York P4LBX20F19001, P3DHX12F08001, P2DHX16F12001, P2LBX16F14501 Low oil pump pressure

Table C-3: System and General Troubleshooting continued

		Problem				Possible Cause	Remedy
						Photo Cell wiring shorted or	Check photo cell (cad cell) wiring for short circuits. Also, check
						room light leaking into photo	for room light leaking into cad cell compartment. Repair light
Furnace will not start.						cell compartment	leak if necessary. See Table C-2.
						Open safety switch.	Check for open limit or auxiliary limit. Also, check internal wiring
							connections; loose connectors, etc.
						No fuel oil.	Check fuel oil supply. Check that	all hand operated fuel oil
							valves are in the 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.
Furnace		will		not	start
						Clogged oil filter.	Replace oil tank filter or in-line filter if used.
without		first pushing oil
							Connect pressure gauge to oil pump. Adjust pump pressure, or
primary		control			reset	Low oil pump pressure.
button.							replace oil pump if necessary. Ensure that erratic pressure read-
(Happens			on	frequent			ings are not caused by defective fuel oil line.
basis)						Air getting into fuel oil lines, or	Check fuel oil lines. Replace any compression fittings found with
						fuel oil line dirty, clogged, or in	high quality flared fittings. Check for any signs of oil leaks. Any
						some manner defective.	oil leak is a 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 necessary.
							If cad cell is dirty, clean it. (Determine why cad cell is getting
Furnace		starts,		but	cuts	Photo Cell (Cad Cell) defec-	dirty). If cad cell is poorly aimed, realign it. NOTE: The photocell
out	requiring			manually			should have a resistance of 100K Ω	in absence of light; a maxi-
resetting the oil protector						tive.	mum of 1500 Ω in the presence of light. Ensure that room light
reset button.							is not leaking into the cad cell compartment. (see diagnostic
							light section, or manually measure cad cell resistance).
						No fuel oil.	Check fuel oil supply. Check that	all hand operated fuel oil
							valves are in the 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
Furnace		starts,		but	cuts		replace oil pump if necessary. Ensure that erratic pressure read-
							ings are not caused by defective fuel oil line.
out	requiring			manually
						Air getting into fuel oil lines, or	Check fuel oil lines. Replace any compression fittings found with
resetting the oil protector
reset button.						fuel oil line dirty, clogged, or in	high quality flared fittings. Check for any signs of oil leaks. Any
						some manner defective.	oil leak is a 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 necessary.
						Water or contaminants in oil.	Drain fuel oil storage tank; replace fuel oil. (Consult with fuel oil
							supplier).
						Frozen oil line.	Gently warm oil line. Insulate oil line. (Outdoor piping size may
							require increased diameter).
						Electrodes out of adjustment	Check electrode settings. Check electrodes for dirt build-up or
						or defective.	cracks in porcelain.
						Poor transformer high voltage	Check contacts between the igniter and electrodes. If OK, re-
						connections or defective trans-
							place the igniter
Oil	burner		sputtering at			former.
nozzle						Fuel oil filter clogged.	Replace fuel oil storage tank filter and / or fuel oil in-line filter.
						Defective oil pump.	Check burner motor / fuel oil pump coupling. Check oil pump
							pressure. Replace fuel oil pump if necessary.
						Fuel oil line partially clogged or	Bleed air from oil line. If problem persists, replace oil line.
						contains air.
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