How Does the Heat Pump Defrost Cycle Work? | HVAC Training скачать в хорошем качестве

How Does the Heat Pump Defrost Cycle Work? | HVAC Training

Ever wondered how the defrost cycle on a heat pump works? When you open a heat pump system and see two circuit boards, one of them is the defrost control board. In heating mode, especially on cold days, frost can build up on the outdoor coil. If that frost becomes too thick, it can block airflow, meaning the system can’t absorb heat properly. That’s when the defrost cycle kicks in—melting the frost so your heat pump can breathe and keep running efficiently. In this video, I’ll break down: What the defrost board does When and why the defrost cycle starts How the defrost cycle keeps your heat pump performing in cold weather Timecodes: 1:00 - How the defrost cycle works 2:38 - Defrost temperature switch (open on rise, close on fall switch) 9:45 - Condenser fan switch is normally close and opens on defrost mode 13:55 - Other parts of the defrost board 19:44 - 24 volts (Y) takes a path that eventually leads to the contactor coil 24:50 - How to check if pressures switches are close 28:10 - FORCING defrost mode 32:00 - Testing a thermistor 35:55 - Recap #hvac #hvacr #defrost #heatpump #airconditioner #frost #troubleshooting #thermistor