Error code

Carrier furnace error code 31

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Is 31 on a Carrier furnace an emergency?

Usually not an emergency. If you smell gas, do not touch switches or try to relight anything: leave, and call the gas utility or 911 from outside.

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What 31 means

“PRESSURE SWITCH DID NOT CLOSE OR REOPENED”

— Carrier (shareddocs.com, Carrier's literature host), Carrier 58MCB gas furnace Service and Maintenance Instructions (status codes). Codes vary by model: check your furnace’s own manual.

Where 31 fits

In plain words, 31 is about venting — the draft or pressure switch did not prove that combustion gases are being pushed out.

Carrier gives one other venting and pressure code for this furnace: 23 (PRESSURE SWITCH DID NOT OPEN).

Next to 31 in Carrier’s table: 24 (SECONDARY VOLTAGE FUSE IS OPEN) and 33 (LIMIT CIRCUIT FAULT).

What to try first

  • Check the vent and intake pipes outside are not blocked; if it continues, call an HVAC technician.

Safety: If you smell gas, do not touch switches or try to relight anything: leave, and call the gas utility or 911 from outside.

How urgent is it?

At least THIS WEEK. fixRAgent treats this code as a this-week repair: the appliance has reported a fault, but the code alone does not point at a safety hazard. This is fixRAgent’s reading, not the manufacturer’s. A photo can raise it — water near wiring, scorch marks, a gas smell — but a code never lowers what the photo shows.

Who to call

HVAC technician. Have the model and serial numbers from the label ready — a photo of the label works.

Recalls and manuals

Check whether your model is under a safety recall on the U.S. Consumer Product Safety Commission’s site: cpsc.gov/Recalls. Your owner’s manual is on Carrier’s support site; search it with the model number from the label.