How to Replace the Auto Air Vent on a Worcester Bosch Greenstar Danesmoor 12/18 (UK)
Step-by-step UK guide to replacing the brass automatic air vent on a Worcester Bosch Greenstar Danesmoor 12/18. Part numbers, torques, commissioning.
The part
Fit a new AAV on Worcester Bosch Greenstar Danesmoor 12/18 when the boiler airlocks on start-up or the pump makes gurgling noises after refilling.
Isolate safely
Isolate flow and return, unscrew the AAV from the top of the pump head or air separator on Worcester Bosch Greenstar Danesmoor 12/18.
Fit and commission
Loosen the AAV cap one full turn once refitted — a fully-closed cap defeats the float.
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
- Any special height?
- Fit the highest point of the Worcester Bosch Greenstar Danesmoor 12/18 circuit — that is where entrained air collects.
- How often should I service?
- Annually — the float sticks with sludge in unfiltered systems.
- 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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