Chaffoteaux 240 Fault Code: Causes, Fixes & Repair Costs
What does the Chaffoteaux 240 fault code mean?
If your Chaffoteaux boiler is displaying what looks like '240', it is worth knowing that this number does not appear as a verified standalone fault code in any published Chaffoteaux manual. The most likely explanation is one of three things: you may be reading a model reference (such as a Flexiflame 240) rather than a fault code; on older Chaffoteaux models like the Britony range, faults are communicated through LED flash sequences that can be misread as numbers; or the display is actually showing '3 P9' (sometimes written 3P9), which is a confirmed Chaffoteaux fault code meaning 'Scheduled Maintenance Due – Contact Service'. The 3 P9 code is not a breakdown alert. It is an automatic reminder that the boiler has reached its programmed service interval, typically 12 months or a set number of operating hours. The boiler will usually continue to run, but a Gas Safe registered engineer needs to carry out an annual service and then reset the internal maintenance counter via the installer menu. If your display shows a different code entirely, check your model's manual on ManualsLib and quote the exact code and model name when calling an engineer, as Chaffoteaux fault codes vary significantly between the Pigma, Talia, Britony, and Mira ranges.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Programmed service interval reached Common
The most common trigger. Chaffoteaux boilers have an internal counter that tracks time or operating hours since the last service was logged. Once that interval expires — typically 12 months — the 3 P9 reminder activates automatically. The boiler is doing exactly what it is designed to do.
- Engineer did not reset the maintenance counter after the last service Common
A Gas Safe engineer may have carried out a full annual service but forgotten to access the installer menu and reset the maintenance counter (parameter 850 on Expert Control models). The boiler has no way of knowing the work was done unless that counter is cleared, so the 3 P9 code remains or reappears shortly after.
- Power cut or PCB replacement has desynchronised the internal counter Sometimes
A prolonged loss of mains power, or the fitting of a replacement PCB, can wipe the stored service date from the boiler's memory. Without that reference point, the boiler treats the situation as an overdue service and activates the reminder as a precaution.
- Misread display — actual fault code differs from 240 Sometimes
On Chaffoteaux models without a clear digital display, or where the screen is partially obscured, characters can be misread. If the boiler is also not functioning normally, the underlying code may be something like A01 (no flame), E06 (no circulation), E07 (no water in primary circuit), or E20 (air pressure switch fault) rather than a maintenance reminder.
How to fix it
- Confirm what is actually on your boiler's display DIY safe
Look carefully at the full display. Is the boiler still producing heat and hot water? If yes and the code reads '3 P9' or similar, this is almost certainly a maintenance reminder and is not an emergency. If the boiler has stopped working entirely, note the exact code shown — including any letters — and check your model's manual to identify the correct fault.
- Check your system pressure DIY safe
Look at the pressure gauge on the front of the boiler. It should read between 1.0 and 1.5 bar when the system is cold. If it has dropped below 1 bar, you can top it up using the filling loop (a small braided hose or valve, usually beneath the boiler). Turn the valve slowly, watch the gauge, and close it once pressure reaches 1.2–1.5 bar. If pressure regularly drops, tell your engineer when you book the service.
- Reset the boiler once DIY safe
Press the reset button on the boiler's front panel and wait about 60 seconds. If the 3 P9 code reappears, that is normal — a reset alone cannot clear a maintenance reminder; only an engineer resetting the internal counter will do that. If the boiler locks out on a different fault code after resetting, do not reset it again. Stop and call an engineer.
- Book a Gas Safe registered engineer for an annual service Gas Safe engineer
A full annual service is the correct fix for the 3 P9 maintenance reminder. The engineer will inspect the heat exchanger, burner, flue, condensate system, seals, and gas pressure, carry out any necessary cleaning or adjustments, and then reset the maintenance counter via the installer menu. Make sure you tell the engineer your exact boiler model so they can access the correct parameter.
- Ask the engineer to investigate any underlying issues found during the service Gas Safe engineer
Annual services sometimes reveal faults that have not yet triggered a lockout — scale on the heat exchanger, a deteriorating expansion vessel, a weeping pressure relief valve, or early signs of pump wear. Addressing these during the service visit is more cost-effective than a separate call-out later.
Parts you may need
- Expansion vessel (replacement) · from £85
- Pressure relief valve · from £35
- Ignition electrode · from £25
- Pump assembly · from £95
- PCB (control board) · from £220
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £75–£220, depending on the underlying cause.
Frequently asked questions
Can I keep using my Chaffoteaux boiler when it shows the 3 P9 or 240 code?
In most cases, yes — a 3 P9 maintenance reminder does not shut the boiler down. It is an advisory alert, and the boiler should continue producing heat and hot water. That said, you should not ignore it. An overdue service means safety checks have not been carried out, and underlying issues such as low pressure, scale build-up, or a failing component could be developing undetected. Book an engineer promptly rather than leaving it until a breakdown occurs.
My engineer serviced the boiler last month but the 3 P9 code has come back — why?
This almost always means the engineer carried out the physical service but did not reset the maintenance counter in the boiler's installer menu. The boiler has no way to know a service took place unless that internal counter is cleared. Contact the engineer and ask them to return and reset it — this is a quick job and should not incur a further call-out charge if it was an oversight on their part.
Is '240' definitely not a real Chaffoteaux fault code?
Based on all available published Chaffoteaux manuals and verified fault code databases, 240 does not appear as a standalone error code. It is most likely a model number reference, a misread of the 3 P9 maintenance reminder, or possibly an LED flash sequence being interpreted as digits on an older Britony-range boiler. If your boiler has stopped working and is showing a code you cannot identify, note it exactly, find your model name on the boiler casing, and call a Gas Safe engineer with both pieces of information.
How much does it cost if the engineer finds a bigger problem during the service?
The service itself typically costs around £75–£100. If the engineer discovers a fault, common repair costs include around £100–£200 for an ignition electrode, £120–£250 for a pressure-related repair, and £150–£300 for a pump replacement. PCB replacement is more expensive — typically £450–£700 including labour — and a heat exchanger can reach £500–£1,000. If your Chaffoteaux boiler is over 12 years old and needs one of those major components, it is worth asking the engineer to compare the repair cost against the price of a new boiler installation.