What does the expansion valve do in an HVAC system?

The expansion valve plays a critical role in an HVAC system by controlling the flow of refrigerant into the evaporator coil. Its primary function is to reduce the pressure of the refrigerant, allowing it to expand and cool before entering the evaporator. This process is essential for effective heat absorption from the surrounding environment.

By modulating the amount of refrigerant that flows into the evaporator coil, the expansion valve ensures that the evaporator operates at optimal efficiency, allowing the refrigerant to absorb as much heat as possible from the indoor air. This, in turn, helps maintain the desired temperature within the space being cooled.

If the expansion valve were to fail or operate incorrectly, it could lead to either too much or too little refrigerant entering the evaporator. This would result in poor system performance, reduced energy efficiency, and potential freeze-ups in the system. Thus, the accurate control of refrigerant flow is vital for the overall operation of the HVAC system.