T-M50 / T-M50 ASME Service manual
Ver. 1.05
29
CONFIDENTIAL
10-14. Left/right computer boards
Unit Part #
#701
AOS Part #
EM306
Checkpoint
N/A
Function
Controls most of the functions of the left & right combustion sections within
the water heater.
Failure event
Malfunctioning computer
Effects on the water
heater if the computer
board fails
When this computer board fails, the control from this computer and/or
communication to the multi-system control will be abnormal.
The following are the typical examples of when the computers fail:
1. Unable to control proper combustion during operation.
2. Unable to detect correct signals from any/all water heater sensors.
3. Unable to control water valves, which may cause output temperature
fluctuations.
4. Errors in its self-diagnostics. In order to self-diagnose properly, the
computer sends a low voltage signal into its circuit. When the computer does
not detect a return signal, from this circuit, the "701" error code will appear.
5. Unable to communicate to other computers in the water heater.
Error codes when the
computer board fails
701
721
761
Diagnostic
Visual inspection: connection / braking of wires, burnt mark on the computer
board.
Color/Number of wires
N/A
5 - 1 / 4 " ( 1 3 2 m m )
8
-
1
/
4
"
(
2
0
8
m
m
)
