Refrigeration and Air Conditioning Control Circuits Quiz

What is the primary difference between low and medium temperature refrigeration systems?

• The type of refrigerant used

• The defrost method

• The compressor capacity

• The size of the evaporator

Answer explanation

The primary difference between low and medium temperature refrigeration systems is the defrost method.

What is the purpose of a defrost time clock in a low temperature refrigeration system?

• To regulate the flow of refrigerant

• To control the compressor operation

• To initiate defrost cycles

• To monitor the evaporator temperature

Answer explanation

The purpose of a defrost time clock in a low temperature refrigeration system is to initiate defrost cycles, making the correct answer 'To initiate defrost cycles'.

Why do low temperature refrigeration systems require active defrost methods?

• To prevent oil return problems

• To reduce energy consumption

• To maintain a constant temperature

• To clear frost and ice buildup on the evaporator

Answer explanation

Low temperature refrigeration systems require active defrost methods to clear frost and ice buildup on the evaporator, ensuring efficient operation.

What is the purpose of a mullion heater in a low temperature refrigeration system?

• To clear frost from the evaporator fins

• To prevent the door gasket from freezing

• To heat the condensate tray

• To maintain the temperature of the drain line

Answer explanation

The purpose of a mullion heater in a low temperature refrigeration system is to prevent the door gasket from freezing.

Why is oil return more pronounced as a problem in low temperature refrigeration systems?

• The compressor capacity

• Due to the type of refrigerant used

• Because of the size of the evaporator

• The low density refrigerant suction vapour

Answer explanation

Oil return is more pronounced in low temperature refrigeration systems due to the low density of refrigerant suction vapour, which makes it harder for the oil to return to the compressor.

What is the purpose of a delay-on-make timer in a refrigeration system?

• To maintain the temperature of the drain line

• To prevent two compressors from starting at the same time

• To prevent the compressor from starting too soon after shutting off

• To initiate defrost cycles

Answer explanation

The purpose of a delay-on-make timer in a refrigeration system is to prevent two compressors from starting at the same time.

What is the function of a pressure control in a refrigeration system?

• To prevent oil return problems

• To control the defrost cycle

• To maintain the temperature of the drain line

• To regulate the flow of refrigerant

Answer explanation

The function of a pressure control in a refrigeration system is to regulate the flow of refrigerant, ensuring proper operation and efficiency.

What is the purpose of a constant cut in thermostat in a refrigeration system?

• To initiate defrost cycles

• To maintain a constant temperature

• To prevent oil return problems

• To regulate the flow of refrigerant

Answer explanation

The purpose of a constant cut in thermostat in a refrigeration system is to maintain a constant temperature.

What is the function of a relay in a refrigeration system?

• To control the defrost cycle

• To start, stop, or regulate the flow of electricity in a second electrical circuit

• To prevent oil return problems

• To regulate the flow of refrigerant

Answer explanation

The function of a relay in a refrigeration system is to start, stop, or regulate the flow of electricity in a second electrical circuit.

What is the purpose of a solenoid valve in a refrigeration system?

• To maintain a constant temperature

• To regulate the flow of refrigerant

• To prevent oil return problems

• To initiate defrost cycles

Answer explanation

The purpose of a solenoid valve in a refrigeration system is to regulate the flow of refrigerant, making it the correct choice.