Mitsubishi Electric EHGT17D-YM9ED Service Manual page 80

DISASSEMBLY PROCEDURE
4. How to remove the converter circuit board, the power
circuit board, and noise filter circuit board
(1) Remove the front panel. (Refer to Procedure 1.)
(2) Remove the frame from the side frame (4 screws 4×10).
(Photo 4-1)
(3) Loosen the fastener bundling the lead wires connected to
the ATW controller board and the controller circuit board.
(4) Disconnect the lead wires connected to the controller
boards, the contactors and the CONT base front as below.
(Photo 4-1 and 4-3)
● ATW controller board
CNP4/ CNBC/ CNBH/ CNW5/ CN851
● Control circuit board
CNDC/ CNAC/ TH7/ CN2/ CN4
● Contactor [BHC1] [BHC2]
2, 4, 6
● Earth wire
CN4P
(5) Disconnect the relay connectors of the lead wires on the
control box. (Photo 4-2)
Connector color Number of pins Applicable parts
White 9
White 16
White 12
White 8
White 10
(6) Release the lead wires from the wiring part and the cable
straps in the control box (Photo 4-2).
(7) Remove the CONT base front from the control box (5
screws 4x10). (Photo 4-3)
(8) Release the lead wires connected to the converter circuit
board, the noise filter circuit board, and the power circuit
board from the fasteners.
(9) Disconnect the lead wires from the converter circuit board,
the noise filter circuit board, and the power circuit board.
(Photo 4-4)
(10) Remove the converter circuit board,and the noise filter
circuit board from the supports.
(11) Remove 4 cross recessed head screws with captive
washer 4×14 to remove the power circuit board from the
support.
Note: When reassembling the electrical parts box, make
sure the wirings are correct.
Tighten cross recessed head screws with captive
washer 4×14.
Temporarily tightening torque: 0.7
Tightening torque: 1.3
Temporarily tighten IPM and diode bridge in the
order from screw A to D.
Tighten IPM and diode bridge in the order from
screw D to A.
OCH722A
LEV-A / Flow SW / HP SW
Thermistor
Booster heater
Primary side pump (power)
Brine pump
Primary side pump (control)
Flow sensor
Pressure sensor
+0.04
N▪m
- 0.10
+0.17
N▪m
- 0.10
PHOTOS/ FIGURES
Photo 4-1
Contactor BHC2
Frame
Contactor BHC1
Screws 4×10
Photo 4-2
Relay
connectors
Photo 4-3
CONT
base
front
Earth wire (CNP4)
Photo 4-4
Converter
circuit
board
Power
circuit
board
Cross recessed head screws
with captive washer 4×14
80
Cable strap
Screws
4×10
Noise filter
circuit board
B
D
C
A
Power circuit board