High
No lights and no functions (with demand) on Worcester Bosch 24i / 28i Junior

Your boiler has completely lost electrical power and is not responding at all, even when you turn the heating or hot water on.

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

No mains Voltage supply. Fuse F1 or F2 blown. Transformer or connector failed. Board fault.

Shared across the 24i / 28i Junior range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s 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

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All 27 fault codes on the 24i / 28i Junior

Seeing a different code? Every code this model can display, in one place.

24i28i200203208265AA1A8BCDEFF1F2Flash once per secondGHILight onNo CH function (DHW OK)No DHW function (CH OK)rET1T3

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