Chaffoteaux Boiler Repairs London

Chaffoteaux Boiler Repair Help Centre

Common Chaffoteaux faults, fault codes, safe checks, and when to call a Gas Safe engineer.

Jump to:
Fault Codes ·
501 Ignition ·
Pressure ·
Frozen Condensate ·
Repair or Replace

Quick Checks Before You Call Anyone

These take 60 seconds and solve a surprising number of lockouts:

1. Check the pressure gauge: If below 1 bar, top up (see guide below). More detail in our complete pressure guide.
2. Note the fault code: Chaffoteaux displays show 3-digit codes like 501, 502, 108, 110. Write it down before calling.
3. Check your fuse box: Boilers need electricity; a tripped switch is an easy fix.
4. Check thermostat and timer: Settings can change after clock changes or dead batteries.
5. Freezing weather? The condensate pipe may be frozen (see winter section below).
6. Reset once only: Press the reset button on the front panel, wait 60 seconds. If it locks out again, stop and call an engineer.

Chaffoteaux Boilers Commonly Found in London

Chaffoteaux is a French manufacturer, now part of the Ariston Group. Their boilers were widely installed across London during the 2000s, particularly the Britony, Calydra, and Celtic ranges. We also see Minima and Niagara models in flats and smaller properties. Many Chaffoteaux boilers are now 15-20 years old and reaching end of life, though parts remain available for most common faults. If you can tell us the model name and fault code, we can advise whether repair or replacement makes more sense.

Chaffoteaux Boiler Fault Codes

Note: Chaffoteaux uses 3-digit fault codes on most models. Older Britony models may show flashing lights instead of digital codes. If you have flashing lights, count the sequence and tell us when you call.

501: Ignition Failure

What is happening: The boiler is trying to ignite but cannot establish a flame after multiple attempts. This is the most common Chaffoteaux fault code.

Common causes: Frozen condensate pipe (winter), gas supply interruption, faulty ignition electrode or lead, blocked or damaged flue, gas valve fault.

What to try: Check if your gas hob or other gas appliances work. In freezing weather, check the condensate pipe for ice. If gas supply is fine but boiler will not ignite, call an engineer.

Note: On older Chaffoteaux boilers, ignition components can wear out and become harder to source. We carry common parts but some repairs may take longer if specific components need ordering.

504: Flame Loss During Operation

What is happening: The boiler ignited successfully but the flame was lost during operation.

Common causes: Gas pressure fluctuation, dirty or worn flame sensor, flue blockage, wind affecting the flue terminal, intermittent gas valve issue.

What to try: Reset once and monitor. If 504 appears repeatedly, especially during windy weather or high demand, call an engineer. Repeated flame loss faults need diagnosis to prevent further damage.

110: Overheat Protection

What is happening: The boiler has shut down because internal temperatures exceeded safe limits.

Common causes: Pump failure or blockage, system sludge restricting flow, expansion vessel fault, low water level, faulty overheat thermostat.

What to try: Let the boiler cool for 30 minutes. Check the pressure gauge and top up if needed. Reset once. If 110 or 117 returns, do not keep resetting. Call an engineer as overheating can damage components.

108: Low Water Pressure

What is happening: System pressure has dropped below the minimum operating level.

Common causes: Small leak in system, recently bled radiators, pressure relief valve discharge, expansion vessel needs recharging.

What to try: Top up pressure using the filling loop (see below). If pressure drops again within days, there may be a leak. Read our pressure guide for step by step instructions.

How to Top Up Pressure (Chaffoteaux)

If you are not comfortable using the filling loop, stop and call a Gas Safe engineer.

Note: Most Chaffoteaux boilers have a filling loop underneath or beside the boiler with two small valves or taps. Some models have a single lever filling device.

1. Locate the filling loop (usually underneath the boiler, a braided silver hose with one or two valves).
2. Ensure the boiler is off and cool.
3. Open the valves slowly, a quarter turn at a time.
4. Watch the pressure gauge rise to between 1.0 and 1.5 bar.
5. Close both valves fully.
6. Switch the boiler back on and reset if required.

Do not exceed 2.0 bar. If you overfill, stop and call an engineer.

If you need to top up frequently (more than once a month), there is likely a leak. Call us for a diagnosis.

Frozen Condensate Pipe (Winter)

In freezing weather, a frozen condensate pipe is one of the most common causes behind 501 and 504 lockouts on Chaffoteaux boilers. This is often safe to resolve yourself. If you are unsure, or the boiler will not restart, call an engineer.

Signs: Boiler locked out with 501 or 504, freezing temperatures outside, gurgling sound when boiler tries to start.

What to do:

1. Locate the condensate pipe (white or grey plastic pipe exiting to an outside drain).
2. Pour warm water (not boiling) over the frozen section.
3. Reset the boiler once thawed.

Do not use a naked flame or heat gun on plastic pipework.

Full instructions: Frozen condensate pipe guide.

If it keeps happening, we can reroute the pipe internally or add insulation to prevent future freezing.

Why These Faults Are Common in London Homes

Hard water, older pipework, and the age of most Chaffoteaux installations make certain faults more likely:

• 108 (low pressure): London’s Victorian and Edwardian properties often have older pipework with small leaks causing gradual pressure loss.
• 501 (ignition failures): Worn ignition electrodes and leads are common on Chaffoteaux boilers now 15+ years old.
• 110/117 (overheat): Hard water causes limescale buildup, restricting flow and leading to overheating faults.
• Heat exchanger scale: London’s hard water causes significant scaling over time, reducing efficiency and causing kettling noises.

Chaffoteaux Boiler Models We Repair

We repair all Chaffoteaux gas boiler models including:

• Britony: Combi and system range, widely installed 2000-2010
• Calydra: Popular combi range, common in London flats
• Celtic: Older combi range, parts availability reducing
• Minima: Compact combi for smaller properties
• Niagara: System boilers with unvented cylinders
• Elexia: Later range before brand discontinuation in UK
• Pigma: Compact range
• MX2: Older floor-standing models

Chaffoteaux: Parts Availability and Age

Chaffoteaux withdrew from the UK market in the early 2010s, but parts remain available for most models through aftermarket suppliers and the Ariston Group (who now own the brand). However, some specific components for older Celtic and MX2 models are becoming harder to source.

If your Chaffoteaux is over 15 years old, we will give you an honest assessment of whether repair makes sense versus replacement with a more modern, efficient boiler.

Common Chaffoteaux Boiler Problems

501 ignition failures: The most common repair. Often caused by worn electrodes, ignition leads, or frozen condensate in winter.

Low pressure (108): Very common on Chaffoteaux combis. Usually a small system leak or expansion vessel issue.

Diverter valve sticking: Hot water works but radiators stay cold, or vice versa. Very common on Britony and Calydra models over 10 years old.

Overheat faults (110/117): Often linked to circulation problems, pump wear, or limescale buildup in the heat exchanger.

PCB failure: Random lockouts, display glitches, or complete failure. PCBs for older models can be expensive to source.

Heat exchanger scale: Kettling noises, overheating, reduced efficiency. See our guide to boiler noises.

Repair or Replace?

Most Chaffoteaux boilers in London are now 15-20 years old and approaching or past their expected lifespan. If yours needs a major repair (heat exchanger, PCB, gas valve), replacement is often more cost effective.

Signs it may be time to replace:

• Multiple faults in the past 12 months
• Parts becoming hard to source for your specific model
• Efficiency noticeably declining (higher gas bills)
• Boiler over 15 years old

We give honest advice either way. Read more: Repair or replace? An engineer’s guide.

If you decide on a new boiler: New boiler installation.

Chaffoteaux Boiler Servicing

Annual servicing is especially important on older boilers like Chaffoteaux. It helps catch developing faults before they become expensive failures and maintains safe operation.

We service all Chaffoteaux models and provide a full report after each visit. Book your boiler service.

Renting? Landlords: Check This

Tenants: Your landlord is usually responsible for boiler repairs. Contact them first and keep written records, especially if you have no heating or hot water.

Landlords: If your rental property has an older Chaffoteaux boiler, consider whether replacement makes sense before the next tenancy. Stay compliant with our Gas Safety Certificate (CP12) service. See our full London landlord checklist.

London Wide Coverage

We repair Chaffoteaux boilers across all London boroughs including North, South, East, West, and Central London. Our engineers are based throughout the city for fast response times.

For coverage and service areas, see our London coverage page.

We Also Repair These Brands

What We Need From You (To Diagnose Faster)

• Boiler model: for example Britony, Calydra, Celtic, Minima, Niagara
• Fault code: the exact code shown on the display (501, 108, 110, etc.) or flashing light sequence
• Pressure reading: (if visible) and whether it drops frequently
• Postcode: so we can route the closest engineer
• Gas supply check: whether other gas appliances work (hob/cooker)

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