BoilerFaultCodesYour boiler has stopped working because a sensor that monitors the temperature of the water returning to the unit has developed a fault.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: NTC return sensor error
What causes this fault?
This fault occurs when the boiler's internal computer receives an illogical or missing signal from the sensor that measures water temperature coming back from your radiators. This is usually caused by the sensor physically failing due to age or a loose connection in the internal wiring preventing the control board from monitoring the system safely.
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 E15 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Remeha Avanta 18V is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.