March 2010 WHC56 Service Manual This manual must be read by Service personnel re- • pairing the above appliance models. Take this manual with you when attending Service study • meetings. The specifications and contents of this manual may • change at any time without prior notification.
Overview of Condensing Gas Water Heater This water heater is a high efficiency, fully condensing appliance. Unlike a traditional water heater, a condensing type captures heat from the exhaust gas and uses it to preheat the incoming cold water as it passes through the secondary heat exchanger as illustrated below.
Principle of Operation Exhaust High-Limit Switch Frost Sensing Switch Anti-Frost Heater Secondary Heat Exchanger Water Level Electrode 2 Water Level Electrode 1 High-Limit Switch Primary Heat Exchanger Thermal Fuse Main Flow Control Valve Igniter Ignition Electrode Flame Rod Burner Heat Exchanger Thermistor Drain trap SET Bypass Flow Control Valve Primary Gas Solenoid Valve...
Explanation of operation 1.Using hot water (1) Turn the ON/OFF button on the remote controller to ON.(The ON/OFF button will turn on the light.) (2) Open the hot water valve to be used. If the water flow sensor detects a water flow above the mini- mum operation water flow volume, pre-purge(purging gas remaining in the combustion chamber before ignition) will be carried out for a fixed duration of time.
Operation Panel, Remote control Main Remote Controller (RC-7508M) Part number B285 Power On/Off Button / Lamp Display Selection Button Set Button Speaker PLEASE NOTE THAT ONE REMOTE CONTROLLER IS REQUIRED PER INSTALLATION – 6 –...
Initial Operation Before the first use of your water heater, make the following preparations. 1 through 4 Follow steps Open the water supply valve. OPEN CLOSED Open a hot water fixture to confirm that water is available, and then close the fixture again.
Setting Hot Water Temperature On this Display Operation Description * The is lit. ON/OFF Press the ON/OFF button to turn it “On”. Use the buttons Here to adjust the (Eg.: 40°C) temperature. While the shower is being used, no one other than the user should change the temperature, the power switch must not be WARNING turned “off”.
Approximate hot water conditions 37 38 39 40 41 42 43 44 45 46 47 48 50 55 60 65 70 75 80 Set the maximum temperature to suit your own preference. Washing Shower, hot water supply, etc. Hot water supply, etc. High temperature dishes, etc.
Sequence Operation Water heating Shutdown p Connect power Fix problem Hot water tap C Bypass flow control valve and main flow control valve Disconnect power move to initial position setting Water flow senso Current leakage safety < 2.0 L/mi device normal Warning indication ON/OFF lamp turns OFF The unit will continue to operature with...
Shutdown procedure Hot water tap CLOSED Water flow sensor detects < 2.0 L/min. Flame lamp goes off Gas proportioning valve closes Primary gas solenoid valve closes Gas solenoid valve 1 closes Gas solenoid valve 2 closes Gas solenoid valve 3 closes Fan motor post purge Main flow control...
Checkpoints and Measures if a Breakdown Occurs Error Codes and Checkpoints Display Description Diagnosis Point (Trouble Point) Remarks Combustion Abnormality Check for abnormal combustion. To reset this error code, the power needs to (F) 10 Joule Drop) be disconnected and then reconnected. Check flue for blockage or obstruction.
Error Descriptions and How to Reset – 15 –...
Main Remote Control (RC-7508M) Power On/Off Button / Lamp Display Selection Button Set Button Speaker Displaying the Maintenance Monitor The Power On/Off Button can be set to either "ON" or "OFF" - unit operation will not be affected by this setting. However, be sure to set the Power On/Off Button to “ON”...
Maintenance Monitor List Data Minimum Data (Display Reading x Multiplier) Value for Item Remarks Multiplier Unit Indication Under judgement  gas judgement result [ab : cd] 2L,2H 2L(Dip switch), 2H(Dip switch) Total Plug-in Time X 100 hour 100 hours Disp. Range  –  Total Combustion Time hour 1 hour...
Circuit Board Replacement * Be sure to read. Reference connection diagram (for simplification, other connections have been omited) It is necessary to transfer data when replacing a circuit board. Vital Buttons for adjusting the manifold Disconnect when pressure settings transferring information about the water heater such as the settings and unit history will have to be transferred to the new board.
Drain Trap Replacement Replace the Drain trap following the procedures below. 1. Disconnect electrical power to the unit. 2. Drain water from the Drain trap using the drain valve located underneath the water heater (Fig.). 3. Disconnect the relay connector(2 positions), remove the fixing screw, and remove drain hose 1 and drain hose 2.
Fan Motor Replacement When changing the fan motor. When Bell-mouth(B) is installed in the old fan motor, install Bell-mouth (B) as shown in figure to maintain the proper air volume. When you change the fan motor, please remove this part from the old fan motor, and install in the new fan motor. After changing the fan motor, please follow the procedure "Circuit Board Settings ".
Anti Frost Heater Replacement Attention in after-sale service Please check the original position and re-install to this position. The anti-frost heater shall be installed with the method described in the diagram below. Heater position (Adjust the edges) Adjust the heater and the heater fastener. Push the heater fastener all the way to the right side of the heat exchanger described in the diagram.
Manifold Gas Pressure Adjustment NOTE: * Use the following procedure to adjust the manifold gas pressure only if it can be done with a high flow rate through the unit. (1) With a manometer or pressure gauge connected to the manifold pressure tap, press and hold the maximum pressure set button.
Maintenance (1) Troubleshooting and Repair. A. Unit does not work at all (operation lamp does not light up). 1. Is the current leakage safety device activated? Check the operation of the current leakage safety device. (1) When the ground-fault lamp of the current leakage safety device lights, press the reset button or disconnected power plug to cancel.
Check for blown current fuse on the circuit board. 4. Blown current fuse. (1) Remove the power plug (current leakage safety device). (2) Visually check the current fuse (10A) on the circuit board to see if it is blown. Not blown Normal Yes Continue to “5.
7. Error display 14 immediately after turning Inspect overheat prevention device (thermal fuse). unit ON. (1) Remove connector 38 on the circuit board and measure the resistance between Blue 25 and Blue 31. 2Ω or less Normal Yes Replace the circuit board. After finding cause of overheating, replace the thermal fuse.
(2) Measure the voltage between Red 1 and Blue 7 of connector 75 on the circuit board. Normal DC 14 - 16V Yes Replace the water flow sensor. Replace the circuit board. 2. Error display 20 immediately after turning unit Inspect the high-limit switch.
4. Water outlet thermistor error. If error display 32 appears, then check the water outlet thermistor. (1) Measure the resistance between White 1 and White 2 of connector M64. Break in wire: ∞Ω Short circuit: 1Ω or less If wire is broken or short-circuited, replace the water outlet thermistor.
If error display 11 appears and there is continuous 7. Gas solenoid valve error. electrical discharge, then check the gas solenoid valves. (1) Open the hot-water supply valve and measure the voltages between: SV0: White 6 and Blue 7 on connector 10 SV1: Black 5 and Blue 7 on connector 10.
10. Flame rod error. If error display 12 or 72 appears, then check the flame rod. (1) Measure the frequency between the flame rod and burner case (GUD) when the remote controller is turned on. 10kHz - 100kHz Normal Yes Continue to (2). Replace the circuit board.
(2) Measure the voltage between Blue 29 of connector 38 and Red 9 of connector 63 on the circuit board. DC 4V or more Normal Replace the circuit board. • Check the clogging of drain piping, drain trap and connection hose. •...
Check the heat exchanger thermistor. 3. Heat exchanger thermistor error. • Check to see if the displayed data of maintenance information monitor no. 32 and no. 42 match. (1) Measure the resistance between White 1 and White 4 of connector Q64. 10 20 30 40 50 60 70 80 Temp.(°C) Normal...
5. Gas proportioning valve error. Check the gas proportioning valve error. (1) Check to see if the flame size changes when pressing the minimum and maximum manifold pressure set button, then measure the voltage between Red 2 and Blue 4 using connector 38 on the circuit board.
(2) Disassembly of each part 1. How to remove transformers (1) Remove two quick fasteners (A and B) in the right figure and remove the water inlet pipe (C). (2) Remove the quick fastener (A) in the right figure and pull the bypass servo (B). (3) Unscrew two fixing screws (A and B) in the right figure and remove the transformers.
2. How to remove the board (1) Unscrew two screws (A and B) that fix the board and the earth screw (C) and remove the board. 3. How to remove the manifold - Unscrew two fixing screws of mounting plate for current leakage safety device in advance.
Installation Filling the drain trap unit with water The drain trap unit can be filled before connecting the vent pipe. Filling the drain trap unit before vent pipe installation. Prior to initial start up, make sure that you fill the drain trap unit with water. DANGER This is to prevent dangerous exhaust gases from entering the building.
Specifications Item Specification Model Name WHC56 Type Installation Internal, Wall Mounted Air Supply/Exhaust Power Vented Ignition Direct Ignition Minimum Pressure for Maximum flow 2.0 bar Minimum Flow Rate 2.5 L/min. Dimensions 61.5 cm(Height) x 46.4 cm(Width) x 24 cm(Depth) Weight 33 kg Water Holding Capacity 1.9 Litre...