Thermostatic always hot

Discussion in 'Shower & bathtub Forum & Blog' started by sharding, Jun 11, 2008.

  1. sharding

    sharding New Member

    Messages:
    10
    Location:
    Seattle/Eastside, WA, USA
    Something is screwed up with the thermostatic valve in our new shower (installed by a contractor -- I'm contacting them, but I'd like to understand the problem myself). The water is hot no matter what position I put the lever in. As far as I can tell, the temperature isn't varying at all, but it's possible there's a minor variation. In any case, it's definitely hot in all positions. This is a Grohe thermostatic valve with the Kensington trim (not sure which valve model number).

    Has anyone seen this before? Bad installation? Defective valve? Just an adjustment needed?

    Thanks.
  2. sharding

    sharding New Member

    Messages:
    10
    Location:
    Seattle/Eastside, WA, USA
    P.S.

    I'm hoping and praying that this is something that can be fixed without cutting open the wall, so answers that suggest that would be greatly appreciated ;)
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,924
    Location:
    New England
    It could be that they didn't turn on the cold water. Some of the valves have in-line shutoffs. It's easy to tell. Take the trim off and look for a slotted round plug on either side of the valve. Normally, when open, it's in-line with the direction of flow. It could be that there's crud in the inlet filter, or there's crud caught in the control cartridge itself. All of these things are fairly easily resolved.

    One of the things that is supposed to be done, per the instructions during installation, is to check the calibration of the thermostat. This should have caught that problem right off. Sounds to me, the plumber did not do that.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,924
    Location:
    New England
    I had another thought...if the hot and cold were reversed on the input to the valve, you might get that result. Basically, the thermostat would see the outlet was hotter than desired, and open the cold side up more. If the cold side was actually hot supply, it would just get hotter.
  5. sharding

    sharding New Member

    Messages:
    10
    Location:
    Seattle/Eastside, WA, USA
    I think this is right. I just noticed that if I start it out with the control pointing up (which I think should be hot, right?), the water runs cold, but once I bring the handle down and increase the temperature, it'll never go cold again....
  6. sharding

    sharding New Member

    Messages:
    10
    Location:
    Seattle/Eastside, WA, USA
    It turned out you were exactly right, jadnashua. We had a competent plumber come in and take a look at it. He swapped the pipes, calibrated the valve and everything is working now. Thanks!
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,924
    Location:
    New England
    Glad it worked out...too bad the first plumber can't read or was just incompentant. I hope you can recover some money from him. Although, the normal procedure is to offer him an opportunity to get it right.
  8. sharding

    sharding New Member

    Messages:
    10
    Location:
    Seattle/Eastside, WA, USA
    It's a long story, but suffice it to say opportunities were offered...
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