The pressure balance valve chamber monitors water pressure balance to protect you from scald due to sudden changes of pressure of hot or cold water.
For example, when someone is taking a shower and other people may be using cold water in the kitchen,.Pressure balance valve detects changes in the cold water pressure, it will automatically reduce the hot water pressure, so that the hot/cold water
pressure are kept balanced. In this process, the temperature of the water will change by no more than a few degrees. You can hardly feel temperature change and are kept free from scalding.