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LWCO leakage?

Booger Member Posts: 5
I have 7 Weil Mclain boilers that I installed in an apt. building last year and each has a GuardDog probe type LWCO... The manual insisted on no dope, just teflon tape, hand tightened... Each LWCO must have dripped at some point and left a nice rust stain on their boiler...

Is there a trick that I am missing on how to fix/prevent this from happening?


  • Mike Kraft_2
    Mike Kraft_2 Member Posts: 398
    Paste and probe

    Mr Booger,

    I feel your pain!I can only assume the reason that no paste dopes are wanted is to avoid a build up on the probe to give it a false water level.As far as hand tightening with teflon.........hmmmmmm.Are you installing the MM 24V Guard Dog?That is a plastic NPT fitting and I believe that hand tightening is what is recommended.

    The 120 volt has a brass probe assembly that is wrench freindly.Perhaps a bit more teflon or try the red tape.

  • Booger
    Booger Member Posts: 5

    Yeah I have the plastic 3/4 NPT... I have them installed on 1 1/4 x 3/4 blk. tees. Maybe I will yank one and test it out with some red tape.......
  • Booger the plastic

    gets hot then sits all summer cold. When it is heated up again it leaks. I have been using teflon pipe dope with tape and it seems to work.
  • Tony_8
    Tony_8 Member Posts: 608
    I have

    Taped only w/o a problem. Hand tight and 1/2 turn w/wrench and 6 wraps of tape (or more). Dope and some plastic threads have a detrimental reaction. This may be the reason for the instructions saying what they do.
  • Tony, if you use the

    dope that is rated for use with PVC it will not be a problem. I have actually had someone who works with this stuff, Plastic that is, give me some feedback on this. I have also found that mixing the teflon tape with the teflon pipe dope allows a deeper thread make up which shpould help with leaking.

    It is important to read what is on the containers of lubricants to make sure they do not react with different conditions.
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