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24-1 8
AIR CONDITIONING
You must have a high heat load to get head pres-
sure within the range of the chart.
When the head pressure is in the chart range, wait
a few minutes. This will allow the pressure to stabi-
lize and the thermometer to register the exact tem-
perature. Then read the discharge pressure and tem-
perature. Consult the chart to see if the temperature
is correct for the discharge pressure reading.
For example, suppose the pressure is 201 PSI. In
the chart, you will see that the minimum temperature
should be 172 degrees and the maximum tempera-
ture is 218 degrees.
If the temperature is in the range, the compressor
and the expansion valve are okay. No further test-
ing is necessary.
If
the temperature is below the minimum, the ex-
pansion valve is flooding the evaporator and the
expansion valve should
be replaced.
If
the temperature is above the maximum, either
the compressor or the expansion valve i s faulty
in
which case the system will have to
be
discharged.
Test the compressor and expansion valve sepa-
rately using Tests 7 and 8 which follow.
A conclusive result from this new test eliminates
the need for a separate compressor and expansion
valve test.
TEST 7
COMPRESSOR CAPACITY TEST
The Over-All Performance Test and the Evaporator
Pressure Regulator Valve Test should be performed
before testing the compressor capacity. These tests
are made with the system fully charged with refrig-
erant. It is necessary to discharge the system before
making the Compressor Capacity Test. It is also nec-
essary to discharge the system in order to perform
the Expansion Valve Test. It is recommended that
tests be made in the order in which they are present-
62x371
v -
Fig. PO-Compressor Test Connections
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