Connecting PVC to brass compression tee?


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Old 09-25-16, 02:39 PM
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Connecting PVC to brass compression tee?

I need to tap into a 3/4" copper water line, using a brass compression tee. The tee has a female side outlet for 3/4 inch threads. I want to run Schedule 40 PVC from the tee to my sprinkler controls.

My question is which method is best for making the transition to PVC:

1. Make the transition with a "PVC male adapter" fitting threaded directly into the brass tee and glue the PVC pipe into that fitting OR

2. Thread a 3/4" CPVC Copper Transition Male Adapter into the brass compression tee and then glue the PVC pipe into the CPVC part of the adapter?

In the first case I'd be threading male plastic threads into the brass female outlet and in the second I'd be threading copper male threads in the brass female outlet. I plan on using Teflon tape in either case, but which would make for the best transition?
 
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Old 09-25-16, 02:47 PM
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Option 2 would be best IMO... Brass to brass is prefered..

Use 1 or two turns of teflon tape and also add teflon dope to the tape.
 
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Old 09-25-16, 06:13 PM
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"Brass to brass is prefered.."

Thanks, it will actually be copper to brass but the principle is the same, right?

As for the Teflon dope you recommended, I just bought a fresh tube of RectorSeal Tplus2 with PTFE. Do you use that along with Teflon tape?
 
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Old 09-25-16, 06:45 PM
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Around here it's common to feed sprinkler lines with PVC fittings. A PVC adapter is normally used for any type of pipe, glue from there.

For water lines, I always use tape plus dope as Lawrosa said. RectorSeal is high quality pipe dope.
Don't overtighten the adapter, snug it up and maybe 1/2 turn with a wrench before checking for leaks.
 
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Old 09-26-16, 11:57 AM
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After doing further research, it appears I will not be able to use the CPVC Copper Transition Male Adapter after all. I wanted to glue PVC pipe to the CPVC part of the Adapter but I hear Schedule 40 PVC and CPVC have different Outside Diameters. So the PVC pipe probably won't slip into the CPVC adapter, even though they're both 3/4"???

Has anyone here had using CPVC fittings on PVC pipe, or vice-versa?
 
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Old 09-26-16, 01:43 PM
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Read here please...

CPVC vs PVC Pipe Comparison and Differences

For cold water no issues IMO. I belive the same glue and primer is used for cpvc as well as PVC
 
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Old 09-26-16, 05:22 PM
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"For cold water no issues IMO. I belive the same glue and primer is used for cpvc as well as PVC"

Agreed. But I'm concerned about the physical dimensions....since PVC is supposedly a little larger, will it physically fit into a CPVC fitting?????
 
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Old 09-26-16, 06:17 PM
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PVC does not fit CPVC fittings. While PVC cement may work the make cement specifically for CPVC.
 
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Old 09-26-16, 07:40 PM
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PVC does not fit CPVC fittings. While PVC cement may work the make cement specifically for CPVC.
AFAIK thought they were the same size...


PVC and CPVC Pipes - Schedule 40 & 80
 
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Old 09-26-16, 11:25 PM
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"PVC does not fit CPVC fittings".

OK, thanks. So my plan for transitioning from the brass compression tee to CPVC and then to PVC won't work. Instead, I'll just thread a PVC male adapter into the brass tee and glue the PVC pipe into the adapter.

I know they make CPVC Copper Transition Male Adapters, which have copper threads on one end and a slip CPVC joint on the other. That's what I had PLANNED to use. But is there such a thing as a PVC Copper Transition Male Adapter that works the same way??? I haven't been able to find such an animal. If it existed I could thread the copper end into the tee and easily transition to PVC from that point.
 
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Old 09-27-16, 12:43 AM
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Mike, using a mixture of PVC for cold and CPVC for the hot side is common here, that's how I re-plumbed my house, so though not a pro I can state for a fact CPVC OD is about the the size of PVC ID size for size comparison.

Edit: From 2002 http://www.doityourself.com/forum/pl...cpvc-pvc.html:
Biggest difference is CPVC is sized using outside diameter (OD). 1/2" is 1/2" on the outside of the pipe, it has about a 3/8" actual inside diameter for water transmission. PVC is sized on inside diameter (ID). 1/2" is about 3/4" in diameter, but 1/2" on the actual pipe as measured on the inside.

Both use solvent welding, but glues are different. Each also has own particular primer.
 
 

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