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mixing valve domestic hot water advice

ron Member Posts: 244
edited May 19 in Plumbing
Have an oil fired hot water heater, I did not find a stat on the tank, and when I use a thermometer at the kitchen sink on full hot I see 140 °F.

I am ok with leaving the hot water tank as is; I have a 1/2" port size Calef. mixing valve (with gauge) on the way. Are there any do's, don'ts, best practices for installing?

Unfinished basement, 40' x 20' single level ranch, 1.5 bath and only 1 shower that would be used by one person. Piping leaving hot water tank is 3/4" and run's alongside cold water pipe length of basement, for about 10' before reducing to 1/2" copper pipe that then runs to each bathroom and kitchen.

I am planning on putting the mixing valve just before where the 1/2" hot water pipe tee's to go to the main bath with shower. And from that point on the existing 1/2" copper pipe everything else is downstream from that. And was planning on teeing before the mixing valve so washing machine gets hot hot water and not ~110°F hot, is this a good idea or should everything get mixing valve hot water including the washing machine? And kitchen dishwasher also would be fed before the mixing valve and would get 140°F.


  • GroundUp
    GroundUp Member Posts: 1,474
    Sounds fine to me, as long as you're comfortable with a little extra premature wear on your clothes from the extra water temp
  • pecmsg
    pecmsg Member Posts: 3,323
    ASHRAE recommends 140* water minimum to control legionnaires disease. After that 120 max at point of use. 
    No need for very hot water at the washing machine. Your just wasting $’s.