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Bad mixing valve

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Snowmelt
Snowmelt Member Posts: 1,415
in THE MAIN WALL
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/CashAcme-24514-ProductOverview.pdf
Ever have this mixing valve go bad on you?

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  • hot_rod
    hot_rod Member Posts: 22,139
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    Bad as in? They tend to lime or scale up easily, all brands do. You need a 20 or more ∆ between hot in and mixed out for them to be accurate. A min. 1 gpm also.

    That 20 gpm is BS! try shoving 20 gpm thru an opening the size of a pea. Sure it's possible but look at the pressure drop, what pump would you use for 45 pressure drop?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Snowmelt
    Snowmelt Member Posts: 1,415
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    It’s only been a month I have the mix at factory setting which was about 120 , the boiler is set at 180, it was nearly Luke warm temperature. I turned it all the way up and still it’s just above Luke warm but not even close to hot.
  • hot_rod
    hot_rod Member Posts: 22,139
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    did it work when you first installed it, or not ever?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Snowmelt
    Snowmelt Member Posts: 1,415
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    Had to work, it was hot to touch where I could only hold it for 5 secounds, now it’s Luke warm.
  • hot_rod
    hot_rod Member Posts: 22,139
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    Snowmelt said:

    Had to work, it was hot to touch where I could only hold it for 5 secounds, now it’s Luke warm.

    Did you try turning the knob all the way open and close to see if it frees up a stuck spool?

    You are sure you have flow going thru, no air lock that could be causing little or no flow?

    Circulator is pumping away from the "H" port?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    Are you pumping away from the Mixed port?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Snowmelt
    Snowmelt Member Posts: 1,415
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    its defiantly stuck closed. I felt the pipe this morning, it may be air bound I will try bleeding the air today. it was working just last week were my wife could feel the floor was warm. the floor didn't feel warm Friday night so Saturday I looked at the valve, it wasn't getting warm.
    of course im pumping away from the mix valve, im not a rookie.
    im leaning towards air or bad mix
  • hot_rod
    hot_rod Member Posts: 22,139
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    very simple innards, but it doesn't take much to gum them up.

    This spool was in a domestic water valve that the water flowing thru started to dissolve the peroxide cured EPDM o-rings that Caleffi uses, a very chemical resistant o-ring design.

    Chemicals added to the public water must have been fairly aggressive. Wonder what those chemicals do to human innards :(
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • kcopp
    kcopp Member Posts: 4,432
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    I have seen grit get in there and mess all kinds of things up.
    Pull it out and flush the lines as best you can.
    May be best to install new valve instead of fixing what you have.
  • hot_rod
    hot_rod Member Posts: 22,139
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    In a bind you can actually remove the guts from a thermostatic valve and move some heat. If there are valves around it you can manually balance it, but it will not change as S&R changes, it's now a dumb valve :)

    You might be amazed how much more flow you move when the guts are taken out. Thermostatic are very flow restrictive devices.

    3- 5 GPM reasonably without throwing some serious pump energy at 'em.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Zman
    Zman Member Posts: 7,569
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    I can't believe they advertise that valve for hydronic heating. Have you seen the pressure drop chart? ~4 PSI at 5 GPM :s
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    GroundUp
  • hot_rod
    hot_rod Member Posts: 22,139
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    Not understanding how Cv works in a valve like that is probably why so many radiant systems slip behind as you approach design conditions.

    You will often see 2 or 3 circulators connected to 3 Cv thermostatic valve!

    If this attaches it is a handy spreadsheet to help understand the effect of CV. Used for design or troubleshooting.

    It applies to ANY valve, zone, ball, balance.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    kcopp
  • Snowmelt
    Snowmelt Member Posts: 1,415
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    Hot rod, it was air in the line. I came home from work, I bleed it out, ( 3 five gallon buckets, then the line became hot.
    kcopp
  • hot_rod
    hot_rod Member Posts: 22,139
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    Snowmelt said:

    Hot rod, it was air in the line. I came home from work, I bleed it out, ( 3 five gallon buckets, then the line became hot.

    It can take a lot longer than one would think to get a good clean purge, you can spend 5 minutes or more on a single loop getting then to run clear. Good that you got it going.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Snowmelt
    Snowmelt Member Posts: 1,415
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    yea my wife was complaining her feet were cold. lol
    hey, were you in NJ a few weeks ago? did a class on your material. john serlerno was the rep?
  • Le John
    Le John Member Posts: 226
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    Hey @Snowmelt should you need to change it I’d recommend the caleffi version. Has a temperature gauge to see what the outlet temp is. Pretty nice valve.
  • hot_rod
    hot_rod Member Posts: 22,139
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    Le John said:

    Hey @Snowmelt should you need to change it I’d recommend the caleffi version. Has a temperature gauge to see what the outlet temp is. Pretty nice valve.


    Nice solder joints!
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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