Two pipe reverse return hydronic system

pitman9

the pipe size drops fairly regularly. In other words you may start with 1-1/4" and end up with 1/2" or vice versa on the return side. You need to do this to maintain proper pressure differential throughout the system.

W/o redesigning and repiping the system there's no way to get this to properly work. One thing that does strike me as a problem is having a loops serve different levels. That throws a dynamic into the mix that I'm not sure how you'd design for.

That said you MAY be able to "cheat" it by installing a globe valve at the inlet or outlet of each emitter to regulate the flow through the emitter. Then it's trial and error to determine where each needs to be set.

I hope this is your home and not a customer's.

Rich Johnson

two pipe reverse return hydronic system

I have installed a two pipe reverse return hydronic system. The system is divided into three seperate circuts. Circut "A" 34,900 btu, circut "B" 39,600 and circut "C" with 33,600 btu.Circut A serves half of the basement and half of the first floor,circut B serves the other half of the basement and and first floor. Circut C serves the second floor. All supply circuts branch off an 1 1/4"trunk with 1" pipe then reduce to 3/4". The return lines begin with 3/4" and end with 1" and then connect into an 1 1/4" return to the boiler. The boiler is a slant fin SE-175DP ,126,000 net I=B=R. The pump is on the return and is a Bell & Gossett series 100. I have 1" ball balance valves on the end of each return circut. My problem is with circut A and B. In circut A I have 8 seperate baseboard units.One 3000 btu unit in the basement hardly gets warm and one 10,800 unit on the first floor is luke warm by the time it gets to the end of it's 18' length. In circut B there are 10 seperate units. In the basement three seperate units have no heat.I had a suggestion to install 1" globe valves at the end of each return. This was to correct the fact that I did not use any smaller diameter pipe than 3/4" pipe on the supply or return.Can any one tell me how to correct my problem?

c.t.kay

balancing

put trvs on the each baseboard run , change the pump to supply side pumping , install a pressure balancing valve.

Rich Johnson

what type valves are trv's and what type of pressure valve do you recommend and where on the system should it go?

c.t.kay

trv

put the trv on each baseboard run,put the pressure /bypass valve after the pump,between the supply piping &the return piping.call tunstall assoc. for the trvs. 413 594 8695 / www.tunstall-inc.com

rich johnson_2

thank you for the information. I hav econtacted tunstall and inquired about their macon valves. I have a question concerning the pressure/bypass valve. Could you describe it for me and wher I can get one .