Spring pressure and _____ pressure are part of the automatic expansion valve?

The correct answer relates to the components of the automatic expansion valve. In an HVAC system, the automatic expansion valve (AEV) is designed to regulate the flow of refrigerant into the evaporator. It operates based on the pressure in the evaporator, which is crucial for maintaining the desired temperature and efficiency of the cooling system.

Spring pressure is used alongside the pressure in the evaporator to control the valve's opening and closing mechanism. This allows the AEV to maintain a constant evaporator pressure, ensuring optimal performance. The dynamic relationship between spring pressure and evaporator pressure is essential for regulating the refrigerant flow, which ultimately helps in achieving stable cooling performance.

Other options do not fit this context. Bulb pressure would refer to the sensing element typically used in thermostatic expansion valves, rather than automatic ones. Condenser pressure relates more to the heat rejection side of the system, while compressor pressure pertains to the pressurized refrigerant output from the compressor, both of which do not directly interact with the AEV's operational mechanism. Thus, the emphasis on evaporator pressure is what solidifies it as the correct choice in this scenario.