M
markyhud
It looks like its on the flow not the return, unless you have reversed the pipes. Why are you getting so much air would be a better question? What is the open vent cold feed arrangement?
Our house was newly built 14 year ago. From what I gather the system is poorly configured. A neighbour in the same style house got British Gas out to see about cover and they said they wouldn't cover it because it was poorly designed!! However it has got gradually noisier over the years and I've just ignored it really. There has never been any kind of cleaner or inhibitor added either. So I've cleaned it using F3 (loads of magnetite/rubbish) and adjusted the level of the water in the f&e tank as it was about 3/4 full when cold. There is only about 300mm between the level of the water and the top of the vent pipe so think this might need adjusted. These two things have made a definite improvement and changing the rubbish cheap AAV was my next step. I do still think I need a professional to check things out and I plan to do this along with having a filter fitted next year.