High Lockout
E37 on Keston C36

Your boiler has detected that the water pressure is too low, which has caused it to stop working to avoid damage.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Water pressure error - You must top up the water pressure for your system

What causes this fault?

This fault occurs when the system lacks enough water to circulate safely, triggering a safety shutdown. The most common reasons are a slow leak in the pipework or radiators, or having recently bled your radiators without topping the pressure back up.

This is common in autumn when homeowners turn their heating back on for the first time and discover the pressure has naturally dropped over the summer.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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