Circuit Board Arrangement; Outdoor Unit Control Box - Mitsubishi Electric PUHY-P250YNW-A Service Handbook

[4-1 Circuit Board Arrangement ]

4-1

Circuit Board Arrangement

4 Electrical Components and Wiring Diagrams
4-1-1

Outdoor Unit Control Box

<HIGH VOLTAGE WARNING>
MAIN BOX
1) Exercise caution not to damage the front panel of the control box. Damage to this part affect the waterproof and dust proof
properties of the control box and may result in damage to its internal components.
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 relay connector in the INV box (RYFAN1). Before plugging in or unplug-
ging connectors, check that the outdoor unit fan is not rotating and that the voltage across Pin 1 (+) and Pin 5 (-) of
connector RYPN in the INV box is 20 VDC or less. 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 in the MAIN BOX, check that the voltage is 20 VDC or below.
6) After servicing, reconnect the relay connector (RYFAN1) in the INV box as it was.
7) When opening or closing the front panel of the control box, do not touch any of the internal components. Before inspecting
inside the control box, turn off the power to the unit, leave it turned off for at least 10 minutes, and check that the voltage across
Pin 1 (+) and Pin 5 (-) of connector RYPN in the INV box is 20 VDC or less. It takes about 10 minutes to discharge electricity
after the power supply is turned off.
8) When the power is on, the compressor is energized even while it is stopped. Before turning on the power, disconnect all power
supply wires from the compressor terminal block, and measure the insulation resistance of the compressor. Check the com-
pressor for a ground fault. If the insulation resistance is 1.0 MΩ or below, connect all power supply wires to the compressor
and turn on the power to the outdoor unit. It is energized to evaporate the liquid refrigerant that has accumulated in the com-
pressor.
BS_04_C
Control box houses high-voltage parts.
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 voltage of the capacitor in the main circuit has dropped to 20 VDC or less.
INV BOX
1
chapter 4 -