T-H2-DV/T-H2-OS Service Manual
Ver. 1.01
54
Error Code
Malfunction description Cancellation method
761
Miscommunication between Parent and Child
units for Easy-Link systems.
Restoring proper cable connections
among all the water heaters. When the
computer detects proper connections
among all the water heaters, "761" error
code will cease to display.
1 Inspect cable connections between Parent and Child units.
2 Check for signs of power surges.
Error Code
Malfunction description Cancellation method
941
Abnormal exhaust temperature
Turn off the power supply
Diagnosis Checkpoint
1 Check how long the water heater has been installed and in use.
2 Check the vent length.
3 Check if there is any blockage in the intake air and/or exhaust.
4 Check if there is dust and lint in burner and heat exchanger, when the water
heater has been installed in laundry room.
5 Check the manifold pressure in the water heater.
6 Check if the exhaust fan motor works properly.
7 Check if the set temperature is higher than 140˚F (60˚C) and the system is
recirculation. Recirculation system with high temperature settings (avove
) can lead to this error code
Error Code
Malfunction description Cancellation method
991
Imperfect combustion
(Refer to section 12-3)
Turn off the power or water supply
If not possible, press and hold the INC
and DEC buttons on the computer board
simultaneously for more than 3 sec.
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.
Check the manifold pressure in the