A.O. Smith 710 ASME Service Manual page 45

Error Code
761
Miscommunication between Parent and Child
units for Easy-Link systems or Multi-Unit system.
1 Inspect cable connections between Parent and Child units.
2 Inspect cable connections between Multi-unit controller and water heaters.
3 Check for signs of power surges.
Error Code
Abnormal burning
991
(Refer to section 12-3)
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, when the water heater has been installed indoors.
6 Check the type of vent cap, when the water heater has been installed
outdoors.
7 Check if there is any blockage in the intake air and/or exhaust.
8 Check if there is dust and lint in burner and heat exchanger, when the water
heater has been installed in laundry room.
9 Check if there is grease and dirt in burner and fan motor, when the water
heater has been installed in restaurant.
10 Check the manifold pressure in the water heater.
Malfunction description
Malfunction description
710 / 710 ASME Service Manual
Restoring
between all the 710 models and the
multi-unit controller (9007675005). When
the computer detects proper connections
between the multi-unit controller and the
units (water heater), "761" error code will
cease to display.
Diagnosis
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
45
CONFIDENTIAL
Ver. 1.00
Cancellation method
proper cable connections
Checkpoint
Cancellation method
Checkpoint