in what position does one fit an automatic air vent in cold water system(direct supply ie,no storage tank.?
Answers:
If by a direct supply you mean from the mains.. You should not need to fit an auto-air vent, and depending on your supply standing pressure the AAV may not operate correctly at higher pressures and could leak badly.
In fact now that I think about it.. I've never seen or heard of an AAV fitted on domestic water pipework. If you have a problem with airlocks on your domestic water, you probably have a pipework configuration/tank position problem.
But I've never ever seen and AAV on a cold main pipe as they are virtually impossible to airlock or entrain air because the high incoming pressure would simply blow any airlocks or restrictions clear.
Other answers:
The air vent should be pointed up so the air will bleed out of the vent..
The air vent should be pointed up so the air will bleed out of the vent..
i suggest u should do this in a kneeling position, for comfort reasons, preferably with a cushion under the knees!
Ideally you want to put a "T" in the original pipe with a short say about 150mm tube out of it then fit the AAV to the top of it. This will allow the air to move up and out the vent.