What is the correct way to fix this?

My in-laws had a new furnace installed a few years ago. The heating contractor tied the CVPC drain lines for the AC evaporator and the humidifier into the main stack by drilling and tapping a hole into the 3" vertical ABS stack pipe. They then screwed a CPVC fitting into the stack and sealed it with silicone caulking.
Over time, I think the protruding fitting caught toilet paper and waste, eventually building up and then plugging the stack completely. It backed right up to the toilet on the floor above and water started pouring out the furnace humidifier.

They called a licensed plumber who eventually diagnosed the problem, removed the toilet upstairs and snaked the stack. But when they asked him to fix the root of the problem, he declined saying that he does not work on furnace AC and humidifier drain lines. My in-laws (seniors) said that the plumber was very young and seemed flustered by the problem and unsure of himself. Perhaps he felt it was too big a job for him to tackle? Regardless, I just want to get it fixed at a reasonable cost. They are on a fixed income and the plumber charged them $380 for his visit, which I thought was a bit much. To be fair, it was after hours (ie. 7pm) and he was there for 1 1/2 hours.

I am a mechanical engineer and quite handy. It doesn't look that difficult. The stack is rigid at the ceiling, but there already is a rubber coupling at the floor level.



My plan is to cut out a section of the stack where they tapped into it, then glue in a 3" x 1 1/2" sanitary elbow and then try to figure out what fittings I need to get from the female 1 1/2" ABS to the 1/2" CPVC.

Before I go ahead, I was hoping get some input from someone more experienced than myself to make sure that this is the right way to fix it. Your advice and any helpful tips will be gratefully received.

TIA

drain

You are trying to fix the wrong problem. It would be a real stretch of my credulity to believe that the fitting could actually cause a stoppage in a vertical pipe. But, the real problem is that the condensate line should NEVER have been connected to the drain line in the first place. ANY TIME there is limited humidity in the air, meaning the entire winter at least, that trap will dry out and the furnace will "inhale" sewer gas from the drain line and blow it all through the house. The condensate is supposed to be connected to an "regularly used" fixture which already has a trap, such as a clothes washer or laundry sink. REmove the 3/4" fitting and glue a section of a coupling over it.

hj said:

You are trying to fix the wrong problem. It would be a real stretch of my credulity to believe that the fitting could actually cause a stoppage in a vertical pipe. But, the real problem is that the condensate line should NEVER have been connected to the drain line in the first place. ANY TIME there is limited humidity in the air, meaning the entire winter at least, that trap will dry out and the furnace will "inhale" sewer gas from the drain line and blow it all through the house. The condensate is supposed to be connected to an "regularly used" fixture which already has a trap, such as a clothes washer or laundry sink.

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Thank you for your advice. I never even considered the trap drying out.

hj said:

Remove the 3/4" fitting and glue a section of a coupling over it.

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I will lose about 1" of the stack when I cut out the fitting. Can I "bridge the gap" with a 3" ABS coupling, or do I need to cut out a larger section of pipe and glue in another piece of 3" ABS pipe using two couplings?

No, that isn't what he was suggesting. If you remove the piece sticking in there, clean it up as much as you can by scraping off the silicon, then buy a proper repair coupling (same as a 'normal' coupling, but doesn't have a stop in it - i.e., it is smooth on the inside), cut it so that one side is maybe 200-degrees or so. Then, apply a liberal amount of cement to both the area of the pipe around the hole, the inside of the repair coupling, and 'snap' it over the pipe, thus sealing the hole. It needs to be more than 180-degrees, so when you snap it around the pipe, it has some spring tension to hold it in place on its own. Too much of an arc, and you won't be able to snap it over the pipe without breaking it or deforming it enough so it won't snap back, too little, and it'll fall off.

If the condensate outlet isn't high enough, you may need to buy a condensate pump to send it to either some drain (washing machine is a common place), or some other available place.

jadnashua said:

No, that isn't what he was suggesting. If you remove the piece sticking in there, clean it up as much as you can by scraping off the silicon, then buy a proper repair coupling (same as a 'normal' coupling, but doesn't have a stop in it - i.e., it is smooth on the inside), cut it so that one side is maybe 200-degrees or so. Then, apply a liberal amount of cement to both the area of the pipe around the hole, the inside of the repair coupling, and 'snap' it over the pipe, thus sealing the hole. It needs to be more than 180-degrees, so when you snap it around the pipe, it has some spring tension to hold it in place on its own. Too much of an arc, and you won't be able to snap it over the pipe without breaking it or deforming it enough so it won't snap back, too little, and it'll fall off.

If the condensate outlet isn't high enough, you may need to buy a condensate pump to send it to either some drain (washing machine is a common place), or some other available place.

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So your taking a repair coupling and sawing it in half and snapping it onto the pipe? Your kidding right?

Would we kid you? You saw it "more than halfway" longitudinally, so there is a big half and a small half. Throw the small half away and snap the big half over the hole after applying cement to the half and the pipe. I do it all the time to make small repairs in pipes.

Thats not a proper repair. Simple as that. Do what you want tho......

I've done that too, cut a repair coupling nearly in half, apply glue to pipe and the "fitting, and snap it on.
It's Killer!

Thats not a proper solvent weld. I dont care who does it.

Try these for a code approved repair.
http://www.missionrubber.com/Products/BandSealCouplings.php#P


The manufacturer would never approve of that installation method. There are snap around couplings but they interlock.

If a guy tried to repair my pipe like that in my house I'd show him the door. Any settling or pipe movement would expose the bad joint.

jadnashua said:

No, that isn't what he was suggesting. If you remove the piece sticking in there, clean it up as much as you can by scraping off the silicon, then buy a proper repair coupling (same as a 'normal' coupling, but doesn't have a stop in it - i.e., it is smooth on the inside), cut it so that one side is maybe 200-degrees or so. Then, apply a liberal amount of cement to both the area of the pipe around the hole, the inside of the repair coupling, and 'snap' it over the pipe, thus sealing the hole. It needs to be more than 180-degrees, so when you snap it around the pipe, it has some spring tension to hold it in place on its own. Too much of an arc, and you won't be able to snap it over the pipe without breaking it or deforming it enough so it won't snap back, too little, and it'll fall off.

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Thank you for the explanation. I was not familiar with repair couplings, only the regular coupling with the stop in it. Can I slide the repair coupling up and down on the 3" stack pipe and glue anywhere in place, or is the ID of the repair coupling slightly tapered like a regular coupling?

jadnashua said:

If the condensate outlet isn't high enough, you may need to buy a condensate pump to send it to either some drain (washing machine is a common place), or some other available place.

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I have enough elevation to make it to the laundry tub, so I am good there. No need for a condensate pump.

I would start by cutting the pipe above the hole the A.C. "guy" drilled in the stack. Then remove the band coupling at the bottom. Then cut the pipe off about 12" or so and solvent weld on a coupling and piece of pipe long enough to be re-installed with two new banded rubber couplings.

All will be well.

I don't think it is tapered. To use one 'whole', you have to be quite quick. It's used when you can deflect one pipe enough to slide it over one end, realign the pipes, then slide it back. Trick is, you have to do that before the cement makes it impossible to move it...and, you must try to get it centered over the two ends. You've got maybe a 3/4" hole, the coupling is 3" or so, and more than a coupling's length covering the hole. If done right, the pipe is probably stronger than before they put the (improper) hole in it.

Hackney plumbing said:

I would start by cutting the pipe above the hole the A.C. "guy" drilled in the stack. Then remove the band coupling at the bottom. Then cut the pipe off about 12" or so and solvent weld on a coupling and piece of pipe long enough to be re-installed with two new banded rubber couplings.

All will be well.

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Got it. Thank you for your advice.

I do the saw the repair coupling all the time, when the idiot carpenter runs a drywall screw though a drainage pipe. Is it legal though? Ahhhhh, good question and here's the answer that we came up with when I was on the code review board. If the code does not specifically say you can't.......you can. And for those of you that are going to start whining about the "workman like manner" clause, that clause is open to interpretation and is soley dependent on who's idea of what "workman like" looks like. BTW Hackney, if the coupling piece and the pipe are primered and the glue properly applied, the patch is solvent welded.

Certainly this forum is known as the home of the Mike Holmes approach: " DO IT RIGHT". But we also have a practical and especially $$$ side to our approach. Many of us do not cringe when a homeowner...or unwary plumber.....drills a hole into a drain pipe, and patches said hole by inserting a well-sealed sheet metal screw, with the tip snipped off short. Is that strictly according to Hoyle? And the patch with 1/2 of a coupling is a tried and true technique with a failure potential less than the rubber coupling.

Common sense sometimes prevails. AND notice we would NOT suggest any such techniques on a pressurized pipe.

Each to his own.

jimbo said:

Certainly this forum is known as the home of the Mike Holmes approach: " DO IT RIGHT". But we also have a practical and especially $$$ side to our approach. Many of us do not cringe when a homeowner...or unwary plumber.....drills a hole into a drain pipe, and patches said hole by inserting a well-sealed sheet metal screw, with the tip snipped off short. Is that strictly according to Hoyle? And the patch with 1/2 of a coupling is a tried and true technique with a failure potential less than the rubber coupling.

Common sense sometimes prevails. AND notice we would NOT suggest any such techniques on a pressurized pipe.

Each to his own.

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Well said Jimbo. With Liberty and Justice for ALL

remember to wear safety goggles so you don't get an eyeful of solvent
What kind of ABS glue do you use? Mine is so thick that it cllings to the dauber, and would not get in my eyes unless I threw it there.

i'd cut the section out and use a Fernco....

the condensate should still not be a direct connection to any sewer line, run it to floor drain or sump pit.... or creat an indirect connection....

As I said.....its not a proper repair and its funny to watch you guys try and justify it.

Pipe and fittings are to be installed according to the manufacturers directions. Pipe and fitting manufacturers do not consider cutting a coupling and snapping it onto the pipe as proper and I DONT EITHER.

Show me one manufacturer that approves your methods. JUST ONE.

Its not a properly solvent welded connection.

No way its comparable to a banded rubber coupling. Banded couplings are approved by the code......fittings that have been cut in order to snap onto a pipe is not.

Why wouldn't you use it on pressure pipe???? According to some of you its a proper solvent weld.......if its a proper solvent weld then your method should work just fine on potable water.

But like Jimbo said.......to each his own.

How freakin hard is it to cut the pipe and use an approved joining method?????? Thats what I get paid to do and thats whats expected of me.

The split repair coupling has less chance of leaking on a waste or vent pipe then a banded coupling.
It's not rocket science.
It's a rare type of repair though; hardly ever used.