Fujitsu Mini-Split Error Code 37: How to Fix It

Q: What does Fujitsu mini-split error code 37 mean?

Error code 37 indicates a fault with the outdoor unit's suction pipe thermistor – a temperature sensor that monitors refrigerant in the suction line. The sensor may be shorted, open, or disconnected.

Q: Can I run my mini-split with error code 37?

It is not recommended. The system may operate inefficiently or fail to cool/heat properly, potentially causing further damage. Turn off the unit and fix the issue before use.

Q: Where is the suction pipe thermistor located?

The suction pipe thermistor is attached to the suction line (larger copper pipe) inside the outdoor unit, usually near the service valve or compressor. It may be held by a clip or zip tie.

Q: How do I test the suction pipe thermistor?

Use a multimeter set to resistance. Disconnect the thermistor from the control board. At room temperature (77°F/25°C), resistance should be around 10k ohms. Consult the manufacturer's resistance-temperature chart for other temperatures.

Q: Is error code 37 common on Fujitsu mini-splits?

Yes, it is a common fault, especially after power surges or aging. The thermistor can fail over time due to heat cycles or moisture. Replacing it is a straightforward fix.

Abstract

Error code 37 on your Fujitsu mini-split indicates a problem with the outdoor unit's suction pipe thermistor. This sensor monitors refrigerant temperature, and a fault can cause improper cooling or heating. This guide walks you through diagnosing and fixing the issue, from checking wiring to replacing the thermistor.