BoilerFaultCodesYour boiler has detected that a safety sensor meant to prevent it from overheating without water has failed, which means the system cannot safely start up.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Dry fire sensor Sensor failed open or closed circuit
What causes this fault?
This fault occurs when the boiler's internal safety system can no longer tell if there is water inside the heat exchanger. It is usually triggered by a physical failure of the dry fire sensor or a broken connection in the wiring that carries signals back to the main control board. Because the boiler cannot guarantee it won't overheat instantly without water, it shuts down as a critical safety precaution.
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 8 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Potterton Envoy 30 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.