Low
S.31 on Glow-worm Ultimate3 Combi

Your boiler is perfectly healthy and is simply waiting for a signal because your heating is currently turned off or set to summer mode.

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

Noheatingdemand:Summermode,eBUScontroller,waitingperiod

Shared across the Ultimate 3 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 your thermostat or programmer settings to ensure the heating is set to 'On' or 'Auto'Increase the target room temperature on your controller above the current room temperatureCheck if your boiler is set to 'Summer' mode and switch it to 'Winter' or 'Combined' mode if you require central heating

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Related fault codes

All 159 fault codes on the Ultimate3 Combi

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

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