Payne PG80ESA Error Code 31: Pressure Switch Did Not Close or Reopened

What Does Code 31 Mean?

Status code 31 on the Payne PG80ESA means the pressure switch did not close, or closed and then reopened, during the draft-proving part of the sequence. The switch confirms the inducer is pulling enough draft to vent combustion gases safely; if it cannot prove that, the Furnace Control CPU will not let the burners light. When the switch is open longer than 5 minutes, the inducer shuts off for 15 minutes before retrying, and if it opens during the blower on-delay the blower runs for the selected off-delay.

Since the PG80ESA is a non-condensing (80% AFUE) furnace, it vents through a metal flue, and the most common trigger is a blocked or restricted vent — snow, ice, leaves, or a bird or insect nest at the termination, or an obstruction in the flue. Disconnected or obstructed pressure tubing between the inducer and the switch is another frequent cause. The manual also lists excessive wind, low inducer voltage, a defective inducer motor, a defective pressure switch, inadequate combustion-air supply, restricted vent, and (if a low-gas-pressure switch is used) low inlet gas pressure.

Code 31 is the mirror image of code 23: code 31 is the switch failing to close (or reopening) when draft should be proven, while code 23 is the switch failing to open when it should. Most of the causes here — inducer, switch, tubing, vent sizing — require professional diagnosis rather than a homeowner repair.

What You'll Notice

• The inducer runs but the burners never light, then the inducer stops and the furnace waits before retrying
• After the switch is open about 5 minutes, the inducer shuts off for roughly 15 minutes before another attempt
• The diagnostic LED flashes three short then one long flash (code 31)
• It happens more on windy days, or after snow or ice, or when the flue is partially blocked
• You may hear the inducer laboring, rattling, or failing to start

Common Causes

How This Is Diagnosed

A technician checks the vent path first — termination and full flue for blockage — then inspects the pressure tubing and port for disconnection, obstruction, or trapped condensate. Inducer performance and its 115V supply are measured, the pressure switch is tested against a manometer for correct closing pressure, and combustion-air supply and vent sizing are verified.

These checks separate a venting/airflow restriction from a weak inducer or a failed switch. Aside from clearing an obviously blocked exterior termination, the diagnosis involves the venting safety system and is not homeowner work.

When to Call a Professional

This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:

• The furnace tries to fire, then the inducer shuts off and waits about 15 minutes before retrying
• The code persists after an obviously blocked flue termination has been cleared
• It occurs mainly on windy days, suggesting a vent-termination or sizing issue
• The inducer is loud, rattles, or does not start
• The pressure tubing looks disconnected, kinked, or damaged

✓ Verified against manufacturer service manual — March 2026