On Sun, 16 Jun 2013 21:44:39 -0500, ChairMan wrote:
I didn't like the way the funky fitting sealed.
The o-ring was on the end of the sliding pipe in the direction of the
flow of water ... whereas, with a union ... the o-ring is in the middle
of the screw-together connection, away from the direct flow of water.
With all that pressure, I was worried the funky tool would leak.
So, in the end, I opted for the schedule 80 union instead:
omg...you're at it again!
Making a mountain out of a mole hill.....
injecting your substandard logic & experience into a simple situation,
dragging out the thread ad nauseum
I know you're close to SV....does Google not work in your area?
The unit is a "telescoping coupling", a simple / effective means for
S119-20 2 inch repair coupling, slip x slip
If you need to make a repair on pipe that is not easily moved, this is
what you need. Telescoping couple, 2" socket by 2" socket. One end
moves in and out to match up with existing pipe. Saves digging up the
whole pipe to make a repair. NSF Rated for potable water, pressure up
I've only installed two, the largest unit I've used is 3/4". Last one
installed in ~2005...no issues on either install.
Kinda like "Shark Bites"... might seem like magic but the design
concepts are sound
and in the age of internet, bad product performance would "blow back"
onto the mfr & sellers post haste.
On Mon, 17 Jun 2013 05:18:41 -0700, email@example.com wrote:
Now that I've taken the thing apart and compared it with a union, I think
that in certain applications they might be great. For example, if your
pipes *move* in use, and if you're below 200 psi, they might be useful.
Also, in my case, I knew I had limited clearance between the bottom of
the pipe and the concrete slab - so I had reasoned (in the store) that it
was "thinner" at its greatest width than a normal schedule 80 union was.
It turns out though that the schedule 80 union just about made it, so I
had room enough for that "fatter" union. Plus, when I took the expansion
coupling (aka telescopic coupling) apart, I was worried that the o-ring,
which goes around the end of the sliding pipe, was directly in the path
of the onrushing water - and I reasoned that it could cause turbulence
compared to the little nub on the inside of the union - and - worse yet -
it might leak since the o-ring is directly in the path of the onrushing
Googling for the PSI of a 2 inch union, I am dismayed that they are only
pressure rated to 150 psi:
So, I guess, in hindsight, *both* unions and expansion couplings don't
handle high PSI. (I forget what the PSI is in the pool pipes though.)
On Sun, 16 Jun 2013 22:45:29 -0700, DD_BobK wrote:
I was looking for people's experience in using this "telescopic coupling"
aka *expansion coupling*.
It looks like the DIY pool repair guy here did exactly what I did:
He *bought* the same coupling that I did; he took it apart, and looked at
where the single o-ring was - and given that it's on the *end* of the
slider pipe, he concluded, as I did, that it might not hold pressure as
well as a union would.
I find out here that even the really fancy ones with multiple Viton/EPDM
o-rings (over $300 each!) are rated only to about 235 PSI:
I guess the results of your "Googling" means that
flexpvc.com is wrong when they call the item a PVC-Couples-
btw 200psi isn't enough for your pool application?
that in certain applications they might be great. For example, if
pipes *move* in use, and if you're below 200 psi, they might be
Totally awesome! DADD has pronounced the telescoping couple as "in
certain applications they might be great."
I'm certain the mfr will be glad to hear that & continue making them.
Question...got any idea of the operating pressure rating for 2" Sch 40
hmmm probably less than 200 psi
Question...got any idea of the operating pressure for a pool filter
Question...got any idea of the length changes in a typical piping
On Mon, 17 Jun 2013 21:16:48 -0500, ChairMan wrote:
That might help; but it's still inline with the water flow,
whereas the union is off the flow direction (AFAIK).
Still - that would have been a good idea had I used the
expansion coupling for the repair.
Next repair I'm going to try just couplings and pipes, to see
if it can be done without a union.
whereas the union is off the flow direction (AFAIK).<<<<
your analysis is wrong... there is no O-ring location problem.
The real problem is "AFAIK" actually means "you really have no idea
what you're talking about...you make stuff up based on faulty logic"
ever heard the punchline "frogs with no legs cannot hear"?
On Tue, 18 Jun 2013 11:34:26 -0500, ChairMan wrote:
I took both apart to visually analyze how they work:
Laying them side by side, the o-ring is in a different position:
Each o-ring seems to be blocking flow slightly differently:
DD_BobK says he knows exactly how they work so I'll let him
explain as they seem to work slightly differently, admittedly
to my inexperienced eyes (having never even seen the telescopic
On Wed, 19 Jun 2013 08:20:54 -0700, Harry K wrote:
Having stared at the two fittings side by side, I'm scratching
my head to find the real *value* of the telescopic fitting over
the union (other than the installation process is a bit easier):
- Telescopic makes measuring easier on the installer
- Telescopic slider *may* handle length fluctuations better
- It's slightly lower in height (for space-challenged locations)
- Telescopic doesn't need a "repair pipe" (it only needs a coupling)
- Telescopic cost about 50% *more* than the union did for me
- Minimum repair is larger with the telescopic than the union
- Telescopic will leak *differently* than does the union (if it leaks)
- Total cost is (far) higher with telescopic than with union
You're preaching to the choir....
I know exactly how these things are designed & how they work.
They work just fine otherwise you'd find tons of complaints about
Your concern about "O-ring in the expansion coupling is in line with
the fluid" is unfounded,
more novice / non-mechanically inclined hand wringing.
Yes, I used one to repair the connection to the manifold of our
sprinkler system. Nobody talked me into it: as soon as I saw it, I knew
that it was what I needed to do the job in the simplest possible way.
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