Is this a new shower mixing valve that was recently installed?

Remove the handle, pull up on the retainer clip to remove it, pull straight out on the cartridge, rotate 180 degrees (the cartridge that is), put cartridge back in, put in retaining clip, put handle on, should work ok.

Oh, turn the water off to the house first.

Bob

Yes, the bathroom was fairly recently remodelled, before I bought the house.

OK, so Hot is now Hot, however it seems to have much lower (approx 50%)pressure than the cold side.

The pressure on the cold side of the mixer seems fine and the hot (as well as cold) water at the sink is fine.

Could I STILL not have this right???

is the valve a moentroll or a posi temp?

Moentrol

Remove the cartidge and flush the lines by turning on the water to the house (with cart out) re-install cartridge. erik

Remove and rotate the catridge 180 degrees. Re-install and that should solve your problem