What the best way to connect Cu plumbing to a PVC supply line.
Pipe is 3/4 inch.
Ive fixed this a couple of time and had it professionally done but the screw
together joint made of a threaded male PVC adapter and CU male threaded
adapter eventually leaks. I am thinking I have an expansion issue here and
I am going to try to make an expansion jiont using a loop of flexible copper
to connect the two.
Any other opinions are welcome and appreciated.
A real plumbing store might have Fernco fittings that size.
If its CPVC, then these things are the nuts.
Some of the Borg stores carry them.
If it is PVC & I were in your shoes I'd be tempted to look for a PVC
to CPVC adapter- then use the CPVC fittings.
I've used "Male" PVC adapters threaded into "Female" metal adapters (brass,
copper, galv, etc.), with a little teflon tape, and they've always held up
well for me. Just don't use "Female" plastic adapters (PVC, CPVC, etc.).
They tend to crack open along the seam.
In any case, my preference is to use the adapters that have a rubber gasket
in the middle. Kind of like a union, with a brass piece on one side and a
CPVC piece on the other. I've seen these with threaded brass or sweated
copper fittings on the metal side, but don't know if I've seen a plain PVC
version or not.
I have a few feet of Teflon chemical transfer hose (unused). Im going to put
barbs on the PVC and Cu and connect them together with the hose. I know this
will make a good connection and if there is a problem with expansion and
contraction it will take care of that too.
Barbs the Ribbed piece you slide a hose over and clamp it.
They have them in HD for Cu and PVC.
Sharkbite doesnt work with regular old PVC. At least thats my understanding.
I really like the chemical transfer hose. Its a little pricey at over $5.00
a ft the last I bought but its great for repairs and last forever. I still
have a few ft left so it's spent money
I just wanted to clarify what you meant and make sure you weren't
doing something wacky.
Actually, they do work with PVC. Why their specs list only CPVC, I
don't know, but as long as the PVC conforms to CTS there's not a
problem. If you're a by-the-book guy, you could use all purpose
primer and cement to glue on a coupling and piece of CPVC to
transition so you could use a Sharkbite. I'm not saying you should,
but you could.
Well, the stuff you have on hand is 'free', but you still have to buy
and install the barbed fittings you mentioned and you'll have four
potential leakage points instead of two.
It's weird how this one joint has been such a problem over the years.
Even if there's a fair amount of expansion going on, repairing one
joint five times is highly unusual.
Yes very weird. I think its because the actual cause of the problem has
never been addressed. I have no direct proof that this is an
expansion/contraction problem but its the only thing I can think of that is
The PVC comes up through a concrete slab from the well, then transistions to
Cu then on to 2 (hot and cold) whole house filters.
I think its because there is just no wiggle room in the pipe and its pulling
loose at the weakest point.
Also to use the Sharkbite I would have to cut off a few inches of PVC and Cu
and then add pipe back on to at least one of them to be able to clean things
up enough to use the sharkbite. With the hose all I need to do is cut back
far enough to get a place I can glue/solder on the barbs
I dont know how you figure I will have 4 leakage points. Ive never had a PVC
glued joint or sweated Cu joint that I made leak on me in my life. I wish I
could say the same for the combination of the two.
One thing I have learned about threading metal in to PVC is to run a tap
into the PVC and use pipe dope instead of PTFE tape.
Don't make it complicated. All you need is a PVC adapter with a male thread
and a copper adapter with a female thread. Threading a copper male fitting
into a PVC female adapter is likely to either split the PVC female adapter
or to leak and is not permitted by some codes/inspectors. Tape or sealer can
reduce the possibility of leaking.
Even simpler for us shameless DIY-ers is to use a rubber coupling that
has a mechanical pipe-clamp at each end and doesn't care if the pipe is
copper or plastic. This works for the big pipes, too, for the black
Don, that what I got now and eventually it leaks. I think its due to
expansion and contraction pulling and pushing on the PVC/Cu joint.
The house wasw built in 74 and I know it has started leaking at least 5 time
since 1990. My wife says it been a regular problem since the house was
built. Its in a utility room and doesnt leak bad enough to cause any damage
as long as you can monitor it.
Well, I got down to Fl this week and fixed the plumbing using my hose
The water had been off all winter and the plumbing was at room temp which
Friday was about 85F.
After the repair I checked the distance between the hose clamps on each end
of the hose then turned on the water.
After leting the water run for a few minutes I checked the distance again
and the clamps had moved apart by almost an 1/8 of an inch.
This is making me feel very warm and fuzzy that my diagnosis was right.
Even if I was dead wrong about why I dont think I will ever have another
problem with this connection
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