Threaded PVC supply line to copper, and hammer arrestor question

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Deathtofishy

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Hello,

I have a duplex that currently has two 1" PVC lines coming from the meter, reduced down to a 3/4" female thread that is connected with a union to the 3/4" copper main lines in the units. (see photos).

One of the supply's has a small leak at the union that I'm planning on addressing. I'm wondering if the union is necessary? or if I can just go from the female PVC to a copper male thread with T plus 2 thread sealant.

I feel like the union is just another point of potential failure and doesn't add much benefit?

At the same time, I'm also planning on replacing the gate valves with ball valves.

It also looks like they put on air chambers for hammer arrestors above? unless these were just stub outs for potential future additions? Seems like a odd location as I thought hammer arrestors were suppose to be near each fixture?

If they are air chambers, I'm assuming I should replace them with actual hammer arrestors. The units currently don't exhibit any water hammer that I am aware of.

Thanks in advance
 

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Reach4

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I have a duplex that currently has two 1" PVC lines coming from the meter, reduced down to a 3/4" female thread that is connected with a union to the 3/4" copper main lines in the units. (see photos).

One of the supply's has a small leak at the union that I'm planning on addressing. I'm wondering if the union is necessary? or if I can just go from the female PVC to a copper male thread with T plus 2 thread sealant.

Female plastic threads are normally a bad idea, unless they are schedule 120 or better. Given that your threads are in a reducer, that might help. I am not sure I would want to touch that interface. I am not a plumber. Maybe somebody with experience can tell you how to handle this without breaking anything.

Where is the meter? If close, maybe replace the pipe from there. Maybe you are fine.

My T plus 2 was not as liquid as I would want for a union. Megaloc and Blue Monster have had some good comments.

A little pipe dope on the mating surface of the union, plus something lubricating the threads, may stop that leak. Silicone grease makes a good lube, and dish detergent is not bad for that either. Lube lets you tighten better with the same amount of wrench torque. Don't stress the plastic. You must use two wrenches on the unions, and make sure to minimize forces on the plastic.

It also looks like they put on air chambers for hammer arrestors above? unless these were just stub outs for potential future additions? Seems like a odd location as I thought hammer arrestors were suppose to be near each fixture?

If they are air chambers, I'm assuming I should replace them with actual hammer arrestors. The units currently don't exhibit any water hammer that I am aware of.
That is the easy one: they are not water hammer arrestors, but rather are for potential future use.

If you have not water hammer, I would not bother adding any except perhaps at the dishwasher and clothes washer.
 
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Deathtofishy

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Meter is FAR... probably 70 feet, and those lines are coming in the bottom of the basement so around 6ft under ground. Definitely do not want to run new lines.

I will stick with the union if that makes the most sense... However, I'm not 100% positive it is leaking at the bottom of the union, or the female to male thread of the PVC before it (possibly both). Current setup looks like they just used Teflon tape, and I've always had much better joints with a dope, like T plus 2.

Leak is extremely minimal, mostly just see some water on the PVC threads, and has been that way for the year that I have owned the property. Residence is currently vacant, thus prompting me to try and deal with it now.

Good to know on the stub outs. One less thing to deal with.
 

Reach4

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Leak is extremely minimal, mostly just see some water on the PVC threads, and has been that way for the year that I have owned the property. Residence is currently vacant, thus prompting me to try and deal with it now.
Maybe loosen the union, and try to give the threads another 1/4 or 1/8 turn. Use two good wrenches. I like my 15 inch Milwaukee adjustable wrench 48-22-7414. Opens to about 1-5/8 (45 mm).
 

Jeff H Young

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You're in a bit of a tough spot. Generally I never ever use a female threaded fitting , the bushing looks like its not in all the way? They probably screwed the nipples in before stabbing the bushing in the 90 and it had expanded
I would remove and replace the valves eliminate the plastic threaded caps and start over down to the PVC (would not go beyond the female bushings).
Ideally I would get the PVC out of the building completely .
 

Deathtofishy

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Yeah that was my thought originally. Just remove everything down to the PVC and go threaded copper to the female PVC, then just to a ball valve. Just wasn't sure on the pipe thread sealant though... Only downfall is I can't tighten it if it starts leaking.

Going to try it in the morning, figure I can use a SharkBite cap while testing for leaks before I solder up the valve and pipe to the rest of the house.

I also saw these transition fittings.

https://www.zoro.com/zoro-select-34-mip-cpvc-transition-adapter-164-304nl/i/G5362594/

Only pain with this is it is a slip fitting. I'd have to cut off the two 45's and put a slip elbow... definitely not looking forward to the idea of cutting those PVC pipes. Age is unknown, and not a lot of room for error if they crack and I need to try to go further back into the stemwall.
 

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Deathtofishy

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Just a follow up for any future readers. In doing a bit more research, I got some great info from irrigation websites where mating copper to PVC in a irrigation system is much more common.

Using a male copper threaded fitting to a female PVC fitting is much more likely to cause issues as the copper doesn't compress like PVC
when threading into the fitting. Which can cause leaks, and worse, fractures in the female fitting that can break later down the road.

Ideally you would want either a male threaded PVC to female threaded metal, a compression fitting, or Sharkbite makes a specific PVC to CTS adapter.

Because of this, I put in a male threaded PVC to slip on the current female fitting, then used the specific adapter from Sharkbite as it was locally available.

While I have some reservations on sharkbite fittings, in this scenario, the fitting will always be visible/accessible, and it is located in a basement with a floor drain. I took the proper precautions in deburring and reaming both the copper and PVC prior to installing the fitting.

Everything went together great and I have not had an issue.
 

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Breplum

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Nice. Thanks for the update.
I have a used those Sharkbite PVC adapters and have used them successfully many times.
For the record (not you OP), do not bury Sharkbites in soil.
 
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