I put the shop loop in the other day, 2 baseboards upstairs which is the highest point in the system, added a ball valve to bleed air while filling, will add auto bleed this week could not find one on the weekend.I filled the system with a hose in the boiler room using a 15lb regulator on it bled the air off in the shop and thought the auto bleed in the boiler room would take care of the rest as I had the make up water on.Finally the problem I don't think the make up water is getting into the system as the supplier talked me into a 20lb regulator on the make up water line as to not fill the expansion tank , The auto bleed is about 15ft above the make up water and i don't think 20 psi is enough to activate it.To get the heat going I shut the expansion tank off and used the hose without the the regulator the auto bleed worked as it should , disconnected the hose and opened the tank it worked last night.