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Balancing zone manifold

dlabrie
dlabrie Member Posts: 21
Hi, We just purchased a home built in 2006 and it has radiant floor heating throughout. There are 4 zones and It works very well except for zone 2. Zone 2 comprises a small den, and a bedroom with an attached bath. The thermostat is in the den at the southern end of the house. The den comes to temperature fine but the bed/bath area doesn't warm up enough before the thermostat in the den shuts down; the den will be 70F and the bed bath, 56-60F. The zone is fed by 4 lines from a copper manifold. There are no balancing valves, just shut offs for each line. I assume 2 lines go to the den and 2 go to the bed/bath.

Can I balance the heat by closing the lines to the den a bit? The lines are not marked; only the zones. My idea is to cool the entire zone down, close 3 of the 4 shutoffs, raise the thermostat, open and close the other 3 lines and determine where the 4 lines go. Then when I've determined which go to the den, I'll close the down a bit.

Is this the way to go or are there better options?

I've attached a picture of the feed to the zone.


Thanks

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 5,689
    edited November 2019
    That's probably you're only option, unless you want to get into some repiping. When you do find out, at least mark those supply and returns for future reference.
    Also, make sure it's not airbound and you're getting full flow. It's a shame the installer didn't put a couple of valves on there for purging. Even one on the end where the return is capped (left) and a ball valve on the other side would've did the trick.
    I suspect maybe larger common piping would help alleviate some of the issue also.
    I'd check supply return temps at the manifold too as a reference.
    steve
    dlabrie
  • HomerJSmith
    HomerJSmith Member Posts: 1,563
    Limiting flow with a ball valve is difficult, but can be done thru trial and error. The last 5% before a ball valve is full closed is where the throttling occurs. Start with a fully closed valve and slowly incrementally open it and check the results. Might work.
    dlabrie
  • dlabrie
    dlabrie Member Posts: 21
    edited November 2019
    I thought I had isolated the bed/bath to lines 1&2 but I checked the den and the floor was up from 67-71 degrees. Half of my bed/bath was up to 70. I'll have to give it a try tomorrow.

    How can I tell if it is airbound or if I have full flow? There is no noise coming from the lines.
  • HomerJSmith
    HomerJSmith Member Posts: 1,563
    If you have heat, you have flow and it wouldn't be airbound.
    dlabrie
  • dlabrie
    dlabrie Member Posts: 21
    I think I have isolated where each line goes. Of the 2 going to the bed/bath one has been running for over an hour and a half and the floor hasn't gotten over 63 degrees. the temp at the feed is 124, at the return, 119. I have a Grundfos pump and it is set to low position. Would it make a difference if I moved it to medium or high?