How to Replace the Fan on a Worcester Bosch Greenstar Danesmoor 12/18 (UK)
Step-by-step UK guide to replacing the combustion fan on a Worcester Bosch Greenstar Danesmoor 12/18. Part numbers, torques, commissioning.
The part
Swap the combustion fan on Worcester Bosch Greenstar Danesmoor 12/18 when you get low-speed lockouts (F28/F29 Vaillant, EA Worcester, F1 Ideal) or bearing whine.
Isolate safely
Remove the case, disconnect the fan plug and Venturi. Note the fan's part number stamped on the motor housing.
Fit and commission
On Worcester Bosch Greenstar Danesmoor 12/18 the fan is torqued to 8–10 Nm — over-tightening cracks the composite plenum.
Recommission checklist
Refill the Worcester Bosch Greenstar Danesmoor 12/18 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
- Which speed sensor connector?
- The Hall-effect sensor on Worcester Bosch Greenstar Danesmoor 12/18 uses a 4-pin JST plug. Do not swap L1/L2.
- Do I need a new gasket?
- Always fit the OEM Viton gasket — the old one hardens and leaks flue gases into the case.
- Do I need to notify the manufacturer?
- Only if the Worcester Bosch Greenstar Danesmoor 12/18 is in warranty — Worcester Bosch require log of any part swap for labour claims.
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