy-Link connections with previous models The 540 (T-H3) can be connected with the previous models ; 520 (T-H2). A. DIPswitch setting on the computer board of the 540 (T-H3) If a Easy-link system contains a 520 (T-H2), change DIPswitch No.6 on the lower bank all of the 540 (T-H3) computer board to the “ON”...
  • Page 77 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 C-1. Temperature settings When the 540 (T-H3) is connected with any 520 (T-H2) as part of an Easy-Link system, the available set temperatures will default to what is available on a 520 (T-H2) (from 100 °F to 175 °F/185 °F as shown below).
  • Page 78 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 HIGH TEMPERATURE MODE The following procedure apply only to case 1 of B. (Refer to P.76) CAUTION Operation Screen Turn on the 120 VAC power supply to the unit. Press the "ON/OFF"...

  • Page 79: High-Altitude Region Support Functions

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-13. High-Altitude Region Support Functions 240 (T-H3J) and 340 (T-H3S) models <Using these functions> Computer board The high-altitude region support functions have four operation levels, with the appropriate level being set up by the installer until the abnormal sound problem is solved.
  • Page 80 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Outdoor models of 240 (T-H3J) / 340 (T-H3S) : Propane DIPswitch settings Output Fan motor Level Elevation reduction speed change No.3 No.4 No.5 0 (DEFAULT) Up to 2,000 ft Up to -11 %...
  • Page 81 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 540 (T-H3) models <Using these functions> computer board The desired level can be specified at the Lower bank of DIPswitches (No.2, No.3 and No.4) on the computer board. See the table below.
  • Page 82 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Outdoor models of 540 (T-H3) : Propane DIPswitch settings Output Fan motor Level Elevation reduction speed change No.2 No.3 No.4 0 (DEFAULT) Up to 2,000 ft Up to -11 % 4,000 ft Up to...

  • Page 83: Adjusting Manifold Gas Pressure

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-14. Adjusting manifold gas pressure The manifold gas pressure on the water heater can be adjusted by following the procedures below. Adjusting the manifold pressure can cause unexpected combustion conditions during operation, which can cause a health hazard, damage the water heater, and/or shorten its lifespan.
  • Page 84 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Fig. 1 Fig. 2 Tube Computer board Manifold port To manometer Fig. 3 MIN button MAX button MAX button MIN button Increase button Decrease button Increase button Decrease button 240 (T-H3J) / 340 (T-H3S) models 540 (T-H3) models...

  • Page 85: Manually Adjusting The Fan Motor Speed Only 540 (T-H3)Models

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-15. Manually adjusting the fan motor speed Only 540 (T-H3)models While the FM+ DIPswitch will automatically increase the fan speed by 6%, the fan motor speed on the 540 (T-H3) models can also be manually adjusted.

  • Page 86: Freeze Protection System

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-16. Freeze protection system The 240 (T-H3J) models, 340 (T-H3S) models and 540 Outdoor (T-H3-OS) models freeze protection system is comprised of the ceramic heating blocks. The ceramic heating blocks will heat up whatever portion of the heat exchanger the blocks are strapped to.
  • Page 87 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Ceramic heating blocks The two heating blocks focus on protecting the inlet and outlet piping inside the water heater, as well as the front drum pipe. The blocks will only activate based on what the freeze protection thermostat senses. The thermostat is located on the intake port for Direct Vent Indoor models, close in vicinity to the inlet and outlet pipes for Outdoor models.

  • Page 88: Draining The Unit And Cleaning The Inlet Water Filter

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 12-17. Draining and cleaning the inlet water filter 1. Close the manual gas shut off valve. 2. Turn off power to the water heater, wait a few seconds. And then turn on again. 3.

  • Page 89: Components Diagram

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 13. Components diagram Case assembly Outdoor models Indoor models Temperature controller Temperature Indoor models remote controller Page...
  • Page 90 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Computer board assembly 240 (T-H3J) and 540 (T-H3) models 340 (T-H3S) models 707 722 Surge box assembly Page...
  • Page 91 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Burner assembly Burner assembly 109 111 Manifold Assembly Page...
  • Page 92 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Water Way assembly 540 (T-H3) models Bypass section Water outlet section (540 (T-H3) models) Water inlet section Page...

  • Page 93: Parts List

    EK159 Case assembly for Indoor models EK164 Case assembly for Outdoor models 319143-505 EK187 Front cover for 240 and 340 Indoor (T-H3J-DV and T-H3S-DV) 319143-506 EK188 Front cover for 240 and 340 Outdoor (T-H3J-DV and T-H3S-OS) 319143-507 EK158 Front cover for 540 Indoor (T-H3-DV)
  • Page 94 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 95 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, Item # Description 240, 340 T-H3J, T-H3S 240, 340 and T-H3S and and 540 and T-H3 540 models T-H3models models models T-K3,...
  • Page 96 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 97 Silicon ring for Outdoor models 319143-524 EK177 Exhaust port for Outdoor models 319143-525 EK198 Heat exchanger assembly for 240 and 340 Indoor (T-H3J-DV and T-H3S-DV) 319143-526 EK199 Heat exchanger assembly for 240 and 340 Outdoor (T-H3J-OS and T-H3S-OS) 319143-527 EK200...
  • Page 98 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 99 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 100 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 101 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 102 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...
  • Page 103 CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 Common parts for Part # other models T-H3J, T-H3S Item # Description 240, 340 T-H3J, T-H3S 240, 340 and and T-H3 and 540 and T-H3 540 models models models models...

  • Page 104: Revisions

    CONFIDENTIAL 240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial Ver. 1.00 15. Revisions Version Description of changes Date 1.00 First edition 12/07/18 Page...

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