BoilerFaultCodesYour boiler has lost its ability to monitor the temperature of the stored hot water, meaning it cannot heat your water reliably or safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Storage vessel thermistor/wiring fault
What causes this fault?
This fault occurs when the sensor responsible for monitoring the temperature inside the boiler's internal hot water storage tank fails or loses its connection. The most common reason is that the sensor has physically degraded over time or the electrical wiring has become loose or corroded, preventing the control board from knowing if the water is hot or cold.
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 08 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Xtrafast 96 120 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.