DISCHARGING, EVACUATING, CHARGING AND CHECKING — Confirmation of Amount of Charged Refrigerant (Cont'd)
HA-24spec tableConfirmation of Amount of Charged Refrigerant (Cont'd)
Sight-glass and pressure diagnosis vs. amount of charge
Temperature of high and low pressure pipes
AppropriateHigh pressure side is hot while low pressure side is cold.
Refrigerant is insufficientHigh pressure side is warm and low pressure side is somewhat cold.
Almost no refrigerantNo difference is felt between high and low presser sides.
Overcharged, or air in systemHigh pressure side is very hot.
Flow of refrigerant viewed through sight glass
AppropriateMostly transparent. Occasionally some bubbles are seen when engine rpm is increased or decreased.
Refrigerant is insufficientBubbles are always flowing. Refrigerant is cloudy.
Almost no refrigerantNothing is visible.
Overcharged, or air in systemIf overcharged, no bubbles are seen. If there is air in the system, large bubbles are seen.
Pressure
AppropriateNormal high pressure: 1,373 - 1,765 kPa (13.7 - 17.7 bar, 14 - 18 kg/cm², 199 - 256 psi); Normal low pressure: 147 - 294 kPa (1.47 - 2.94 bar, 1.5 - 3 kg/cm², 21 - 43 psi)
Refrigerant is insufficientBoth high and low pressure values are insufficient.
Almost no refrigerantHigh pressure value is very small.
Overcharged, or air in systemBoth high and low pressure values are excessive.
Action to take
AppropriateBubbles may be generated when the liquid tank strainer is clogged, or when the expansion valve is opened excessively.
Refrigerant is insufficientAdd refrigerant after checking for leaks.
Almost no refrigerantCheck the refrigerant system.
Overcharged, or air in systemStop the compressor and extract excessive refrigerant. If air is found, evacuate, then charge the specified amount of refrigerant.
CAUTION
The condition of bubbles seen through the sight glass as well as the intake and discharge pressures are influenced by the ambient temperature, wind velocity, weather, and by the air temperature in front of the condenser, etc.