Can I connect PEX to these?

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MCTMike

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I'm in a tub to shower conversion, and here the incoming water lines. I'm thinking of running PEX to the new mixing valve. Can I get to PEX from here without needing to cut into the copper? Some kind of adapter?

PXL_20220107_232042660.jpgPXL_20220107_232157803.jpg
 
You could but shouldn’t.

You could unscrew those tub unions off the male pipe threads and use a female pex adapter in its place.

That’s not good because you would be leaving those stop valves buried in the wall. Those need to be removed.
 
Looks like you had an old Price Pfister valve with integral stop valves that you’re removing.
 
Got it. So to get to PEX, I'd need to sweat a new PEX adapter directly into the copper. Do you think I can just heat the stops with MAPP gas and twist them off? Or will I need to cut into the bendy lines below them?
 
Got it. So to get to PEX, I'd need to sweat a new PEX adapter directly into the copper. Do you think I can just heat the stops with MAPP gas and twist them off? Or will I need to cut into the bendy lines below them?

You could heat them up and remove them.

Or you could make the transition down lower where it would be accessible from the tub access hole.
 
Yep. Cutting lower is probably what I'm going to do. There's a kink just below the existing stop on the hot line. So I'll drop down to where the copper is straightest and sweat in a PEX adapter.

What size of PEX hose is standard for showers?
 
I would cut the copper off down where it's clean and straight and use a couple of Shark bite type push connectors to connect the pex.
 
Yep. Cutting lower is probably what I'm going to do. There's a kink just below the existing stop on the hot line. So I'll drop down to where the copper is straightest and sweat in a PEX adapter.

What size of PEX hose is standard for showers?
Depends on how energy efficient you want to be. Runing 3/8 for what water, lets you get the hot water there in roughly half the time (9/16th, actually), and thus waste less heated water.

I‘d replace as much of he copper as possible with PEX. And even though code allows the burning of sharkbite fittings, I still don’t like to see them buried. If they are installed correctly they probably won’t leak. If you don’t do them right the o-ring gets damaged, and then they almost certainly leak. If you go with the sharkbite fittings get their chamfer tool, and install them exactly like the directions say to. They have manufacturers videos on YouTube on how to do them right.
 
That looks like soft copper to me. That’s a no go according to sharkbite with their pushfit fittings.
 
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