Whats Inside :

1. Control Panel
2. Over Heat Stat
3. Automatic Air Vent
4. Heating Elements
5. Copper Heat Exchanger
6. Printed Circuit Board
7. Voltage Free Control  Connections
8. Circulation Pump
9. Flow & Return Sensors
10. Flow Switch
11. Pressure Guage
12. Expansion Vessel
13. Heating Flow
14. Heating Return
15. Pressure Relieve Valve
16. White Metal Enclosure