Heating - Mitsubishi Electric PUHZ-W90VHA Service Manual

OPERATING PROCEDURE
8. Removing the solenoid valve coil <Four-way valve> (21S4)
linear expansion valve coil (LEV (A), LEV (B)) and solenoid
valve coil <Bypass valve> (SV)
(1) Remove the service panel. (See figure 1.)
(2) Remove the top panel. (See figure 1.)
(3) Remove the electrical parts box. (See photo 3.)
[Removing the solenoid valve coil <Four-way valve> ]
(4) Remove solenoid valve coil <Four-way valve> fixing
screw(M4x6).
(5) Remove the solenoid valve coil <Four-way valve>.
(6) Disconnect the connector 21S4 (green) on the controller
circuit board.
[Removing the linear expansion valve coil]
(4) Remove the linear expansion valve coil by sliding the coil
upward.
(5) Disconnect the connectors, LEV A (white) and LEV B (red),
on the controller circuit board.
[Removing the solenoid valve coil <Bypass valve>]
(4) Remove the solenoid valve coil <Bypass valve> fixing
screw(M4x6).
(5) Remove the solenoid valve coil <Bypass valve> by sliding
the coil upward.
(6) Disconnect the connector SV2 (blue) on the controller cir-
cuit board.
9. Removing the four-way valve
(1) Remove the service panel. (See figure 1.)
(2) Remove the top panel. (See figure 1.)
(3) Remove the electrical parts box. (See photo 3.)
(4) Remove 3 stay fixing screws (4x10) and remove the stay.
(5) Remove 3 right side panel fixing screw (5x10) in the rear
of the unit and remove the right side panel.
(6) Remove the solenoid valve coil <Four-way valve>.
(See photo 8.)
(7) Recover refrigerant.
(8) Remove the welded part of four-way valve.
Note 1: Recover refrigerant without letting it out in the air.
Note 2: The welded part can be removed easily by
removing the right side panel.
Note 3: When installing the four-way valve, make sure to
cover it with a wet cloth to prevent it from heating
(120°C or more), then braze the pipes so that the
inside of pipes are not oxidized.
10. Removing linear expansion valve
(1) Remove the service panel. (See figure 1.)
(2) Remove the top panel. (See figure 1.)
(3) Remove the electrical parts box. (See photo 3.)
(4) Remove 3 stay fixing screws (4x10) and remove the stay.
(5) Remove 3 right side panel fixing screw (5x10) in the rear
of the unit and then remove the right side panel.
(6) Remove the linear expansion valve.
(7) Recover refrigerant.
(8) Remove the welded part of linear expansion valve.
Note 1: Collect refrigerant without spreading it in the air.
Note 2: The welded part can be removed easily by
removing the back panel.
Note 3: When installing the linear expansion valve, cover
it with a wet cloth to prevent it from heating
(120°C or more), then braze the pipes so that the
inside of pipes are not oxidized.
PHOTOS&ILLUSTRATION
Photo 8
Solenoid
Four-way valve
valve coil(21S4)
High pressure
Solenoid
switch
valve coil(SV)
Photo 9
Solenoid
valve coil(21S4)
Stay fixing screw
40
LEV-A
LEV-B
Bypass valve
Stay fixing
screw
Stay fixing
screw
Four-way valve