Medium
17 on Unical Alkon C 28 HE

Your boiler has detected an issue with the electrical power supply coming into your home, meaning the voltage or frequency is currently unstable for the unit to operate safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse 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 C 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.

DIY fix possible

Turn the boiler off using the main power switch or at the fused spur wall switch.Wait for approximately 30 seconds.Turn the power back on and check if the error clears once the system reboots.

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