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  1. #1
    Join Date
    May 2018
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    Pipe Dope Vs No Dope - Gas Valve Pressure Ports

    You know that little hex screw for manifold pressure. I always got mixed answers for this, do you apply pipe dope to that screw ? What about when changing orfices? I usaully do it on the test ports but not on orfices. Just annoying cause anytime I want to perform manometer test gotta go get the dope from the truck.

  2. #2
    Join Date
    May 2006
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    most vavles i have seen the pressure port has a screw with a rubber gasket on it so if you tighten it down properly it should not leak any ways it does then use the pipe dope spareingly

  3. #3
    Join Date
    Jan 2004
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    Quote Originally Posted by HvacPhil View Post
    You know that little hex screw for manifold pressure. I always got mixed answers for this, do you apply pipe dope to that screw ? What about when changing orfices? I usaully do it on the test ports but not on orfices. Just annoying cause anytime I want to perform manometer test gotta go get the dope from the truck.
    I virtually never use dope on them. Dope is just to over come friction. On a small plug like that, none is needed.
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  4. #4
    Join Date
    Apr 2004
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    MN
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    I don't think I've ever applied dope to one.
    A Veteran is a person, who at some point in their life, wrote a blank check payable to the United States of America for payment up to and including their life.
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  5. #5
    Join Date
    Jul 2019
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    Oklahoma home its in the name
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    I use a smidgen of leak lock or the yellow reactor seal if it's completely dry but usually there's enough of the assembly grease left that I just put it back together.

    Sent from my rotary telephone using Tapatalk

  6. #6
    Join Date
    Jul 2019
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    Oklahoma home its in the name
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    I try to be really careful with pipe dope because I have noticed that most of my gas valve failures on newer furnaces have been ones that the installer used lots of pipe dope on.
    And some of my most irritating persistent callbacks have been due to tiny particles of what looks like pipe dope jammed in the pilot feed hole on Ancient furnaces.

    Sent from my rotary telephone using Tapatalk

  7. #7
    Join Date
    Jul 2019
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    Oklahoma home its in the name
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    I would keep a tube of pipe dope in the bag with a manometer if you decide to use it.
    Quote Originally Posted by HvacPhil View Post
    You know that little hex screw for manifold pressure. I always got mixed answers for this, do you apply pipe dope to that screw ? What about when changing orfices? I usaully do it on the test ports but not on orfices. Just annoying cause anytime I want to perform manometer test gotta go get the dope from the truck.
    Sent from my rotary telephone using Tapatalk

  8. #8
    Join Date
    Jun 2012
    Location
    Northern NV
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    My pet peeve was always teflon tape. That is almost a guaranteed combination valve killer, the bit of tape in the gas side of the system...

  9. #9
    Join Date
    May 2014
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    Bay Area California
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    I always get a chuckle when I hear that.

    Maybe there's a difference between dope and sealant. Does your can actually say dope? Mine says sealant.


    Quote Originally Posted by beenthere View Post
    I virtually never use dope on them. Dope is just to over come friction. On a small plug like that, none is needed.
    I do a triple evac with nitro to remove non condensables.

  10. #10
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    Jan 2004
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    PA
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  11. #11
    Join Date
    May 2014
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    Bay Area California
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    Before I got into this trade, I was doing construction. This is back when galvy piping was the norm. There was this one house where every other pipe joint leaked. Come to find out the guy was spitting his tobaccy on the threads instead of using a thread sealant.

    LOL.

    I've gone round and round with plumbers. I keep telling them that if your thread sealant is only to lubricate the threads, then stop using it, and use oil. Oil will lubricate the threads better than a thread sealant.

    For some reason, they keep using their thread sealant, and never want to use oil. Which would lubricate the threads better. Go figure.
    I do a triple evac with nitro to remove non condensables.

  12. #12
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    Way back in the 70s. It was all pipe dope around here. Didn't hear of thread sealant being used on pipes until the mid to late 80s.
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  13. #13
    Join Date
    May 2014
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    Any tech I have worked with has always called it pipe dope, and so do I. Just sayin' my can says sealant.

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    I do a triple evac with nitro to remove non condensables.

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