T-M50 / T-M50 ASME Service manual
Ver. 1.05
30
CONFIDENTIAL
10-15. Central computer boards
Unit Part #
#702
AOS Part #
EM307
Checkpoint
N/A
Function
1. Controls the left/right computer boards for burner control.
2. Sets the installation type (indoor, outdoor, or direct-vent) using dipswitches.
3. Controls multi-unit systems including the Easy-link system.
4. Sets the output temperature of the water heater without the use of a
remote controller.
5. Sets the gas type (propane or natural gas).
6. Sets the pump control mode.
7. Controls the external fan motor.
Failure event
Malfunctioning computer
Effects on the water
heater if the computer
board fails
When the central computer board fails, the control from central computer
board and/or communication to the multi-unit controller (TM-MC01) will be
abnormal.
The following are the typical results from an central computer board failure:
1. Unable to control normal operations of the water heater.
2. Unable to control multi-unit systems, which can result in T-M50 operating as
individual units instead.
3. Unable to communicate other T-M50 and/or the multi-unit controller during
the multi-unit system operations.
Error codes when the
computer board fails
741
761
Diagnostic
Visual inspection: connection / braking of wires, burnt mark on the computer
board.
Color/Number of wires
N/A
5 - 1 / 2 " ( 1 3 9 m m )
6
-
1
/
2
"
(
1
6
5
m
m
)
