Medium
S.41 on Vaillant ecoTEC plus 612 H system A VU GB 126/5-5 A

Your boiler has too much water in the system, causing the pressure to rise to a level that is higher than recommended for safe operation.

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 > 2.8 bar

From this model's manual
Verified against the Vaillant/Vaillant Ecotec Plus 832 Lpg Vuw Gb 326 5 5 4704459 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 filling loop valves are fully closedBleed a radiator from the top valve to release excess waterMonitor the pressure gauge until it returns to between 1.0 and 1.5 barReset the boiler if the code does not clear automatically

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

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

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

F.22View →F.75View →S.42View →

All 94 fault codes on the ecoTEC plus 612 H system A VU GB 126/5-5 A

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

F.00F.01F.02F.03F.10F.11F.12F.13F.20F.22F.23F.24F.25F.26F.27F.28F.29F.32F.42F.49F.52F.53F.54F.56F.57F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.77F.78F.80F.81F.83F.84F.85F.90F.91F.92F.93S.00S.01S.02S.03S.04S.05S.06S.07S.08S.10S.11S.13S.14S.15S.16S.17S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.39S.40S.42S.46S.53S.54S.57S.58S.61S.62S.63S.76S.96S.97S.98

Related guides you might find useful

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Boiler leaking water

Turn it off first. Where the water comes from tells you which part has gone.

Read →

Low pressure: how to repressurise

Step by step using the filling loop.

Read →