Carrier 58MVC Error Code 23: Pressure Switch Did Not Open
What Does Code 23 Mean?
Status code 23 on the Carrier 58MVC means the control board expected the pressure switch to return to its open (default) position, but it remained closed. The pressure switch is a safety device that monitors whether the inducer motor is creating proper draft for venting combustion gases.
When the switch stays closed when it should be open, it typically means the switch contacts have become stuck or there is an obstruction in the pressure tubing that is holding the switch in the wrong position. This prevents the furnace from verifying that venting conditions are safe before the next ignition cycle.
A stuck pressure switch can sometimes be a sign of condensation buildup in the tubing, debris in the hose, or simply a worn-out switch. Because this involves the furnace's combustion safety system, diagnosis and repair should be handled by a qualified technician who can test the switch, inspect the tubing, and replace components as needed.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Obstructed pressure tubing | Common | ✗ Call a pro → |
| Pressure switch stuck closed | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- When this code appears — the pressure switch and tubing need professional inspection to determine if the switch is defective or the tubing is blocked
✓ Verified against manufacturer service manual — March 2026