Control Box Of The Heat Source Unit - Mitsubishi Electric PQHY-P72ZLMU-A Service Handbook

[ III Heat source Unit Components ]

[2] Control Box of the Heat source Unit

1. Control Box
<HIGH VOLTAGE WARNING>
DC reactor
(DCL)
Smoothing
capacitor
(C1,C2)
Noise filter
board
Power supply
terminal block
(TB1)
Note1
1) Handle the control box carefully. Deformation of the control box bottom may allow water and dust to enter the control box and
lead to component damage.
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) 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 graound 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 heat source unit. The liquid refrigerant in the compressor will evaporate by en-
ergizing the compressor.
HWE15150
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 between FT-P and FT-N on INV Board has dropped to DC20V or less.
(It takes about 10 minutes to discharge electricity after the power supply is turned off.)
INV board Note2
Ground Rush current
terminal
protection resistor
(R1,R5) Note2
Magnetic contactor
(52C)
Pump interlock terminal block
(TB8)
- 83 -
Control board
M-NET board
Terminal block for
I/O board
transmission line
(TB3, TB7)
GB