Carrier HVAC Error Code 25: How to Fix It
Medium 30-60 minutes Medium Severity
Verified June 2026
- Error Code
- 25
- Brand
- Carrier
- Product Type
- hvac
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 30-60 minutes
Ad
Tools You'll Need
- Multimeter
- Screwdriver set
- Wire brush or contact cleaner
How to Fix Error Code 25
-
Safety First: Power Down
Always disconnect power before servicing HVAC equipment. -
Locate the Thermistor
-
Visual Inspection
-
Test the Thermistor with a Multimeter
Ensure power is off before testing. -
Replace the Thermistor if Faulty
Ensure the replacement thermistor matches your unit's specifications. -
Check Control Board
Control board repair should only be done by a qualified technician. -
Restore Power and Test
Parts You May Need
Thermistor temperature sensor
Check Price on Amazon
Thermistor temperature sensor
Check Price on Amazon
Thermistor temperature sensor
Check Price on Amazon
Thermistor temperature sensor
Check Price on Amazon
Ad
When to Call a Professional
If you're uncomfortable working with electrical components, or if the thermistor tests fine but the error persists (likely control board failure), call a licensed HVAC technician.Frequently Asked Questions
Can I bypass a thermistor fault?
No, bypassing is dangerous and can cause system damage or fire. Always replace a faulty thermistor.
Will error code 25 lock out my system?
Yes, most Carrier systems will shut down and display the code until the fault is resolved.
How much does it cost to fix error 25?
DIY replacement of a thermistor costs $10-$30 for the part. Professional service may be $150-$300.
Is error 25 common in Carrier HVAC systems?
Yes, thermistor faults are relatively common due to aging or environmental wear.
Can dirty filters cause error 25?
No, dirty filters don't directly cause this error, but they can lead to other issues.