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Check the performance of the air conditioning system
Install manifold with gauges. Increase the engine speed to 2000 min -1 and set the controls for maximum cooling and high fan speed. Open all windows and doors.
| Fig. 9.4. Places setup dry bulb (1) and psychrometer (2) to test the operation of the air conditioning system
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Install a thermometer in a dry cool air outlet channel (Fig. 9.4). Set psychrometer near the entrance of the cooling unit. Check the pressure on the high pressure gauge which should be equal to 1373-1575 kPa. If the pressure is too high, add water to the condenser. If the pressure is too low, close the front part of the condenser. Make sure the temperature showing the dry thermometer inlet air is 25-35 ?� C.
| Fig. 9.5. A plot of the relative humidity on the difference of temperature of dry and wet thermometers at the input
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On the psychrometric chart, determine the relative humidity (in%), compare the wet and dry thermometer in psychrometer inlet for air (Fig. 9.5). Example: temperature of dry and wet thermometer at the inlet of the evaporator are respectively 19,5 and 25 ?� C, the point of intersection of the dashed lines in the graph corresponds to 60%. Measure the dry bulb temperature at the outlet of cold air and calculate the difference between the values of the temperature of dry and wet thermometers at the input. Make sure that the point of intersection of the relative humidity and the temperature difference between the values is within the shaded section of the chart shown in Fig. 9.5. If the intersection point is inside this area, so air conditioning is working properly.
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