Error code

Carrier furnace error code 33

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Is 33 on a Carrier furnace an emergency?

Treat it as urgent — deal with it today. If you smell gas, do not touch switches or try to relight anything: leave, and call the gas utility or 911 from outside.

Take the photo. We’ll tell you what it is.

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What 33 means

“LIMIT CIRCUIT FAULT”

— 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 33 fits

In plain words, 33 is about the heating circuit — an element, a relay or a safety limit in the heating path.

Carrier gives 2 other heating circuit codes for this furnace: 13 (LIMIT CIRCUIT LOCKOUT), 21 (GAS HEATING LOCKOUT).

Next to 33 in Carrier’s table: 31 (PRESSURE SWITCH DID NOT CLOSE OR REOPENED) and 34 (IGNITION PROVING FAILURE).

What to try first

  • Replace a dirty filter and open all vents. If it continues, turn the furnace off and call an HVAC technician; a flame rollout trip is a combustion safety fault.

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 TODAY. fixRAgent treats this code as needing attention today. It points at water where it should not be, overheating, a combustion or ignition safety shutdown, food that may be warming, or a wiring problem. 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.