Hydro Testing

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jlakes85
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Joined: Thu Feb 23, 2012 6:07 am

Hydro Testing

Post by jlakes85 »

Hi All,

I'm in the midst of hydroing the dry pipe and aux pipe for the shay. Im having some issues getting everything absolutely leak proof so I don't loose 30+psi per drop. What would be the recommended tape/dope for the thread fittings. Also what would work best in steam service?

-jlakes85
SteveM
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Location: Wisconsin

Re: Hydro Testing

Post by SteveM »

Not sure about the live steam world, but my plumber prefers the liquid brush-on dope to the tape.

Steve
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FLSTEAM
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Location: Central Florida

Re: Hydro Testing

Post by FLSTEAM »

PTFE Pipe dope available at Lowes, HD or ACE

JB
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Bill Shields
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Re: Hydro Testing

Post by Bill Shields »

Here is a never-ending discussion...tape or dope or Loctite thread sealant.

Plumbers (in general) tend to go with what is quick and easy and generally don't have to deal with steam. They DO have to work with propane and natural gas where the paint on dope is pretty much required (gasoila?)

In most cases the biggest difference is in how the stuff is applied (carefully) and in some cases how well the threads are cut.

be careful with everything so that you don't get the 'sealant' down inside the pipe and gunked up into all sorts of places you don't want it once the threads are made up. Our little needle valves, INJECTORS, etc: often do not react well to this stuff inside the lines where only water is expected.

I cannot say that I have ever had a totally water-tight (no leak) cold hydro..it goes with the territory.

I can say that most of the steamers I have ever seen / worked on / built, tended to leak a little here and there until they were good and hot and ready to stop leaking on their own good time.
Too many things going on to bother listing them.
jlakes85
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Re: Hydro Testing

Post by jlakes85 »

Hi Bill,

Sounds good. I guess I might have to lean on the pump handle a bit for the full 15 min to keep the Needle on 400 psi
Marty_Knox
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Re: Hydro Testing

Post by Marty_Knox »

Why are you testing to 400 PSI? Are you going to run at 200 PSI?
jlakes85
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Re: Hydro Testing

Post by jlakes85 »

Hi Marty,

Design pressure is 125 psi.
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Bill Shields
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Re: Hydro Testing

Post by Bill Shields »

ok...so again the question...why 400 psi.>>>?????
Too many things going on to bother listing them.
Marty_Knox
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Re: Hydro Testing

Post by Marty_Knox »

We make the initial at twice working pressure, retests at 1 1/2 working pressure. There is no advantage to exceeding this. In fact, there are some inspectors who will condemn a boiler that sees more than twice working pressure.
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NP317
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Re: Hydro Testing

Post by NP317 »

Washington State Boiler Code declares that a hydro pressure test more than 200% of Maximum Allowed Working Pressure results in a damaged pressure vessel.
This causes the State to downgrade the MAWP.
Know your local Code.
~RN
jlakes85
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Re: Hydro Testing

Post by jlakes85 »

Hi All,

Excellent information as always. I'm glad I was just testing only the dry pipe and aux pipe to start. These are comprised of 3/8 class 3000 fittings and sch 80 threaded pipe.
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Harlock
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Re: Hydro Testing

Post by Harlock »

I have been very happy with LocTite 567 High Temperature Thread Sealant with PTFE. I have not used thread tape in a very long time.
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