Chaffoteaux 716 Fault Code: Causes, Fixes & Repair Costs
What does the Chaffoteaux 716 fault code mean?
Fault code 716 on a Chaffoteaux boiler most likely indicates a fan, air pressure, or flue-related problem, though the precise definition depends on your specific model. Chaffoteaux uses different fault code systems across its wide product range — including the Britony, Pigma, Urbia, Mira, Inoa, Alixia, Talia, and Serelia — and codes in the 7xx range on display-equipped models are typically associated with component-level communication or operational errors. On many Chaffoteaux models, the boiler monitors the fan's output signal before allowing ignition; if the PCB does not receive confirmation that the fan is running correctly, the boiler locks out and displays a fault code. Code 716 is consistent with this fan or air-pressure supervision circuit triggering a lockout. Because Chaffoteaux's fault code numbering is model-specific, you should confirm the meaning against your own boiler's manual (available free at ManualsLib.com) before proceeding. If in doubt, call a Gas Safe registered engineer with your exact model name and the code displayed.
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
- Faulty fan motor Common
The fan must start and reach a stable speed before the boiler is permitted to fire. If the PCB receives no speed signal from the fan — or an out-of-range signal — it locks the boiler out. Fan motors can fail gradually due to worn bearings or a burnt-out winding, and on older Chaffoteaux boilers the fan assembly is a common wear item.
- Loose or damaged fan wiring Common
Years of vibration can work wiring connectors loose at the fan terminal or at the PCB plug. A broken wire or corroded pin interrupts the feedback signal, causing the boiler to behave exactly as though the fan itself has failed. An engineer can identify this quickly with a continuity check.
- Faulty air pressure switch Common
The air pressure switch monitors the draught created by the fan and gives the boiler the all-clear to attempt ignition. If the switch diaphragm splits, the switch contacts stick, or the rubber sensing tube becomes blocked or kinked, the switch will not change state correctly and the boiler locks out. This is a relatively straightforward replacement for a Gas Safe engineer.
- Blocked or restricted flue Sometimes
A partial or complete blockage in the flue — caused by a bird's nest, debris, or a damaged terminal — increases back-pressure in the heat exchanger. The boiler detects the abnormal air pressure condition and shuts down to prevent combustion gases entering the property. The external flue terminal should be visually checked from ground level.
- Frozen condensate pipe Sometimes
In cold weather the plastic condensate pipe that exits through an outside wall can freeze solid. The resulting blockage creates abnormal pressure conditions inside the boiler, which can trigger the same fan or air-pressure fault pathway. This is one of the few causes a homeowner can address safely by thawing the pipe with warm (not boiling) water.
- PCB fault Rare
If the PCB itself is damaged — through age, moisture ingress, or a power surge — it may send incorrect signals to the fan or fail to interpret the fan's feedback correctly. Because the PCB controls the entire ignition sequence, a fault here can mimic almost any component failure. PCB issues are usually only confirmed after all other causes have been ruled out.
How to fix it
- Reset the boiler once DIY safe
Locate the reset button on your Chaffoteaux boiler (typically a button or rotary switch on the front panel — consult your manual if unsure). Press and hold it for the duration specified in your manual, then release and wait up to two minutes for the boiler to attempt a restart. If the fault clears and the boiler runs normally, monitor it over the next few hours. If fault code 716 returns, do not keep resetting — repeated resets without fixing the underlying cause can damage components.
- Check the gas supply to your home DIY safe
Make sure your gas meter isolation valve is open and that other gas appliances in the property (such as a gas hob) are working normally. If there is no gas supply to the house, contact your gas supplier rather than a boiler engineer.
- In cold weather, check the external condensate pipe for freezing DIY safe
Go outside and locate the white plastic pipe (typically 21.5 mm or 32 mm diameter) that exits through an outside wall, usually low down near the boiler. If it is frozen, pour warm — not boiling — water along the pipe until it clears, then return indoors and reset the boiler. Insulating the pipe with foam lagging after thawing can prevent a repeat.
- Check the boiler's system pressure DIY safe
Look at the pressure gauge on the boiler fascia. It should read between 1.0 and 1.5 bar when the system is cold. If it reads below 1 bar, repressurise using the filling loop following your boiler manual's instructions, then attempt a reset. Note that low pressure alone is unlikely to cause a 716 code, but it is worth ruling out before calling an engineer.
- Visually inspect the external flue terminal DIY safe
From a safe ground-level position, look at the flue terminal on the outside of your property. Check whether it appears blocked by debris, a bird's nest, ice, or physical damage. Do not climb ladders or attempt to clear a blockage yourself — report what you see to the engineer.
- Call a Gas Safe registered engineer to diagnose and repair the fault Gas Safe engineer
If the fault persists after the homeowner checks above, a Gas Safe engineer is required. They will test the fan motor and its wiring harness, inspect and test the air pressure switch and its sensing tube, check for flue restrictions, and use a multimeter to verify signals at the PCB. They will also confirm the precise meaning of code 716 for your specific Chaffoteaux model. Do not attempt to open the boiler casing, handle the fan assembly, or work on any gas components yourself.
Parts you may need
- Boiler fan assembly (Chaffoteaux compatible) · from £120
- Air pressure switch · from £35
- Air pressure switch sensing tube and fittings · from £12
- Fan wiring harness / loom · from £25
- PCB (printed circuit board) · from £200
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 £150–£380, depending on the underlying cause.
Frequently asked questions
Is fault code 716 the same on all Chaffoteaux boilers?
No. Chaffoteaux produces a wide range of boilers — including the Britony, Urbia, Inoa, Alixia, Talia, and Expert Control series — and each product family can use a different fault code system. Some older models do not have a numeric display at all and indicate faults through LED flash sequences instead. Code 716 is most plausibly a fan or air-pressure supervision fault on models that do display three-digit codes, but you should always cross-reference with the manual for your specific model. You can find official Chaffoteaux manuals free at ManualsLib.com, or call a Gas Safe engineer with your model name and the exact code.
Can I fix a Chaffoteaux 716 fault myself?
The safe homeowner checks are limited to: resetting the boiler once or twice, thawing a frozen condensate pipe in cold weather, and topping up system pressure via the filling loop if the gauge reads below 1 bar. Beyond that, the fault almost certainly involves the fan, air pressure switch, flue, wiring, or PCB — all of which must be inspected and repaired by a Gas Safe registered engineer. Working on these components without the correct qualification is unsafe and illegal.
How much does it cost to repair a Chaffoteaux fan fault in the UK?
For the most common repairs — fan replacement or air pressure switch replacement including labour — most UK homeowners pay between £150 and £380. A straightforward air pressure switch swap at the lower end of that range, a fan motor replacement with parts and an hour or two of labour in the middle, and a more involved fan-plus-wiring diagnosis at the upper end. If the PCB turns out to be the root cause, costs can rise to £400–£600 or more, since PCBs are among the most expensive boiler components. If your Chaffoteaux boiler is over 10–12 years old and needs a PCB or fan assembly, it is worth getting a boiler replacement quote alongside the repair quote, as the economics can favour a new installation.
Why does my Chaffoteaux boiler keep showing fault code 716 after I reset it?
A fault that returns within minutes or hours of a reset indicates an underlying component issue that is not going to resolve on its own. The most likely culprits are a fan motor that is beginning to fail, a faulty air pressure switch that is not switching reliably, or a wiring connection that is intermittently breaking contact. Repeatedly resetting the boiler without addressing the root cause risks overworking associated components and can occasionally contribute to PCB damage. Limit resets to two or three attempts and then call a Gas Safe registered engineer to carry out a proper diagnosis.