BoilerFaultCodesYour boiler has shut down because an external safety device, such as a thermostat or water pressure switch, has detected a potential issue and stopped the burner from firing.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner blocked, fault in the external safety chain
What causes this fault?
This fault occurs when an additional safety device outside the boiler's main control board breaks the electrical circuit to prevent damage. It is usually triggered by a secondary sensor detecting that the system pressure is too low or that the water temperature has exceeded a safe limit. Essentially, an external 'shout' has told the boiler to stop firing for your safety.
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 E0 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Viessmann Vitodens 100 Compact 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.