High
1 2 on Glow-worm EnergySaver Combi

Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.

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.

What the manual says

Manufacturer manual

Loss of system pressure, i.e. less than 0.7bar. (Display will repeatedly flash '1' then '2')

From this model's manual
Verified against the Glow Worm Energysaver Combi installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the water pressure inside your heating system drops below a safe level, causing the boiler to shut down to prevent damage. The most common reasons are a slow leak from a pipe or radiator, or a loss of air in the expansion vessel which helps manage pressure changes. If you have recently bled your radiators, this can also cause the pressure to drop enough to trigger this code.

This issue is frequently seen at the start of autumn when homeowners turn their heating back on after the summer and find that small, slow leaks have lowered the pressure over time.

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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