Mitsubishi Electric PURY-P72 Service Handbook page 83

[ III Outdoor Unit Components ]
(3) PURY-P72, P96, P120, P144YKMU-A
1) When opening or closing the front panel of the control box, do not let it come into contact with any of the internal components.
Before inspecting the inside of the control box, turn off the power, keep the unit off for at least 10 minutes, and confirm that
the capacitor voltage (inverter main circuit) has dropped to 20 VDC or less. It takes about 10 minutes to discharge electricity
after the power supply is turned off.
2) Faston terminals have a locking function. Make sure the cable heads are securely locked in place. Press the tab on the ter-
minals to remove them.
3) Control box houses high temperature parts. Be well careful even after turning off the power source.
4) Perform the service after disconnecting the fan board connector (CNINV) and the inverter board connector (CN1 or
CNFAN). To plug or unplugb connectors, check that the outdoor unit fan is not rotating and that the voltage of ca-
pacitor in the main circuit is 20 VDC or below. The capacitor may collect a charge and cause an electric shock when
the outdoor unit fan rotates in windy conditions. Refer to the wiring nameplate for details.
5) To connect wiring to TB7, check that the voltage is 20 VDC or below.
6) Reconnect the connector (CNINV) back to the fan board and reconnect the connector (CN1 or CNFAN) back to the inverter
board after servicing.
7) When the power is turned on, the compressor is energized even while it is not operating. Before turning on the power, discon-
nect all power supply wires from the compressor terminal block, and measure the insulation resistance of the compressor.
Check the compressor for a ground fault. If the insulation resistance is 1.0 M or below, connect all power supply wires to the
compressor and turn on the power to the outdoor unit. The liquid refrigerant in the compressor will evaporate by energizing
the compressor.
HWE1116D - 74 - GB