monoflows in a single pipe loop

allenh

I didn't built this - it came with the house.

Gas Slant Fin boiler with 2 zones. Each zone is for a floor. First floor works fine.

Second floor has 3/4 loop in third floor attic. This loop in running the 5 kick heaters in second floor. There is a taco 007 pulling the water around the loop from the basement, The previous homeowner apparantly did the plumbing. Right now its a 3/4 pipe to first kick heater where he diverted all water into the kick heater and then back to the main loop running around the attic. So its all in series. And the same for all the next kick heaters. He just elbowed off the main. What is happening is there kick heaters take their btus the temp of water is reduced and kick heaters at the end of the loop don't get hot enough. Master b.r. is on last heater.

What I want to know is: if I add a monoflow T's would they work better on the feed or return side of the kick heater? And on the main loop what should be the distance between the monoflow and the regular T? All kick heater runs are reduced to 1/2 copper and have a run of about 9 ft to heater and same return length. And all kick heaters are buried in finished walls so all access has to be done in the attic.

Mark Eatherton1

With high presure drops...

which is what you have, you need a diverter tee and a venturi tee. NIBCO makes a drop in insert tee that has half the pressure drop of the real monoflow tees. With 5 FCU's, and 10 diverter tees, it may be necessary to bump the pump size to guarantee flow.

One potential problem with what you've described is the fact that the FCU's will still "see" flow even though the room is satisfied. If you can install a zone valve on the branch piping serving the FCU, you will do a better job of delivering the hottest water to the cold spots.

ME