BoilerFaultCodesWhat the manual says
Manufacturer manualNo power at control board. Possible causes: Permanent mains supply to boiler, Boiler mains switch, Fuse F1 (2.5A) or Fuse F3 (0.5A), Transformer (both coils below 100Ω), or replace control board.
From this model's manual
Verified against the Worcester Bosch/Worcester Bosch Greenstar I Junior installation & service 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.
Find a Gas Safe engineer
Search the official register →
Boiler cover options
Avoid the next call-out bill
A cover plan would handle faults like Off / Off: no call-out fees, no surprise bills.
Approved partner
Get a quote →
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Affiliate links. We may earn a commission at no extra cost to you.
All 38 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 light6a1213141516171819109115A8Blue indicator light flashingBlue indicator light offBlue light onDouble flash Blue lightEAERRORFAFast flashFast flash (Reset button Off)Fast flash / FlashingFast flash / Not a fault codeFast flash / OffLOCKOUTNo lightNo light / Not a fault codeOff (No light)On / OffSlow flashSteady on (Burner lit)