A TXV is designed to maintain...

A TXV is designed to maintain...

• A. Constant evaporator pressure
• B. Constant evaporator superheat
• C. Constant condenser temperature
• D. Constant discharge pressure

Answer: (B)

A thermostatic expansion valve is designed to keep the refrigerant leaving the evaporator at a constant amount of superheat. Superheat is the temperature rise of the refrigerant vapor above its saturation (boiling) temperature at the evaporator pressure. By sensing the evaporator outlet temperature and adjusting the valve opening, the TXV maintains a set superheat as load and conditions change. This keeps the evaporator producing mostly vapor, protecting the compressor from liquid slugging and ensuring stable, efficient operation. The other options describe goals (constant evaporator pressure, constant condenser temperature, or constant discharge pressure) that are not what a TXV regulates; those are controlled by other parts of the system and operating conditions, not by the TXV.

A thermostatic expansion valve is designed to keep the refrigerant leaving the evaporator at a constant amount of superheat. Superheat is the temperature rise of the refrigerant vapor above its saturation (boiling) temperature at the evaporator pressure. By sensing the evaporator outlet temperature and adjusting the valve opening, the TXV maintains a set superheat as load and conditions change. This keeps the evaporator producing mostly vapor, protecting the compressor from liquid slugging and ensuring stable, efficient operation. The other options describe goals (constant evaporator pressure, constant condenser temperature, or constant discharge pressure) that are not what a TXV regulates; those are controlled by other parts of the system and operating conditions, not by the TXV.