What does Carrier and Bryant 34 mean?

On Carrier 59SC5A single-stage 4-way multipoise condensing gas furnace (Series 1 and 2): The control will try three more times before lockout 14. The label lists a coated flame sensor, a manual gas valve shut off, a defective gas valve, a defective hot surface igniter and low inlet gas pressure among things to check. On Bryant 926TC two-stage variable-speed ECM multipoise condensing gas furnace: Minor 1 is an ignition fault during four consecutive ignition trials. Minors 5 to 8 are flame lost before or after the on-delay in low heat or high heat.

Is it safe to keep running my Carrier and Bryant with 34?

Check a few things first. Call a licensed technician if it repeats. Flame sensor cleaning, igniter, gas valve and gas pressure checks are service work. Call a licensed technician if it repeats. Flame sensor, gas valve and gas pressure checks are service work.

What can I check myself for Carrier and Bryant 34?

Check the thermostat is set to Heat, set above room temperature, and has fresh batteries if it uses them. Make sure the manual gas shutoff valve is open, following the lighting instructions on the furnace label. Turn the furnace power off at the switch or breaker, wait one minute, then turn it back on to see whether the code returns. Look outside at the furnace vent and intake pipe ends. Make sure snow, leaves or a nest are not blocking them. Look only, do not touch the pipes.

Home/HVAC & Water Heater Codes/Carrier and Bryant/34

Carrier and Bryant 34 Error Code: Ignition proving failure

Updated October 2026 · Sourced from Carrier and Bryant documentation

🧭 Check a few things first

Carrier and Bryant 34 means different things on different series:

Carrier 59SC5A single-stage 4-way multipoise condensing gas furnace (Series 1 and 2): The control will try three more times before lockout 14. The label lists a coated flame sensor, a manual gas valve shut off, a defective gas valve, a defective hot surface igniter and low inlet gas pressure among things to check.
Bryant 926TC two-stage variable-speed ECM multipoise condensing gas furnace: Minor 1 is an ignition fault during four consecutive ignition trials. Minors 5 to 8 are flame lost before or after the on-delay in low heat or high heat.

Is it safe to keep running? Check the steps below first. Call a licensed technician if it repeats. Flame sensor cleaning, igniter, gas valve and gas pressure checks are service work.

34 at a glance

Code / how it shows	Meaning	Applies to
34 Status LED flashes: first digit is short flashes, second digit is long flashes	Ignition proving failure	Carrier 59SC5A single-stage 4-way multipoise condensing gas furnace (Series 1 and 2)
34 Also: 34.1, 34.5, 34.6, 34.7, 34.8 Status LED flashes: first digit is short flashes, second digit is long flashes; display shows 34.1 and up	Ignition fault or flame lost	Bryant 926TC two-stage variable-speed ECM multipoise condensing gas furnace

Check this first

Only steps a homeowner can do safely. Do not open electrical panels or the burner area.

Check the thermostat is set to Heat, set above room temperature, and has fresh batteries if it uses them.
Make sure the manual gas shutoff valve is open, following the lighting instructions on the furnace label.
Turn the furnace power off at the switch or breaker, wait one minute, then turn it back on to see whether the code returns.
Look outside at the furnace vent and intake pipe ends. Make sure snow, leaves or a nest are not blocking them. Look only, do not touch the pipes.

🛑 Stop and call a licensed pro if

Call a licensed technician if it repeats. Flame sensor cleaning, igniter, gas valve and gas pressure checks are service work.
Call a licensed technician if it repeats. Flame sensor, gas valve and gas pressure checks are service work.
You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
Flame rollout, limit or pressure switch codes that come back after one reset.
Anything involving the control board, gas valve, flame sensor, igniter or venting.
A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.

Safe first steps for any Carrier and Bryant code

Count the LED flashes through the blower door window before you switch anything off. Cutting power can clear the code.
Replace or clean the furnace air filter.
Check the thermostat: correct mode, set above room temperature, and fresh batteries.
Make sure the furnace power switch and breaker are on. If the furnace has locked out, turning the power off and back on once restarts it.
Make sure the gas valve is in the ON position, following the lighting instructions on the furnace label only.
On high-efficiency furnaces, look at the outside vent and intake pipes for snow, ice, leaves or nests (look only, do not take pipes apart).

Sources: Carrier 59SC5A Installation, Start-up, Operating and Service and Maintenance Instructions, Fig. 62 Service Label, p.67; Bryant 926TC Installation, Start-up, Operating and Service and Maintenance Instructions, Service Label (Status Code Table), p.56. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.

Shaun Cain · Certified HVAC & Refrigeration Technician · Ask an HVAC technician

Related Carrier and Bryant codes

LED off : Status LED off (no power to control)LED on : Status LED steady on (normal)Rapid flashing : Rapid flashing LED (reversed polarity)11 : No previous fault code stored 12 : Blower on after power up 13 : Limit circuit lockout 14 : Ignition lockout 21 : Gas heating lockout 22 : Abnormal flame-proving signal 23 : Pressure switch did not open 24 : Secondary voltage fuse is open 31 : Pressure switch did not close or reopened

All 21 Carrier and Bryant codes and series →

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