In my bathtub, I have a Moen product with 1 handle which you rotate clockwise to close and anti-clock wise to open water from cold to hot. When you turn the water on and move the handle from cold towards hot, the water stops flowing. Cold water comes fine, but no hot water flows out, it just stops.

IF you have hot water in the kitchen/Lavatories then It seems like you have blockage inside your faucet on the hot side, shut off water to the tub faucet, remove the cartridge, turn on water for a few seconds to flush out any debris from the faucet, inspect the O rings on the Cartridge, clean lubricate the O ring with plumber grease, install the cartridge and see if it is fixed, if not fixed you can call Moen and at 1-800-882-0116 and they will send you new cartridge for free, open the links below the first one will show the parts and the second one will show how to remove and install a cartridge, Thanks.

John

http://www.moen.com/shared/pdf/L82691pt.pdf

Installation Help / Animated Tutorial - Installing the Moen 1225 / 1200 Cartridge

I agree with everything John said except "The Plumbers Grease". On the "O" rings.
Never use petroleum products on neoprene. It will rot the "O" rings.
Moen recommends Silicon Jel and even includes a small packet with every cartridgee. Good luck, Tom