Low
S.36 on Glow-worm 30cxi

Your boiler is currently idle because it is not receiving a signal from your thermostat or timer to turn on the 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

No Heating demand from external controls 24V

From this model's manual
Verified against the Glow Worm Glow Worm 30cxi installation & service manual, page 52.
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 set higher than the current room temperature.Ensure your external timer or programmer is set to the 'On' position.Replace the batteries in your wireless room thermostat if it uses them.Check that no smart home devices or switches have disabled the heating demand.

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like S.36: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

S.31View →S.33View →

Related guides you might find useful

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →