ESCO LIGHT COMMERCIAL
REFRIGERATION EXAM STUDY GUIDE 2026
COMPREHENSIVE QUESTIONS AND
SOLUTIONS
◉ What is the normal operating position for compressor service
valve?
Answer: Front seated
◉ What type of oil is used with HFC refrigerant?
Answer: Polyol ester.
◉ When a compressor service valve is back seated, which port is
closed?
Answer: Service port.
◉ The suction accumulator prevents flood back from which of the
following:
Answer: Flooding after hot gas termination.
◉ On an expansion valve refrigeration system, a low pressure
control can indirectly be used for:
, Answer: Controlling box temperature
◉ What valve is used to prevent evaporator pressure from falling
below a set limit?
Answer: Evaporator pressure regulator (EPR)
◉ What valve is used to connect multiple evaporators of different
temperatures to a single compressor?
Answer: Evaporator pressure regulator (EPR)
◉ What valve is used to control excessive pressure entering the
compressor during a hot pull down?
Answer: Crankcase pressure regulator (CPR)
◉ The oil return orifice inside a suction line accumulator is designed
to:
Answer: Meter liquid refrigerant and oil at an acceptable rate.
◉ Why do suction line filter dryers have two service ports?
Answer: To enable checking pressure drop across the dryer.
◉ Head pressure control valves permit hot gas to travel directly to:
Answer: Condenser
REFRIGERATION EXAM STUDY GUIDE 2026
COMPREHENSIVE QUESTIONS AND
SOLUTIONS
◉ What is the normal operating position for compressor service
valve?
Answer: Front seated
◉ What type of oil is used with HFC refrigerant?
Answer: Polyol ester.
◉ When a compressor service valve is back seated, which port is
closed?
Answer: Service port.
◉ The suction accumulator prevents flood back from which of the
following:
Answer: Flooding after hot gas termination.
◉ On an expansion valve refrigeration system, a low pressure
control can indirectly be used for:
, Answer: Controlling box temperature
◉ What valve is used to prevent evaporator pressure from falling
below a set limit?
Answer: Evaporator pressure regulator (EPR)
◉ What valve is used to connect multiple evaporators of different
temperatures to a single compressor?
Answer: Evaporator pressure regulator (EPR)
◉ What valve is used to control excessive pressure entering the
compressor during a hot pull down?
Answer: Crankcase pressure regulator (CPR)
◉ The oil return orifice inside a suction line accumulator is designed
to:
Answer: Meter liquid refrigerant and oil at an acceptable rate.
◉ Why do suction line filter dryers have two service ports?
Answer: To enable checking pressure drop across the dryer.
◉ Head pressure control valves permit hot gas to travel directly to:
Answer: Condenser
