BoilerFaultCodesYour boiler is having trouble directing water to the right place, meaning you might not have any heating or hot water until it is fixed.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Diverter valve by Viessmann
What causes this fault?
This fault occurs when the internal motor that moves the diverter valve fails to reach its intended position, often because the valve has become stuck or stiff. This is usually caused by a buildup of debris or sludge from the heating system water getting inside the moving parts, or eventually, the motor simply wearing out over time.
This issue is frequently noticed in autumn when homeowners switch their heating back on for the first time, putting strain on a valve that has remained stationary all summer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like 65:1 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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