Carrier · Status code
Carrier 59SC6A status code 25: control program and configuration faults
Major code 25 covers control-program and configuration faults. The Comfort 96 control must run the model program printed on the rating plate; when that program is missing, corrupted, wrong for the furnace, or the installer settings were damaged, the control reports one of the seven sub-codes and may stop heating or fall back to defaults.
On the control
- Code
- 25
- Minor
- 25.1 · 25.2 · 25.3 · 25.4 · 25.5 · 25.6 · 25.7
- Door LED
- 2 short flashes then 5 long
- Controller
- 59SC6A integrated furnace control with 3-digit LCD display and door LED
- Applies to
- Carrier Comfort 96 (59SC6A)
- Manual
- 59SC6A-01SI REV D
What each minor code says, verbatim
| Display | Manufacturer wording |
|---|---|
| 25.1 | No program info in micro, no heating operation. |
| 25.2 | Corrupted program file, reprogram control using service app or super plug (supplied separately), no heating operation. |
| 25.3 | Twinned units are not identical, program #'s do not match. Ensure furnaces are identical (same program #) when twinning. Main unit will not operate in heating. |
| 25.4 | Main program invalid, using backup program to operate. Reprogram control to correct issue. Control still operates normally. |
| 25.5 | Installer settings corrupted. Try reselecting installer settings, or reprogram control. Control will operate using default installer settings. |
| 25.6 | Wrong program for control used - reprogram control so program matches control used. No heating operation. |
| 25.7 | Non-Condensing program detected in a Condensing model. |
A code is a condition, not a diagnosis
Program faults usually follow control-board replacement, a failed reprogramming attempt, or power loss mid-update. Sub-codes 25.3 and 25.6 also appear when two furnaces are twinned without matching programs. The rating plate's program number is the reference.
Which furnaces this applies to
Documented for Carrier 59SC6A Comfort 96 furnaces in installation instructions 59SC6A-01SI REV D. The label also prints the instruction: if the program in the furnace control is missing, not recognized or corrupted, reprogram it with the correct program number as listed on the rating plate and replace the control if the issue remains.
Scope: Carrier 59SC6A Comfort 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.
- Read the model program number from the rating plate and note it for the technician, along with when the fault first appeared.
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.
What a technician does
- A technician verifies the control's stored program against the rating plate and reprograms it using Carrier's approved method (NFC service app or the correct super plug). If the program will not load, the control is replaced and programmed.
Related components and symptoms
Questions people ask
What does the 25.7 non-condensing warning mean?
It means the control detected a program intended for a non-condensing (80% class) furnace inside a condensing furnace. The control is reprogrammed with the correct program number from the rating plate.
What is a super plug?
A super plug is a Carrier service accessory pre-loaded with a model program, used to copy the correct program onto a replacement control board when the mobile app is not used.
Seeing code 25 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.