A automatic solar controller operates just like your home air conditioner thermostat. The auto control compares the air temperature near your solar collector panels with the swimming pool water temperature, and activates a motorized valve to divert water to the solar panels whenever the temperature near the panels is warmer than the pool water temperature—and the pool water temperature is less than the desired temperature. The controller closes the motorized diverter valve when the pool water reaches the desired temperature, or whenever the temperature near the solar collector panels is less than the pool water temperature. This feature maximizes the amount of energy collected, keeps the pool from overheating in the summer, and reduces the chance of bacteria growth.

For normal operation set the switch to AUTO and adjust the temperature setting. Your solar auto control activates the motorized diverter valve when it detects a four degree difference between the solar and pool water temperature sensors, and the pool water is below the desired temperature. The motorized valve closes when the temperature difference falls to 1-2 degrees, or the pool water reaches the desired temperature.

If you want to cool your pool, change the pump to run for about eight hours overnight and set the switch to the (top) ON position. This way, the system will simply run in manual mode; i.e., whenever the pool pump is running.