High
Red flashing light on Glow-worm Ci Range

Your boiler has encountered a general operation error and needs to be restarted to resume heating and hot water.

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

Fault occurred. Reset boiler: Turn the On/Off switch to ( 0 ), wait for five seconds. Turn the On/Off switch to ( I ) the boiler is reset.

From this model's manual
Verified against the Glow Worm Ci Range 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 boiler's internal computer detects an interruption in the normal operating sequence, causing it to shut down for safety. The most common reasons include a failure to sense a flame correctly or a momentary communication error between the electronic components. If the reset doesn't work, it usually indicates that a part like the ignition lead or the main circuit board is failing to send the correct signals.

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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