Medium
F 05 on Ideal Logic Max Combi 2

Your boiler is having trouble monitoring the temperature of the water returning from your radiators, which may cause it to run less efficiently or stop working intermittently.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Return Thermistor fault (soft fault)

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

Press the Reset button on the front control panelTurn the boiler power off and back on at the fused spur switchCheck that all radiator valves are open to ensure water is flowing back to the boiler correctly

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