110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
43
CONFIDENTIAL
Error Code
Malfunction description
Cancellation method
74
Miscommunication between water heater and
temperature remote controller
Restoring proper cable connections
between the water heater and the
Remote controller (9007666005). When
the computer detects proper connections
between the water heater and the
remote controller, "74" error code will
cease to display.
Diagnosis
Checkpoint
1 Temperature remote controller (9007666005) or PCB fault
2 Check for signs of power surges.
Error Code
Malfunction description
Cancellation method
99
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.
Diagnosis
Checkpoint
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 place.
4 Check the altitude/elevation of area of where the water r 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.
