Carrier DHMSHAQ09XA1 Service Manual page 19

DIAGNOSIS AND SOLUTION (CONT)
Fig. 23 – Test the DC Voltage
Use a multimeter to test the DC voltage between L2 port and S port of the outdoor unit. The red pin of the multimeter connects with the L2
port while the black pin is for the S port. When air conditioner is running normal, the voltage moves alternately between −50V to 50V. If the
outdoor unit has a malfunction, the voltage will move alternately with positive value. If the indoor unit has malfunction, the voltage will have
a certain value.
Fig. 24 – Test the Reactor Resistance
Use a multimeter to test the resistance of the reactor which does not connect with the capacitor. The normal value should be around zero (0)
ohm. Otherwise, the reactor has a malfunction and needs to be replaced.
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