PVC Repair

Zman

I am working on a project where we are trying to locate a leak within a circulation pipe on a commercial hot tub. The leak is underground in a 3" Sch 80 PVC pipe. The pipe is in an area where it is running parallel with many other pipes that are so close together that cutting the pipe and coupling it back together would be very difficult. We have unearthed a section of pipe where the leak detection company thought it was leaking but there is no leak at that location.

I would very much like to drill a 1 1/4" hole in the pipe and insert a camera but am not confident that the hole can be repaired.

I am considering the idea of slicing a repair coupling the longways and cementing it over the hole using stainless hose clamps to secure it. My quick math says I can achieve ~2" of overlap around the hole. This idea seems similar to the various saddle connections commonly used on the water pipes. The max water temp in the pipe is ~110 degrees and the pipe at that location should not see more than 2-3 PSI.

Has anyone made repairs like this? Is it crazy to attempt?

TIA

Carl

pecmsg

https://www.pvcfittingsonline.com/fittings/schedule-80-pvc/saddles.html?matchtype=&network=x&device=m&adposition=&keyword=&gad_source=1&gclid=Cj0KCQiAyeWrBhDDARIsAGP1mWQtdp1dBR02SNC-Os7dn7c5HLdNDZvBOXpxxBEz_be0QMaYEQvNK3YaAl1oEALw_wcB

hot_rod

Got enough room for a PVC dresser coupling?

Zman

@pecmsg That product is the basis for what I am considering. I am not sure I have room for more than a hose clamp on the bottom side so I am wondering I can use something like 1/2 of that product without the TEE?

Zman

hot_rod said:

Got enough room for a PVC dresser coupling?

Unfortunately, No...

pecmsg

Zman said:

@pecmsg That product is the basis for what I am considering. I am not sure I have room for more than a hose clamp on the bottom side so I am wondering I can use something like 1/2 of that product without the TEE?

Large hose clamps

ChrisJ

Is there enough room to clean and plastic weld the crack / hole?

Zman

ChrisJ said:

Is there enough room to clean and plastic weld the crack / hole?

I am much more skilled with primer and cement than plastic welding . Would you propose welding the coupler as a patch? Do you think the weld would be significantly better than the split coupler and hose clamps?

mattmia2

Tap it and screw an npt plug in it.

mattmia2

It is schedule 80 but how much pressure is it actually?

Matt_67

Did exactly what you are thinking once, it held a 5 psi test and lasted until we could make a permanent repair later. I don't know how long it would have lasted.

Zman

mattmia2 said:

It is schedule 80 but how much pressure is it actually?

Very little pressure, <3PSI

Zman

mattmia2 said:

Tap it and screw an npt plug in it.

I have done that with 1/2" hole. I think that the pipe curvature will be an issue with a tapered plug that big...

HomerJSmith

I'm cheap! Did I tell you I'm cheap. This is how I would do it. I would take a piece of pipe that is long enough to cover the hole you want to drill in the pipe plus several inches on each side of the hole. I would cut the piece of pipe the same size as the pipe you want to repair length wise in half.
I would heat the the half piece of pipe and heat it with a heat gun and form it around a piece of pipe that is the size of pipe you want to patch. The heated patch should fit tightly around the pipe that you want to cover. Prime and glue the half patch onto the pipe with a hole in it and band it, if you wish, with stainless steel bands. Walla! An be sure and give it a tail light warranty. joke

I have done this before and never had a complaint, of course, all complaints are handled by my office in Budapest.
I think someone may have had this idea. hmmm

mattmia2

Zman said:

mattmia2 said:

Tap it and screw an npt plug in it.

I have done that with 1/2" hole. I think that the pipe curvature will be an issue with a tapered plug that big...

I think it will work as long as the plug is tall enough because of the way pvc kind of deforms and seals on itself.

ChrisJ

Zman said:

ChrisJ said:

Is there enough room to clean and plastic weld the crack / hole?

I am much more skilled with primer and cement than plastic welding . Would you propose welding the coupler as a patch? Do you think the weld would be significantly better than the split coupler and hose clamps?

I was talking about actually welding whatever's leaking closed rather than trying to cut the pipe etc.
Also welding the hole from the camera closed.

I'd consider plastic welding PVC to be as strong as new undamaged pipe. When done correctly.

mattmia2

You could probably get a slip coupling and cut it in half and solvent weld it over the hole you drill for the camera.

Which is probably what you mean by repair coupling. I thought fernco when i read that.

pecmsg

When I have to drill and tap PVC use the hub of a fitting. Twice the thickness to tap!

HomerJSmith

You could probably get a slip coupling and cut it in half

Slip couplings are tapered.
I have a plastic welder that I got from Harbor Freight and I bought the welding sticks on Amazon, which in your case is PVC. Not difficult to do with a little practice.

realliveplumber

pecmsg said:

When I have to drill and tap PVC use the hub of a fitting. Twice the thickness to tap!

That is a great idea. We have to install a flow meter for a swimming pool. I would have drilled and tapped the pipe.