114 Boiler Fault Code: What It Means on Every Brand

The 114 fault code appears on 3 brands — Ariston, ATAG 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: Engineer may be needed 3 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 114 means	Severity	DIY?
AAriston	Fault code 114 on Ariston boilers signals a problem with the external (outdoor) temperature sensor circuit. Full guide →	Engineer may be needed	No
AATAG	Fault code 114 on an ATAG boiler indicates that the boiler's outdoor temperature sensor is not behaving as expected. Full guide →	Engineer may be needed	Some checks
CChaffoteaux	Fault code 114 on Chaffoteaux boilers most commonly indicates a problem with the outdoor (external) temperature sensor — either a short circuit, open circuit, or the sensor being… Full guide →	Engineer may be needed	No

114 brand by brand

Ariston 114

Fault code 114 on Ariston boilers signals a problem with the external (outdoor) temperature sensor circuit. Specifically, the boiler's control board has detected either an open circuit or a short circuit on the outdoor sensor wiring. This sensor is used for weather compensation — it allows the boiler to adjust its output based on how cold it is outside. If the wiring loses continuity, the connection corrodes, or the sensor itself fails internally, code 114 will appear. One important nuance: if no outdoor sensor has ever been fitted to your system, code 114 appearing is more likely to point toward a fault with the PCB (printed circuit board) itself rather than any external sensor. Despite displaying this code, many Ariston boilers will continue running in a default fallback mode, so you may still have heating and hot water — but the fault should not be ignored.

Causes, fixes & costs for Ariston 114 → · All Ariston codes

ATAG 114

Fault code 114 on an ATAG boiler indicates that the boiler's outdoor temperature sensor is not behaving as expected. The boiler cannot read a valid signal from the external sensor — this could be because the sensor is physically absent, its wiring has become disconnected or damaged, the sensor itself has failed, or a configuration parameter is set incorrectly. The outdoor sensor is used to help the boiler modulate heating output based on how cold it is outside (a feature known as weather compensation), so when this signal is lost or falls outside acceptable limits, the boiler logs fault 114. In many cases the boiler will continue to heat your home, but without the benefit of weather-compensated control.

Causes, fixes & costs for ATAG 114 → · All ATAG codes

Chaffoteaux 114

Fault code 114 on Chaffoteaux boilers most commonly indicates a problem with the outdoor (external) temperature sensor — either a short circuit, open circuit, or the sensor being completely disconnected. On modern models such as the Talia and Inoa, the boiler uses this sensor (or an internet-sourced external temperature feed) to optimise heating output, so when the reading is unavailable the boiler flags a fault. Some models may still provide heat while the fault is active, but efficiency and weather compensation are compromised. On older models such as the Mira Green Ultra 30, code 114 can instead point to a control board or internal communication fault, often triggered by a power outage or supply interruption. Knowing your exact model is important — if you recently had a smart thermostat fitted or experienced a power cut, that context will help an engineer diagnose the fault quickly.

Causes, fixes & costs for Chaffoteaux 114 → · All Chaffoteaux codes

Frequently asked questions

Is the 114 fault code the same on every boiler?

No. 114 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 114 fault myself?

On some brands there are safe homeowner checks first — typically system pressure, the condensate pipe in cold weather, and a single reset. Where the code is a simple pressure or reset condition, that may be all it needs. Never open the boiler casing yourself.

Who should I call about a 114 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.