High
17 on Unical Alkon R 28 HE

Your boiler has detected an issue with the electrical power supply coming into your home, meaning the electrical frequency or voltage is outside of the safe operating range.

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

FLAME CONTROL FREQUENCY BEYOND LIMIT Depends on the power supply mains (Frequency and voltage beyond default limits)

From this model's manual
Verified against the Unical Alkon R 28 He installation & service manual, page 41.
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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