Common problems guide

The most common Chaffoteaux Britony Duo 55 problems

The faults most likely to send a Chaffoteaux Britony Duo 55 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.

The 5 most common faults

01

BUBNEB STAYS ON High Engineer

Your boiler is failing to ignite properly because debris or trapped air is interfering with the gas or water flow, meaning your heating and hot water will not work.

Est. cost: £120-250
Parts: Gas valve, Water section diaphragm, Slow ignition device

Full guide for BUBNEB STAYS ON

02

HEATING BODY NOISE High Engineer

Your boiler is making loud banging or kettling noises because of internal debris buildup, incorrect gas settings, or restricted water circulation.

Est. cost: £150-350
Parts: Heat exchanger, Pump, Gas valve

Full guide for HEATING BODY NOISE

03

UNSTABLE FLAMES Emergency Engineer

Your boiler is struggling to keep a steady flame, which suggests either moisture is trapped in the gas supply or the system cannot breathe properly through its exhaust.

Est. cost: £150-300
Parts: Flue seals, Gas valve, Air pressure switch

Full guide for UNSTABLE FLAMES

04

POOR PILOT FLAME Emergency Engineer

The small pilot flame that acts as a signal to ignite your boiler is too weak or flickering, so the system is shutting down for safety to prevent gas from escaping unburnt.

Est. cost: £120-200
Parts: Pilot injector, Pilot burner assembly, Pilot tubing

Full guide for POOR PILOT FLAME

05

EXPLOSIVE IGNITION Emergency Engineer

Your boiler is struggling to light smoothly, causing a small 'pop' or bang sound when it tries to start instead of igniting quietly.

Est. cost: £120-250
Parts: Gas valve, Ignition electrode, Pilot assembly

Full guide for EXPLOSIVE IGNITION

Parts most often replaced

on the Chaffoteaux Britony Duo 55

Gas valveWater section diaphragmSlow ignition deviceHeat exchangerPumpFlue seals

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

You can smell gas or see signs of a leak
The Chaffoteaux shows an Emergency or High severity code
The boiler keeps locking out after repeated resets
You've tried the DIY checks and the fault hasn't cleared
There's visible water leaking from the boiler
The flame is yellow or orange instead of blue

See the full 5-code list for the Chaffoteaux Britony Duo 55