Low
S.00 on Vaillant Atmomax

Your boiler is currently in standby mode because your thermostat or programmer is not telling it to turn the heating on.

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

Heating mode error – no heat demand

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 temperatureEnsure your heating programmer or timer is set to 'On' or 'Auto'Replace the batteries in your wireless thermostat if the screen is blank

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