Mitsubishi Electric PUZ-A18NHA2 Service Manual page 107

OPERATING PROCEDURE
3. Removing the electrical parts box
(1) Remove the service panel. (See photo 1.)
(2) Remove the top panel. (See photo 1.)
(3) Remove the front panel. (See photo 1.)
(4) Disconnect the indoor/outdoor connecting wire from
terminal block.
(5) Remove all the following connectors from controller circuit board;
fan motor, linear expansion valve, thermistor<Outdoor pipe>,
thermistor<Discharge>, thermistor<Outdoor 2-phase pipe>,
thermistor<Outdoor>, high pressure switch, four-way valve
and bypass valve.
Pull out the disconnected wire from the electrical parts box.
<Diagram symbol in the connector housing>
• Fan motor (CNF1)
• Linear expansion valve (LEV-A)
• Thermistor <Outdoor pipe> (TH3)
• Thermistor <Discharge> (TH4)
• Thermistor <Outdoor 2-phase pipe, Outdoor> (TH6/7)
• High pressure switch (63H)
(6) Remove the terminal cover and disconnect the compressor
lead wire.
(7) Remove the electrical parts box fixing screws, 1 from the
front, the right and the rear side, and detach the electrical
parts box by pulling it upward.
4. Removing the thermistor <Outdoor 2-phase pipe> (TH6)
and thermistor <Outdoor pipe> (TH3)
(1) Remove the service panel. (See photo 1.)
(2) Remove the top panel. (See photo 1.)
(3) Remove the front panel. (See photo 1.)
(4) Remove the conduit cover and cord cover.
(5) Remove the back panel fixing screws, 4 from the right and
3 from the rear side, and detach the back panel.
(See photo 1.)
(6) Disconnect the connector TH3 (white) or TH6/7 (red) on
the controller circuit board in the electrical parts box.
(7) Loosen the clamp for the lead wire in the rear of the
electrical parts box.
(8) Pull out the thermistor <Outdoor pipe> (TH3) and
thermistor <Outdoor 2-phase pipe> (TH6) from the
sensor holder.
Note: Replace the thermistor <Outdoor 2-phase pipe> (TH6)
and the thermistor <Outdoor> (TH7) together since
they are combined.
Refer to No. 5. to remove the thermistor <Outdoor> (TH7).
Photo 5
Electrical parts box
Electrical
parts box
fixing
screw
Photo 6
Electrical
parts box
107
PHOTOS
Controller circuit
board (C.B.)
Terminal block(TB1)
Thermistor
<Outdoor 2-phase pipe>
(TH6)
Thermistor
<Outdoor pipe>
(TH3)
Clamp