Rheem furnace 2 blinks: pressure switch circuit open (RGPN, RGPS, RGLN, RGLS, green LED)

Furnace control display or LED

2 blinks

“PS Circuit open”

RGPN / RGPS UPFLOW/HORIZONTAL, RGLN / RGLS DOWNFLOW; (-)GPN / (-)GPP, (-)GLN · INSTALLATION INSTRUCTIONS FOR UPFLOW/HORIZONTAL & DOWNFLOW INDUCED DRAFT GAS FURNACES RGPN/RGPS UPFLOW/HORIZONTAL SERIES RGLN/RGLS DOWNFLOW SERIES, p. 39
Technician

What it means

In the installation instructions for the Rheem RGPN, RGPS, RGLN and RGLS series, the troubleshooting chart has a legend headed “BLINK CODES (GREEN LED)”, and 2 blinks there is “PS Circuit open”, PS standing for the pressure switch 92-24161-38-12, p. 39. The 2005 edition of these instructions, for the (-)GPN, (-)GPP and (-)GLN series, prints the same legend 92-24161-38-05, p. 37.

Separately, an undated Rheem support article, “Standard Furnace Diagnostic Flash Codes”, lists “2 Blinks = Pressure Switch Failure (remains open)”. It names no models and no LED color, and says: “Does not include Modulating, LXE, or Two Stage furnaces.” (TP0002) Rheem’s FAQ, which also names no models, calls 2 blinks the negative pressure switch circuit being open (Rheem support article “Gas Furnace Technical Frequently Asked Questions”, undated).

The RGPN, RGPS, RGLN and RGLS instructions describe a normally open pressure switch that monitors pressure conditions in the furnace vent system during the heating cycle 92-24161-38-12, p. 35. In their sequence of operation, each call for heat starts the induced draft blower (inducer) on a pre-purge, the air-proving negative pressure switch closes, and the spark igniter is energized 30 seconds after the switch closes. At the end of the cycle the inducer stops after a 10-second post-purge and the switch opens 92-24161-38-12, p. 30. Ignition in that sequence follows the switch closing.

The Safety Features section of the same instructions, separate from the code legend, lists the reasons the pressure switch may not close 92-24161-38-12, p. 35:

• an inoperative induced draft blower;
• a loose or leaky pressure switch hose;
• a blockage in the vent;
• severe downdrafts canceling the draft from the inducer fan;
• a leaky gasket at the induced draft blower;
• an improperly sized or installed vent.

Check these first

No owner’s manual for the RGPN, RGPS, RGLN or RGLS series is among the Rheem documents used for these pages, and the installation instructions give an owner no checks for 2 blinks. What the instructions give an owner:

1. They refer you to the lighting instructions on the furnace itself 92-24161-38-12, p. 30.
2. Their start-up steps end with: if the appliance will not operate, shut the furnace down and call your service technician or gas supplier 92-24161-38-12, p. 30.

A blocked vent is one of the reasons the switch may not close. The documents give an owner no vent check for these furnaces. The instructions recommend that a qualified installer, service agency or the gas supplier inspect the flue passageways, the vent system and the main burners, and warn that holes in the vent pipe or heat exchanger can let toxic fumes into the home, causing carbon monoxide poisoning 92-24161-38-12, p. 38.

If the furnace overheats or the gas supply fails to shut off, the instructions say to shut off the manual gas valve to the appliance before shutting off the electrical supply 92-24161-38-12, p. 30.

When to call a licensed technician

• The six reasons above: the inducer, the pressure switch hose, the vent and its sizing, downdrafts and the inducer gasket 92-24161-38-12, p. 35.
• The checks in Rheem’s FAQ, which are written for technicians: a Magnehelic gauge reading of the negative pressure from the induced draft blower against the switch’s closing setting, a blocked pressure switch tube port on the induced draft blower housing, and a blocked or restricted vent pipe (Rheem support article “Gas Furnace Technical Frequently Asked Questions”, undated).
• A leaking vent pipe or heat exchanger, which the instructions say must be replaced 92-24161-38-12, p. 38.

Notes for different models

Board or series	Code	Wording	Source
RGPN, RGPS, RGLN, RGLS (blink legend, green LED)	2 Blinks	“PS Circuit open”	92-24161-38-12, p. 39
(-)GPN, (-)GPP, (-)GLN, 2005 edition (blink legend, green LED)	2 Blinks	“PS Circuit open”	92-24161-38-05, p. 37
Rheem support article TP0002 (models and LED color not named)	2 Blinks	“Pressure Switch Failure (remains open)”	TP0002
7-segment code lists, single-stage: 92P, 92T, 95P, 95T, 801S, 801P, 801T	57	“PRESS SWITCH STUCK OPEN WHEN SHOULD BE CLOSED”	92-24161-118-16, p. 87; 92-24161-154-03, p. 87; 92-24161-111-17, p. 87; 92-24161-120-16, p. 87; 92-24161-142-15, p. 39; 92-24161-143-14, p. 34; 92-24161-144-09, p. 39; 92-24161-145-10, p. 34
7-segment code list, two-stage 96P	45	“LOW PRESSURE SWITCH OPEN, INDUCER ON HIGH SPEED”	92-24161-122-12, p. 88
7-segment code list, two-stage 96P	46	“LOW PRESSURE SWITCH OPEN, INIDUCER ON LOW SPEED”	92-24161-122-12, p. 88
7-segment code list, two-stage 96P	57	“HIGH PRESSURE SWITCH OPEN”	92-24161-122-12, p. 88

The documents do not match blink counts to the two-digit codes; the rows for 57, 45 and 46 are other boards, listed here for comparison.

4 blinks is the opposite case: the switch stays closed. The legend calls it “PS Circuit closed” 92-24161-38-12, p. 39 and TP0002 “Pressure Switch Failure (remains closed)” (TP0002). Rheem’s FAQ says the switch contacts remain closed during the off cycle, and the furnace will not go into the ignition sequence if the switch does not open from the previous call for heat (Rheem support article “Gas Furnace Technical Frequently Asked Questions”, undated). The instructions add that the switch contacts must open before the unit can go through another heating cycle 92-24161-38-12, p. 35.

TP0002 leaves out modulating, LXE and two-stage furnaces. Rheem’s two-stage RGPQ and RGLQ furnaces have their own installation instructions (92-24161-51-07); their code table was not reviewed for these pages.

Related Rheem and Ruud codes

• 3 blinks “Limit circuit open”
• 4 blinks “PS Circuit closed”

See also

• Heat pump vs gas calculator
• HVAC and furnace tax credits in 2025 and 2026: 25C, 25D, 30C

Other gas furnaces: Carrier, Goodman, Lennox

All Rheem and Ruud codes

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