ESCO Air Conditioning Practice Exam

What is the purpose of an evaporator pressure regulating valve?

1. To prevent compressor flooding

2. To prevent evaporator pressure from falling below a set limit

3. To increase condensing pressure

4. To minimize superheat

The correct answer is: To prevent compressor flooding

An evaporator pressure regulating valve is used to prevent the compressor from flooding with liquid refrigerant. This is important because if the compressor is flooded, it can cause damage and decrease its efficiency. Option B may seem like a correct answer, but it is not the main purpose of the valve. The valve is not used to increase the condensing pressure, which is the pressure of the refrigerant leaving the condenser. Lastly, it is not used to minimize superheat, which is the temperature difference between the refrigerant and its boiling point. The main purpose of the evaporator pressure regulating valve is to protect the compressor from being flooded.