Table C4: System And General Troubleshooting - ECR International WML-C Operation And Maintenance Manual

TABLE C4: SYSTEM AND GENERAL TROUBLESHOOTING

Problem
Furnace will not start.
Furnace will not start.
Furnace will not start without
first pushing oil primary
control reset button.
(Happens on frequent basis)
Furnace starts, but cuts out
requiring manually resetting
the oil protector reset button.
Furnace starts, but cuts out
requiring manually resetting
the oil protector reset button.
Possible Cause
Thermostat not calling for heat.
No power to furnace.
Thermostat faulty.
Oil primary control faulty.
Photo Cell wiring shorted or room
light leaking into photo
compartment
Open safety switch.
No fuel oil.
Clogged nozzle.
Clogged oil filter.
Low oil pump pressure.
Air getting into fuel oil lines, or fuel
oil line dirty, clogged, or in some
manner defective.
Defective burner motor.
Photo Cell (Cad Cell) defective.
No fuel oil.
Clogged nozzle.
Clogged oil filter.
Low oil pump pressure.
Air getting into fuel oil lines, or fuel
oil line dirty, clogged, or in some
manner defective.
Defective burner motor.
Water or contaminants in oil.
Frozen oil line.
Check thermostat and adjust. Also, check thermostat for accuracy; if it is
a mercury switch type, it might be off level.
Check furnace switch, main electrical panel furnace fuse or circuit
breaker. Also look for any other hand operated switch, such as an old
poorly located furnace switch, which was not removed during furnace
replacement.
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.
Check reset button on oil primary control. Remove thermostat wires
from oil primary control terminals T1 - T2. Check for 24v across T -T. If
no voltage is present, check for 115v to oil primary control. If 115v is
present, go to Table C-3.
Check photo cell (cad cell) wiring for short circuits. Also, check for room
cell light leaking into cad cell compartment. Repair light leak if necessary.
See Table C-3.
Check for open limit or auxiliary limit. Also, check internal wiring
connections; loose connectors, etc.
Check fuel oil supply. Check that all hand operated fuel oil valves are in
the open position. Fill oil storage tank if necessary.
Replace nozzle with high quality replacement. Use rating plate or Tables
in Appendix A as a guide.
Replace oil tank filter or in-line filter if used.
Connect pressure gauge to oil pump. Adjust pump pressure, or replace
oil pump if necessary. Ensure that erratic pressure readings are not
caused by defective fuel oil line.
Check fuel oil lines. Replace any compression fittings found with high
quality flared fittings. Check for any signs of oil leaks. Any oil leak is a
potential source of air or contaminants.
Check burner motor. If burner motor is cutting out on over-load,
determine why. Replace if necessary.
If cad cell is dirty, clean it. (Determine why cad cell is getting dirty). If
cad cell is poorly aimed, realign it. NOTE: The photocell should have a
resistance of 100K Ω in absence of light; a maximum of 1500 Ω in the
presence of light. Ensure that room light is not leaking into the cad cell
compartment. (See diagnostic light section).
Check fuel oil supply. Check that all hand operated fuel oil valves are in
the open position. Fill oil storage tank if necessary.
Replace nozzle with high quality replacement. Use rating plate or Tables
in Appendix A as a guide.
Replace oil tank filter or in-line filter if used.
Connect pressure gauge to oil pump. Adjust pump pressure, or replace
oil pump if necessary. Ensure that erratic pressure readings are not
caused by defective fuel oil line.
Check fuel oil lines. Replace any compression fittings found with high
quality flared fittings. Check for any signs of oil leaks. Any oil leak is a
potential source of air or contaminants.
Check burner motor. If burner motor is cutting out on over-load,
determine why. Replace if necessary.
Drain fuel oil storage tank, replace fuel oil. (Consult with fuel oil
supplier).
Gently warm oil line. Insulate oil line. (Outdoor piping size may require
increased diameter).
29
Remedy
30318 R4 9/9/2005