Pentair 36–43 MFD Start Capacitor (U18 1399) manifolds 5 kW flo thru heater 5 kW flo thru heater is designed for compatible ACC style applications using a 12 inch by 2 inch 230 volt generic format The Praher top and side mount 5 spoke gasket in the 9 5 8 inch outside diameter size is intended for compatible valve assemblies that require a properly matched sealing component to maintain dependable performance 36–43 MFD rating for matching motor startup requirements The Pentair 36–43 MFD Start Capacitor (U18 1399) is a replacement electrical component used to help provide the startup boost required by compatible pool and spa pump motors