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P/N 30149, Rev. G [12/15/2016]
Table C2: System and General Troubleshooting
Problem
Possible Cause
Remedy
Furnace will not start.
Thermostat not calling for heat
Check thermostat and adjust.
Check thermostat for accuracy; if mercury switch type, it might be off level.
No power to furnace
Check furnace switch, main electrical panel furnace fuse or circuit breaker.
Look for any other hand operated switch, such as old poorly located furnace
switch, which was not removed during furnace replacement.
Thermostat faulty
Remove thermostat wires from oil primary control terminals T-T. Place a
jumper across T-T. If furnace starts, replace thermostat, thermostat sub-base
(if equipped), or both.
Oil primary control faulty
Check reset button on oil primary control.
Remove thermostat wires from oil primary control terminals T - T.
Check for 24V across T -T. If no voltage is present, check for 115V to oil
primary control.
If 115V is present, refer to oil primary control documentation provided with
oil burner.
Photo Cell wiring shorted or
room light leaking into photo
cell compartment
Check photo cell (cad cell) wiring for short circuits.
Check for room light leaking into cad cell compartment. Repair light leak if
necessary.
Open safety switch
Check for open limit or auxiliary limit.
Check internal wiring connections; loose connectors, etc.
Furnace will not start
without first pushing oil
primary control reset
button.
(Happens on frequent
basis)
No fuel oil
Check fuel oil supply.
Check all hand operated fuel oil valves are in open position. Fill oil storage
tank if necessary.
Clogged nozzle
Replace nozzle with high quality replacement.
Use rating plate or Tables in Appendix A as a guide.
Clogged oil filter
Replace oil tank filter or in-line filter if used.
Low oil pump pressure
Connect pressure gauge to oil pump.
Adjust pump pressure, or replace oil pump if necessary.
Verify erratic pressure readings are not caused by defective fuel oil line.
Air getting into fuel oil lines, or
fuel oil line dirty, clogged, or in
some manner defective
Check fuel oil lines.
Replace any compression fittings found with high quality flared fittings.
Check for signs of oil leaks. Any oil leak is potential source of air or
contaminants.
Defective burner motor
Check burner motor.
If burner motor is cutting out on over-load, determine why. Replace if neces-
sary.
WARNING
Electrical shock hazard. Only a trained, experienced
service technician should perform troubleshooting
procedure. Failure to do so could result in death or
serious injury.
!
APPENDIX C - SEQUENCE OF OPERATION AND TROUBLESHOOTING
