Coleman P*HBX12F08001 Installation Instructions Manual page 14

035-14289-000 Rev. A (0701)
PROBLEM
Thermostat
not calling for heat
No power to furnace
Thermostat faulty
Furnace will not start
Protector relay faulty
Photo cell wiring
shorted or room light
leaking into photo cell
compartment
Open safety switch
No fuel oil
Clogged nozzle
Clogged oil pump filter
Furnace will not start
without first pushing
protector relay reset
low oil pump pressure
button
(Happens on a
Air getting into fuel oil
frequent basis)
lines, or fuel oil line
dirty, clogged or in
some manner defective
Defective burner motor Check burner motor. If burner motor is cutting out on over-load, determine
Photo Cell (Cad Cell)
defective
No fuel oil
Clogged nozzle
Clogged oil filter
Furnace starts, but
cuts out requiring
Low oil pump pressure
manually resetting the
oil protector reset but-
ton
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
14
SYSTEM TROUBLESHOOTING
POSSIBLE CAUSE
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.
Check reset button on protector relay. Remove thermostat wires from pro-
tector relay terminals TT. Place a jumper across TT. If furnace starts, replace
thermostat, thermostat sub-base (if equipped), or both.
Check reset button on protector relay. Remove thermostat wires from pro-
tector relay terminals TT. Check for 24v across T.T. If no voltage is present,
check for 115v to protector relay. If 115v is present, replace protector relay.
Check photo cell (cad cell) wiring for short circuits. Also check for room light
leaking in to cad cell compartment. Repair light leak if necessary.
Check for open limit or auxiliary limit, open door switch (if equipped). 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 table in
this manual 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 lines.
Check oil lines, Replace any compression fittings found with high quality
flared fittings. Check for any signs of oil leaks. An oil leak is a potential
source of air or contaminants.
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 photo cell should have a resistance of
100 K ohms in absence of light; a maximum of 1500 ohms in the presence
of light. Ensure that room light is not leaking into the cad cell compartment.
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 table in
this manual 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 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
whey. 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 in-
creased diameter.
REMEDY
Unitary Products Group