Low
d.16 on Glow-worm Sustain 12s

Your boiler is currently receiving a signal from your wall thermostat indicating that it is being told to turn on, which is normal operation rather than a fault.

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

Status of the 24V room thermostat

From this model's manual
Verified against the Glow Worm Sustain 12s installation & service manual, page 29.
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 wall thermostat to see if it is set to 'on' or 'heating demand'.Turn the temperature setting on your wall thermostat down to see if the status code changes.If the code persists while the heating is off, consult your thermostat manual for wiring or battery issues.

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