High
Burner goes out on Ferroli Sigma 40 FF

Your boiler is struggling to keep its flame lit, which means it cannot heat your water or home reliably.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Insufficient gas supply. Check gas pressure to main burner. Boiler dirty. Check and clean heat exchanger. Burner or injector dirty. Check and clean burner or injector. Faulty flow temperature sensor. Replace flow temperature sensor

From this model's manual
Verified against the Ferroli/Ferroli Sigma 40 Ff installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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 Burner goes out: 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.

All 10 fault codes on the Sigma 40 FF

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

121Boiler lockoutBoiler sootingBurner air ports blockedBurner fails to igniteCondensate in boilerFan runs boiler does not workIncorrect gas rateRadiators cold in winter

Related guides you might find useful

Pilot light keeps going out

Older boilers — thermocouple, draught, gas supply.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →