How to Replace the Gas Valve on a Worcester Bosch Greenstar 8000 Life 30 (UK)
Step-by-step UK guide to replacing the modulating gas valve on a Worcester Bosch Greenstar 8000 Life 30. Part numbers, torques, commissioning.
The part
Change the modulating gas valve on Worcester Bosch Greenstar 8000 Life 30 for hard ignition, F27 flame-lift or repeated flame loss faults.
Isolate safely
Cap the gas at the isolator, disconnect the multi-pin harness and undo the gas valve union. Fit a new fibre washer.
Fit and commission
Perform a full gas rate and combustion analysis after fitting the Worcester Bosch Greenstar 8000 Life 30 valve — CO/CO2 ratio must fall inside the OEM window.
Recommission checklist
Refill the Worcester Bosch Greenstar 8000 Life 30 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
- Do I need to gas-tighten test?
- Yes — a soundness test and let-by test is mandatory before recommissioning.
- Which spanner size?
- Most Worcester Bosch Greenstar 8000 Life 30 gas valve inlets are ½" BSP, 24 mm across flats; use two spanners to avoid rotating the manifold.
- Do I need to notify the manufacturer?
- Only if the Worcester Bosch Greenstar 8000 Life 30 is in warranty — Worcester Bosch require log of any part swap for labour claims.
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