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. The pressure switch should open when the inducer stops and draft ceases; if it stays closed, the board cannot confirm the venting system is behaving correctly between cycles.
The most common cause is obstructed pressure tubing. The small hose linking the pressure switch to the inducer housing can be blocked by condensate, debris, or insect nests. Because the 355MAV is a condensing furnace, moisture in that tubing is a realistic culprit. With the hose plugged, the switch cannot sense true draft pressure and may hold its previous position.
A pressure switch stuck closed is the other likely cause — its diaphragm can stiffen or its contacts can stick so the switch will not open on demand. This is different from codes 31 and 32, where a pressure switch fails to CLOSE (or reopens) during a heat call; code 23 is specifically a switch that will not OPEN when draft stops. Diagnosis involves testing the switch and clearing the tubing, which is technician work.
What You'll Notice
- The furnace hesitates to start a new cycle, or the sequence stalls before ignition
- The status LED flashes code 23 (two short flashes, three long flashes)
- You may notice the inducer behavior differs from a normal start-stop pattern
- The problem can be intermittent if the tubing is only partly blocked or the switch sticks occasionally
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Obstructed pressure tubing | Most common | ✗ Call a pro → |
| Pressure switch stuck closed | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician disconnects the pressure switch hose and confirms whether the contacts open when draft is removed; a switch that stays closed with the hose off is faulty and replaced. If the switch itself is fine, the pressure tubing and its port on the inducer housing are inspected and cleared of condensate or debris.
Because the 355MAV is a condensing furnace, the technician also looks for moisture that could migrate into the tubing. These checks require accessing the inducer and switch assembly, so they are performed by a qualified technician rather than the homeowner.
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 shows code 23 and the pressure tubing or switch needs inspection
- The switch appears physically stuck and does not respond to changes in draft
- The fault is intermittent and hard to reproduce
- You are not equipped to safely test the pressure switch and clear its tubing
Frequently Asked Questions
What does code 23 mean on a Bryant 355MAV?
It means a pressure switch did not open when the inducer stopped and draft ceased. The usual causes are obstructed pressure tubing or a switch stuck in the closed position, both of which a technician should check.
How is code 23 different from codes 31 and 32?
Code 23 is a switch that fails to OPEN when it should. Codes 31 and 32 are pressure switches that fail to CLOSE (or that reopen) during a high-heat or low-heat call. They are opposite conditions on the same type of safety switch.
Sources
✓ Verified against manufacturer service manual — March 2026