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Need help with valve on hot water base board system

stihmatastihmata Member Posts: 11
I have ahot water boiler system that has a valve with a thumb screw valve on the copper pipe just above the boiler (in a loop of one zone)

I have regular shut offs (with facet handles shutoffs) everywhare else.

But this one has be baffled, is there a way to shut this thumb valve down to do a circulator change out ?

Or is this thumb valve just a flow control to limit the amount of hot water that enters that particular section of the heater loop.

I can send pic if needed.

What I really need to do is close this valve so water does not return to boiler to do the switch of pump.

But it looks like it just regulates the amount of water flowing through the pipe.

If I can shut the valve , should I count the number of turns and return it to the same position when finished (thats was my thought),

Which direction shuts this type of valve off?

Its a thumb screw on a valve bass in line with the pipe (soldered in just like control valve) I think its a limiter valve ,

But need to know if I can shut it down by turning thumb screw?

Thanks all


  • stihmatastihmata Member Posts: 11

    Any idea will be greatly appreciated
  • KakashiKakashi Member Posts: 88

    Post a picture. Could be a few things. If a valve is closed a little it could be for throttling part of the zone.

    Is the thing with the thumb screw going to your expansion tank?
  • stihmatastihmata Member Posts: 11
    Looks like this but no handle just thumb screw instead

    Looks like a valve body soldered into pipe nut has a thumb screw instead of handle

  • stihmatastihmata Member Posts: 11

    No its a return line just before it goes back into air valve (purge)

    I will take picture, in a min.

    It is not going to expan/tank its in line with a zone loop
  • stihmatastihmata Member Posts: 11
    Here is picture of my valve

    This is it
  • stihmatastihmata Member Posts: 11
    edited April 2014

    The last picture is the air valve where all return line go into

    Can anyone tell my the proper name of the thumb screw valve so I can try and find directions on the use.

    Im pretty sure its a balace valve to keep the heat even through out the house. But I could be wrong
  • KakashiKakashi Member Posts: 88
    flow control

    Looks like a flow control valve. As for the brand's not a taco or b&g.
  • KakashiKakashi Member Posts: 88
    3rd pic

    I think you may have your return and supply mixed up. I think I see a flow restrictor for your hot water coil.

    I don't want to assume anything. If you have hot water and heat and don't see any major leaks, don't touch it, unless you wanna pay out of your kaaazoo for a plumber or hvac tech to come out and fix it after chasing the Easter Bunny.
  • stihmatastihmata Member Posts: 11
    Flow Valve


    Im trying to isolate the loop so I can switch out circulator pump

    Yes I may have them confuse as to which is the feed side.

    All I really need is to be told how to control flow valve with the Thumb Screw.

    Can I close that valve?

    If so does it close clockwise or counter clockwise?

    I will mark and count the number of turns when I close it down.

    I want to completely stop any flow of water to switch the pump out.

    I have work on boilers for years but never worked on this type of valve before.

  • Wayne HeidWayne Heid Member Posts: 49
    Flow check

    That's a flow check. It's nothing more than a weighted plug that will prevent reverse flow or ghost flow. The thumb screw is there to lift the weight for purging or gravity flow. I doubt it will help you much as an isolation valve for the circ.

  • stihmatastihmata Member Posts: 11
    Thanks Wayne

    Thats what I was thinking

    Question if I were to shut down the fill line and than shut down the flow to all my baseboards (have Valves on them)

    Would this prevent the radiator that this line is for from flowing back into the boiler?

    If so than I can drain the lower end and change the circulator.

    I nevr seen a set up like this

    There is no main valve coming out of boiler only manifold than the circulators.
  • Wayne HeidWayne Heid Member Posts: 49

    That might work if every flow check held perfectly but I wouldn't count on it. I'd just drain the system, change the pump (maybe add isolation valves while you're at it?), refill and purge. You're going to need to fill and purge any way you do it.

  • KakashiKakashi Member Posts: 88

    Any valves in the return? zone valves?

    If it's a 007 and you're able to pull a vacuum on the system go for a 007 cartridge, take the screws out sllllllloooooooooooooooooow, you will see a little water at first. If it gushes out then you know you can't pull a vacuum.

    While your at it get a 30 psi pop relief valve, they always seem to go bad when ever I look at them.

    Turn the power off first :)
  • stihmatastihmata Member Posts: 11
    edited April 2014
    Thanks guys

    Thanks for all the responses

    If I were to drain the system down,

    When I go to refill what is the best way , I have two purge valves inline with the circulator pumps.

    Once system is shut down and drained (replace cir pumps)

    Then to refill just open supply back up and open purge valves with hose attached in into bucket , I than let water purge out of each zone until almost no air is visible.

    Than run circulator pumps the air in the system should be than bleed out with the automatic bleeders I have on rads


    Did I miss anything?

  • stihmatastihmata Member Posts: 11

    No Its an old one Need to change whole pump

    But great idea
  • Wayne HeidWayne Heid Member Posts: 49
    edited April 2014
    Fill and purge

    You'll want to fill the entire system first, then isolate all but one zone and purge it independently of the other zones. The idea is to push the air through the entire zone circuit and out the purge valve. To do this you'd need to close a valve between the purge point and the header or boiler. That way the purge water has no choice but to flow through the circuit you're trying to flush - and nothing else. Sometimes it helps to imagine the flow of water through the piping - almost like following a maze.

    Then isolate the purged circuit and move on to the next circuit and purge it. Until you've done them all. Then open all the isolation valves and start the circulators and check for flow in all circuits. Let it run for a while to work out the small bubbles you couldn't get with the purge.

    Oh, and don't do this with a hot boiler. Otherwise you risk damaging the boiler.

    Good luck.

  • stihmatastihmata Member Posts: 11
    Thanks all

    I am going to drain the system down install the pumps and do the refill purge.

    I will wait a few weeks as to the circ is still working just old and noisy.

    It an older Taco 03 and I believe it was replaced by the 007

    Thanks again
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