Open Loop Solar Water Heating System

with PV Panel


Open Loop Systems are suitable for single application domestic hot water (DHW) systems, in mild and moderate climates. One or two tanks can be used in various configurations and they retrofit easily into existing systems. An Open Loop System is for climates where there is no risk of freezing. Recirculation freeze protection can be provided by the Recirculation feature in the controller. At about 42ºF. the pump will turn on for a short time, circulating the water through the loop and preventing freezing. 


NOTE: The information presented in this page is for guidance only - no part of this may be used for any agreement, whether express or implied, or to form any contract. THERMO TECHNOLOGIES reserves the right to change specifications and prices without prior notice.

1. Solar Collector 5. Tempering Valve 9. Circulating Pump
2. Manual Air Valve 6. Collector Return 10. Roma Valve
3. Hot Water to Taps 7.Collector Supply 11. DHW Electric Tank
4.Cold Feed 8. Non Return Valve 12. Immersion Heater
  • City water enters the storage tank at line pressure, filling the collector through the drain fitting and isolation valves.
  • A controller or a PV panel establishes that heat is available from the collector, and turns on the pump.
  • The pump circulates water from the tank to be heated by the collector.
  • When no more heat is available from the collector, the controller turns off the pump.
  • The Recirculation feature in the controller will turn the pump on if the temperature at the collector approaches freezing.
  • The optional freeze protection drip valve will allow water to drip from the system if the temperature approaches freezing, providing protection should there be a power outage.
Contact Thermo Technologies