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Primary Secondary Question ...

yaca Member Posts: 6
Hello Board, I added some drawings below if you can please view, I have a few questions on converting my current heating system to a primary secondary setup. The original install has pumps on return side of zones and system wont reach desired temp on cold days, lucky if system heats up floors to 65 degs on a cold day. So perhaps a flow problem or air problem and plan on reconfiguring zones to Phase A drawing with webstone primary seconday purge valves. Just not certain if I have too many circulators on this system. Someone told me I don't need a primary pump on connection point E and F. I would think its needed even though there are pumps on zones. They also commented on changing zone pumps to zone valves but I read that the pumps provide more pressure and help digest the air into the system and system will eventually move any air out of the system.
I also have a mascot 2 combi unit ready for install but not quite ready to plug into system just yet, almost there and was thinking of using a caleffi hydra separator. So was thinking connection point A and Y would connect to secondary side of separator, both points A and Y are 1 1/4 copper and then I was wasn't sure what size pipe to use for connections A1 and A2 and also connections A3 and A4. The Mascot 2 only offers 3/4 connections out of unit and if thats the case would you suggest connecting 3/4 inch copper for primary size considering hydra seperator would be within two feet from combi unit.

Any suggestions or corrections to this hookup would be greatly appreciated

Thank you


  • Ironman
    Ironman Member Posts: 7,225
    Not like that. Like this:

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,645
    Yes, not the way you have it. That would make the last zone the coolest water. What water temps are you running now?

    If it's currently setup as the first drawing, with no mixing anywhere all water temps will be the same. What are your supply and return temps? What leads you to think it's a flow problem other than pumping into the expansion tank?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • yaca
    yaca Member Posts: 6
    Thank you Bob for diagram.
  • yaca
    yaca Member Posts: 6

    yaca → Solid_Fuel_Man
    Hi and Yes its currently setup as in the first diagram. Not certain of return temps but they feel equally as hot compared to the supply pipes. I actually plan on relocating the Circulating pumps to supply side this weekend and adding a temp gauge to return raceway. So at first I thought maybe a air problem but each zone has a few baseboards connected in a series loop with a cast iron radiator at the end of each loop/zone. The third and first floor never reach their desired temps or anything close to it and when I try to bleed out the air at last device of loop which is the radiator no water or very little air comes out. The system did work but some how some way my father when he was around was able to get it to work even on the coldest of days, not sure if he raised the temp to 190 which I tried but still the same struggle.
    I read a few books and did some research which would suggest Pumps on supply side ahead of tank, maybe I should correct that first. Any suggestions greatly appreci