Quick answer: Carrier furnaces flash a two-digit status code on an LED: a long flash is the first digit and short flashes are the second. The codes we fix most often are 31 (pressure switch did not close), 33 (limit circuit fault), 34 (ignition proving fault), 13 (limit lockout) and 14 (ignition lockout). Bryant, Payne and Day & Night furnaces are built by the same company and generally use the same codes.
Safety first: if you smell gas, do not reset or relight anything. Leave the home and call your gas utility (Nicor Gas 1-888-642-6748, or North Shore Gas 1-866-556-6005) or 911 from outside.
How to Read a Carrier Status Code
Look at the amber or red LED through the sight glass on the blower door. One long flash followed by three short flashes is code 13. Three long and one short is code 31. A steady or slow flash with no long pulses usually means normal operation. Some Carrier boards also store the last several codes, which a technician can retrieve.
Code meanings can differ slightly between board generations, so confirm against the label inside your blower door.
Carrier Furnace Status Code List
| Code | Meaning | What it usually points to |
|---|---|---|
| 11 | No previous code stored | Normal; the fault history is clear |
| 12 | Blower on after power up | Power was interrupted during a heating cycle; the blower runs briefly |
| 13 | Limit circuit lockout | The limit or rollout switch opened repeatedly or stayed open; furnace locks out for about 3 hours |
| 14 | Ignition lockout | Four failed ignition attempts in a row; locks out for about 3 hours |
| 15 | Blower motor lockout | Blower motor failed to reach speed (variable-speed models) |
| 21 | Gas heating lockout | Gas valve stayed energized with no call for heat; power must be reset |
| 22 | Abnormal flame-proving signal | Flame sensed while the gas valve should be closed |
| 23 | Pressure switch did not open | Switch stuck closed or the hose is blocked |
| 24 | Secondary voltage fuse open | A short in the 24-volt wiring blew the 3-amp fuse on the board |
| 25 | Model selection or setup error | Wrong model plug or setup after a board replacement |
| 31 | Pressure switch did not close or reopened | Blocked vent or intake, condensate problem, hose, inducer |
| 32 | Low-heat pressure switch did not close | Same causes as 31, on two-stage furnaces |
| 33 | Limit circuit fault | High limit, rollout or draft safeguard switch open |
| 34 | Ignition proving fault | Flame not sensed after the gas valve opened; often the flame sensor |
| 41 | Blower motor fault | Blower not running at the commanded speed |
| 42 | Inducer motor fault | Inducer not running at the expected speed |
| 43 | Low-heat pressure switch open while high-heat switch closed | Pressure switch or venting problem on two-stage furnaces |
| 45 | Control circuitry lockout | Internal control board fault; the board usually needs replacing |
The Carrier Codes We See Most
- Code 31: pressure switch did not close
- Code 33: limit circuit fault
- Codes 13 and 14: limit and ignition lockouts
- Code 34: ignition proving fault. The burners lit, but the flame sensor did not confirm it in time. A dirty flame sensor is the usual cause, and cleaning it is a $245 flat-rate repair with us. A weak igniter or low gas pressure can also cause it.
- Code 24: secondary voltage fuse. The small 3-amp fuse on the board blew. Replacing the fuse is quick, but we find the short first, often a chewed thermostat wire or a wire touching the outdoor AC unit.
Safe Checks Before You Call
- Replace a dirty filter and open any closed supply vents.
- Clear snow from the PVC intake and exhaust pipes.
- Check the condensate drain on a high-efficiency furnace for a clog or a full pump.
- Reset power once. If the code comes back, call for service.
What Carrier Code Repairs Cost
| Common repair behind a furnace code | Our flat-rate price |
|---|---|
| Flame sensor cleaning and flame signal test | $245 |
| Flame sensor replacement | $275 |
| Hot surface igniter replacement | $305 |
| Pressure switch hose replacement | $250 |
| Pressure switch replacement | $355 |
| High-efficiency condensate trap cleaning or replacement | $290 |
| High limit switch replacement | $340 |
| Flame rollout switch replacement | $325 |
| Flue or PVC vent pipe repair | $435 |
| Inducer motor replacement | $570 to $1,410 |
| Control board replacement | $475 to $1,505 |
| Gas valve replacement | $505 to $1,120 |
| Blower motor replacement | $830 (PSC) to $2,220 (variable speed) |
Prices are flat-rate with parts and labor, as of November 2026. The $75 diagnostic is waived when you approve the repair, and Comfort Club members save 10 to 15% on repairs. Exact pricing depends on your furnace model and whether the part is in stock on our trucks.
Seeing a Carrier code in the Northwest Suburbs?
Pure Comfort Heating and Cooling services every major furnace brand from our shop in Streamwood, IL. Diagnostics are $75, or $99 on evenings, weekends and holidays, and the fee is waived when you approve the repair. You approve a flat-rate price before any work starts, and phones are answered 24/7.
Other Error Code Guides
- Furnace blinking light codes by brand
- Lennox furnace error codes
- Goodman, Amana and Daikin flash codes
- Trane and American Standard blink codes
- Furnace pressure switch errors
Frequently Asked Questions
How do I read a Carrier furnace code?
Count the flashes on the LED. A long flash is the first digit and short flashes are the second digit, so one long and four short is code 14.
Are Bryant and Payne codes the same as Carrier?
Generally yes. Bryant, Payne and Day & Night furnaces are built by Carrier and use the same control boards and status codes, but always confirm against the label on your door.
Will a Carrier furnace reset itself after a lockout?
Codes 13 and 14 usually reset automatically after about three hours. Code 21 requires turning power off and on. If the code returns, there is still a problem to fix.
Do you repair Carrier furnaces?
Yes. We repair Carrier, Bryant and Payne furnaces across the Northwest and West Suburbs, with a $75 diagnostic that is waived when you approve the repair.
We diagnose and repair furnaces from our shop in Streamwood across Streamwood, Bartlett, Hoffman Estates, Schaumburg, Elgin, Hanover Park, Roselle, Arlington Heights and the rest of the Northwest and West Suburbs. See our furnace repair page for flat-rate prices.