We have a rain barrel water collection system for our coop. It includes a paddle heater in the barrel itself and a circulating pump for the water bar. We have been using a HEATIT thermostat control for the pump that is supposed to turn the pump on when the temperature falls to 38 degrees but have noticed that it wasn't working with the recent drop in temperature this past week. This is the second one that has stopped working for us. Does anyone have any idea why or if there is any way to fix them?