High
L4 or F4 on Ideal Logic Combi C24 C30 C35

Your boiler has stopped working because it can no longer accurately read the temperature of the water inside the unit.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

FLOW THERMISTOR FAULT

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

L5View →F5View →

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