Does it matter at all whether PVC unions are on one way or the other?

ot by this site

No.

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.

Paul

the right way, or, at least knowing

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.

right way, or, at least knowing

He could still get the all black** union at a plumbing supply store, right?

I just looked for a black 2" checkvalve and had no trouble finding one.

Makes sense.

Since all mine were horizontal, I simply arbitrarily faced them all in the same direction (as each other).

That way, I can swap pumps if I ever need to.

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.

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 ...

This makes sense.

BTW, I just noticed that what I *thought* were schedule 40 unions were actually schedule 80 unions:

I wonder why these schedule 80 unions are white and not gray?

Do you think I should lubricate the union with pool lube?

Following the huckleberry trail, I certainly took your advice to heart!

I bought 1" wide 120 grit aluminum oxide sanding cloth:

I took pains to keep the results as perfectly round as possible:

Even so, I'm a bit worried because the 2.5" coupling is a tad too large:

But, I had called Jandy & they said simply to use a lot of glue!

Adding the reducing bushing, the plumbing is back to original 2" size:

Ah, you mean in the pictures in this thread. At first I thought you meant all black 2" plastic pipe was white pipe painted black.

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 ...

ngs the right way, or, at least knowing

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.

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.

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!

I understand.

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!

Strainer? Volute?

Googling ... Volute: noun, A spiral scroll, Forming a spiral curve or curves

So I assume the strainer is the pool pump basket, which has an o-ring at the top under the cover, which I do lube with the pool lube.

And, the volute is most likely the clamp-on connection where the impeller does its work; so, yes, I do lube that also with pool lube.

Thanks for the recommendation (and vocabulary). :)

I dont't know what that measurement is supposed to show. If the point is that it's not showing 2.5", it's not supposed to. The 2.5" is the inside diameter of the PIPE that the fitting mates with. It's not the inside diameter of the fitting which is going to be a lot larger. The real question is if it fits snuggly when it's put on, which I hope it does.

He cut it flush with the valve because the coupling is going OVER the jandy valve. He doesn't want any pipe left outside the valve. It was either go over it, or get the special tool to bore out the pipe already glued inside the valve.

I don't see why there should be a lot of play in this. If that Jandy valve is designed to work with 2.5" fittings, then a 2.5" fitting should fit over it just like any PVC pipe connection. If it doesn't and there is a lot of play, then glue isn't the answer. You might get away with it, but that joint will not be nearly as strong as it's supposed to be.

There was no 'pipe'.

On the filter Jandy valve, what *looked* like a pipe was really a whole bunch of couplings inserted butt-to-butt with the actual two-inch pipe hiding inside.

On the cleaner Jandy valve, it was just butt-to-butt elbows.

I would have *loved* to have some 2-inch pipe to simply connect a fitting to - but - there were no "pipes" to be found there!

That was the entire problem, in the first place, which had prevented a simple repair, over the years (by me or the previous owner).