Refrigeration

Question 1

With reference to refrigeration systems, State the indications of Air in the System

Answer 1

• Small Bubbles in Sight Glass
• High Discharge Pressure
• Compressor Overheating
• Increased Running Time
• Condenser Pressure Gauge Reading High

Question 2

With reference to refrigeration systems, State the indications of Undercharge of Refrigeration Gas

Answer 2

• Large Bubbles in Sight Glass
• Low Discharge Pressure
• Low Suction Pressure
• Increase in Fridge Temperatures
• Increased Running Time
• Low Ammeter Reading

Question 3

State the condition of the refrigerant between each component

Answer 3

Compressor –> Condenser = High Pressure Gas
Condenser –> Expansion V/V = High Pressure Liquid
Expansion V/V –> Evaporator = Low Pressure Liquid
Evaporator –> Compressor = Low Pressure Gas

Question 4

Describe how air is removed from the Refrigeration System

Answer 4

1), Close condenser outlet to trap refrigerant in the system.
2), With circulating water on (to cool the system), Charge the System so that the condenser or reviser can fill.
3), Air, being lighter will collect at the top of the condenser or receiver.
4), Release the trapped air by carefully opening the purge valve at the highest point.

Question 5

Describe how and where refrigerant gas is added to the system

Answer 5

1), Weigh the Cylinder
2), Connect the cylinder to the charging v/v located on the suction side of the compressor with the charging hose.
3), Purge the air from the charging hose.
4), Open the charging v/v to allow for refrigerant to flow.
5), Monitor Pressure and System Performance.
6), Close the Charging v/v
7), Verify System Operation
8), Disconnect the Refrigerant Cylinder.