Payne PG8MAA Error Code 23: Pressure Switch Did Not Open
What Does Code 23 Mean?
Status code 23 on the Payne PG8MAA means the Integrated Furnace Control expected the pressure switch to be open at a certain point in the sequence, but it stayed closed. The board relies on the switch's open-and-closed transitions to confirm the draft system is behaving correctly, so a switch that will not open signals a problem.
The manual attributes this to obstructed pressure tubing or a pressure switch stuck in the closed position. In either case the board reads a 'closed' signal when it should read 'open,' which prevents the normal, safe progression of the ignition sequence.
This is the opposite condition from status code 31, where the switch did not CLOSE (or reopened) when it should have been closed. Because verifying and correcting tubing or a failed switch calls for HVAC knowledge and instruments, code 23 is a professional repair rather than a DIY item.
What You'll Notice
- The furnace fails to sequence normally and does not produce heat.
- It faults out around the point where draft is being proven.
- The problem is consistent rather than weather-related, unlike some wind-driven venting faults.
- There are no obvious external vent blockages that a homeowner can see.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Pressure tubing obstructed or kinked | Most common | ✗ Call a pro → |
| Pressure switch stuck in the closed position | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician checks the small pressure-switch tubing for obstruction, kinks, or trapped moisture, and tests the switch's electrical operation against the inducer's draft. If the tubing is clear but the switch stays closed when it should open, the switch is faulty and is replaced. Verification uses a manometer and continuity checks that are beyond homeowner tools.
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 consistently faults at the draft-proving step and will not heat
- You suspect the pressure tubing is blocked or the switch is stuck closed
- The fault persists with no visible external vent blockage
Frequently Asked Questions
What does 'pressure switch did not open' actually mean?
At a point in the cycle the control expects the switch contacts to open; code 23 means they stayed closed, usually from obstructed tubing or a switch stuck closed. A technician can confirm which.
Can I fix code 23 myself?
No. It requires inspecting internal pressure tubing and testing the switch with proper instruments, which is professional work on this furnace.
Sources
✓ Verified against manufacturer service manual — March 2026