I have a Suncruiser 38J that has weak shower pressure. I took the check valve out of the hot water tank inlet. That worked as long as I used the water pump but then the variable speed water pump quit. I replaced it with a cheaper version because I read the new ones have a plastic disk that breaks and Shurflo is going to use a aluminum disk. So I'm waiting till they upgrade hopefully this winter. Does the water heater outlet have a check valve? Also the only way I get hot water is to put the water valve by pass heater position. If I put the valve in normal operation I don't get hot water. I know it sounds strange but that's how I have to set the valve.