On Nov 18, 5:01 pm, "Edwin Pawlowski" wrote:
"werwer" wrote in message
There is one accumulator in the system. It hangs down from
the piping and I assume it has a bladder. This is what I don't
understand. Why is it below the piping? If air gets into the
system (which it has) it has nowhere to escape. It continues to
race around the loop causing noise in the pump and flow regulation
valves.

Somewhere there is a vent valve of some sort.http://www.taco-hvac.com/en/products...ts.html?curren...
or perhapshttp://www.watts.com/pro/_productsFull_tree.asp?catId=64&parCat=250&p...
Series AS Air Separators are used in commercial and residential, hydronic
heating applications to separate air from water in the piping system. They
consist of a heavy, cast-iron body construction with a 1/2 in. female
threaded connection for an expansion tank, and a 1/8 in. female threaded
connection for a float vent. Series AS provides continuous purging and
venting of air in the system when installed with Watts Model ET expansion
tank and Model FV4 float-vent. Maximum Pressu 125psi (8.6 bar).

If you still have air racing around the systems, something is wrong. Keep
the feed valve to the boiler open also or it will just suck in more air
during the cooling cycles as the water contracts.

Yes, there is one of those. Ok, now I'll have a closer look. Thanks.