Chaffoteaux 714 Fault Code: Causes, Fixes & Repair Costs
What does the Chaffoteaux 714 fault code mean?
Fault code 714 on Chaffoteaux boilers falls within the 7xx error code family, which relates to temperature sensor (NTC thermistor) faults on zone circuits. Based on the numbering pattern used across the Chaffoteaux range — where the first digit identifies the functional area of the boiler — code 714 most likely indicates a problem with a flow or return NTC temperature sensor on a specific heating zone. The closely related code 704 is confirmed to relate to a return temperature sensor fault on zone 3, suggesting 714 follows the same sensor-fault logic on a different zone or circuit. NTC thermistors continuously feed water temperature data to the PCB; when one gives an implausible or absent reading, the boiler raises this fault and may lock out for safety. Because Chaffoteaux fault codes vary between models (Britony, Calydra, Alixia, Urbia, Pigma, and others), always cross-reference your specific boiler's installation manual to confirm the exact definition for your model.
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 NTC temperature sensor Common
The NTC thermistor itself may have failed due to normal wear, scale build-up around the sensor body, or physical damage. A failed sensor sends an out-of-range resistance value to the PCB, triggering the fault. This is the most common cause across the 7xx fault code family on Chaffoteaux boilers.
- Loose or corroded sensor wiring Common
The low-voltage wiring connecting the NTC probe to the PCB can work loose over time or suffer corrosion at the connector plug. Even a slightly poor connection can produce an erratic resistance reading that the boiler interprets as a sensor fault.
- Power surge or intermittent supply issue Sometimes
A brief power surge or an unstable mains supply can cause the PCB to log a spurious sensor error. If the fault clears after a single reset and does not return, this is the likely explanation.
- PCB (printed circuit board) failure Rare
If the control board itself has developed a fault on the sensor input circuit, it may incorrectly report a sensor error even when the thermistor and wiring are both healthy. PCB faults can mimic almost any sensor code and are usually identified by elimination.
How to fix it
- Check your boiler model manual for the exact code definition DIY safe
Chaffoteaux fault codes differ between model ranges. Before doing anything else, locate your boiler's installation or user manual — these are available on ManualsLib.com — and confirm what 714 means for your specific appliance. The first digit indicates the functional area, so also check nearby codes (e.g. 704, 710, 711) to understand the pattern for your model.
- Reset the boiler once or twice DIY safe
Press and hold the reset button as described in your user manual. A single spurious sensor reading caused by a power blip will often clear with one reset. Do not reset more than two or three times in succession — repeated lockouts indicate a genuine fault that needs investigation, and some Chaffoteaux models limit the number of permitted resets for safety reasons.
- Check system pressure is within range DIY safe
Confirm the pressure gauge reads between 1.0 and 1.5 bar when the system is cold. Although low pressure is not a direct cause of a sensor fault, it can contribute to abnormal temperature readings. Top up via the filling loop if pressure has dropped below 1 bar, following your boiler manual's instructions.
- Visually inspect accessible wiring around the boiler DIY safe
With the boiler switched off at the mains, take a careful look at any visible wiring around the boiler casing for obvious signs of damage, burning, or loose connectors. Do not open the boiler casing or touch internal components. If you spot damaged wiring, report this to the engineer — do not attempt repairs yourself.
- Call a Gas Safe registered engineer to diagnose and repair Gas Safe engineer
A qualified engineer will open the boiler casing, locate the relevant NTC sensor for the zone indicated by code 714, and test its resistance with a multimeter. If the resistance reading is outside the manufacturer's specification, the sensor is replaced — a small amount of thermal paste should be applied to ensure good thermal contact. If the sensor tests within spec, the engineer will trace the wiring harness for faults and, if necessary, test the PCB sensor input circuit. Do not attempt any of these steps yourself.
Parts you may need
- NTC temperature sensor / thermistor (zone circuit) · from £25
- Sensor wiring harness / connector plug · from £18
- PCB (printed circuit board) · from £280
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 £110–£280, depending on the underlying cause.
Frequently asked questions
Is Chaffoteaux fault code 714 dangerous — do I need to turn the boiler off?
In most cases the boiler will lock itself out automatically as a precaution, so there is no immediate safety risk from the fault code itself. You do not normally need to isolate the boiler unless you smell gas, see water leaking, or notice any physical damage. If there is any smell of gas, turn off the gas supply at the meter and call the National Gas Emergency Service on 0800 111 999 immediately.
What is the typical repair cost for a Chaffoteaux 714 fault in the UK?
For a straightforward NTC sensor replacement you should expect to pay roughly £110–£280 all-in, covering the call-out or diagnostic fee (typically £60–£100 for an independent Gas Safe engineer), labour, and the sensor itself (usually £15–£40 for the part). Prices in London and the South East tend to run around 15–25% higher. If the fault turns out to be a PCB failure rather than the sensor, the cost rises significantly — a replacement PCB can cost £200–£400 for the part alone, so in that scenario a total bill of £350–£550 or more is possible. Always get a written quote before authorising any work.
Could code 714 be a different fault on my specific Chaffoteaux model?
Yes, it is possible. Chaffoteaux has produced many boiler ranges over the years and the fault code tables are not identical across all models. The 7xx series generally covers sensor-related faults, but the precise meaning of 714 can vary. Check your installation or service manual (available on ManualsLib) for the definitive list for your model. If you cannot locate your manual, give the engineer both the full model name and the fault code before the visit so they can look it up in advance.
My Chaffoteaux boiler is over 10 years old and showing fault 714 — should I repair or replace?
Chaffoteaux boilers typically have a reliable service life of around 10–15 years with annual servicing. If the fault is simply a worn NTC sensor, a repair is almost always worthwhile regardless of age. However, if the engineer finds that the PCB is the root cause — or if this fault appears alongside other recurring issues — it is worth getting a quote for a replacement boiler to compare. A new A-rated condensing boiler will also reduce your energy bills, which can offset some of the replacement cost over time.