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Bosch/Buderus DHW temperature sensor failure

KenJ Member Posts: 8
I have a Bosch Greenstar boiler with a TT Smart indirect DHW tank. The Bosch/ Buderus boilers use their own cylinder temperature sensor so you have to take out the Smart tank aquastat and insert the sensor in its place. Supply water is treated for hardness and iron. My boiler is only 3 years old and I have had two of those temperature sensors go bad. I called Bosh customer support and they say they have not had any trouble with those sensors. Anybody else run across this issue or have any ideas for a cause?


  • GW
    GW Member Posts: 4,699
    Does not make sense, there should be no contact with the water anyway. You’re saying you’re pulling out the sensors, and they’re dry? No corrosion?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
  • KenJ
    KenJ Member Posts: 8
    I figured it out. Don't know why the system installer that replaced the first sensor didn't. The drywell tube had water in it. I had found some other posts about this model having leaking drywells so I pulled mine out. I could not find any leaks in the drywell tube so it must have come in from the opening at top. I sealed the threads good as they had some water corrosion on them so water may have been seeping by the threads.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,805
    Replace the well...

    There was an error rendering this rich post.

    HVACNUT Member Posts: 5,857
    Replace the tank. It never should have made it out of R&D.