Air Conditioning and Heating R-12 All Caterpillar Machines – Refrigerant Expansion Valve System



Illustration 1 g00358258

Refrigerant Flow Through Air Conditioning System

(1) Compressor

(2) Condenser Coil

(3) Receiver-Dryer

(4) Expansion Valve

(5) External Equalizer Line

(6) Evaporator Coil

(A) Air conditioner refrigerant as a high pressure, high temperature vapor

(B) Air conditioner refrigerant as a high pressure, high temperature liquid

(C) Air conditioner refrigerant as a low pressure and low temperature liquid

(D) Air conditioner refrigerant as a low pressure and low temperature vapor

The air conditioner refrigerant begins to flow in the air conditioning system at the air conditioning compressor (1). The primary purpose of the compressor (1) is changing the air conditioner refrigerant from a vapor that has low pressure into a vapor that has high pressure. Also, the compressor (1) changes the air conditioner refrigerant to a vapor with high temperature. An increase in the pressure from the compressor (1) causes the increase in the temperature of the refrigerant. The refrigerant is sent through condenser coil (2). In condenser coil (2), heat is transferred from the refrigerant to the ambient air. This changes the air conditioner refrigerant to a high temperature and high pressure liquid.

From the condenser coil (2), the refrigerant moves to the receiver-dryer (3). In the receiver-dryer, moisture is removed from the refrigerant. The air conditioner refrigerant moves from the receiver-dryer (3) to the expansion valve (4). In the expansion valve, the air conditioner refrigerant is changed from a high pressure and high temperature liquid. The refrigerant expands in the evaporator coil (6). The refrigerant becomes a low pressure and low temperature liquid. When the refrigerant expands in the evaporator coil, the refrigerant absorbs heat from the cab. This changes the refrigerant to a low pressure and low temperature vapor. The refrigerant returns to the compressor (1) as a low pressure and low temperature vapor. This marks the end of the cycle. The cycle is repeated continuously.

Note: Frost can be used as an indication of blockage in the air conditioning system.

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