Low
d.60 on Vaillant ecoFIT Pure 418

Your boiler is temporarily pausing because internal temperature sensors have detected heat rising too quickly, likely due to a circulation issue.

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

Number of blocks by the temperature sensor

DIY fix possible

Check that all radiator valves are fully openEnsure there is enough water pressure in the system (typically 1.0 to 1.5 bar)Bleed any air out of your radiators

Find a Gas Safe engineer
Search the official register →

Related fault codes

F.20View →F.22View →F.24View →

Related guides you might find useful

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →

Radiators cold at the bottom

Sludge build-up — needs flushing, not bleeding.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →