I have recently replaced my hot water tank, i had opened the tub/shower valve in order to release pressure in tank with water supply to tank turned off only, noticed that by turning off water supply to tank only that shower control valve would not let any water run at all cold water as well I then installed new tank then turned water sully to tank on with shower control valve on both hot and cold equally until all air was bled from system i noticed at that time hot side of water pressure greatly diminished and has not improved in 2 days, i have also taken apart tub/shower valve to inspect for debry and there wasn't any blockage. i guess my question is, is there a way to re-set the equalization in valve? what is the sequence

Plumbing - American Standard