107 Boiler Fault Code: What It Means on Every Brand

The 107 fault code appears on 2 brands — Ariston and Chaffoteaux — and it does not mean the same thing on each. The same two or three characters can signal a pressure problem on one boiler and an ignition fault on another, so identify your brand first and use the table below to jump to the right page.

Up to: Lockout — engineer likely 2 brands use this code Meaning differs by brand

Which brand is your boiler?

The brand is printed on the front casing. Tap your brand for the full causes, fixes and repair costs.

Brand	What 107 means	Severity	DIY?
AAriston	Fault code 107 on Ariston boilers signals an 'Insufficient Circulation' condition. Full guide →	Lockout — engineer likely	No
CChaffoteaux	Fault code 107 on Chaffoteaux boilers points to a problem with water temperature sensing on the central heating flow circuit. Full guide →	Engineer may be needed	No

107 brand by brand

Ariston 107

Fault code 107 on Ariston boilers signals an 'Insufficient Circulation' condition. The boiler's onboard monitoring has detected that the return pipe temperature is running more than 30°C higher than the flow pipe temperature — a physically abnormal situation, since the water returning to the boiler should always be cooler than the water leaving it. When this threshold is crossed, the boiler locks out as a safety precaution to prevent overheating and internal damage. The root cause is either a genuine circulation problem (water is not moving freely around the system) or a faulty temperature sensor giving a misleading reading. This fault code applies across the full range of Ariston boiler models.

Causes, fixes & costs for Ariston 107 → · All Ariston codes

Chaffoteaux 107

Fault code 107 on Chaffoteaux boilers points to a problem with water temperature sensing on the central heating flow circuit. The exact interpretation depends on your model: on newer units running the Expert Control system, it is described as a Flow Check Failed condition, meaning the boiler cannot confirm adequate water circulation. On older models such as the Britony Combi SE, code 107 corresponds to a central heating flow thermistor fault — either an open circuit (broken connection) or a short circuit within the sensor or its wiring. In both cases the underlying issue is the same: the boiler's control board is not receiving a reliable temperature signal from the flow sensor, so it shuts down as a safety precaution. Always cross-reference with your specific model's manual to confirm which interpretation applies to your unit.

Causes, fixes & costs for Chaffoteaux 107 → · All Chaffoteaux codes

Frequently asked questions

Is the 107 fault code the same on every boiler?

No. 107 means different things on different brands — see the table above. Always identify your boiler's brand (it is printed on the front casing) before acting on any advice about the code.

Can I fix a 107 fault myself?

Not usually. On every brand listed, 107 points to a fault that needs a suitably registered engineer to diagnose and repair. A single reset to rule out a transient glitch is reasonable; repeated resets are not.

Who should I call about a 107 fault?

For gas boilers, a Gas Safe registered engineer — it is a legal requirement for any work on the appliance. If you smell gas at any point, leave the property and call the National Gas Emergency line on 0800 111 999.

General guidance only — not a substitute for professional advice, and not certified by a registered engineer. Any work on a gas appliance must be carried out by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.