Payne PG80ESA Error Code 23: Pressure Switch Did Not Open
What Does Code 23 Mean?
Status code 23 on the Payne PG80ESA means the pressure switch did not open when expected. This switch should close only while the inducer is running and creating draft, and open again once the inducer stops and pressure equalizes. When it stays closed at the wrong time, the Furnace Control CPU cannot verify the safety interlock and flags code 23.
The manual's stated cause is a pressure switch stuck closed — the switch contacts may be mechanically stuck or welded from repeated cycling. It can also be mimicked by the sensing side: a partial blockage in the pressure tubing or port, or condensation trapped in the tubing, can hold pressure against the switch so it does not release. On this 80% non-condensing furnace, moisture in the sensing line is a realistic contributor in humid conditions.
Code 23 is the mirror image of code 31. Code 31 is the switch failing to close (or reopening) when draft should be proven; code 23 is the switch failing to open when it should. Both point at the pressure switch and its sensing path, and both require professional testing rather than a homeowner fix.
What You'll Notice
- The furnace fails to start a new heating cycle, or delays, because the control still sees the switch closed
- The diagnostic LED flashes two short then three long flashes (code 23)
- It may appear after humid weather or long run cycles, when condensation can collect in the tubing
- The inducer may not sequence normally at the start of a call for heat
- The problem clears intermittently, then returns as the switch or tubing acts up
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Pressure switch stuck in closed position | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician connects a manometer to read actual pressure at the switch and watches whether the switch opens and closes at the correct set points. The pressure tubing and port are inspected for kinks, blockage, or trapped condensate, and the switch is tested for proper open/close operation.
The goal is to separate a mechanically stuck switch from a sensing path that is holding pressure. If the switch does not release at the correct pressure it is replaced; if the tubing or port is blocked or wet, that is cleared. Both involve the venting safety system and are not homeowner tasks.
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 will not begin a cycle because the pressure switch is not opening as expected
- The code appears after humid weather or long running cycles (possible condensation in the tubing)
- The pressure switch or its sensing tubing may be stuck, blocked, or failed
- The problem comes and goes but keeps returning
Frequently Asked Questions
What does 'pressure switch did not open' mean on my Payne furnace?
The pressure switch should open once the inducer stops, but it stayed closed. The control reads that as a stuck switch or a sensing line that is still holding pressure, so it flags code 23.
Is code 23 the same as code 31?
No, they are opposites on the same switch. Code 31 is the switch failing to close (or reopening) when draft should be proven; code 23 is the switch failing to open when it should. Both need the switch and tubing checked.
Can I fix code 23 myself?
No. Testing the pressure switch and clearing or replacing its sensing tubing is part of the venting safety system and should be done by a qualified HVAC technician with a manometer.
Sources
✓ Verified against manufacturer service manual — March 2026