Can't Get Old PVC to Seal to Old PVC

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Old 01-16-17, 08:11 AM
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Can't Get Old PVC to Seal to Old PVC

I am replacing my water softener. It is connected using 3/4 inch PVC pipe. Twice when I have connected it where I try to connect one new pvc fitting to an old pvc pipe I can't get it to seal completely. All my other connections seal good.

I am using two products by Oatey:

1) Clear cleaner for ABS, CPCV, and PVC. Here: Clear Cleaner | Plastic Pipe Cements & Primers | Oatey

2) Medium clear PVC cement. Here: PVC Medium Clear Cement | Plastic Pipe Cements & Primers | Oatey

The old pipe is roughly 20 years old.

What am I doing wrong and what do I have to do to get a connection that seals on the third time?

Thanks for your help with this.
 
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Old 01-16-17, 09:03 AM
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One guess would be that what you are calling your old pvc, is actually cpvc.

The older Genova cpvc (yellowish color) was slightly smaller than todays pvc fittings and I know that in the past I have had a heck of a time getting fittings that fit correctly when doing old work. I'm not a plumber, so maybe wait for their replies. But I would be willing to guess that's the problem.

Hopefully you aren't putting water pressure to it until your glue has set up. See average set times.
 
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Old 01-16-17, 09:27 AM
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XSleeper. I wondered that myself earlier today. The old pipe definitely has a yellowish tinge when compared to the new white PVC pipe. However on the side it is labeled PVC. How is CPVC labeled?

The second time I waited 10 hours before applying water to it.
 
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Old 01-16-17, 09:46 AM
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The pipe is smaller than 1" isn't it. I only ask because 1" and above most of the fittings are non pressure made for drains. You have to be careful to buy pressure fittings. They have a deeper socket.
 
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Old 01-16-17, 10:59 AM
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I used CPVC upstream of my Acid Neutralizer Filter because my water is extremely acidic. I thought most of it for residential use looks like this and has that clear yellow stripe on it I know mine does. It should say CPVC on the pipe. ( see second pic down)

What is the average life expectancy of CPVC pipe?
 
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Old 01-16-17, 11:12 AM
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Ray2047: My pipe size is 3/4 inch.

zoesdad: Thanks. That picture helps. The two differences I notice are:

1) While my pipe is more yellow than new PVC on mine I don't see the yellow stripe that your picture shows.

2) On my pipe it says PVC whereas your picture reads CPVC.
 
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Old 01-16-17, 11:47 AM
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Bob-

Looks like yours is PVC then and not CPVC. I’m no expert but the only thing I can think of is like XSleeper mentioned: if not enough time is given for dry time I think the joint can fail.

I haven’t done that much with either PVC or CPVC but I think it can get a little tricky trying to figure out whether the fitting is seating properly or not. I think the pipe should go pretty far into the fitting but it may not go all the way to the stop when it’s dry.

But when you put the solvent on and twist and push- the pipe then can reach the stop. I think that is correct – but I am not 100% sure. If I remember correctly I think some of the time I couldn’t get the pipe to go all the way to the stop – but the pipes seemed to hold together. I don’t know whether a plumber would approve of that – but I think that’s what happened to me.

Is there any way you have the wrong size fittings? Probably not – I guess that would be very noticeable.
 
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Old 01-16-17, 01:51 PM
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Dry fit the pipe should only go about 2/3 of the way to the bottom of the fitting.

Try using some relatively fine sandpaper on the pipe and wiping the dust off with a clean rag before using the primer. Slather on a good coat of the cement before the primer fully evaporates.

Push the pipe and fitting together turning about 90 degrees and then hold the pipe and fitting tightly together for at least 30 seconds (longer in cooler temperatures) or the cement may push the two apart before it sets.
 
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Old 01-17-17, 12:30 PM
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Thanks

I want to say thanks to everyone who helped with this.

I redid the connection the third time. Here is what I did different from the second time:

- Sanded the old pipe then cleaned it with a wet cloth
- Waited 2 hours between gluing each connection.

I again left it dry 10 hours before applying water.

The connections to the main plumbing now work! No leaks.
 
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Old 01-17-17, 02:44 PM
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Good job! Thanks for letting us know. It may help someone else.
 
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