BoilerFaultCodesAriston 1 12 Fault Code
Also written as 112 — same fault.
The Ariston 1 12 fault code means: your boiler has lost its connection to one of its internal temperature sensors, meaning it cannot correctly measure the warmth of the water returning to the system and has shut down as a precaution.. It appears on 15 Ariston models in our database.
Technical description: C.H. Return temp. probe circuit open / short circuit
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ariston models that show the 1 12 fault code
Click a model for the full fault code list and model-specific repair notes.
- Challenger 80E Repair: £120-200
- Clas HE 24 Repair: £120-200
- Clas HE 28 Repair: £120-200
- Clas HE 35 Repair: £120-200
- Clas HE Evo Repair: £120-220
- Clas Net One Repair: £120-220
- Clas One Repair: £120-200
- Clas System 28 Repair: £120-200
- E-Combi Evo Repair: £120-220
- E-Combi One Repair: £120-200
- E-Combi One 24 Repair: £100-£180
- E-Combi One 30 Repair: £120-200
- Egis Repair: £120-180
- HS Premium Repair: £120-200
- Microsystem 15 Repair: £120-200
Source
Ariston 1 12 fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026