Any PVC experts?

[run53]

I'm looking for a way to add antifreeze to my Polaris return line.

If I look at the terminating fitting on the return (see pic below) it looks like it might be threaded. I tried unthreading it to no avail, but not too hard as I didn't want to break anything.

If you look closely, you can see a cap that is definitely threaded into the end and it is cemented in ( I can see the purple primer) so no way that is unthreading. The connection I am asking about is the one I circled in red on the picture.

Can any of you PVC experts tell if that is a threaded fitting to the tee? If so I will try harder to unthread as that would be a perfect place to add the anti-freeze.

 

[Bama Rambler]

That piece isn't threaded. It's a glued joint. The plug in the end of it is threaded, but you stated that it's cemented in so there's no way to get it out.

 

[run53]

OK, thanks. I'm glad I didn't try to force it then.

I think the best option for me then is to add a threaded tee on the pipe going down to the ground. If I do that would it be better to cut below the coupling or cut just above the coupling and remove that coupling? Or does it even make a difference (sorry PVC newbie here).

 

[jblizzle]

Well, the Tee will not likely fit above the coupling, but it is also not quite large enough to just replace the coupling. So likely the easiest is to just put the Tee completely below the coupling leaving 3" or so of pipe between them.

 

[n8henry]

The part circled in your picture has a piece at the very end. It has about a 1 inch square part that sticks out. Is the piece with the square part glued? That should be what unthreads.[attachment=0:308jyzgk]cleanout plug.jpg[/attachment:308jyzgk]

 

[duraleigh]

+1 what n8henry just posted. That plug should not be glued. Is that where you see the purple primer?

 

[run53]

+1 what n8henry just posted. That plug should not be glued. Is that where you see the purple primer?

Yes, it certainly looks like it should be threaded there and I didn't expect it to be glued but there is something there and I was afraid to try too hard to unthread it. Actually, I wouldn't call it purple primer on that plug. It's more like light blueish gunk (not sure what else to call it). I assumed the blue was primer, but maybe not. Maybe some kind of lubricant? When I get home, I will take a closeup of that plug and post it here.

 

[jblizzle]

Could just be pipe dope to help it seal. Can you feel if it is like paste or is it hard?

 

[run53]

Could just be pipe dope to help it seal. Can you feel if it is like paste or is it hard?

I'll bet that's what it is. I'm not home now, but I looked at a youtube video of a guy putting pipe dope on an iron thread and the color looked exactly like that (light blue)

Like I mentioned, I did try to loosen the plug but didn't want to over do it in fear of breaking the tee. Perhaps I can lightly tap my wrench with a hammer to see if I can loosen it up.

 

[hoosierrun]

I wonder if you could pour hot water over it while you apply torque from a wrench to the square plug? You would need to wear gloves if the water is too hot. I'm not sure what the heat limit is on that PVC pipe? It might be rated for 150 degrees or more (experts answer that please), but the idea would be to soften that pipe sealant by warming it and perhaps create a little expansion on the outer pipe.

 

[run53]

I wonder if you could pour hot water over it while you apply torque from a wrench to the square plug? You would need to wear gloves if the water is too hot. I'm not sure what the heat limit is on that PVC pipe? It might be rated for 150 degrees or more (experts answer that please), but the idea would be to soften that pipe sealant by warming it and perhaps create a little expansion on the outer pipe.

Good idea. I also read that applying a hair dryer might help too. My biggest concern is ruining the existing tee so I will proceed with caution. Although, since the pool is closed for the season, I will have plenty of time to re-plumb if I really mess it up

 

[duraleigh]

I see no other visible primer on your other glued joints so I doubt that blue stuff is primer. You never know what folks will do but pipe dope (which is easy to unscrew) is all that should've been used.

Use a pipe wrench to hold the pipe securely when you attempt to unscrew the cap......it'll keep you from putting unnecessary force on your other joints.

There should be no need to heat the pipe but sched 40 is usually rated at 200 psi @ 170 degress, I think.

 

[run53]

I see no other visible primer on your other glued joints so I doubt that blue stuff is primer. You never know what folks will do but pipe dope (which is easy to unscrew) is all that should've been used.

Use a pipe wrench to hold the pipe securely when you attempt to unscrew the cap......it'll keep you from putting unnecessary force on your other joints.

There should be no need to heat the pipe but sched 40 is usually rated at 200 psi @ 170 degress, I think.

After all the feedback here, I agree, it's probably just pipe dope. The pipe wrench is a great suggestion for keeping the rest of the joints safe while I try to unscrew.

I will try this as soon as I get home from work and let you folks know.

 

[run53]

well...you guys were all correct!!

With a little persuasion, the plug twisted right off. It was pipe dope and Teflon taped.

So, I started filling the line with anti-freeze. The line is around 45 feet or 1.5" pvc. So I expected to be able to fill it up with approx 4 gallons of anti-freeze. However I noticed that the return was full at about 2 gallons and it started coming back out at me. I was a little concerned thinking there was a lot of water left in the line. But then I went back out about a half hour later and was able to add more without overflowing. Not sure I understand why this is so. I only added a little because it was getting dark and couldn't see things too well. I will try to add some more in the morning. Not that I need that much in there, but I was getting concerned that my job of blowing out the lines was not that great.

Is there any explanation as to why waiting would allow me to put more anti-freeze into the line. Some kind of air lock or something?

 

[toofast]

Silly question, did you blow out the lines first (assuming it needs blown out) ? Or just add AF mixing with the water in the line.

 

[run53]

Silly question, did you blow out the lines first (assuming it needs blown out) ? Or just add AF mixing with the water in the line.

I used a mighty vac to blow out all the lines. I let each line bubble for several minutes before capping them with a threaded cap.

 

[toofast]

Silly question, did you blow out the lines first (assuming it needs blown out) ? Or just add AF mixing with the water in the line.

I used a mighty vac to blow out all the lines. I let each line bubble for several minutes before capping them with a threaded cap.

Oops....sorry if I missed that above....

Could be am air pocket...it burped and more AF went in...

 

[danjaymor]

There should be no need to heat the pipe but sched 40 is usually rated at 200 psi @ 170 degress, I think.

Hi, guys! First time poster, but have been reading the site for over a month now, great stuff!

As a PVC pipe manufacturer, I wanted to clarify on pressure vs. temp ratings. 2" Sch 40 is rated at about 220 psi @ 73 degrees, which is the standard temperature threshold that various types of PVC pipe carry their pressure rating at.

It is very important to note that pressure ratings are de-rated at higher temperatures, by a factor of about 10-15% for every 10 degree climb in water temperature. Maximum recommended operating temperature for standard PVC pipe is 140 degrees F. At that temperature that 2" sch 40 is about 40 psi rated pipe. Please note that I am talking about standard PVC which is what is most common and what is used in pool plumbing and construction, not CPVC pipe (-Chlorinated- Poly Vinyl Chloride) which is formulated and designed for hot water use in some indoor plumbing.

 

[danjaymor]

With a little persuasion, the plug twisted right off. It was pipe dope and Teflon taped.

I also wanted to add, that when you reinstall the plug just use the pipe dope and skip the Teflon tape. We don't recommend that tape be used on plastic threaded fittings as overuse of the tape can add too much material to the threads and act as a splitting maul when tightened. Pipe dope only is recommended, it works better and being viscous fills and "travels" within any voids much better......

 

[run53]

With a little persuasion, the plug twisted right off. It was pipe dope and Teflon taped.

I also wanted to add, that when you reinstall the plug just use the pipe dope and skip the Teflon tape. We don't recommend that tape be used on plastic threaded fittings as overuse of the tape can add too much material to the threads and act as a splitting maul when tightened. Pipe dope only is recommended, it works better and being viscous fills and "travels" within any voids much better......

Welcome to the forum!

Thanks for the suggestions. Does this also apply to the threaded return plugs I use when closing the pool? The reason I ask is that just about every pool closing how-to I've read says to put 3 winds of teflon on the threaded plug.