BoilerFaultCodesYour boiler has shut down because a safety sensor detected that the exhaust gases are too hot or are not escaping correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner does not start. Flue gas limiter has tripped. (Reset required: Turn control knob 'Reset' to the right until 'CL' appears, then turn back).
What causes this fault?
This fault occurs when a safety sensor detects that the gases produced by the burner are reaching dangerously high temperatures before they can exit the flue. The most common reasons are a build-up of debris or limescale inside the heat exchanger, which prevents heat from being transferred to your water, or a physical blockage within the flue pipe itself.
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.
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A boiler cover plan would cover faults like E03 — no call-out fees, no surprises.
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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.
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