What does Carrier code 23 mean?
Carrier furnace code 23 means the low-heat pressure switch did not open when the heat call began on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Carrier code 23?
- A pressure switch stuck closed
- A pinched or incorrectly connected pressure hose
- Shorted pressure-switch wiring or a control fault
Can I troubleshoot Carrier code 23?
- Turn furnace power off for five minutes and do not bypass or jumper the pressure switch.
- Check only the outdoor vent openings for obvious snow, ice, leaves, or nests before restoring power once.
How much does Carrier code 23 cost to fix?
A pressure switch replacement typically costs between $175 and $650 nationally.
When should I call a technician?
Call a technician if the code returns; the switch, hose, wiring, and inducer draft need testing.
Sources and model scope
Fault codes vary by model and control board. Confirm the diagnostic chart inside your furnace panel or the official manual before acting.
Scope used here: Carrier-family two-stage controls covered by troubleshooting guide 58-3T.
- Carrier Corporation: Deluxe 2-Stage Gas-Fired Induced-Combustion Furnaces — Troubleshooting Guide
58-3T · Carrier-family two-stage furnace controls covered by document 58-3T; codes vary on other boards and model generations.
Compiled by Warmlo Editorial · Reviewed August 2026
This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.