BoilerFaultCodesYour boiler has detected trapped air or a blockage in the internal pump system, which is preventing water from circulating properly to heat your home.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Automatic Air Vent
What causes this fault?
This fault occurs when air becomes trapped within the boiler's internal reservoir or the pump itself, creating an air lock that stops water flow. The most common reason is a failure of the automatic air vent to release gases, or a build-up of sludge that has blocked the internal de-aerator assembly.
This issue often surfaces in autumn when the heating is turned back on after summer, causing dormant air bubbles or settled debris to move into the pump system.
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 E85762 — no call-out fees, no surprises.
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