Carrier · Status code
Carrier 59TP6C status code 34: flame lost after ignition
Major code 34 records flame loss that happens after a successful ignition. The sub-codes say which stage lost flame (low heat or high heat) and when: before the blower on-delay finished, or after it. The blower on-delay is the period after the burners light before the blower starts moving air (45 seconds in low heat, 25 seconds in high heat on this control).
On the control
- Code
- 34
- Minor
- 34.5 · 34.6 · 34.7 · 34.8
- Door LED
- 3 short flashes then 4 long
- Controller
- 59TP6C integrated furnace control with 3-digit LCD display and door LED
- Applies to
- Carrier Performance 96 (59TP6C)
- Manual
- 59TP6C-01SI REV A
What each minor code says, verbatim
| Display | Manufacturer wording |
|---|---|
| 34.5 | Low heat flame lost before on-delay |
| 34.6 | Low heat flame lost after on-delay |
| 34.7 | High heat flame lost before on-delay |
| 34.8 | High heat flame lost after on-delay |
A code is a condition, not a diagnosis
Flame that is proven and then lost points at the flame-sensing path or at conditions that snuff the flame: a fouled or failing flame sensor, a cracked sensor wire, condensate dripping onto the burner area, combustion-air disturbance from the venting, or gas supply that drops after light-off. The distinction between before and after the blower on-delay helps narrow when the disturbance happens. Testing includes flame-signal measurement during the transition.
Which furnaces this applies to
Documented for Carrier 59TP6C furnaces (all nine sizes) in installation instructions 59TP6C-01SI REV A, edition 06/23. Only sub-codes 5 through 8 are printed on the two-stage 59TP6C label; the single-stage sibling's label carries its own 34.x set, so sub-code numbers must not be compared across stages.
Scope: Carrier 59TP6C Performance 96 furnaces with the on-board 3-digit display control. Not sure which control you have? Send us the full model number from the rating plate.
Safe things to look at first
- Read the full code on the control display through the door, including any minor digit (for example 33.2), and write it down.
- Look, without touching, for obvious conditions you can report: snow or ice at the vent terminations, water on the floor, a loaded filter, a condensate pump that is full or off.
- Note whether the furnace still heats at all, and how long it runs before the code returns.
- Note how long the furnace runs before the code appears, and whether the fault is on low or high fire.
- Check the floor around the furnace for water and the vent terminations for blockage.
Do not
- Do not bypass or jumper the door switch, limit switches, rollout switches or pressure switches.
- Do not open the burner compartment, disconnect tubing, or adjust the gas valve or gas pressure.
- Do not keep cycling power to force the furnace to relight; repeated resets hide the fault and can allow unburned gas to build up after ignition failures. If the code returns, stop and call.
Homeowner-safe checks (look and read only)
- Note how long the furnace runs before the code appears
- Check the vent terminations and the floor for water
When to call a technician
- If the furnace stops heating
- If the fault repeats at the same point in the cycle
Also documented on the same controller family: Carrier Performance 97 (59TP7A).
What a technician does
- A technician measures the flame signal during a full cycle, through the blower on-delay and any stage change, and inspects the flame sensor, its wiring and the burner area.
- Gas supply pressure and venting are checked when the fault repeats at the same point in the cycle every time.
Same code, other equipment
- Carrier single-stage sibling controls (59SC6A): The single-stage Comfort 96 uses 34.1 to 34.3 for its ignition and flame-loss wording; the numbers differ from the two-stage label. Read the label on your furnace. source
Related components and symptoms
Questions people ask
Why does 34.7 or 34.8 appear only on cold days?
High-heat flame loss in cold weather often traces to venting or condensate: ice at the termination, a sagging vent holding water, or a drain that freezes mid-cycle. The technician checks the whole flue and condensate path.
Is code 34 the same as an ignitor failure?
No. Code 34 means ignition succeeded and the flame was then lost. A failed ignitor stops ignition from succeeding in the first place, which reports under the ignition-related sub-codes.
Seeing code 34 on your Carrier?
Tell us the full code, the model number and whether the furnace still heats on low. BC Wide prioritizes no-heat calls across Greater Vancouver.