Medium
S.41 on Vaillant ecoTEC exclusive 835 VUW 356/5-7

Your boiler has detected that the water pressure is too high, often caused by the filling loop being left open or a fault in the expansion system.

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 > 2.8 bar

From this model's manual
Verified against the Vaillant/Vaillant Ecotec Exclusive installation & service 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

Check that the silver braided filling loop valves are tightly closedBleed water from a radiator using a radiator key to reduce the pressureMonitor the pressure gauge to ensure it returns to between 1.0 and 1.5 barReset the boiler once the pressure is within the normal range

Find a Gas Safe engineer
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Avoid the next call-out bill

A cover plan would handle faults like S.41: no call-out fees, no surprise bills.

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Related fault codes

All 207 fault codes on the ecoTEC exclusive 835 VUW 356/5-7

Seeing a different code? Every code this model can display, in one place.

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