High
34 on Johnson Starley C26d

Your boiler is not receiving enough electrical power from your home's supply to operate safely.

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

Low mains supply voltage. Electrical supply fault to property. Faulty wiring to appliance. Check incoming mains supply. Check wiring to appliance.

From this model's manual
Verified against the Johnson Starley C26d installation & service manual, page 28.
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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