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monoflow alternative?

Al's right.... Which radiant heat are u using? Stapled up system? High mass system? No matter which you use, radiant system required lowered water temps. There's a book fron Dan's list about installing radaint zone from hot water system..


  • Royboy
    Royboy Member Posts: 223
    what about a ball valve instead?

    I'm putting a small area of suspended-tube radiant under a hardwood floor in a kitchen remodel project to replace a fin-tube baseboard that had to be removed. the radiant tube will be off a baseboard loop and my first thought was to use a monoflow T to divert some but not all of the flow through the radiant tubing. then I thought maybe I should use a monoflows at both Ts to get even more flow and now I'm wondering why not just use a ball valve that I - or the homeowner - can adjust to add resistance in the original loop. the piping is quite accessible for adjustments. I suppose a balancing valve could also be used ...


    thanks - Roy
  • balance valve

    Hi Roy,

    The balance valve between the risers will create a pressure drop in the main, just like the monoflo or diverter tee(s) will do. A ball valve is not the best option for balancing. We recommend and sell a butterball valve for balancing. It has a butterfly-type disc on the inside, perfect for controling flow, but looks like a ball valve on the outside. It also has a scale to keep track of adjustments.

    Good thinking! It has been done before and will be again.
    Let us know how it works out for you.

    Best regards, Pat
  • Al Letellier_9
    Al Letellier_9 Member Posts: 929
    radiant loop

    How are you going to control the temp to that radiant. even if the hydronic loop is reset, it may be too high a temp for that hardwood. Flow alone may not be enough control to prevent damage to that hardwood. Do the calculations and decide how to regulate temp. You can use a mixing block or a simple 3 way mixer, but you'll need another circ to do the job correctly.

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  • Jerry_15
    Jerry_15 Member Posts: 379

    You can use a mono-flow first, and then tie in an in line valve with a remote capillary temp adjustment for room temperature, or floor temperature, or both, although I doubt the higher temp will be a problem under wood, as opposed to tile. Danfos among others makes them, check on-line. This will give you full room temp adjustment without wiring. This also has been done before, good simple fix. Good-luck PS - Be sure the rad valve is going the right way, it will work backwards but chatter like hell when it reaches shut-off point.
  • I'm not quite right, or I screwed this one up

    Sorry Roy, Al ,et al,

    I zeroed in on the flow and forgot about temperature. My apologies are offered. The required water tewmperature could be completely different between staple-up and baseboard, or they could be the same. It is harder to control temp with flow balance than it is to control with a mixing valve, which will require that second mini-circulator.

    Can we have some more info on this remodel?
    1) Design water temp for the radiant

    2) Design water temp for the rest of system

    3) Flow rates for each

    The balance valve in the main has worked successfully when a monoflo size was no longer available in a single temperature application.

    Best regards, Pat

  • Jed_2
    Jed_2 Member Posts: 781
    I would consider

    Ultra-Fin in this instance, with XPA tubing. It's made for wood floors, and hi SWT. T'stat location would be a consideration, and a flow balancing device would be required. If you're tapping a high temp zone for a radiant suspended application, know the heat requirements of the radiant area. It can be done successfully. Just putting in pex tubing at high temps would not be a method I would suggest.

  • Royboy
    Royboy Member Posts: 223
    some further details

    thanks, guys for the input. to this point I am operating pretty low-tech and seat-of-the-pants - which I know is not necessarily the preferred approach for many here. my gut sense is that the remodel has actually decreased the heat load in the space due to better shell insulation (but this would be very tough to calculate due to old remodeled structure) and thus I'm not sure this will even be much needed - just that one side of the kitchen has an exterior wall and once had a baseboard fin-tube radiator and no longer has any.

    I am doing a suspended pex-tube installation of about 60 sf. one piece of inspiration I got for this approach was a column by John Siegenthaler in PM magazine. this is the link (sorry, not sure how to post this as a clickable link):

    from that I got the impression that the regular 170-180 boiler output temp would work OK for this sort of installation I'm hoping that I can get the proper amount of flow to deliver roughly the right amount of heat. not intending to zone separately.

    Pat - is the butterball valve somehow different from what would ordinarily be termed a balancing valve?

    thanks - Roy
  • just as you thought

    Hi Roy,

    Thanks for the link and the info, that clears up a lot. However the question of water temperature and hardwood floors still is in play.

    I've just read Siggy's article and your original post refers to using something other than the two diverter tees shown in Fig. 1 as a possibility. I stand by the idea that a balance valve in the main (no diverter tees) gives some control of flow thru your suspended tube piping loop. The tees give a fixed fow rate.

    Balance valves are a way to control that flow thru the tubing and ultimately the final floor temperature, which we have to be careful of since it is hardwood flooring. It is also a slave to the house t-stat and cannot be controlled separately unless the homeowner wants to open/close the balance valve, and it still has to be under a call for heat.

    It may be we are being careful, but check out the restrictions on your water temperature for the flooring being used. Double check and document, even the smallest jobs.

    The proper amount of flow is going to depend on the heat loss of the room. The water temp is going to determine the output of the 60 sq. ft. You can expect 1200 btuh if you are transfering 20 btu per sq. ft., a typical output. Maybe the radiant guys can give you a better idea.

    The butterball valve is just one of many good balancing valves. Go with what your local wholesaler has in stock.

    Best regards, Pat
  • Jed_2
    Jed_2 Member Posts: 781
    Balancing vlv in the main

    yes, a balancing valve in the main, and a remote sensing TRV in the branch. Set the balancing valve for design flow conditions, and let the TRV modulate flow and room temp. This is with full boiler water operating temps.

    Ultra Fins are made for wood floors, and Hot Rod's evaluation was impressive.

This discussion has been closed.