I redid both bathrooms in the house with brand new Moen-Adler faucets all the way around and a new water heater and did not change up the copper in the walls at all really, just the connectors to the new faucets..
Anyway, when I turn on the shower upstairs to hot I just get luke warm water, but if I turn on the tub and sink at the same time the shower gets hot like it should. For this reason I did not think it was a matter of adjusting the posi-temp in the faucet and that didn't help anyway.
Is this indicitive of anything familiar to any pros out there?
If the lines weren't flushed after the HWH replacement, you may have solder and some other foreign matter clogging the shower valve's hot side. That would throw the pressure out of whack, too. (Maybe.)
Could also be the hot water limit setting on the valve is set way too low.