Heat Pump Defrost Thermostat Sensor DFT Testing!

In this HVAC Heat Pump Defrost Video, I go over the pivotal role that the DFT Defrost Limit Sensor has in making sure that defrost cycle happens so that the Heat Pump doesn't freeze solid in wintertime. I go over how to read the model number, what the letters and numbers mean in the model number, what the resistance values should be at certain temperatures, why the limit sensor doesn't open until it gets to the appropriate temp, and why it does not close until it gets down to the right temp. These are shown and discussed for a deeper understanding of how a heat pump and defrost board works in order to troubleshoot problems when they arise.