Carrier Furnace Error Code 34: Meaning & How to Fix It

By the ErrorCodePro Editorial Team · Last reviewed October 20, 2026

Carrier furnace error code 34 means: Flame wasn't proved. Carrier lists a gas valve turned off, a manual shut-off closed, low inlet gas pressure, or a dirty flame sensor. After 4 tries it becomes 14 (ignition lockout, auto-resets after 3 hours). [1] Keep using it? No. Don't keep resetting it. If it locks out again, call a technician.. Start with the owner checks below, beginning with: check the gas supply valve.

Smell gas? Leave the building now. Do not touch light switches, phones or appliances inside. Call your gas utility or 911 from outside. CO alarm sounding or headache, dizziness or nausea? Get everyone outside and call 911. Gas valves, burners, venting and wiring are for a licensed technician only. See our safety policy.

Quick facts

Code	34
Also shown as	14
Brand / appliance	Carrier furnace (weathermaker 8000 two-stage gas furnaces (58dxt/58uxt); status codes are short flashes then long flashes)
System	Heating
Official meaning	Flame wasn't proved. Carrier lists a gas valve turned off, a manual shut-off closed, low inlet gas pressure, or a dirty flame sensor. After 4 tries it becomes 14 (ignition lockout, auto-resets after 3 hours). [1]
Keep using it?	No. Don't keep resetting it. If it locks out again, call a technician.
DIY-safe?	Owner checks only (listed below)
Support	Carrier dealer or Carrier customer relations (carrier.com)

On this page: Meaning · Steps · Parts · When to call a technician · Related codes · FAQ

What error code 34 means on a Carrier furnace

Flame wasn't proved. Carrier lists a gas valve turned off, a manual shut-off closed, low inlet gas pressure, or a dirty flame sensor. After 4 tries it becomes 14 (ignition lockout, auto-resets after 3 hours). [1]

This is a heating code. Codes and wording can vary by model, so check your owner's manual for your model number.

How to fix Carrier furnace error code 34 (safe owner checks)

Owner checks only: on heating, cooling and water-heating equipment, limit yourself to reading the code and checking the thermostat, breaker and service switch, air filter, condensate drain, that the gas supply valve is open (no disassembly) and that vent terminals are clear of snow or debris. Reset power only if your manual allows it.

Safety first: disconnect power before you remove any panel or reach into the sump or drum. Do not touch wiring, the control board or the motor. If you see water near electrical parts, stop and call a technician. These steps are based on Carrier's published guidance [1], rewritten for clarity.

Check the gas supply valve. Make sure the manual gas valve at the furnace is open (handle in line with the pipe) and that other gas appliances work. Don't take anything apart.
Check the thermostat. Make sure it's set to HEAT above room temperature, with fresh batteries.

Parts that may be involved

Exact parts depend on your model number. This page lists part types only, never part numbers.

No specific part is implied by the manufacturer's guidance for this code.

When to call a technician

Licensed HVAC technician for anything inside the furnace: igniter, flame sensor, pressure switch, inducer, limits, gas valve, wiring or board
Gas valves, burners, igniters, flame sensors, venting/flue or CO concerns: licensed HVAC technician or plumber
Refrigerant work: EPA 608-certified technician only
Smell of gas: leave and call the gas utility or 911
Anything involving wiring, the control board, the motor or the water valve electrics
The appliance is under warranty: contact Carrier dealer or Carrier customer relations (carrier.com) first

Frequently asked questions

What does error code 34 mean on a Carrier furnace?

Carrier lists 34 as follows: Flame wasn't proved. Carrier lists a gas valve turned off, a manual shut-off closed, low inlet gas pressure, or a dirty flame sensor. After 4 tries it becomes 14 (ignition lockout, auto-resets after 3 hours).

Is it safe to keep using the furnace with 34?

No. Don't keep resetting it. If it locks out again, call a technician..

Can I fix Carrier furnace error 34 myself?

Only with the owner checks on this page, starting with: check the gas supply valve. If it persists, call a technician or Carrier dealer or Carrier customer relations (carrier.com).

Is 14 the same as 34?

Yes. Carrier's documentation lists 14 with the same meaning as 34; the display format depends on the model.

Sources

https://www.shareddocs.com/hvac/docs/1009/Public/03/58D_U-9SM.pdf (official)

Last reviewed: October 20, 2026. ErrorCodePro is not affiliated with Carrier.