Jabsco HD4 40PSI Par-Max Fresh Water Pump The Par-Max fresh water pump by Jabsco features a pressure controlled diaphragm to provide you with a freshwater system that is as easy to use as your homes. The self-priming capability and quick connect ports makes for easy installation and servicing. For on demand operation, this Jabsco model features an integrated sealed pressure switch. This fresh water pump is able to run dry without damage to the unit itself. This model features a heavy duty motor