The flow control device used to maintain system temperature is the _____.

The flow control device used to maintain system temperature is the evaporator pressure valve. This device plays a critical role in regulating the pressure within the evaporator, which directly impacts the refrigerant flow and the cooling capability of the system. By maintaining proper pressure levels, the evaporator pressure valve ensures that the system can efficiently absorb heat from the environment, thereby maintaining the desired temperature set point.

In contrast, while expansion valves also regulate refrigerant flow, they primarily control the amount of refrigerant entering the evaporator rather than inherently maintaining system temperature on their own. Condenser outlets are crucial for discharging refrigerant but do not actively control temperature in the same way. Heat exchangers are vital for transferring heat but do not function as flow control devices. Therefore, the evaporator pressure valve is specifically designed to help maintain the optimal operating temperature of refrigerant within the system.