A.O. Smith T-D2-OS - Page 45

T-D2-IN / T-D2-OS Service Manual
Ver. 1.00
45
CONFIDENTIAL
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
co
de will cease to display.
Diagnosis Checkpoint
1 Inspect cable connections between Parent and Child units.
2 Check for signs of power surges.
Error Code
Malfunction description Cancellation method
991
Imperfect combustion
(Refer to section 12-3)
T
urn 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 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.