Payne PG8MAA Error Code 23: Pressure Switch Did Not Open
What Does Code 23 Mean?
Status code 23 on the Payne PG8MAA indicates that the pressure switch failed to open when the control board expected it to. During the startup sequence, the control board checks that the pressure switch is open (no draft present) before energizing the inducer motor. If the switch remains closed, the board knows the switch is stuck and will not proceed with the heating cycle.
The pressure switch is a safety device that monitors combustion gas venting. Under normal conditions, the switch is open when the inducer is off and closes when the inducer creates sufficient draft. A switch that stays closed regardless of inducer operation cannot provide reliable safety verification.
The most common cause is a pressure switch with contacts that are mechanically stuck or welded in the closed position. Moisture or water intrusion in the pressure tubing or switch housing can also hold the diaphragm in the closed position. A technician should test the switch, check the tubing for obstructions or moisture, and replace the switch if it does not open properly.
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 → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace will not start and displays code 23
- The pressure switch has been exposed to condensate or moisture
- The furnace is in a location prone to high humidity
Sources
✓ Verified against manufacturer service manual — March 2026