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Workin in my Old School

PeterGriffin Member Posts: 79
I've been out of high school for 2 full years now, and this week I was back in it, running the heating lines for new coils. There was one wing in the school that never really had the right temperature (and on -40 days, you could feel it). Today, as my coworker and I were trying to read over the blueprints, he noticed that there was a mistake as they had the heating supply and return on the same line.

We confirmed what we thought was the supply line by checking a few coils, and tracing it back far enough until there was actually a label on the insulation. However, when we found what we now know as the return line, we found that the last coil it was picking up, actually had the globe valve and zone valve on backwards.

Sorry for the long story, but my questions basically are...
Does it matter if a zone valve is on the supply or return side? I know a globe valve is supposed to be on the return.

Will having a zone valve and globe valve in backwards adversely affect the zone it's heating? if so, will it also affect the balance of the other zones on that same line?

There should never be automatic air vents on the top of a line if the flow is going downwards, correct? Only on the highest point of a supply line?

Thank you,



  • Al Letellier_9
    Al Letellier_9 Member Posts: 929
    zone valve placement

    It really doesn't matter where the zone valve is. I've seen it done both ways. Having the valve in backwards may effect flow by creating noise or chatter in the valve and or the ability of the valve to seat properly. The globe valve most likely was used to regulate flow and will not work properly if installed backwards. AS far as vents are concerned, air will rise to the highest point, whether on supply or the return, so.....
  • Brad White
    Brad White Member Posts: 2,398
    I agree with Al

    The control valve position does not matter and I too have seen it in both locations. I usually put it on supply. One practitioner told me that he always puts them on the returns because he can index them all closed to vent the coils.

    Good find on your part, Rankin, picking up that old error. I think this will get you in the running for Homecoming King. Finally you get the approval of the Headmaster, the things you have to do...

    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • PeterGriffin
    PeterGriffin Member Posts: 79


    Right on then, thank you both...

    as a side note, Mr. White, I have been stupid busy with work and stuff, and have yet to read through the stuff you sent me, but I did manage to make it back home to Cape Breton Island, I got to take in lots of fiddle tunes and many different fiddle players, but no Natalie MacMaster...sigh.
  • Josh M.
    Josh M. Member Posts: 360
  • PeterGriffin
    PeterGriffin Member Posts: 79


This discussion has been closed.