Thermo Pride GMC-85 Installation And Service Manual page 35

All installations and services must be performed by qualified service personnel.
After pre-purge, does the
ignition control (GMC) or
the oil primary (OMC)
produce a spark at the
ignition electrodes?
Yes
While ignition electrodes
are sparking does fuel
valve open?
Yes
Is there 24 VAC across the power
No
terminals of the ignition control
module (GMC) or 120 VAC across
the ignition transformer (OMC)?
Check wiring to the electrodes and
ignition control module fuse (GMC)
or the ignition transformer and the
electrodes (OMC). Also, check ignition
electrode gap. Reset if necessary.
Replace electrodes, ignition control
module (GMC) or ignition transformer (OMC).
Is there 24 VAC (GMC) across
"MV" terminals on ignition
No
control module during ignition
attempt. Does the oil solenoid
valve have 120 VAC across it
during the ignition attempt (OMC)?
Check wiring to fuel valve.
If valve does not open,
replace fuel valve.
No
Yes
No
Yes
34
On the GMC,has the burner
motor centrifugal switch
closed? If 120 VAC is
measured across the switch,
replace the burner motor. Else,
replace thermostat. On the OMC,
try resetting the oil primary
control by depressing the
RESET button. Check cad cell
function. If all else fails,
replace the oil primary.
On the GMC, reset the module
by interrupting power to system
for more than one second. If this
does not work, replace ignition
control module. On the OMC, try
resetting the oil primary control
by depressing the RESET button.
If this does not work, replace the
oil primary.