Low Hot Water Pressure In Shower And Tub. That moving part is probably calcified or you have debris inside the cartridge preventing it from balancing h c water mixture as it should. If there is try the hot water heater valve.
Water storage tanks use gravity to deliver water. If a tank is positioned lower than your house it could be the main culprit here. That moving part is probably calcified or you have debris inside the cartridge preventing it from balancing h c water mixture as it should.
But if the water pressure is low only in your shower you can remove elevation from the list of suspects.
If you re having a problem with only the hot water pressure in your shower this can only be because of a few very specific things. Depending on brand of the faucet the this device could be a small ball or rod moving from left to right to balance pressure and h c water demand. If a tank is positioned lower than your house it could be the main culprit here. Low water pressure on a bathtub can make showering unpleasant.