High
ON every 0.5-secs (RED LED) on Vokera Compact HE

Your boiler has detected a critical internal safety fault and has locked itself down to prevent damage, meaning it will not provide any heating or hot water until a professional engineer repairs it.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Final fault, e.g.: water pressure switch, condense pressure switch, fan/flue problem, limit thermostat

From this model's manual
Verified against the Compact He 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.

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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Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like ON every 0.5-secs (RED LED): no call-out fees, no surprise bills.

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