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GV90+ Flowing in Reverse

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MDB
MDB Member Posts: 2
I have a Weil-McLain GV90+ that appears to be flowing in reverse. Does anyone know how/why this is happening? I've had numerous techs look at it with no luck.

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  • delta T
    delta T Member Posts: 884
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    Make sure both the internal circulators are functioning properly, if one or the other has died it can cause some funky flow patterns. Why do you think it is flowing in reverse?
  • MDB
    MDB Member Posts: 2
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    When the boiler fires and starts circulating the return side is too hot to touch and the supply side starts cool and slowly begins to heat up. It never reaches 100 degrees according to the gauge.
  • Tom_133
    Tom_133 Member Posts: 888
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    I agree with delta T, there are two pumps internally, one is for keeping the boiler internally at temp and flowing one sends it out to the system based on water temp. You could post pics and that may help us determine whats wrong, if its not the internal circ.
    Tom
    Montpelier Vt
  • DZoro
    DZoro Member Posts: 1,048
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    The board on those boilers can play tricks. Sometimes they will show a 120v on the meter at the pumps....But there is no "power" behind the 120v. At the pump wire in a shop light and see if it actually turns on. Trust me it's a pain but have been bit by this issue a few times.
    delta T
  • delta T
    delta T Member Posts: 884
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    agree with Dennis, you need an amp probe or something to really tell if the pumps are running or not. Wasted hours on a GV90 one time because of this. Sounds like you have an internal pump not working for sure. If one is gone, I would replace both as the other is likely close to failure as well.