Bryant 355MAV Error Code 23: Pressure Switch Did Not Open
What Does Code 23 Mean?
Status code 23 on the Bryant 355MAV means a pressure switch failed to open when the control board expected it to. During normal operation, the pressure switch should open when the inducer motor stops, confirming that draft has ceased. If the switch remains closed, the control cannot verify that the venting system is functioning properly between heating cycles.
The most common cause is obstructed pressure tubing. The small rubber or silicone hose that connects the pressure switch to the inducer housing can become blocked by condensation, debris, or insect nests. When the tubing is blocked, the pressure switch cannot sense the actual draft pressure and may remain in its last position.
A pressure switch stuck in the closed position is the other likely cause. The switch contains a flexible diaphragm and mechanical contacts that can wear over time. If the contacts weld together or the diaphragm becomes stiff, the switch may not open when pressure drops. A technician can test the switch by disconnecting the hose and checking whether the contacts open, then inspect and clear the tubing.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Obstructed pressure tubing | Most common | ✗ Call a pro → |
| Pressure switch stuck closed | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace shows code 23 — a technician needs to inspect and clear the pressure tubing and test the pressure switch
- The pressure switch appears to be physically stuck and not responding to changes in draft pressure
✓ Verified against manufacturer service manual — March 2026