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Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
Natural of Fault
Diagnosis
Check
point
• Fluctuation of hot
water temperature
6 Fault of PCB in the water heater
No voltage flow adjustment valve
Normal: 7.0 to 16 VDC between (red-black)
J
7 Flow adjustment valve fault
Normal: 0.09 to 0.2 kΩ between (red-black)
J
Error Code
Malfunction description
Cancellation method
031
Incorrect DIPswitch setting fault
Turn off the power or water supply
Diagnosis
Check point
Check the DIPswitch settings on PCB
Error Code
Malfunction description
Cancellation method
101
Warning for the “991” error code
(Refer to section 12-3)
On the PCB, press the INC and DEC
buttons simultaneously for 3 sec. Then
turn the power off.
Diagnosis
Check point
1 Check the gas type of the water heater.
2 Check how long the water heater has been installed and in use.
3 Check the installation location.
4 Check the altitude/elevation of area of where the water heater
installed.
5 Check the vent length.
6 Check if there is any blockage in the intake air and/or exhaust.
7 Check if there is dust and lint in burner and heat exchanger,
when the water heater has been installed in laundry room.
8 Check if there is grease and dirt in burner and fan motor, when
the water heater has been installed in restaurant.
9 Check the manifold pressure in the water heater.