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.

Mixing Valve Checks vs Heat Trap

Options
nj6964
nj6964 Member Posts: 22
in Domestic Hot Water
I have an indirect water heater I’ve decided to increase its temp to 140 and add a Caleffi 521519 mixing valve (based on recommendations from HH). I see it comes with or without check valves. I was expecting to have to create a heat trap, but if the mixing valve has checks, do you still need a heat trap? Any advantages/disadvantages? Thanks!

Comments

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
    Options
    Correct, you don't need a heat trap if you use a mixing valve with checks.
    Advantage is you don't have to pipe the heat trap. Disadvantage is that check valves break.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • nj6964
    nj6964 Member Posts: 22
    Options
    Thanks. So from a flow perspective, maybe better off piping the heat trap and not having the added flow restriction of the check valve?
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
    Options
    Unless your water pressure is below 30 psi, you don't need to worry about flow restriction.
    If you have galvanized pipe anywhere in your house, go with the heat trap. Debris from the buildup and release of minerals in galvanized pipe can damage the check valves.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • nj6964
    nj6964 Member Posts: 22
    Options
    No galvanized anywhere, comes in copper, goes to pex. I think I’ll make life easier and just use the check valves. Thanks!

Categories