Low hot water pressure in my bath tub faucet. Faucet is a meon roman style side mount. Hot water pressure is fine in the sink faucets. Problem is only in the tub. I have replaced the cartridge with no effect. Pressure is low even without the cartridge installed.

I have a feeling it is not so much a loss in pressure but more of a volume problem as the sinks have a 1/4" opening (seat)and the tub has 1/2" -3/4" opening and here lies the problem.

Many installers use 5/8 OD (1/2" ID) copper tubing and connect a tub spout with a larger opening then the supply pipe can handle so water basically dribbles out.

The problem seems to have just started over the past 12 months. Previously, the pressure was fine.