Refrigeration CYCLE - TM-5-4120-386-140016

TM 5-4120-386-14

1 - 9 . Refrigeration CYCLE - Continued.

(4) The dehydrator (6) removes any moisture (water vapor) or dirt that may be

carried by the liquid refrigerant,

(5) The solenoid valve (7) is controlled by the temperature selector on the control

panel. This valve. will shut off the flow of refrigerant to the evaporator section

when the temperature in the conditioned area reaches the set point.

(6) The expansion valve (8) senses the temperature and pressure of the refrigerant

as it leaves the evaporator coil. By use of the feeler bulb in the bulb well (10) and

"external equalizer line" the valve constantly adjusts the flow of liquid refrigerant

to the evaporator coil (9).

(7) As the high pressure liquid refrigerant leaves the expansion valve (8), it enters

the evaporator coil (9). As the liquid enters the coil, due to the size difference

between the coil and the tubing, the pressure is suddenly decreased. As the

pressure decreases, the liquid refrigerant "flashes" to a gas. The evaporator

blower circulates the warm air from the conditioned space over and through the

evaporator coil (9). Liquid refrigerant absorbs heat when it changes from a liquid

to a gas. As the air from the conditioned spaces comes in contact with the

evaporator coil (9), the air is cooled.

(8) To prevent compressor damage during start-up, solenoid valve (16) is normally

open to equalize pressure on both sides of the compressor.

b. Bypass System. This unit has a bypass system which allows cooling operation at low

cooling loads without cycling the compressor on and off. In bypass, the refrigerant flow is

from the discharge to the suction of the compressor, bypassing the evaporator coil (9).

(1) When the temperature selector on the control panel senses that cooling

conditions have reached the set point, it. closes the solenoid valve (7) to shut off

refrigerant flow to the evaporator coil (9).

(2) As the compressor suction pressure starts to drop, the pressure regulator (11)

opens to allow flow of hot gas from the compressor.

(3) The quench valve (17) senses the temperate of the gas at the suction side of

the compressor. To prevent excessively hot gas from reaching the compressor,

the quench valve (17) opens to allow liquid refrigerant to mix with the hot gas.

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