I recently had copper pipes installed and a new tub/shower fixture with scald gaurd, volume control and seperate temperature control. When I decrease the volume, the water temp significantly lowers, and when I increase the volume, the temp rises. I don't think the volume conrol should affect the water temp. I called the company, and they said that that the water temp will lower when volume decreases...thay said that is a safety feature. That doesn't make any sense to me. Why pay a lot more for volume control, only to freeze when you decrease the volume, and fry when you increase it. They say there is nothing wrong. Should the volume control affect water temp???