We recently had to replace our hot water heater. After everything was hooked back-up the water pressure in the bathtup faucet was hardly there. The warmer you turn the water the less water pressure there is. This only happens with the tub faucet and not the bathroom sinks or kitchen. :confused: Anybody help!!

By disturbing the pipes you have dislodged minerals built up in the pipe walls and now it's blocking the hot water inlet ports of the tubs faucet.
Shut the water off and open up the faucet. Check and clean the inlet ports. Now, while the valve's open turn on the water to flush out the supply line. There should be a strong stream coming out of the open valve body. If there is then button it back up. Good luck, Tom