ESCO Air Conditioning Practice Exam

What effect does a rise in evaporator pressure have on an automatic expansion valve?

1. Causes it to close

2. Causes it to open

3. Increases liquid refrigerant storage

4. Reduces flash gas

The correct answer is: Causes it to close

A rise in evaporator pressure causes the automatic expansion valve to close. This is because the automatic expansion valve is designed to regulate the flow of refrigerant into the evaporator coil based on the pressure in the evaporator. When the evaporator pressure rises, it signals the automatic expansion valve to restrict the flow of refrigerant in order to maintain the desired pressure and temperature in the evaporator coil. This helps to ensure efficient operation of the cooling system. The other options are incorrect: -B: A rise in evaporator pressure does not cause the automatic expansion valve to open. -C: Increasing liquid refrigerant storage is not a direct effect of a rise in evaporator pressure. -D: A rise in evaporator pressure does not reduce flash gas.