4 inch repair coupling - will it slide completely over a pipe?

[Stephen Tashiro]

How is a "repair couping" such as ihttps://www.homedepot.com/p/Charlotte-Pipe-4-in-PVC-DWV-Repair-Coupling-PVC001301200HD/203393309 installed? If a new pipe is being inserted between two old pipes, can the repair coupling slide completely over the new pipe as it is put in place and then side back to overlap an old pipe to join the two?

[Kev Williams]

PVC couplings like the one pictured in the link have a inner 'dam' (I don't know what you call it ;) ) in the center of the coupling, so that the pipe inserted can only go half way into the coupling and no farther, to insure each section of pipe is covered equally by the coupling...

At least the smaller couplers have the 'dam', not totally sure a 4"er does...

[Stephen Tashiro]

PVC couplings like the one pictured in the link have a inner 'dam' (I don't know what you call it ;) ) in the center of the coupling, so that the pipe inserted can only go half way into the coupling and no farther, to insure each section of pipe is covered equally by the coupling...

The (plain) 4 inch couplings do have that dam or ridge in the middle. The "repair" coupling does not. I've examined the repair coupling in the store, but never installed one.

[Paul F Franklin]

True repair couplings have no stop in the middle and are also not tapered as much so they will slide over the pipe completely. But they are tricky to install on PVC because the solvent used to weld the fittings flashes off so fast it's very easy to get the fitting stuck in the wrong place. You can get "slower" PVC solvent that gives you a little more time, but you still have to work fast and only have one shot to get it right. I have also heard that the PVC repair couplings are more prone to leaks. The lack of taper in the fitting means there is less force on the joint during solvent welding so there is a greater chance of a poor solvent weld.

[Tom M King]

You can't hesitate in putting it in place. Stop moving, and that's probably where it's going to be. Use tape to mark where it's supposed to end up, on the second piece. The solvent (glue) will most likely dissolve any pen, or pencil mark.

Don't pressurize it until the next day, and I've never had one to leak. You can't rely on any interference fit for any help because there isn't any.

I wear old work gloves over nitrile gloves (just because that's the only kind of those I keep, and the glue doesn't play well with them). You need to use enough glue to make a mess on bare hands.

edited to add: I forgot to answer your question. Yes, that's the way it works.

[Jerome Stanek]

You could use a fernco coupler

[Ole Anderson]

You could use a fernco coupler Yep that is the answer. I had a long run of 2" from my kitchen sink that got clogged with all sorts of stuff that shouldn't have gone through the garbage disposer. My buddy, a plumber, gave me a Fernco coupling. I just cut the pipe, cleaned it out and installed the Fernco. That was 35 years ago, still working fine. In case you don't know, a Fernco is a rubber coupling with worm gear clamps. They make all sorts of adapters in all sizes.

[Robert Engel]

you could use a fernco coupler

this^^^^^^

[Stephen Tashiro]

You could use a fernco coupler

Yes, I've been using them in replacing a section of 4 inch cast iron sewer line with PVC. The replacement line has too little slope since it had to go between two given points in the old line and the section of the old line had too little slope. If I can figure out how to fix the plumbing in this house, it may involve re-setting the PVC that I just put in. (In the meantime, I want a working bathroom.) So I used Fernco rubber couplings in case I have to take the new line apart. My interest in the plastic repair coupling (so far) is just curiosity.

Which brings up some questions about the rubber couplings.

1. If they are to be buried, is it best to protect the band clamps from getting clogged with dirt by covering them with something? - to help a future plumber who needs to take the clamps off?

2. On the American Valve torque wrench for the band clamps ( https://www.lowes.com/pd/AMERICAN-VALVE-Torque-Wrench/1244081 ) what is the purpose of the metal "wing" that rides along the shaft? ( I haven't figured out how to use this wrench to loosen clamps. Is there a way? According to answers on Amazon, the more expensive wrench made by Rigid can both tighten and losen the clamps.)

[Roger Feeley]

The description in the link says that it's not for use with pressure. Only for drains and vents. +1 on the thing being a nightmare to install with pvc cement. As previously posted, there are 'slower' pvc cements but they are still lightening fast. If I was going to use this thing, I would use a 15 minute epoxy and some sort of clamp to keep it from slipping while the epoxy cured.

But why fight the fight? You can't put it under pressure. Just use a neoprene fitting. Unless... it's going to be behind a wall. If you are putting this fitting where it can't be accessed and replaced, then go with the epoxy.

[Ronald Blue]

The description in the link says that it's not for use with pressure. Only for drains and vents. +1 on the thing being a nightmare to install with pvc cement. As previously posted, there are 'slower' pvc cements but they are still lightening fast. If I was going to use this thing, I would use a 15 minute epoxy and some sort of clamp to keep it from slipping while the epoxy cured.

But why fight the fight? You can't put it under pressure. Just use a neoprene fitting. Unless... it's going to be behind a wall. If you are putting this fitting where it can't be accessed and replaced, then go with the epoxy.

I would be hesitant to use epoxy because that's not doing the same thing that the PVC cement does. PVC cement actually joins the two pieces by a solvent weld which means the two pieces melt together. Even if it's roughed up with an abrasive I would be worried the epoxy it might fail. Even if there is no pressure on the pipe I would be reluctant to deviate from accepted joining methods here. I went to this web site https://www.epoxyworks.com/index.php/gluing-plastic-with-gflex-epoxy/ and while you can join many types of plastic successfully with proper preparation they don't show any PVC drain pipe being joined. Only some small tubing. I'm certain that it would have to be certified by a variety of agencies before it would be approved. Also joining parts in a controlled environment is one thing. But often times plumbing is done in some nasty and unavoidable conditions and I don't think you could achieve consistent reliable results with epoxy. Just my two cents.

[Stephen Tashiro]

Perhaps the purpose of the little "wing" on the torque wrench shaft is to be a primitive handle that lets you use the wrench to untighten the band clamps on Fernco couplers.

On another forum, someone suggested using Denso tape to protect the couplers when they are buried.

[Jason Roehl]

The description in the link says that it's not for use with pressure. Only for drains and vents. +1 on the thing being a nightmare to install with pvc cement. As previously posted, there are 'slower' pvc cements but they are still lightening fast. If I was going to use this thing, I would use a 15 minute epoxy and some sort of clamp to keep it from slipping while the epoxy cured.

But why fight the fight? You can't put it under pressure. Just use a neoprene fitting. Unless... it's going to be behind a wall. If you are putting this fitting where it can't be accessed and replaced, then go with the epoxy.

What home has a 4" PVC line under pressure or used for anything but drain or vent?