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4-1. PURGING PROCEDURES AND LEAK TEST

1) Remove service port cap of stop valve on the side of the outdoor unit gas pipe. (The 

stop valve will not work in its initial state fresh out of the factory, totally closed with cap 
on.)

2) Connect gauge manifold valve and vacuum pump to service port of stop valve on the 

gas pipe side of the outdoor unit.

4-2. TEST RUN

1) Press the E.O. SW once for COOL, and twice for HEAT 

operation. Test run will be performed for 30 minutes. If 
the upper lamp of the operation indicator blinks every 0.5 
seconds, inspect the indoor/outdoor unit connecting wire 
(A) for mis-wiring.  After the test run, emergency mode 
(set temperature 24ºC) will start.

2) To stop operation, press the E.O. SW several times until 

all LED lamps turn off. Refer to operating instructions for 
details. 

Checking the remote (infrared) signal reception

Press the ON/OFF button on the remote controller (4) and 
check that an electronic sound is heard from the indoor 
unit. Press the ON/OFF button again to turn the air conditioner off.
•  Once the compressor stops, the restart preventive device operates so the compressor 

will not operate for 3 minutes to protect the air conditioner.

4-3. AUTO RESTART FUNCTION

This product is equipped with an auto restart function. When the power supply is stopped 
during operation, such as during blackouts, the function automatically starts operation in 
the previous setting once the power supply is resumed. (Refer to the operating instruc-
tions for details.) 

5-1. REMOVING AND INSTALLING THE PANEL ASSEMBLY

5-3. PUMPING DOWN

When relocating or disposing of the air conditioner, pump down the system following the 
procedure below so that no refrigerant is released into the atmosphere.
1) Connect the gauge manifold valve to the service port of the stop valve on the gas pipe 

side of the outdoor unit.

2) Fully close the stop valve on the liquid pipe side of the outdoor unit.
3) Close the stop valve on the gas pipe side of the outdoor unit almost completely so that 

it can be easily closed fully when the pressure gauge shows 0 MPa [Gauge] (0 kgf/
cm

2

).

4) Start the emergency COOL operation.
  To start the emergency operation in COOL mode, disconnect the power supply plug 

and/or turn off the breaker. After 15 seconds, connect the power supply plug and/or 
turn on the breaker, and then press the E.O. SW once. (The emergency COOL 
operation can be performed continuously for up to 30 minutes.)

5) Fully close the stop valve on the gas pipe side of the outdoor unit when the pressure 

gauge shows 0.05 to 0 MPa [Gauge] (approx. 0.5 to 0 kgf/cm

2

).

6) Stop the emergency COOL operation.
 

Press the E.O. SW twice to stop the operation.

5-2. REMOVING THE INDOOR UNIT

Remove the bottom of the indoor unit from the installation 
plate.
When releasing the corner part, release both left and right 
bottom corner part of indoor unit and pull it downward and 
forward as shown in the figure on the right.

If the above method cannot be used

Remove the panel and insert hexagonal wrenches and right as shown in the figure below, 
then push unit is lowered and the hooks are released.

Removal procedure

1) Remove the 2 screws which fix the panel assem-

bly.

2) Remove the panel assembly. Be sure to remove 

its bottom end first.

Installation procedure

1) Install the panel assembly following the removal 

procedure in reverse. 

2) Be sure to press the positions as indicated by the 

arrows in order to attach the assembly completely 
to the unit.

Stop valve for 
GAS

Stop valve cap
(Torque 19.6 to 
29.4 N•m, 200  
to 300 kgf▪cm)

Vacuum pump (or the vacuum 
pump with the function to 
prevent the back flow)

Gauge manifold valve 
(for R410A)

Compound pressure gauge 
(for R410A)

-0.101MPa  
(-760 mmHg)

Handle 
Low

Handle High

Adapter for pre-
venting the back 
flow

Charge hose 
(for R410A)

*Close

*Open

Hexagonal wrench

Precautions when using the control valve

When attaching the control valve 
to the service port, valve core may 
deform or loosen if excess pressure 
is applied. This may cause gas leak.

Service port

Charge hose 

Body

Close

Open

Control valve

A

When attaching the control valve to 
the service port, make sure that the 
valve core is in closed position, and 
then tighten part A. Do not tighten 
part A or turn the body when valve 
core is in open position.

Service port cap
(Torque 13.7 to 
17.7 N•m, 140 to 
180 kgf•cm)

*4 to 5 turns

3) Run the vacuum pump. (Vacuumize for more than 15 minutes.)
4) Check the vacuum with gauge manifold valve, then close gauge manifold valve, and 

stop the vacuum pump.

5) Leave as it is for one or two minutes. Make sure pointer gauge manifold valve remains 

in the same position. Confirm that pressure gauge shows –0.101 Mpa [Gauge] (–760 
mmHg).

6) Remove gauge manifold valve quickly from service port of stop valve.
7) After refrigerant pipes are connected and evacuated, fully open all stop valves on both 

sides of gas pipe and liquid pipe. Operating without fully opening lowers the perform-
ance and this causes trouble.

8) Refer to 1-3., and charge the prescribed amount of refrigerant if needed. Be sure to 

charge slowly with liquid refrigerant. Otherwise, composition of the refrigerant in the 
system may be changed and affect performance of the air conditioner.

9) Tighten cap of service port to obtain the initial status.
10) Leak test

Stop valve 
for LIQUID

Caution:

•  After test run or remote signal reception check, turn off the unit with the E.O. SW or 

the remote controller before turning off the power supply. Not doing so will cause the 
unit to start operation automatically when power supply is resumed.

To the user

•  After installing the unit, make sure to explain the user about auto restart function. 
•  If auto restart function is unnecessary, it can be deactivated. Consult the service 

representative to deactivate the function. Refer to the service manual for details.

Push

Lower

Square hole

4.  PURGING PROCEDURES, LEAK TEST, AND TEST RUN

Pressure gauge
(for R410A)

5. RELOCATION AND MAINTENANCE

Emergency  
operation switch
(E.O. SW)

HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 
100-8310, JAPAN
AUTHORIZED REPRESENTATIVE IN EU:
MITSUBISHI ELECTRIC EUROPE B.V.
HARMAN HOUSE, 1 GEORGE STREET, UXBRIDGE, MIDDLESEX UB8 1QQ, U.K.

This product is designed and intended for use in the residential, commercial and 
light-industrial environment.

The product at hand is based on  •  Low Voltage Directive 2006/95/EC
the following EU regulations: 

•  Electromagnetic Compatibility Directive 2004/108/ 

EC

4-4. EXPLANATION TO THE USER

•  Using the OPERATING INSTRUCTIONS, explain to the user how to use the air condi-

tioner (how to use the remote controller, how to remove the air filters, how to remove 
or put the remote controller in the remote controller holder, how to clean, precautions 
for operation, etc.)

•  Recommend the user to read the OPERATING INSTRUCTIONS carefully.

When pumping down the refrigerant, stop the compressor before disconnecting 
the refrigerant pipes. The compressor may burst if air etc. get into it.

 

WARNING

Summary of Contents for MSZ-HC25VA

Page 1: ...the refrigerant pipes are connected and when the stop valve is open air could be drawn in and the pressure in the refrigeration cycle could become abnormally high This could cause the pipes to burst or injury N Fasten a flare nut with a torque wrench as specified in this manual If fastened too tight a flare nut may break after a long period and cause refrigerant leakage N The unit shall be installed ...

Page 2: ...ose or soft PVC hose 15 mm inner dia or hard PVC pipe VP16 1 or 2 J Refrigeration oil 1 K Power supply cord 1 Air inlet Air outlet Outdoor unit installation Units should be installed by licensed contractor according to local code requirements Terminal block Fixing screw Indoor outdoor unit con necting wire A VA clamp Lead wire Indoor terminal block Indoor outdoor unit connecting wire A Outdoor ter...

Page 3: ... and gas pipings to indoor unit Apply a thin coat of refrigeration oil J on the seat surface of pipe For connection first align the center then tighten the first 3 to 4 turns of flare nut Use tightening torque table below as a guideline for indoor unit side union joint section and tighten using two wrenches Excessive tightening damages the flare section Outdoor unit connection Connect pipes to stop va...

Page 4: ... indicated by the arrows in order to attach the assembly completely to the unit Stop valve for GAS Stop valve cap Torque 19 6 to 29 4 N m 200 to 300 kgf cm Vacuum pump or the vacuum pump with the function to prevent the back flow Gauge manifold valve for R410A Compound pressure gauge for R410A 0 101MPa 760 mmHg Handle Low Handle High Adapter for pre venting the back flow Charge hose for R410A Close ...

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