Bryant 340MAV Error Code 23: Pressure Switch Did Not Open
What Does Code 23 Mean?
Status code 23 on the Bryant 340MAV indicates the pressure switch did not open as expected during the furnace operating sequence. The pressure switch monitors the negative pressure generated by the inducer motor and should open (break contact) at a specific point in the heating cycle.
The service documentation for the 340MAV identifies four possible causes: obstructed pressure tubing, a pressure switch stuck closed, a defective inducer motor, and a defective pressure switch. Obstructed tubing is the most common cause — kinks, clogs, or disconnections in the rubber hose prevent the switch from sensing the pressure change. A stuck-closed switch has a mechanical failure in its diaphragm or contacts. A defective inducer motor may not create sufficient pressure to allow the switch to open. A defective pressure switch may fail to open even when pressure conditions are correct.
A technician will inspect the tubing first as it is the most accessible, then test the pressure switch contacts with a multimeter, and measure inducer motor draw to determine if the motor is operating correctly.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Contact a technician to diagnose and repair the pressure switch or inducer motor — the furnace will not complete a heating cycle with this fault active
- Do not substitute non-OEM pressure switches; the 340MAV requires switches calibrated to its specific inducer pressure specifications
✓ Verified against manufacturer service manual — March 2026