Carrier 58MVP instruction manual trol board

25.	Connect 1 side of a slope manometer with a tee to collector box pressure tap. Connect other side	Ð	Ð	26
	with a tee to gas valve air pressure fitting. Refer to pressure check diagram in Appendix C.
26.	Turn power on and wait several sec, then jumper R and W/W1 thermostat terminals on furnace con-	Ð	Ð	27
	trol board.
27.	Monitor slope manometer. Does pressure reading appear to be stable when fault occurs?	14	28	Ð
28.	Check for a sag in vent pipe. If problem persists, replace inducer motor.	Ð	Ð	8
29.	Disconnect jumper wire across R and W/W1 thermostat terminals and wait until blower stops.	Ð	Ð	30
30.	Jumper R, W/W1, and W2 thermostat terminals on furnace control board.	Ð	Ð	31
31.	Does high-pressure switch HPS make, then break several times at start of cycle before faulting out?	32	33	Ð
32.	The problem is either a sag in vent pipe or a clogged drain trap or line.	Ð	Ð	17
33.	Does fault occur before main burners ignite?	34	51	Ð
34.	Do you have 24v between C (Common) on high-pressure switch HPS and Com on furnace control	36	35	Ð
	board?
35.	The YELLOW wire to high-pressure switch HPS is not making good connection. Repair or replace	Ð	Ð	8
	it.
	Do you have at least 1.90 in. wc pressure drop across heat exchangers when fault occurs? Deter-
36.	mine this by connecting 1 side of slope manometer with a tee to collector box pressure tap. Con-	45	37	Ð
	nect other side with a tee to gas valve air pressure fitting. Refer to pressure check diagram in Ap-
	pendix C.
37.	Is inducer motor MTR1 rotating in direction indicated on inducer housing?	39	38	Ð
38.	Replace inducer motor or inducer motor assembly.	Ð	Ð	8
39.	Turn power off.	Ð	Ð	40
40.	Is inducer wheel okay?	42	41	Ð
41.	If possible, replace inducer wheel. Otherwise, replace inducer motor assembly.	Ð	Ð	8
42.	Is there any frost build-up on combustion-air inlet?	43	44	Ð
43.	The problem is caused by reversed vent and combustion-air pipes or some other moist air entering	Ð	Ð	17
	combustion-air pipe.
44.	You have excessive restriction in combustion-air or vent pipe.	Ð	Ð	8
45.	Turn power off and disconnect jumper wire across R, W/W1, and W2 thermostat terminals.	Ð	Ð	46
46.	Turn power on and wait several sec, then jumper R, W/W1, and W2 thermostat terminals on fur-	Ð	Ð	47
	nace control board.
47.	Do you have 24v between connector terminal PL2-4 and Com on furnace control board when fault	11	48	Ð
	occurs?
48.	Turn power off.	Ð	Ð	49
49.	Do you have continuity across terminal PL2-4 and N.O. (Normally Open) contact on high-pressure	14	50	Ð
	switch HPS?
50.	The BROWN wire from high-pressure switch HPS to furnace control board is not making good con-	Ð	Ð	8
	nection. Repair wire or replace harness.
51.	Turn power off and disconnect jumper wire across R, W/W1, and W2 thermostat terminals.	Ð	Ð	52
52.	Connect 1 side of a slope manometer with a tee to collector box pressure tap. Connect other side	Ð	Ð	53
	with a tee to gas valve air pressure fitting. Refer to pressure check diagram in Appendix C.
53.	Turn power on and wait several sec, then jumper R, W/W1, and W2 thermostat terminals on fur-	Ð	Ð	54
	nace control board.
54.	Monitor slope manometer. Does pressure reading appear to be stable when fault occurs?	55	56	Ð
55.	Replace pressure switch assembly. If problem persists, check wiring for an intermittent connection	Ð	Ð	8
	in high-pressure switch HPS circuit.
56.	Check for a sag in vent pipe. If problem persists, replace inducer motor.	Ð	Ð	8

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