BoilerFaultCodesYour boiler has detected a loose connection or a fault with the sensor that monitors the temperature of the water 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: —
What causes this fault?
This fault occurs when the boiler's control board receives an impossible electrical reading from the sensor that monitors cooled water returning from your radiators. The most common reason is that the sensor has developed an internal electrical short or the wiring connecting it to the main board has become loose or damaged. Because the boiler can no longer safely track the water temperature, it shuts down to prevent overheating.
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 F.10 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Vaillant Turbomax Plus 824/828E 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.