How does a reversing valve function in heat pump systems?

A reversing valve is a critical component in heat pump systems, as it is specifically designed to control the direction of refrigerant flow within the system. By doing so, the reversing valve enables the heat pump to switch between heating and cooling modes.

In heating mode, the valve directs refrigerant to absorb heat from the outside air and deliver that heat indoors. Conversely, in cooling mode, the reversing valve alters the flow so that the refrigerant removes heat from the indoor air and expels it outside. This switch is essential for the heat pump to function effectively in both seasons, making the reversing valve a pivotal part of the system's operation.

The other options do not accurately describe the function of a reversing valve. Increasing system pressure is typically handled by the compressor, filtering particulates is the job of air filters, and measuring the temperature of refrigerant would require a separate temperature sensor, not the reversing valve itself. Thus, the correct understanding of the reversing valve’s role is key to grasping how heat pumps operate.