Performance Test of A/C System

Performance Test of A/C System
After finishing all repairs, make sure to carry out performance test of air conditioning system as follows.

Procedure
1. Connect high and low side charging hoses of manifold gauge set to hose fittings of compressor.
2. Run up engine, and keep compressor speed at 2000 rpm.
3. Operate air conditioning, and set blower switch at "HI", temperature lever at "COOL".
4. Keep all windows and doors open
5. Insert at dry bulb thermometer (1) in cool air outlet, and place psychrometer (2) (dry and wet bulb thermometer) close to inlet of cooling unit.
6. The high pressure gauge reading should be within specified pressure range.

High pressure gauge reading
1470 - 1160 kPa (15.0 - 18.0 kg/sq.cm, 213 - 256 psi)

NOTE: If the gauge indicates too high, pour water on condenser or if it is too low, cover front surface of condenser.




7. The dry bulb thermometer at air inlet should be within 25 to 35 °C (77 to 95 °F).
Under above conditions, operate air conditioning system until a stabilized condition on high and low pressure gauges and thermometers has been established.

How to Read the Standard Performance Curve
1. Read psychrometer reading at the inlet, and get relative humidity from psychrometric chart. (See figure HOW TO READ RELATIVE HUMIDITY (°F) or HOW TO READ RELATIVE HUMIDITY (°C).)




2. Measure dry bulb temperature at cool air outlet, then find out the difference between inlet and outlet temperatures.




3. Check the relative humidity-to-temperature difference relationship using the graph.
As an example of 17 °C (62.6 °F) temperature difference and 60% relative humidity shown in it, if their crossing point falls within the area between two lines, cooling performance then is satisfactory and proper.