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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.
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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
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Originally Posted by
HvacPhil
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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I don't think I've ever applied dope to one.
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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
"Is this before or after you fired the parts cannon at it?" - senior tech
I'm tired of these mediocre "semi flammable" refrigerants. If we're going to do it let's do it right.
Unless we change direction we are likely to end up where we are going.
"It's not new, it's better than new!" Maru.
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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
"Is this before or after you fired the parts cannon at it?" - senior tech
I'm tired of these mediocre "semi flammable" refrigerants. If we're going to do it let's do it right.
Unless we change direction we are likely to end up where we are going.
"It's not new, it's better than new!" Maru.
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I would keep a tube of pipe dope in the bag with a manometer if you decide to use it.
Originally Posted by
HvacPhil
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
"Is this before or after you fired the parts cannon at it?" - senior tech
I'm tired of these mediocre "semi flammable" refrigerants. If we're going to do it let's do it right.
Unless we change direction we are likely to end up where we are going.
"It's not new, it's better than new!" Maru.
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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...
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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.
Originally Posted by
beenthere
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.
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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.
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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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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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Lots of guys around here I see using Teflon tape and compound.
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I use leak lock thread sealant. It dont come un done when i am done.
Sent from my rotary telephone using Tapatalk
"Is this before or after you fired the parts cannon at it?" - senior tech
I'm tired of these mediocre "semi flammable" refrigerants. If we're going to do it let's do it right.
Unless we change direction we are likely to end up where we are going.
"It's not new, it's better than new!" Maru.
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We've had posts on this subject for as long as I've been on site. This is not an opinion. I know this is repetitious for many but this is what is taught in apprentice classes. Or at least was taught because who knows what some might say in classes.
Pipe threads are different in that they are tapered. They don't need a sealant they need a lubricant. Years ago pipe dope was mixed by plumbers. White lead and linseed oil. White lead is no more. Almost any thing oily will allow the threads to seal.
If a connection leaks there is a bad thread. A fitting should be able to complete three turns before getting tight. That's the test for the thread depth. If it can't there is a bad thread probably from maladjustment on the thread die ( and yes most can be adjusted)
A pipe thread is almost self sealing as long as the threads are good. I knew a fitter that used STP, the oil treatment. Not good because the fittings tightened too far stressing the fittings. I'm referring to valve bodies.
A sealant is used on straight threads. Many sealants say they can be used on tapered pipe threads also.
Teflon is a lubricant and works OK. Using a joint compound with Teflon is redundant. Like said, if there is a leak it should be corrected and not the dope's fault.
When using dope, only the first three threads should be doped otherwise the job looks sloppy. I knew a contractor that would send plumbers back to clean up their joints.
That's all I know. Oh ya, why wouldn't a manifold tap be doped? There is a chance it could leak so dope it.
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You can be anything you want......As long as you don't suck at it.
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For a small plug such as this I use the white Teflon paste. Just wipe the top of the container with my finger and then apply around the pipe threads. The brush does too much IMO.
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I dab a little drop of Nylog on the threads. Don't know if it actually needs it, but it makes me feel better.
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