Rheem · Furnace

44 Low pressure switch closed (stuck)

High severity Rheem/Ruud 802P / 80MDP 80% two-stage furnace (UT 1028-928 IFC)RGPE/RGLE

What the control is telling you

Low-fire pressure switch (LPC) is closed when it should be open, before the inducer starts. The furnace will not start a heat cycle. RGPE/RGLE: thermostat shows Call For Service.

Applies to: 802P/80MDP (802PA050-150); RGPE/RGLE 2-stage 80+

Likely causes

Pressure switch contacts welded
Shorted or miswired switch wiring
Water in switch or hose

Test and repair steps

With the inducer off, check LPC contacts - must be open.
Check switch wiring for a short.
Check switch and hoses for water or moisture.
Replace the switch if contacts stay closed.

Settings for these units

Filter sizes as shipped, upflow (Table 19) · RGPE/RGLE

Cabinet width	Input	Bottom filter	Side filter	Quantity
17-1/2 in.	50, 75 (000 Btu/h)	15-3/4 x 25 in.	15-3/4 x 25 in.	1
21 in.	75, 100 (000 Btu/h)	19-1/4 x 25 in.	15-3/4 x 25 in.	1
24-1/2 in.	125 (000 Btu/h)	22-3/4 x 25 in.	15-3/4 x 25 in.	1

Use one filter location only - do not double-filter or filter the supply side.

21 in./100K: cut 3-1/2 in. off filter and frame for a side filter; 24-1/2 in./125K: cut 7 in.

Reduced clearance to combustibles, upflow/horizontal (Fig. 4) · Rheem/Ruud 802P / 80MDP 80% two-stage furnace (UT 1028-928 IFC)

Model size	Cabinet width (A)	Right side	Top	Front	Vent
050 (5)	14 in.	4 in. (note 2)	1 in.	3 in.	6 in. (note 3)
075 (7)	17-1/2 in.	3 in. (note 2)	1 in.	3 in.	6 in. (note 3)
100 (10)	21 in.	0	1 in.	3 in.	6 in. (note 3)
125 (12)	24-1/2 in.	0	1 in.	3 in.	6 in. (note 3)
150 (15)	24-1/2 in.	0	1 in.	3 in.	6 in. (note 3)

Note 2: right side may be 0 in. with type B vent.

Note 3: vent clearance may be 1 in. with type B vent.

Reduced clearance to combustibles (Fig. 3 and 4) · RGPE/RGLE

Models that show this code

15 models in Rheem/Ruud 802P / 80MDP 80% two-stage furnace (UT 1028-928 IFC), RGPE/RGLE

R802PA050314MSAR802PA075417MSAR802PA100521MSAR802PA125524MSAR802PA150524MSARGLE-05(-)BMKRRGLE-07(-)AMKRRGLE-07(-)BRQRRGLE-10(-)BRMRRGLE-12(-)ARMRRGPE-05(-)BMKRRGPE-07(-)AMKRRGPE-07(-)BRQRRGPE-10(-)BRMRRGPE-12(-)ARMR

Other codes on the same units

22 Main limit open
23 HALC limit open (HALC LIMIT OPEN)
26 Line and neutral reversed
33 Rollout switch (MRLC) open
45 Low pressure switch open - inducer high speed
46 Low pressure switch open - inducer low speed
55 Pressure switch stuck closed
57 Pressure switch stuck open

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Source: 802P: 92-24161-146-02, Diagnostics and Fault Codes table, p.40, 51; RGPE/RGLE: Table 16 p.49 / Table 20. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.