What happens to an expansion valve if it receives no pressure from the capillary tube?

When an expansion valve receives no pressure from the capillary tube, it will close. The capillary tube is responsible for transmitting the low-side pressure signal to the expansion valve, which allows it to modulate the flow of refrigerant based on the demand from the evaporator. If there is no pressure, the sensing mechanism within the expansion valve fails to receive the necessary feedback. As a result, the valve responds by closing to prevent further flow of refrigerant into the evaporator. This reaction helps to safeguard the system from potential problems like flooding the evaporator or inefficient cooling, making it crucial for maintaining proper refrigerant flow and optimal performance of the air conditioning system.