What It Means
Outdoor discharge line temperature sensor hardware fault.
York All Systems
York Error Code F25
Troubleshooting guide for the York system fault F25.
Possible Causes
- Discharge temperature sensor open, shorted, or out of range.
- Sensor harness connector loose, corroded, or damaged.
- Sensor unclipped or lacking good thermal contact with line.
- Faulty discharge temperature sensor requiring replacement.
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.
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Full Diagnosis
F25 indicates the outdoor unit's discharge-line temperature sensor is reading open, shorted, or outside its valid range — a sensor hardware fault, not an actual overheat event. This differs from F4, which is the protection trip that fires when discharge temperature actually exceeds the safe limit; F25 can occur even with a cool compressor if the sensor itself has failed. It's also a separate sensor position from F6 (ambient) and F7 (suction), each monitoring a different point in the refrigerant circuit. The outdoor unit typically locks out the compressor since the board can no longer verify safe discharge conditions.
All Recorded Causes
Check the discharge temperature sensor's wiring harness and connector at the outdoor PCB for damage, corrosion, or looseness. Verify the sensor is properly clamped to the discharge line and making good thermal contact. Test the sensor's resistance at a known temperature against the manufacturer's chart. Replace the sensor if it reads open, shorted, or wildly inconsistent with actual line temperature.
Verify Before Replacing Parts
- Confirm the exact York model family and default context before acting on a generic code description.
- Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since check the discharge temperature sensor's wiring harness and connector at the outdoor PCB f….
- Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm verify the sensor is properly clamped to the discharge line and making good thermal contac….
- After the correction, run the system long enough to confirm the default fault does not return under normal load.
Not sure which system this York code is on?
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