BoilerFaultCodesYour boiler has detected an issue with the wiring or the sensors that monitor the water temperature returning to the unit.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: All Boilers
What causes this fault?
This fault occurs when the boiler's control system receives an inconsistent or impossible signal from the return temperature sensor. It is usually caused by a physical failure of the sensor's internal components or a loose connection in the wiring that prevents the boiler from safely monitoring water temperature. In some cases, it can also be triggered if the electronic control board is no longer able to process the data it receives.
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 →Protect yourself from future repair bills
A boiler cover plan would cover faults like 112 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
Affiliate links — we may earn a commission at no extra cost to you.