I'm a big believer in doing things the right way, or, at least knowing
what the right way is (so that the next time you do it the right way).
So I ask what seems like a very basic question:
Q: Does it matter which direction I put these 2" PVC unions on?
If it mattered, then the manufacturer of the union would mold an arrow
into the side of the union indicating the direction of flow; just like
they do on check valves.
You see arrows like that on globe valves (and I'd expect needle valves
too)cuz the disk is meant to close against the flow. You don't see them
on gate valves, butterfly valves or ball valves cuz in those cases the
closure isn't affected by the direction of flow.
The black and white one seems to be mismatched. I learned the hard way
that even though they seem to go together, the threads may not fully
mate, allowing the outside ring to slip when tightened.
Also, if the "O" ring is in the removable part, you will be able to
better keep track of it when it comes out of the groove.
A union that is vertical should have the ring on the upper part. that
way gravity will help getting the threads started.
Otherwise, as stated, not much difference.
Doh! I warned him about that a few days ago. Said I
wasn't sure that half of one union would mate correctly
with half of another, because they may not be designed
exactly the same. I've never tried to do that because
I'd be concerned about it leaking. And also you have
the other half of the new union whether you use it or not.
On Sun, 12 May 2013 14:39:30 -0700 (PDT), " email@example.com"
He could still get the all black** union at a plumbing supply store,
I just looked for a black 2" checkvalve and had no trouble finding
**I can't remember if black is PVC, APS, JPG, or whatever.
The black is black paint on top of white schedule 40 plumbing.
The reason for the black paint is to prevent UV degradation of
the PVC pipes.
I looked it up a while back, and, it turns out that the pipes
get "brittle" in the sun; so they're almost always painted
black if they're outside (like mine are) in the blazing sun.
Here you can see the white pipe hasn't been painted black
yet as I just finished the plumbing today ...
I'm no expert, but my pool equipment is white schedule 40 PVC pipe
painted black to protect it from the sun.
When I went to Home Depot, all the schedule 40 PVC was white; the
schedule 80 PVC was mostly gray (the schedule 80 unions were white);
and the drain pipe was black.
Not sure if that holds true elsewhere though ...
Hardware stores, maybe including HD used to sell mostly black plastic
pipe, and no white plastic pipe, but white came in later and I guess
it's better in some way, because that is all HD has now. (Maybe grey
pipe too but that's the flexible stuff I havent' used.) To get black
recently (so it would mach my basement sink drain and my sump pump
drain) I had to go to a plumbing supply store.
It seems to me a curious thing that they paint them black.
Not only is black ugly, but it absorbs more heat from the sun.
White paint would offer UV protection, look better, and
absorb less heat. That's what I use where that is an issue.
On Mon, 13 May 2013 06:37:41 -0700, firstname.lastname@example.org wrote:
You have an interesting point there, in that it's the 'paint' and
not the 'color' of that paint that protects PVC from UV radiation.
Dunno why mine are black ... but ... since they are ... I'm going
to get out my license to prove I'm over 18 and have them unlock
the double padlocked spray paint cage at Home Depot when it's all
working and buttoned up ... and grab me some flat black stuff to go!
That isn't the issue. He has a PVC union. The issue is that
one half of a 10 year old union from manufacturer A may not
seal correctly with one half of a new union he buys today from
manufacturer B. It might work, it might not. Unless it's difficult
for some reason to replace the whole union, I don't see why
anyone would screw around. And you already have the other
half paid for, because you can't buy half a union.
On Mon, 13 May 2013 06:31:45 -0700, email@example.com wrote:
If it leaks, I'll replace that part of the plumbing, since, with the
unions, everything should be easy.
If it's any consolation, that unused "yellowed" union is, in fact,
the same age and batch as the existing "blackened" union is.
To explain further, about a year or so ago, I had replaced a broken
Jandy valve after draining the pool, and at that time, I added the one
now-blackened union on the outlet of the pump. I knew that a union
only on the outlet pipe without a union on the inlet pipe was useless,
but I was adding it knowing that someday (like yesterday) I would
be adding a union to the inlet side of the pump.
I had bought two unions at the time, so I left the unused union
outside in a plastic bucket. Over time, that unused union yellowed.
So, the good news is that the unions are 'matched' in time and batch;
the bad news is that one sat outside in the hot sun for a year.
I'll let you know if it leaks; but if it does, it will be easy to
replace, since the hard part was always the inlet side, and not
the outlet side.
Note: If it wasn't easy to replace, you can rest assured I would
have used all new equipment!
On Sun, 12 May 2013 14:39:30 -0700, firstname.lastname@example.org wrote:
I did read that; and I do agree that I'm putting half an
old union with half a new union.
Time will tell.
Now that the hardest part (the parts at the Jandy valves) has
been cut out, repairs on all other sections should be much
simpler, in case they leak.
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