Mitsubishi Electric PUHZ-RP8YHA Technical & Service Manual page 73

OPERATING PROCEDURE
5. Removing the electrical parts box
(1) Remove
• Service panel.
• Waterproof sheet for the electrical parts.
(2) Disconnect
• Power wire from TB1, and the indoor / outdoor connecting
wire from TB2 (see photo 6).
• Fan motor relay connector.
• Lead wires in the compressor terminal cover (see photo 6).
(3) Disconnect all the following connectors from the con-
troller circuit board.
• LEV-A (Linear expansion valve / 6P, white)
• TH3 (Thermistor <Outdoor pipe> / 3P, white)
• TH32 (Thermistor <Outdoor pipe> / 3P, black)
• TH4 (Thermistor <Discharge> / 3P, white)
• TH6/7 (Thermistor <Outdoor 2-phase pipe>, <Outdoor> / 4P,
red)
• 63H (High pressure switch / 3P, yellow)
• 63L (Low pressure switch / 3P, red)
• 21S4 (4-way solenoid valve / 3P, green)
• SV2 (Bypass solenoid valve / 3P, blue)
(4) Remove
• 4 electrical parts box fixing screws (5o10).
• Electrical parts box by sliding it towards you (see photo6).
6. Removing the thermistor <Outdoor 2-phase pipe> (TH6)
and thermistor <Outdoor> (TH7)
w TH6 and TH7 are replaced together, since they are combined
together at the connector to the controller circuit board.
(1) Remove the service panel and the front panel.
(2) Disconnect the connector TH6/7 (4P, red) from the controller
circuit board.
(3) Loosen all the clamps for the lead wire and cut 2 fasteners
(see photo 7).
(4) Pull out
• Thermistor <Outdoor 2-phase pipe> (TH6) from the sensor
holder mounted on the heat exchanger.
• Thermistor <Outdoor pipe> (TH7) from the sensor holder
(see photo 7).
7. Removing the thermistor <Outdoor pipe>
(1) Remove the service panel and the front panel.
(2) Disconnect the connector TH3 (3P, white) or TH32 (3P, black)
from the controller circuit board.
(3) Loosen all the clamps for the lead wire and cut 2 fasteners
(see photo 7).
(4) Pull out the thermistor (TH3 or TH32) from the sensor holder
mounted on the heat exchanger (see photo 7).
w When there is difficulty in pulling out TH3 from the heat
exchanger, open the side panel (right) by removing 2 side
panel fixing screws (5o10).
Electrical parts box
Photo 6
fixing screw
Outdoor
Controller
circuit
board
Electrical
parts box
Terminal
block (TB1)
Electrical
parts box
pedestal
Thermistor
Photo 7
<Outdoor>
(TH7)
Thermistor
<Outdoor pipe>
(TH32)
Clamp
Clamp
73
PHOTOS
Compressor
Cover panel
Terminal cover
Screw tightening
Terminal
torque
block
•
1.7~2.1N m
(TB2)
Thermistor
Clamp
<Outdoor 2-
phase pipe>
(TH6)
Fan motor
lead wire
penetration
part
Thermistor
<Outdoor pipe>
(TH3)
Fastener
Cover
panel
fixing
screw