Low
F39 on Ferroli Domiproject

Your boiler has lost signal or is receiving an incorrect reading from the sensor that monitors the outdoor temperature.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Optional external probe error

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Locate the outdoor sensor on your external wall and check for any visible damage or loose wiring.Turn the boiler power off and back on again to see if the fault clears.Check if the outdoor sensor has been obstructed or covered by debris.

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