Midea MCH2U-18PHH2 Service Manual page 60

Pic 1: Use a multimeter to test the
DC voltage between 2(old: L2) port
and 3 port of outdoor unit. The red
pin of multimeter connects with 2
(old: L2) port while the black pin is
for 3 port.
When AC is normal running, the
voltage will move alternately
between positive value and
negative value.
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