When I run the tub water it is very hot. when I turn the shower on the water is warm, the faucet is all the way to the hot.
Try searching 'adjust anti-scald shower valve', lots of info/videos are available. I believe it's a plumbing code requirement for this kind of safety feature.
If the anti-scald setting is at "highest" and you have a single valve shower tap, the balancing valve inside the tap is defective, they can be replaced usually. check the temp setting as mentioned in previous post 1st, usually the issue 90% of the time and easy to adjust.
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