Grohe Thermostatic shower valve issue

Discussion in 'Shower & Bathtub Forum & Blog' started by geogridshorthair, Dec 23, 2013.

  1. geogridshorthair

    geogridshorthair Geologist

    Oct 26, 2008
    self employeed
    southern california
    The Back Story:

    We had a water softener where the tank of resin ruptured and sent tiny resin pellets throughout the plumbing lines.
    A plumber was called in to flush all our lines, but he failed to take apart the shower valve in the extra bath.

    Our problem:

    When using this shower we get hot water for about 5 minutes and gradually the temp gets colder until the water temp is uncomfortable. Using a digital thermometer the temp stabilizes at about 80 degrees. Even if the Grohe valve is turned to the hottest position.

    About 8 years ago I rebuilt this shower valve ie., new cartridge and both hot and cold plunger valves. The unit worked great until the recent water softener issue.

    I thought the cartridge had failed so I ordered a replacement and installed it. However, I did not remove the two plunger valves (hot and cold). The problem was not solved. I failed to think the issue was related to the resin pellets.

    This time I removed the two valves and noticed the resin pellets on one of them.

    Anyone have any experience with this issue and this cartridge?
    Can I clean this cartridge? If so, any recommendations on how to do that?

    I can't go back to Grohe because I convinced them to give me this cartridge for free and since it might be contaminated because I failed to clean the pellets before installing it, well that is my issue.

    I'm also looking for advice on how to calibrate the temp on this, once it works properly.

    Open to discussion, looking for ideas.

    Thanks in advance,

    aka Geogridshorthair

    New information

    Since posting I found an old Grohe cartridge from the first rebuild. For sh:ts and giggles I installed it. What is interesting is that I get no cold water through this cartridge, only hot water. If I turn the valve to cold the water volume goes to zero. In any other position there is water volume and it is scalding hot.

    When I put the new (replacement) cartridge in I get only lukewarm water. Go figure!

    I'm about ready to tear this out and install separate hot/cold valves.

    Attached Files:

    Last edited: Dec 23, 2013
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