Pex to pipe thread transition

[BillHoughton]

The water heater in my 2007 Itasca Navion has brass check valves in and out, with 1/2" pipe thread. The plumbing is mainly PEX, and the PEX seals to the check valves with a conical plastic gasket, held in place by a nut that threads on. There's no need to put pipe tape on the check valve threads, is there?

[BillHoughton]

Thanks to both of you. I was pretty darned sure I didn't need to tape it; you've reassured me.

And the fittings in question are accessible, if that's the word, through either an access hatch that's 9" by 9" or the base of the closet (removing the floor) that's not much wider, but far enough down that only one arm reaches. So I'm not going to be changing the fittings out for anything else, just replacing the conical gaskets. Removing and replacing the check valves called for 1/2" drive tools, and all the fancy stuff I'd collected over the years: universal joint drives to let me angle the foot-long extension, so I could apply the heavy duty ratchet - and so on. There's no reason that I can see for Winnebago not to have made the access hatch larger...grumble, grumble, mumble, mumble.

[time2roll]

Tape or dope goes on tapered pipe threads only. If there is a gasket or flare, no tape or dope.

[enblethen]

No need for pipe tape if the nut is loose on pipe. Don't care for that type of connection. Nice to have swivel type connector.