I suspect that I have a have a shower valve problem.

When I turn on the shower in the master bath I get full volume of water when the shower handle is turned for cold water. When I turn the handle for hot water the volume of water decrease substantially and the water is warm never hot. I do get good hot water from other bathroom and kitchen sinks.

Am I looking at a shower valve that is incorrectly seated or am I looking at a bigger problem.

Thanks,

Boyd