Medium
S.52 on Vaillant ecoTEC Combi

Your boiler has detected that the water pressure inside the system has risen too high, which could cause a safety relief valve to leak.

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

Water pressure > 2,9 bar

From this model's manual
Verified against the Vaillant Ecotec installation & service manual, page 43.
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

Check that the filling loop valves are fully closed and not leaking water into the systemIdentify a radiator in your home with a bleed valveOpen the bleed valve slightly to release a small amount of water until the pressure gauge on the boiler drops to between 1.0 and 1.5 bar

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