Multicirculator/Multizone

MechTech_2

I've stumbled across a problem job with multiple circulators & multiple zones on a direct/return piping system where the common header is smaller than I'd like to see. The problem is that some pumps can't move any water when other upstream larger size pumps are operating. My question is can I resolve this problem with balancing valves on each secondary return leg, or is my only solution a reciprocating saw, and building a generously sized common header.  

Gordy

Repipe

Balance valves in that scenerio is a band aid for poor piping practice. You'll end up with poor performing pumps, and wasted energy. If that method would even work. Kind of a setup for unintended consequences. JMO



Edit: With little info, and no pics, I would also check the math on the circs in place.

heatpro02920

Get the sawzall warmed up

I did this before with a lot of wasted energy and time, repipe it how you know it will work save the aggravation...



I had a system with some serious piping issues, some one started with the wrong ideas and then others added zones and water heaters and long story short a couple decades later when it needed a boiler I walked in, and swapped the boiler for what was there instead of asking how everything worked {which I now do} I just swapped out the boiler and thought I could call it a day.... nope, now all of these issues like slow heat in some zones, flow through zones that were not calling when others did, ect ect ect came to my attention, so I tried to fix it with band aids, a couple large zone valves, a check valve here and there with some globe valves here and there..

I just wasted more time, the end result was rip it out and repipe it the correct way, and i never had a problem again, now if I was smart enough back then to look at it, see potential problems and ask if they were indeed issues previously, I would have saved myself thousands and many hours and head scratching, I still have a couple 2 " globe valves from that job sitting on the shelf as well as a $1200 grundfos pump that was one of my last efforts.. some day I will use them, but until then they sit on a shelf collecting dust, way out of warranty..

gennady

Delta t

I would calculate loads for each zone, measure radiation, and decrease flow via increasing delta t. Usually radiation is oversized so you can go to delta t over 40-50F. Then balance zone to calculated delta T. It worked for me.