Thermostatic mixing valve help

Discussion in 'General Plumbing Help' started by dmichel, Dec 11, 2017.

Help Support Plumbing Forums by donating using the link above.
  1. Dec 11, 2017 #1

    dmichel

    dmichel

    dmichel

    Member

    Joined:
    Dec 11, 2017
    Messages:
    5
    Likes Received:
    0
    Location:
    ,
    Hi everyone. Thanks for any help in advance. I moved into my house about a year and everything worked fine. The last couple of days I've been unable to get really hot water in our master bath. The shower, sink, and tub all get warm but not hot. Warm enough to shower but just barely. The hot water tank is fine as the rest of the house has properly hot water. I suspect a thermostatic mixing valve, but the problem is there isn't one in the mechanical room near the tank, and everything else in the house is drywalled so I fear there my be one buried in a wall or under a floor. But this seems stupid and I'd have thought against code. Anybody have any suggestions of what else it could be or where to look if I'm on the right track.

    Cheers
     
  2. Dec 11, 2017 #2

    Mr_David

    Mr_David

    Mr_David

    Easily Amused Professional

    Joined:
    Jan 12, 2010
    Messages:
    3,868
    Likes Received:
    930
    Location:
    Santee,Ca,
    what kind of shower valve do you have. Could be the mixer in that.
    I would repair that first if you can't find a common mixer for the bathroom. Could be cold water is passing through valve even when iy is closed.
     
  3. Dec 11, 2017 #3

    dmichel

    dmichel

    dmichel

    Member

    Joined:
    Dec 11, 2017
    Messages:
    5
    Likes Received:
    0
    Location:
    ,
    Not sure the brand but it's fairly nice with 2 body sprays Integrated. Is that a common practice with all washroom water supplies going through a shower valve?
     
  4. Dec 12, 2017 #4

    dmichel

    dmichel

    dmichel

    Member

    Joined:
    Dec 11, 2017
    Messages:
    5
    Likes Received:
    0
    Location:
    ,
    Figured out it's a delta monitor with sprays. I think it has a built in thermostatic mixer but the documentation isn't great.
     
  5. Dec 12, 2017 #5

    Mr_David

    Mr_David

    Mr_David

    Easily Amused Professional

    Joined:
    Jan 12, 2010
    Messages:
    3,868
    Likes Received:
    930
    Location:
    Santee,Ca,
    Delta Monitors I believe are pressure balanced valves, Not thermostatic.
    There is a difference.
    The water supply to other fixture does not intentionally pass through the mixer valve but on occasion upon failure of inner seal may allow cold/hot to pass through the valve while it is in the closed position. Moen were notorious for this. Delta monitors ?? unknown if they do.

    We used to check for this by shutting off the water supply to water heater.
    if water is crossing over it will be evident when you turn on the hot water at a fixture. Should be getting no water from hot side. If you have a significant flow go listen to each fixture and see if you hear water passing though it.
     
  6. Mar 13, 2018 #6

    dmichel

    dmichel

    dmichel

    Member

    Joined:
    Dec 11, 2017
    Messages:
    5
    Likes Received:
    0
    Location:
    ,
    Reviving an older thread. I changed out the shower valve in December. The new cartridge fixed the problem. At least for a while. It's been about 3 months and the same problem has returned. I assume the repair cartridge has failed again but after 3 months seems excessively short. Anyone have any insight?
     
  7. Mar 14, 2018 #7

    ExtraMilePlumbing

    ExtraMilePlumbing

    ExtraMilePlumbing

    Well-Known Member

    Joined:
    Aug 21, 2014
    Messages:
    438
    Likes Received:
    67
    Location:
    ,
    What’s the water pressure to the house? Also water quality(lot of chlorine)? How old is the water heater ? Do you flush it once a year? It could be a lot of sediment from the water heater clogging up that sensitive cartridge, also repeat the steps mr David suggested(this time it might be another single handle faucet)could also be the quality of cartridge , did you get it from manufacture and grease it up before you installed it
     
  8. Mar 14, 2018 #8

    dmichel

    dmichel

    dmichel

    Member

    Joined:
    Dec 11, 2017
    Messages:
    5
    Likes Received:
    0
    Location:
    ,
    Water pressure is good but I don't know the psi. We are on a well with a submersible pump. No chlorine and a few year old water heater. Haven't flushed it, maybe that's the next step. I tore down the old cartridge and there was a bit of rust discoloration but nothing obviously clogging the pressure balance valve.
     
  9. Mar 14, 2018 #9

    ExtraMilePlumbing

    ExtraMilePlumbing

    ExtraMilePlumbing

    Well-Known Member

    Joined:
    Aug 21, 2014
    Messages:
    438
    Likes Received:
    67
    Location:
    ,
    Just replace the cartridge with a manufacture one , also make sure it’s not another single handle valve crossing over, they sell water gauges in any hardware store
     
  10. Mar 14, 2018 #10

    Matt30

    Matt30

    Matt30

    Professional Professional

    Joined:
    Jan 17, 2012
    Messages:
    1,924
    Likes Received:
    756
    Location:
    Halifax, Nova Scotia
    Long time no see extra mile!
     
  11. Mar 15, 2018 #11

    ExtraMilePlumbing

    ExtraMilePlumbing

    ExtraMilePlumbing

    Well-Known Member

    Joined:
    Aug 21, 2014
    Messages:
    438
    Likes Received:
    67
    Location:
    ,


    I know, I’m glad to be back and with more experience to help others, 2 more years till I open my own doors can’t wait.
     

Share This Page