PVC pipe joints

[LCHIEN]

Yeah this was a fun weekend.
A/C drain started leaking onto the 2nd floor ceiling and the supply side of the sprinkler system had a leak.

We noticed a continuously damp spot around the ground where two control valves for the sprinker came up.

I did a lot of digging which was not easy because the house was 4 inches away on one side, the sidewalk 4 inches away on the adjoining side and shrubs real close by on the other two sides. 15 years of roots (some 1/2" diameter) made digging an alternate cutters and spade operation.

When I finally got to the bottom there was a "T" joint with a tiny crack spraying a micro jet of water 15" into the now exposed air.
I turned off the water supply (whoever installed the sprinkler tied it in right after the water meter with no valve. I went into the house and heard drip, drip... from upstairs. I could not imagine how cutting off the water would cause such a leak and sure enough it was an independent A/C drain overflow leaking thru the ceiling. Just a coincidence.

Anyway, I had to take out a complex EL/Tee/EL thing and replace it, using in-line connectors to replace the two vertical runs I cut to remove it..
I made the final joint with a compression fitting because I could not make the joint there. I reapplied pressure.

Well here's my question. (Finally). I allowed the PVC glue to set for a couple of three hours but since the supply side was in common with the house water inlet I had to reapply pressure to get water back into the house (wife was getting antsy w/o water AND A/C for three hours). I noticed that the PVC glue said to allow it to set for 24-48 hours before applying pressure!

Well I only used 1/10th of that and it seems to be holding. I guess that 24-48 hours is really conservative? Anybody ever had a PVC joint come apart applying pressure too soon?

And here's a bonus question - are PVC pipes really supposed to last for the lifetime of the house? Doesn't seem like it to me.

[JR]

It only takes a few minutes for PVC cement to set up. It actually causes the PVC to sort of melt together, making a really tight bond. That's why it's important to apply cement to both mating pieces.

I don't know about the bonus question, though. I've seen PVC coming from the meter for some time now. I'd have thought it was risky, but what do I know.

Oh, BTW, I don't envy you those repairs. That sprinkler installation was definitely done by a dumba$$, as are many of them. Mine's got seven valves down inside a concrete well, all jumbled up on one another. Every repair is an adventure.

You should be ok on the "glue-up" part of the thing.

JR

[TheChadNC]

As long as you used primer and primed the connections you should have no problems. Even without primer I have pressurized connections within an hour after gluing. The main thing is to make sure the piece is braced so that the pipe can not move to allow it to blow apart.

[lkazista]

PVC joints set up in like 10 seconds. If you primed both sides, and glued both sides, and gave it 2 hours to set up, you will have NO problems.

Did you install a shut off for the sprinkler while you were there?

I have plumber friend who says that properly installed copper will still last longer than PVC, but PVC should last like 50+ years on supplies, and much loner on drains.

Lee

[just4funsies]

The only time you need more than a few minutes is when you use a retarded-set glue, or the weather is extremely cold. Cleaning and priming to remove the factory glaze (from BOTH pipe and fittings) is always a good thing. Modern PVC piping is going to last a LONG time if installed properly. BAD things are sharp rocks, tree roots, and excess glue running down the inside or outside of the pipe. I am more concerned that you used a compression fitting on the upstream (constantly-pressurized) side of the valve. Although often the only way to work in tight spaces, these things are problematic, especially on old pipe, and will almost invariably leak after the passage of time. It doesn't help that the rubber compression rings will break down or become brittle with acid soils or temperature extremes. That will certainly be the weak link in your piping, so don't forget where you put it.

[JimD]

I see no cause for concern. I have often applied pressure within less than an hour and never had a leak. I also think you need a shutoff. My landscaper actually put on the shutoff for both the sprinklers and the house - he got there first. The sprinkler shutoff worked fine but the house shutoff leaked a little and had to be fixed.

My sorry sprinkler story is a valve that blows fuses but cannot be found. I followed the pipes from the heads that do not work but still couldn't find the valve. Fortunately that area of the yard has not dried out too bad. Still need to find the valve.

Jim

[Pappy]

Alternative to compression fittings is called a Shark Fitting. Glued to a piece of PVC and the other side slips in. A ring of 'teeth' inside the fitting grips the pipe. There is a ring on the fitting that can be depressed to release the fitting if the need arises.

[DaveStL]

The only time you need more than a few minutes is when you use a retarded-set glue, or the weather is extremely cold.

Too late now, but when you need a fast set-up, use the blue glue-- it's "hotter". I saw pool guys using Christie's, and have since used it myself. Downside is it doesn't seem to keep as long.

[LCHIEN]

...

I am more concerned that you used a compression fitting on the upstream (constantly-pressurized) side of the valve. Although often the only way to work in tight spaces, these things are problematic, especially on old pipe, and will almost invariably leak after the passage of time. It doesn't help that the rubber compression rings will break down or become brittle with acid soils or temperature extremes. That will certainly be the weak link in your piping, so don't forget where you put it.

Hmmm, haven't buried it yet. Maybe I should remove the compression fitting and try to glue it. Neither piece has much freedom of movement forwards and backwards (if any) and neither can be twisted to make that good seal. That's one reason I used the compression fitting. That and the fact it was half under water.

[just4funsies]

Yeah, Loring, I know it's tough going in tight and wet spaces. Sometimes, it's better to take out a whole assembly and re-plumb, even though costlier and more time consuming, in order to get all the joints right, but it will last longer, provided you can do a good joint, get the insertions straight and bottomed out. Been in the sprinkler biz 33 years, though, and never saw a compression fitting hold up for long under less than ideal conditions in a pressurized line. Water finds a way out.

There are a couple of products out there that may help. Both are widely marketed under the trade name "Quik-Fix". One is a 2-piece clamshell type coupling that is glued OVER a pipe break. It snaps around the joint. I have found that these work OK for repairing a hole in an existing pipe, but are less desirable in making a joint between two pieces of pipe. The other "Quik-Fix" is a telescoping fitting that is glued at both ends, and incorporates an integral double-o-ring slip joint in the middle. One end is glued in place while the fitting is at its shortest, and then the other end is glued in place as the fitting is "stretched". The advantage this fitting has over conventional compression-type fittings is that the o-ring seals are factory assemblies, made on fresh surfaces, rather than on old pipe surfaces in the bottom of a hole. The o-rings seem to be less susceptible to deterioration from age and environment than the more familiar compression types. The down side is that you must be able to make a gap of about 8" (depending on diameter) between your two pipe ends to have room to put this fitting in, and you need to keep the fitting stabilized against any angular offset (both initial and eventual) for the o-ring joint to remain leak-free.

You'll also be better off, no matter how "hot" your glue is, if you don't glue wet surfaces. Dig the hole deeper if you have to, so that the water settles below the joints you're trying to make. It's extra work, but the results will be more permanent. Good luck!

[LCHIEN]

thanks, J4F. I especially appreciate your staying up 'til 03:51 to reply to my message!

[JimD]

I agree you cannot effectively glue wet pieces.

I've had to repair a couple of spots in our sprinklers and I just cut out the piece, dug up a foot or more of pipe on both sides and then I lifted the pipe to slip in the union to make the repair (after putting glue on everything). If you cannot get some pipe dug up to pry up, something like a compression fitting might be your only way to go. I watched my landscaper make a repair by digging up pipe like this and prying the repair into position (that was the only repair he did, the cable company was paying for that one). I get a bit tense doing things this way but so far its always worked.

Jim