Is a transition fitting needed to join PVC to CPVC of the same nominal size?

I've seen this question asked, and answered in various ways, on other forums, often by people who appear to be guessing/speculating.

I note that they do sell such fittings:
PVC & CPVC Adapter, 3/4" # 51577 by Genova Products (http://plumbing.hardwarestore.com/52-333-cpvc-adaptors/pvc-and-cpvc-adapter-101512.aspx)

Some folks claim that a transition fitting is necessary because the pipes have different outside diameters. Others claim no transition is needed.

Certainly, you would need to use universal glue.

Someone suggested using threaded fittings to join them, and gluing the threads. My local hardware store guy (who doesn't have the transition fittings) said that would work. That's what I tentatively plan to do.

This is a cold water application BTW. I'm putting a PVC strainer inline in a CPVC system.

Thanks.

For $1.69 why argue?

If I could hand someone $1.69 and walk away with what I need, I'd do that.

Sadly, that's not an option.

I can pay around $12.00 to order 2 adapters with P&H, wait for them to arrive and hope that they are indeed what I ordered.

The strainer itself took me a month, and various follow-ups with the vendor, to obtain.

I'd like to avoid that.

I asked ahead of time, and the vendor said they would include the adapters for cpvc. They didn't, and now they're telling me I don't need them.

At first glance, PVC and CPVC pipe look the same, but they aren't. Although they are both a type of plastic plumbing pipe, they vary in composition and outside diameter. For this reason, you cannot simply join the two types of plastic with a coupling. You can, however, solvent-weld a special fitting designed to compensate for the diameter difference. When solvent-welding PVC to CPVC, you'll need a primer and adhesive that will soften both types of pipe.


Good luck Tom

What city and state are you in, John?

What city and state are you in, John?

I'm in the western Maryland suburbs of DC.

I think I'm going to go with solvent-welding the threaded fittings (I bought them yesterday) to make the transition and see if that works.

If it fails at some point, it will be easy enough to repair/replace with the transition fittings.

The strainer is on a tank/gravity fed system at my cabin in WV. If it fails, the worst that will happen is I'm out 50 gal of water and the dishes may not get done on my next trip.

A related question... I plan to invert the Y-strainer so that the cleanout points up. That way I can drain the system for the winter without having to dismantle the stainer (to avoid residual water pooling and freezing). I figure that should really work just as well as a downward orientation, since it's fed by pressure rather than gravity. Someone tell me if I'm wrong...