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Carrier gas furnace code 25: Model plug missing or wrong, or a setup switch error
Gas furnace, Canada and United States
The control cannot confirm the furnace model, because the model plug is missing or incorrect, or because a setup switch is in the wrong position. If 25 flashes only 4 times at power-up, the control is using the model stored in its memory.
On the status light, this code is 2 short flashes, then 5 long flashes.
This needs a licensed gas technician. There is nothing safe to check yourself. Leave the covers on and book a professional.
Only some models show this code. Check the list below.
What causes it
Standard amber-LED furnaces
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The model plug is missing or wrong. This happens when a replacement control is fitted without moving the model plug across.
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Setup switch SW1-1 (code recall) or SW1-6 (component test), or both, were left on during a call for heat.
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Two different furnace models are twinned together.
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A replacement control of the wrong type or software version is fitted.
Ultra-low NOx furnaces
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The model plug is missing or wrong.
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On 58CU0A, setup switch SW1-1 or SW1-6, or both, were left on during a call for heat.
How to read this code on your unit
The amber status light (red on some older boards) on the furnace control shows through a small window in the blower access door. A steady light means the control has power and no fault to show. A code is two digits. Count the short flashes for the first digit, then the long flashes for the second, so 3 short flashes followed by 3 long flashes is code 33, and 1 short then 1 long is code 11. Write the code down before you open the door or switch the furnace off.
Booking a licensed gas technician
Book a licensed gas technicianlicensed gas technician
- Turn the unit off and leave the covers on. Gas components must only be serviced by a licensed technician.
- Note the code, how often it appears, and the model and serial numbers from the rating label.
- Book a licensed gas technician and give them those details.
Models that show this code
116 models in 15 ranges
| Range | Models |
|---|---|
| 58CVA/CVX | 58CVA070-12, 58CVA090-16, 58CVA110-20, 58CVA135-22, 58CVA155-22, 58CVX070-12, 58CVX090-16, 58CVX110-20, 58CVX135-22, 58CVX155-22 |
| 58SP0A/58SP1A | 58SP0A045V14-12, 58SP0A045V17-16, 58SP0A070V17-16, 58SP0A070V21-20, 58SP0A090V21-20, 58SP0A090V24-20, 58SP0A110V24-22, 58SP1A045V14-12, 58SP1A045V17-16, 58SP1A070V17-16, 58SP1A070V21-20, 58SP1A090V21-20, 58SP1A090V24-20, 58SP1A110V24-22 |
| 58TN0A/58TN1A | 58TN0A045C17-12, 58TN0A070C14-12, 58TN0A070C17-16, 58TN0A070C21-20, 58TN0A090C17-16, 58TN0A090C21-20, 58TN0A110C21-20, 58TN0A135C24-22, 58TN1A045C17-12, 58TN1A070C14-12, 58TN1A070C17-16, 58TN1A070C21-20, 58TN1A090C17-16, 58TN1A090C21-20, 58TN1A110C21-20, 58TN1A135C24-22 |
| 58TP0A/58TP1A | 58TP0A045V14-12, 58TP0A070V14-12, 58TP0A070V17-16, 58TP0A090V17-16, 58TP0A090V21-20, 58TP0A110V21-22, 58TP0A135V24-22, 58TP1A045V14-12, 58TP1A070V14-12, 58TP1A070V17-16, 58TP1A090V17-16, 58TP1A090V21-20, 58TP1A110V21-22, 58TP1A135V24-22 |
| 59MN7A | 59MN7A060V17-14, 59MN7A080V17-14, 59MN7A060V21-20, 59MN7A080V21-20, 59MN7A100V21-22, 59MN7A120V24-22 |
| 59MN7B | 59MN7B060C17-14, 59MN7B060C21-20, 59MN7B080C17-14, 59MN7B080C21-20, 59MN7B100C21-22, 59MN7B120C24-22 |
| 59SP6A | 59SP6A040V14-10, 59SP6A040V17-12, 59SP6A060V14-12, 59SP6A060V17-14, 59SP6A080V17-16, 59SP6A080V21-20, 59SP6A100V21-20, 59SP6A120V24-22 |
| 59TN6A | 59TN6A060V17-14, 59TN6A080V17-14, 59TN6A080V21-20, 59TN6A100V21-22, 59TN6A120V24-22 |
| 59TN6B | 59TN6B060C17-14, 59TN6B080C17-14, 59TN6B080C21-20, 59TN6B100C21-22, 59TN6B120C24-22 |
| 59TP6A | 59TP6A040V14-10, 59TP6A040V14-12, 59TP6A060V17-12, 59TP6A060V17-14, 59TP6A080V17-16, 59TP6A080V21-20, 59TP6A100V21-20, 59TP6A120V24-22 |
| 59TP6B | 59TP6B040V14-10, 59TP6B040V17-12, 59TP6B060V14-12, 59TP6B060V17-14, 59TP6B080V17-16, 59TP6B080V21-20, 59TP6B100V21-20, 59TP6B120V24-22 |
| 58CU0A | 58CU0A040C17-12, 58CU0A060C17-16, 58CU0A080C21-20, 58CU0A100C21-20 |
| 58SU0A | 58SU0A040E17-12, 58SU0A060E17-16, 58SU0A080E21-20, 58SU0A100E21-20 |
| 59CU5A | 59CU5A060C17-16, 59CU5A080C21-20, 59CU5A100C21-22 |
| 59SU5A | 59SU5A040E17-12, 59SU5A060E17-16, 59SU5A080E21-20, 59SU5A100E21-20, 59SU5A100E21-22 |
Where this comes from
- 58SP0A/58SP1A 80% single-stage variable-speed gas furnace, installation, start-up, operating and service instructions (58SP0A-02SI) , page 26
- 59TP6A two-stage variable-speed condensing gas furnace, installation, start-up, operating and service instructions (59TP6A-10SI) , page 73, 90
- 58CVA/CVX variable-speed induced-combustion gas furnace, installation, start-up, operating and service instructions (58CV-13SI) , page 37, 58
- 58SU0A 80% single-stage ultra-low NOx gas furnace, installation, start-up, operating and service instructions (58SU0A-06SI) , page 33
- 59SU5A single-stage ultra-low NOx condensing gas furnace, installation, start-up, operating and service instructions (59SU5A-05SI) , page 51
- 58CU0A 80% communicating ultra-low NOx gas furnace, installation, start-up, operating and service instructions (58CU0A-03SI) , page 23
- 59CU5A single-stage communicating ultra-low NOx condensing gas furnace, installation, start-up, operating and service instructions (59CU5A-01SI) , page 65
Checked against the manufacturer's manual on 9 October 2026.
Other Carrier gas furnace codes
| Code | Meaning | What you can do |
|---|---|---|
| 24 | 24-volt fuse on the control has blown | Call a pro |
| 25.1 | Control has no program loaded | Call a pro |
| 25.2 | Control program file is corrupted | Call a pro |
| 25.3 | Twinned furnaces are not identical | Call a pro |
| 25.4 | Main program invalid, running on the backup program | Call a pro |
| 25.5 | Installer settings are corrupted | Call a pro |
| 25.6 | Wrong program loaded for this control | Call a pro |
| 25.7 | Non-condensing program in a condensing furnace | Call a pro |
| 27.1 | Program in super plug is missing or corrupted | Call a pro |
| 27.2 | Program in super plug is missing or corrupted | Call a pro |
| 27.3 | Program in super plug is missing or corrupted | Call a pro |
| btL | Firmware failed to load | Call a pro |
See all configuration error codes on gas furnaces across brands.