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DHW mixing valve recommendations

markt Member Posts: 26
Have a 40 gal indirect DHW, frequently run out of hot water post-bath. Want a little more hot water. Lots of mixing valves out there, I've no experience with them. Recommendations?

Strong preference for longevity, reliability, etc. over low price.


  • jonny88
    jonny88 Member Posts: 1,139

    I know Holby makes a great valve.A mixing valve should add roughly 15 gallons to your tank.How much hot water are you using and what size pipe do you have going to your tank currently.
  • Rich_49
    Rich_49 Member Posts: 2,565
    Taco 5000

    Series mixing valve . And store the water in tank 150 or slightly higher
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • SWEI
    SWEI Member Posts: 7,356
    Symmons, Leonard, Caleffi

    all good products.

    Alan Forbes pointed us at this one -- clever design
  • markt
    markt Member Posts: 26
    water use and pipe

    I don't really know how much hot water I use, except that filling a bathtub pretty much uses it all. That's the only time there's any issue.

    I have 3/4" pipe from meter to tank, but 1/2" from tank to bathroom. I don't have great pressure, but that's a different problem...
  • markt
    markt Member Posts: 26

    The Honeywell looks like a quick install for a conventional water heater with inlet and outlet on top, but my indirect has cold inlet at bottom (Lochinvar Squire)
  • markt
    markt Member Posts: 26
    Caleffi differences?

    What's the difference between the ~$100 Caleffi and the $500 Caleffi?
  • jonny88
    jonny88 Member Posts: 1,139

    On the literature it says you require 1in boiler feed and return piping.What pump are you using between boiler and tank.
  • hot_rod
    hot_rod Member Posts: 14,786
    High Flow

    rates for the two on the right. The two on the left are commonly used for residential and light commercial applications. The gauge feature is very handy for setting and adjusting output temperature. Inspectors love them also :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • markt
    markt Member Posts: 26

    You're referring to the Lochnivar lit? I do have a 1" between boiler and tank, and circulated by a Grundfos UPS15-58FC, currently on medium setting.

    Presumably you're getting at the issue of recovery time on the tank?
  • jonny88
    jonny88 Member Posts: 1,139
    aquastat setting

    has this problem always occured or is it something that developed over time,whats the setting on the aquastat
  • markt
    markt Member Posts: 26
    it's all brand new

    Just installed a couple months ago. It's been this way since installed. Aquastat at 120.

    I was assuming it's not a defect or malfunction, it's just that a bath uses up all the hot water. I haven't attempted to measure recovery, but it seems OK. It just seems like the tank size is a little small for our usage.

    But maybe I shouldn't assume that... perhaps it's not all correct.

    Perhaps I should measure the bath size and compare to tank...
  • jonny88
    jonny88 Member Posts: 1,139

    as rich says raise temp to 140 -150 and install mix valve pity about your undersized 1/2 " piping good luck
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