I just installed a heat pump for our pool, and it is about 15 feet away from the equipment pad, plus about 3 feet higher than the pump (the only reasonable location for it). Usually, a check valve is required on the outlet of the heat pump to prevent high concentrations of chlorine from backing up into the heater after the pump turns off. However, considering the distance and height, plus the fact that I have a SWG chlorinator, it seems like the check valve is not needed in my particular situation. I left it off, but can easily install it if I need to. Any thoughts from the experts?