1.  Solar Sensor
2.  Isolation Valve - Ball Valve (Optional)
3.  Isolation Valve - Check Valve (Optional)
4.  3-Way Valve
5.  Controller
6.  Water Sensor
7.  Check Valve
8.  Filter *
9.  Pump *
10. Heater By-Pass Ball Valve *
11. Auxiliary Heater *
12. Straps
13. Vacuum Relief Valve