UK trade guideBoiler Spares 5 min readUpdated 11 July 2026

How to Replace the Pcb on a Worcester Bosch Greenstar 8000 Life 35 (UK)

Step-by-step UK guide to replacing the printed circuit board on a Worcester Bosch Greenstar 8000 Life 35. Part numbers, torques, commissioning.

Worcester Bosch

The part

Replace the main control PCB — the most common cause of no-heat, no-DHW and intermittent lockouts on Worcester Bosch Greenstar 8000 Life 35.

Isolate safely

Isolate at the fused spur and lock off. Discharge any residual mains voltage before touching connectors.

Fit and commission

Photograph every plug and its position on the Worcester Bosch Greenstar 8000 Life 35 PCB before unclipping — connector positions differ subtly across firmware revisions.

Recommission checklist

Refill the Worcester Bosch Greenstar 8000 Life 35 to 1.2 bar cold. Bleed high-point radiators and the internal AAV.

Run a full flue-gas analysis after 15 minutes. Log the reading against the OEM commissioning envelope in the Benchmark book.

Frequently asked questions

PCB part number location?
On Worcester Bosch Greenstar 8000 Life 35 the PCB label is on the top-right of the board, printed as an 8748-series code. Match every digit.
Do I need to re-parameterise?
Yes — enter the correct boiler model code in the service menu after fitting so the ignition curve, fan speed and gas rate match.
Do I need to notify the manufacturer?
Only if the Worcester Bosch Greenstar 8000 Life 35 is in warranty — Worcester Bosch require log of any part swap for labour claims.
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