What It Means
Invalid or missing model plug or improper setup switch setting.
Carrier Furnace
Carrier Furnace Error Code 25
Troubleshooting guide for the Carrier Furnace system fault 25.
Possible Causes
- Missing, unseated, or wrong model plug.
- Incorrect setup DIP switch positions.
- Damaged model plug connector.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
New to this code? Click to see why this happens
Full Diagnosis
Model Selection or Setup Error. Model plug is missing/incorrect or setup switch is positioned improperly.
All Recorded Causes
Verify model plug is installed and matches unit model number. Check all DIP switch positions against installation instructions for this specific model. Replace model plug if damaged.
Verify Before Replacing Parts
- Confirm the exact Carrier model family and furnaces context before acting on a generic code description.
- Start with the exact model documentation and verify the full operating sequence before replacing parts, particularly around verify model plug is installed and matches unit model number.
- Use the listed causes as branches to confirm or eliminate with measurements, not assumptions — check all DIP switch positions against installation instructions for this specific model is a reasonable second branch.
- After the correction, run the system long enough to confirm the furnaces fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Carrier Furnace diagnostics step-by-step — so you confirm the cause before swapping parts.
