Thermo Pride GMD1-60N Installation And Service Manual page 31

All installations and services must be performed by qualified service personnel.
DIAGNOSTIC FEATURES
: Power must be disconnected before servicing.
The 50A65-143 control continuously monitors its own operation and the operation of the
system. If a failure occurs, the LED will indicate a failure code as shown below. If the
failure is internal to the control, the light will stay on continuously. In this case,
the entire control should be replaced, as the control is not field-repairable.
If the sensed failure is in the system (external to the control), the LED will flash in the
following flash-pause sequences to indicate failure status (each flash will last
approximately 0.25 seconds, and each pause will last approximately 2 seconds).
1 flash, then pause
2 flashes, then pause
3 flashes, then pause
4 flashes, then pause
6 flashes, then pause
7 flashes, then pause
8 flashes, then pause
Continuous flashing
(No pause)
The LED will also flash once at power-up.
System lockout
Pressure switch stuck closed
Pressure switch stuck open
Open limit switch or rollout switch
115 Volt AC power reversed
Low flame sense signal
Check igniter or improper grounding
Flame has been sensed when
no flame should be present
(No call for heat)
30