Pictured below is another of our solar water heating pump controller variations. Again based on our 2013 solar water heating pump controller with relay, this controller is modified to use digital waterproof temperature sensors (ds18b20), and also to have a user programmable temperature limit.
This controller is designed to be used with solar heated hot tubs and jacuzzis. As the volume of water in a hot tub is relatively small (compared to swimming pools for example) it is possible for the water in the tub to become unpleasantly or even dangerously hot after an extended period of sunshine.
This controller has been modified to have a user programmable maximum temperature. When the temperature of the water in the hot tub reaches this maximum, the pump will turn off and stay off until the hot tub temperature has dropped by at least 2 degrees Celcius.
Programming the maximum temperature is simply the matter of holding the button to enter programming mode at start up, then pressing it X times where 20 + 2*X is the desired maximum. For example, 8 presses for a 36 degree Celcius maximum.
If you need a solar water heating pump controller for a domestic system, swimming pool, or hot tub, with or without an LCD display, email firstname.lastname@example.org with details of your exact requirements.