High
No light on Worcester Bosch Greenstar 24i / 28i Junior

Your boiler has completely lost power and is not showing any lights or signs of life.

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

Check: Permanent mains supply to boiler; Boiler mains switch on; Fuse F1; Fuse F2; Transformer (both coils below 100Ω); Otherwise replace control board (if boiler does not operate correctly).

Shared across the Greenstar 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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All 35 fault codes on the Greenstar 24i / 28i Junior

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

2 pulses2 pulses / No light2 pulses No light5 pulses5 pulses / No light5 pulses No light6a1213141516171819109115A7A8b1Blue indicator light offEAERRORFAFast flashFast flash / FlashingFast flash / OffLOCKOUTNo light / Not a fault codeOff (No light)Off / OffOn / OffSlow flashSteady on (Burner lit)

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