Low
S.36 on Vaillant Atmomax

Your boiler is in a standby mode because it hasn't received a signal from your thermostat to start heating.

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

Not heating demand form low voltage

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s 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 your room thermostat is turned up higher than the current room temperature.Replace the batteries in your wireless thermostat or programmer.Ensure your heating timer or app is set to an 'On' period.

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