HVACopediaCarrier · Air conditioner
56 OAT / coil thermistor out of range
What the control is telling you
Amber STATUS light flashes 56. Outdoor air and outdoor coil temperatures do not make sense together, e.g. the coil shows heating while cooling is called. Type: Event; reset: None.
Applies to: Carrier Infinity 19VS variable speed air conditioner 24VNA9 (AOC control + inverter)
Likely causes
- Coil sensor loose or in the wrong place
- Outdoor air sensor touching sheet metal or badly placed
- Outdoor coil blocked
Test and repair steps
- Check the coil sensor is clipped to the distributor inlet tube.
- Make sure the OAT sensor body is not touching the cabinet.
- Inspect the outdoor coil for blockage.
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Source: Carrier 25VNA8 / 24VNA9 Service Manual, Table 6 Fault Code Actions, p.20. Summarized in our own words; check the original manual for your model.
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