Low
S.40 on Vaillant ecoTEC exclusive 627 VU 256/5-7

Your boiler has temporarily reduced its heating performance to protect itself, meaning your radiators might not get as warm as usual while hot water continues to work normally.

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.

What the manual says

Manufacturer manual

Comfort protection active / Comfort protection mode is active: Product running with limited heating comfort

From this model's manual
Verified against the Vaillant/Vaillant Vaillantpro 0020193966 04 Ecotec Exclusive System Installation I 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

Wait to see if the boiler automatically exits protection mode once it finishes a current cycle or system check.Check that your heating controls and thermostat are not accidentally demanding more than the system can currently deliver.Restart the boiler using the reset button or power switch if the message persists for a long time.

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Related fault codes

S.39View →S.41View →S.42View →

All 72 fault codes on the ecoTEC exclusive 627 VU 256/5-7

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.33F.35F.42F.49F.55F.56F.57F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.77F.78F.80F.81F.82F.83F.84F.85F.90F.94S.34S.36S.37S.39S.41S.42S.46S.53S.54S.55S.56S.57S.58S.59S.76S.86S.88S.92S.93S.96S.97S.98S.99

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