BoilerFaultCodesYour boiler is struggling to direct hot water to your taps or radiators because a mechanical internal valve has stuck or failed.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: 3 Way Valve Assembly (Body, ‘O’Rings, Clips & key no.13)
What causes this fault?
This fault occurs when the mechanical valve responsible for switching water flow between your heating and your taps becomes seized due to a buildup of debris or internal wear. The most common reason is sludge within the system water causing the valve to stick, which eventually prevents the motor from being able to move it into the correct position.
This issue often becomes apparent in autumn when homeowners switch their central heating back on for the first time after the summer months.
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 E85752 — no call-out fees, no surprises.
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