Emergency
Main burner “lifts” on Chaffoteaux Corvec 28 OF BF

Your boiler is struggling to breathe properly because it is recycling its own exhaust fumes, which means it cannot burn gas safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description

Re-circulation of flue products. Terminal badly sited and flue set wrongly assembled. Terminal not fitted in wall liner. Over-gassed. Check sealing of blue.

Engineer required

This is a emergency 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 →

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 →