-On controller you set max. temp of pool sensorB. There is 1 sensorA on the roof and 1 sensorB for the pool.
-If the roof sensorA is more hot then the pool sensorB then the controller will turn on the circulation pump.
-If roof sensorA is colder then pool sensorB then the pump is switched off.
-If the pool sensorB reaches set max. temp of pool sensorB then the pump is also turned off.