BoilerFaultCodesYour boiler is struggling to identify its specific model configuration due to an internal electrical communication error.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Open circuit on coding resistor
What causes this fault?
This fault occurs when the boiler's main control board loses contact with a small internal component that tells the computer which specific model it is installed in. The most common reason is a loose electrical connection or a failed resistor chip, which prevents the boiler from operating safely because it no longer knows its own power settings.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F.43 — no call-out fees, no surprises.
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