If the point where the cooling water is injected into the exhaust is less than 15cms above the waterline, then when the engine is stopped, there is a risk that cooling water will siphon into the engine.
This can be prevented by fitting a Vetus air vent at least 40cm above th waterline. Anti-syphon device ASDV has a valve and is suitable for hose 13-32mm.
Airvent type ASDV is interchangeable with type AIRVENT and has the same fixing hole centres. It has the advantage that the air bleed connection rotates through 360°. In addition, the valve can be maintained without removing the vent from the wall and no tools are required to do this. For replacement, a set with 5 valves is available as a spare part.