Coolerguys 12v PWM Fan Thermostat Controller

Independent setpoint & differential

The instructions for this board are equally bad as those for the common board twice its size, but where this one really shines is the independent control of the low setpoint and the differential. With the other option, they are inexplicably tied together, like power windows and air conditioning options on a Japanese car. For my application, I needed a lower setpoint than the minimum (30 C), so I attached a resistive load in parallel with the thermistor to bring down the range. It works great with some PWM-controlled D5 water pumps.