Ariston 114 Fault Code: Causes, Fixes & Repair Costs
What does the Ariston 114 fault code mean?
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.
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
- Loose or disconnected sensor wiring Common
The most common trigger for code 114. The cables connecting the outdoor sensor to the boiler's PCB can work loose over time due to vibration or thermal cycling. Even a slightly poor connection can break the circuit and trigger the fault.
- Corroded sensor terminals or connectors Common
The outdoor sensor is exposed to the elements, and its terminal block or connector pins can corrode, particularly in damp or coastal environments. Corrosion increases electrical resistance and can eventually open-circuit the sensor signal entirely.
- Failed outdoor temperature sensor Sometimes
The sensor's internal thermistor can develop an open or short circuit through age or moisture ingress, making it impossible for the PCB to read a valid temperature. When the reading falls outside the expected range, the boiler logs code 114.
- PCB fault (no sensor fitted) Rare
If your system has never had an outdoor weather compensation sensor installed and code 114 still appears, the control board itself is the more likely culprit. A firmware issue or hardware fault on the PCB can cause the board to report a sensor error erroneously.
How to fix it
- Check whether an outdoor sensor is actually installed DIY safe
Look outside for a small plastic sensor unit mounted on an external wall — typically on a north-facing wall away from direct sunlight. If one is fitted, trace its cable back to the boiler. If no sensor is installed at all, skip to step 4, as the PCB is likely involved and you'll need an engineer promptly.
- Reset the boiler (once or twice only) DIY safe
On most Ariston models such as the E-Combi Evo, the reset button is on the control panel or behind a small flap. Press and hold it for roughly 5–10 seconds until the boiler restarts. If the fault clears and does not return within a day or two, keep an eye on it. Do not reset more than two or three times — repeated resets will not cure an underlying fault and can mask the problem.
- Inspect the sensor cable for obvious damage DIY safe
Visually trace the cable from the outdoor sensor to where it enters the property and connects to the boiler. Look for any sections where the cable is pinched, chafed, cut, or has pulled free from its connector. Do not open the boiler casing or touch any internal components — this visual check is limited to the external cable run only.
- Have a Gas Safe engineer test the sensor and wiring Gas Safe engineer
An engineer will use a multimeter to check the sensor's resistance across its operating temperature range and verify continuity of the wiring back to the PCB terminal block. If a loose connection is found and reseated, this is a quick and inexpensive fix. If the sensor has failed, it will need replacing with the correct Ariston part.
- Have the engineer assess the PCB if the sensor checks out Gas Safe engineer
If the wiring and sensor both test correctly but code 114 persists — or if no sensor was ever fitted — the engineer will need to evaluate the PCB for firmware issues or hardware damage. Depending on their findings, a PCB update, repair, or full replacement may be recommended.
- Call a Gas Safe registered engineer if you have not already done so Gas Safe engineer
If the reset did not resolve the fault or it keeps returning, contact a Gas Safe registered engineer to carry out a full diagnostic. This fault can involve the PCB in some cases, and any internal boiler work must be performed by a qualified professional.
Parts you may need
- Ariston outdoor/weather compensation temperature sensor · from £45
- Sensor wiring harness/connector · from £18
- Ariston 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 £100–£280, depending on the underlying cause.
Frequently asked questions
Can my Ariston boiler still run with fault code 114 showing?
In many cases, yes — Ariston boilers typically fall back to a default operating mode when the outdoor sensor circuit fails, so you may still get heating and hot water. However, weather compensation will not be working, which can affect efficiency, and you should still get the fault investigated promptly to rule out a PCB issue.
What if I don't have an outdoor sensor fitted — why is code 114 appearing?
If no external weather compensation sensor has ever been installed on your system, code 114 is more likely to indicate a fault on the PCB itself rather than a missing or broken sensor. You should not attempt to diagnose or replace the PCB yourself — contact a Gas Safe registered engineer for a proper assessment. PCB replacement typically costs in the region of £400–£550 including labour, which is why an engineer will often check whether a simple firmware reset is possible first.
How much does it cost to fix Ariston fault code 114 in the UK?
For the most common causes — a loose connection or a failed outdoor sensor — you can expect to pay roughly £100–£280 including the engineer's call-out and any parts. A straightforward wiring reseat at the lower end, a new sensor with labour at the higher end. If the PCB turns out to be at fault, costs rise significantly (typically £400–£550), which is why engineers always check the simpler causes first.
Is fault code 114 dangerous?
No, code 114 is not a safety-critical fault in the way that a gas pressure or flue fault would be. It relates to an external temperature sensor circuit rather than gas combustion or sealed-system safety. That said, it should not be left indefinitely, as it may indicate a PCB issue that could worsen over time.