How to Replace the Auto Air Vent on a Viessmann Vitodens 200-W 32 (UK)
Step-by-step UK guide to replacing the brass automatic air vent on a Viessmann Vitodens 200-W 32. Part numbers, torques, commissioning.
Viessmann
The part
Fit a new AAV on Viessmann Vitodens 200-W 32 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 Viessmann Vitodens 200-W 32.
Fit and commission
Loosen the AAV cap one full turn once refitted — a fully-closed cap defeats the float.
Recommission checklist
Refill the Viessmann Vitodens 200-W 32 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 Viessmann Vitodens 200-W 32 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 Viessmann Vitodens 200-W 32 is in warranty — Viessmann require log of any part swap for labour claims.
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