Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Adding Caleffi thermal mixing valve - does it reduce flow?

Options
I ordered their top of the line valve. I was surprised to see how thick the thermometer well is in the output flange. Also the flow in and out of the valve looks very small also. I really want the safety but before I install I am wondering how much pressure/flow loss should I expect?

Comments

  • unclejohn
    unclejohn Member Posts: 1,833
    Options
    @hotrod will be in touch shortly with more info on that that you could ever need. A veritable fountain of info.
  • cwilliams2000
    cwilliams2000 Member Posts: 140
    Options
    I appreciate that. I know I have seen some of his videos. Hopefully it will be good news. I definitely want my tank at 150, and reduce my output to 120 for safety and extending the output capacity. I just dont want to have a crazy reduction in flow.
  • hot_rod
    hot_rod Member Posts: 22,256
    Options
    is it a 521 series? That valve has a 3 cv

    so if you are flowing 3 gallons per minute through it you lose 1 psi

    Do say you have 60 psi water pressure and you are running a shower that is flowing 3 gpm oh HOT, you have )9 psi at that fixture

    When I get home I will send a Cv spread sheet that you plug in your glow rates and it shows pressure drop

    Remember when showering typically you are blending hot and cold, so the 2.5 or 3 gpm is not all flowing through the valve

    increasing to a 1” valve size doesn’t change the Cv, by the way

    We offer higher Cv valves but the lose accuracy at low flows, say a 2/2 gpm or lower
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • cwilliams2000
    cwilliams2000 Member Posts: 140
    Options
    Ok. So I took the plunge and the 521 is now installed! I had ordered two valves and chickened out a bit and installed the one without gauges. Seems to be working great already. Its about 125 coming out at 4.5 setting. I have little kids and I will be lowered it probably to about 115-120 but its great to have the tank around 150 now. Very well made, no leaks and I soaked the gaskets first per the directions. I will likely buy a spare body just in case for years down the road to ensure I have a direct replacements. I am not the best solderer but everything came out OK and no leaks. Thanks to all!
  • cwilliams2000
    cwilliams2000 Member Posts: 140
    Options
    Should also have mentioned the install was alittle tricky since I also have the watts/grundfos recir pump down the line a bit after the valve but everything seems ok!
  • unclejohn
    unclejohn Member Posts: 1,833
    Options
    Yeah but until you figure the glow rate all is nought.