Low
D.18 on Vaillant Combi Compact 242EB

Your boiler is staying in a cooling-down phase where the pump runs continuously to prevent the internal components from overheating.

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.

Technical description

Pump mode return

DIY fix possible

Check if all radiator valves (TRVs) are fully open to allow water to circulateEnsure the room thermostat is turned down to see if the pump stops after several minutesWait up to 20 minutes for the boiler to complete its natural overrun cycle

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D.17View →

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