Mitsubishi Electric CMB-PW202V-J How to use

Service Handbook
AIR CONDITIONERS
MODEL
CMB-PW202V-J

ii
HWE09070 GB
Safety Precautions
Before installing the unit, thoroughly read the following safety precautions.
Observe these safety precautions for your safety.
WARNING
This symbol is intended to alert the user to the presence of important instructions that must be followed to avoid
the risk of serious injury or death.
CAUTION
This symbol is intended to alert the user to the presence of important instructions that must be followed to avoid
the risk of serious injury or damage to the unit.
After reading this manual, give it to the user to retain for future reference.
Keep this manual for easy reference. When the unit is moved or repaired, give this manual to those who provide these
services.
When the user changes, make sure that the new user receives this manual.
WARNING
Ask your dealer or a qualified technician to install the
unit.
Improper installation by the user may result in water leak-
age, electric shock, smoke, and/or fire.
Properly install the unit on a surface that can with-
stand the weight of the unit.
Unit installed on an unstable surface may fall and cause in-
jury.
Only use specified cables. Securely connect each ca-
ble so that the terminals do not carry the weight of the
cable.
Improperly connected or fixed cables may produce heat
and start a fire.
Take appropriate safety measures against strong
winds and earthquakes to prevent the unit from falling.
If the unit is not installed properly, the unit may fall and
cause serious injury to the person or damage to the unit.
Do not make any modifications or alterations to the
unit. Consult your dealer for repair.
Improper repair may result in water leakage, electric shock,
smoke, and/or fire.
Do not touch the heat exchanger fins.
The fins are sharp and dangerous.
In the event of a refrigerant leak, thoroughly ventilate
the room.
If refrigerant gas leaks and comes in contact with an open
flame, poisonous gases will be produced.
When installing the All-Fresh type units, take it into
consideration that the outside air may be discharged
directly into the room when the thermo is turned off.
Direct exposure to outdoor air may have an adverse effect
on health. It may also result in food spoilage.
Properly install the unit according to the instructions
in the installation manual.
Improper installation may result in water leakage, electric
shock, smoke, and/or fire.
Have all electrical work performed by an authorized
electrician according to the local regulations and in-
structions in this manual, and a dedicated circuit must
be used.
Insufficient capacity of the power supply circuit or improper
installation may result in malfunctions of the unit, electric
shock, smoke, and/or fire.

ii
HWE09070 GB
WARNING
Securely attach the terminal block cover (panel) to the
unit.
If the terminal block cover (panel) is not installed properly,
dust and/or water may infiltrate and pose a risk of electric
shock, smoke, and/or fire.
Only use the type of refrigerant that is indicated on the
unit when installing or reinstalling the unit.
Infiltration of any other type of refrigerant or air into the unit
may adversely affect the refrigerant cycle and may cause
the pipes to burst or explode.
When installing the unit in a small room, exercise cau-
tion and take measures against leaked refrigerant
reaching the limiting concentration.
Consult your dealer with any questions regarding limiting
concentrations and for precautionary measures before in-
stalling the unit. Leaked refrigerant gas exceeding the lim-
iting concentration causes oxygen deficiency.
Consult your dealer or a specialist when moving or re-
installing the unit.
Improper installation may result in water leakage, electric
shock, and/or fire.
After completing the service work, check for a gas
leak.
If leaked refrigerant is exposed to a heat source, such as a
fan heater, stove, or electric grill, poisonous gases may be
produced.
Do not try to defeat the safety features of the unit.
Forced operation of the pressure switch or the temperature
switch by defeating the safety features of these devices, or
the use of accessories other than the ones that are recom-
mended by MITSUBISHI may result in smoke, fire, and/or
explosion.
Only use accessories recommended by MITSUBISHI.
Ask a qualified technician to install the unit. Improper instal-
lation by the user may result in water leakage, electric
shock, smoke, and/or fire.
Control box houses high-voltage parts.
When opening or closing the front panel of the control box,
do not let it come into contact with any of the internal com-
ponents. Before inspecting the inside of the control box,
turn off the power, keep the unit off for at least 10 minutes,
and confirm that the voltage between FT-P and FT-N on
INV Board has dropped to DC20V or less. (It takes about
10 minutes to discharge electricity after the power supply is
turned off.)

iiiiii
HWE09070 GB
Precautions for handling units for use with R410A
CAUTION
Do not use the existing refrigerant piping.
A large amount of chlorine that is contained in the residual
refrigerant and refrigerator oil in the existing piping may
cause the refrigerator oil in the new unit to deteriorate.
R410A is a high-pressure refrigerant and can cause the
existing pipes to burst.
Use refrigerant pipes made of phosphorus deoxidized
copper. Keep the inner and outer surfaces of the pipes
clean and free of such contaminants as sulfur, oxides,
dust, dirt, shaving particles, oil, and water.
These types of contaminants inside the refrigerant pipes
may cause the refrigerant oil to deteriorate.
Store the pipes to be installed indoors, and keep both
ends of the pipes sealed until immediately before braz-
ing. (Keep elbows and other joints wrapped in plastic.)
Infiltration of dust, dirt, or water into the refrigerant system
may cause the refrigerating machine oil to deteriorate or
cause the unit to malfunction.
Use a small amount of ester oil, ether oil, or alkylben-
zene to coat flares and flanges.
Infiltration of a large amount of mineral oil may cause the re-
frigerating machine oil to deteriorate.
Charge liquid refrigerant (as opposed to gaseous re-
frigerant) into the system.
If gaseous refrigerant is charged into the system, the com-
position of the refrigerant in the cylinder will change and
may result in performance loss.
Use a vacuum pump with a reverse-flow check valve.
If a vacuum pump that is not equipped with a reverse-flow
check valve is used, the vacuum pump oil may flow into the
refrigerant cycle and cause the refrigerating machine oil to
deteriorate.
Prepare tools for exclusive use with R410A. Do not use
the following tools if they have been used with the con-
ventional refrigerant (gauge manifold, charging hose,
gas leak detector, reverse-flow check valve, refrigerant
charge base, vacuum gauge, and refrigerant recovery
equipment.).
If the refrigerant or the refrigerating machine oil left on
these tools are mixed in with R410A, it may cause the re-
frigerating machine oil to deteriorate.
Infiltration of water may cause the refrigerating machine
oil to deteriorate.
Gas leak detectors for conventional refrigerants will not
detect an R410A leak because R410A is free of chlorine.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of the refrig-
erant will change, and the unit may experience power loss.
Exercise special care when handling the tools for use
with R410A.
Infiltration of dust, dirt, or water into the refrigerant system
may cause the refrigerating machine oil to deteriorate.
Only use refrigerant R410A.
The use of other types of refrigerant that contain chlorine
(i.e. R22) may cause the refrigerating machine oil to deteri-
orate.

iv
HWE09070 GB
Before installing the unit
WARNING
Do not install the unit where a gas leak may occur.
If gaseous refrigerant leaks and piles up around the unit, it
may be ignited.
Do not use the unit to keep food items, animals, plants,
artifacts, or for other special purposes.
The unit is not designed to preserve food products.
Do not use the unit in an unusual environment.
Do not install the unit where a large amount of oil or steam
is present or where acidic or alkaline solutions or chemical
sprays are used frequently. Doing so may lead to a re-
markable drop in performance, electric shock, malfunc-
tions, smoke, and/or fire.
The presence of organic solvents or corrosive gas (i.e.
ammonia, sulfur compounds, and acid) may cause gas
leakage or water leakage.
When installing the unit in a hospital, take appropriate
measures to reduce noise interference.
High-frequency medical equipment may interfere with the
normal operation of the air conditioner or vice versa.
Do not install the unit on or over things that cannot get
wet.
When the humidity level exceeds 80% or if the drainage
system is clogged, the indoor unit may drip water. Drain wa-
ter is also discharged from the outdoor unit. Install a central-
ized drainage system if necessary.
Select the installation site carefully.
Install the unit in a place where the noise from the unit will
not be a problem. (Install indoor unit and WCB at least 5
m away from each other when installed in a space with low
background noise, e.g., hotel rooms.)
Install the unit in the ceiling of an area where people are
not always present, e.g., hallway, office kitchen, rest-
rooms. (Do not install the unit in the middle of a room.)
Install the indoor unit on a level surface.
Improper installation may result in water leakage, electric
shock, smoke, fire, or malfunctions.

vv
HWE09070 GB
Before installing the unit (moving and reinstalling the unit) and performing
electrical work
CAUTION
Properly ground the unit.
Do not connect the grounding wire to a gas pipe, water pipe,
lightning rod, or grounding wire from a telephone pole. Im-
proper grounding may result in electric shock, smoke, fire,
and/or malfunction due to noise interference.
Do not put tension on the power supply wires.
If tension is put on the wires, they may break and result in
excessive heat, smoke, and/or fire.
Install an earth leakage breaker to avoid the risk of
electric shock.
Failure to install an earth leakage breaker may result in
electric shock, smoke, and/or fire.
Use the kind of power supply wires that are specified
in the installation manual.
The use of wrong kind of power supply wires may result in
current leak, electric shock, and/or fire.
Use breakers and fuses (current breaker, remote
switch <switch + Type-B fuse>, moulded case circuit
breaker) with the proper current capacity.
The use of wrong capacity fuses, steel wires, or copper
wires may result in malfunctions, smoke, and/or fire.
Do not spray water on the air conditioner or immerse
the air conditioner in water.
Otherwise, electric shock and/or fire may result.
When handling units, always wear protective gloves to
protect your hands from metal parts and high-tempera-
ture parts.
Periodically check the installation base for damage.
If the unit is left on a damaged platform, it may fall and
cause injury.
Properly install the drain pipes according to the in-
structions in the installation manual. Keep them insu-
lated to avoid dew condensation.
Improper plumbing work may result in water leakage and
damage to the furnishings.
Exercise caution when transporting products.
Products weighing more than 20 kg should not be carried
alone.
Do not carry the product by the PP bands that are used on
some products.
Do not touch the heat exchanger fins. They are sharp and
dangerous.
When lifting the unit with a crane, secure all four corners
to prevent the unit from falling.
Properly dispose of the packing materials.
Nails and wood pieces in the package may pose a risk of
injury.
Plastic bags may pose a risk of choking hazard to chil-
dren. Tear plastic bags into pieces before disposing of
them.

vi
HWE09070 GB
Before the test run
CAUTION
Turn on the unit at least 12 hours before the test run.
Keep the unit turned on throughout the season. If the unit is
turned off in the middle of a season, it may result in malfunc-
tions.
To avoid the risk of electric shock or malfunction of the
unit, do not operate switches with wet hands.
Do not touch the refrigerant pipes with bare hands dur-
ing and immediately after operation.
During or immediately after operation, certain parts of the
unit such as pipes and compressor may be either very cold
or hot, depending on the state of the refrigerant in the unit
at the time. To reduce the risk of frost bites and burns, do
not touch these parts with bare hands.
Do not operate the unit without panels and safety
guards.
Rotating, high-temperature, or high-voltage parts on the unit
pose a risk of burns and/or electric shock.
Do not turn off the power immediately after stopping
the operation.
Keep the unit on for at least five minutes before turning off
the power to prevent water leakage or malfunction.
Do not operate the unit without the air filter.
Dust particles may build up in the system and cause mal-
functions.

CONTENTS
HWE09070 GB
I Read Before Servicing
[1] Read Before Servicing.............................................................................................................. 3
[2] Necessary Tools and Materials ................................................................................................ 4
[3] Piping Materials ........................................................................................................................ 5
[4] Storage of Piping ...................................................................................................................... 7
[5] Pipe Processing........................................................................................................................ 7
[6] Brazing...................................................................................................................................... 8
[7] Air Tightness Test..................................................................................................................... 9
[8] Vacuum Drying (Evacuation) ..................................................................................................10
[9] Refrigerant Charging .............................................................................................................. 12
[10] Remedies to be taken in case of a Refrigerant Leak............................................................ 12
[11] Characteristics of the Conventional and the New Refrigerants ............................................ 13
[12] Notes on Refrigerating Machine Oil...................................................................................... 14
II Restrictions
[1] System configuration .............................................................................................................. 17
[2] Switch Settings and Address Settings .................................................................................... 18
[3] An Example of a System to which an MA Remote Controller is connected ........................... 20
[4] Restrictions on Pipe Length.................................................................................................... 23
III WCB Components
[1] WCB Components .................................................................................................................. 29
[2] Control Box of the WCB.......................................................................................................... 30
[3] WCB Circuit Board.................................................................................................................. 31
IV Electrical Wiring Diagram
[1] Electrical Wiring Diagram of the WCB .................................................................................... 35
V Refrigerant Circuit
[1] Refrigerant Circuit Diagram .................................................................................................... 39
[2] Principal Parts and Functions ................................................................................................. 40
VI Control
[1] Functions and Factory Settings of the Dipswitches ................................................................ 43
[2] Controlling WCB ..................................................................................................................... 44
[3] Operation Flow Chart.............................................................................................................. 46
VII Test Run Mode
[1] Items to be checked before a Test Run.................................................................................. 55
[2] Adjusting the Refrigerant Amount........................................................................................... 56
[3] The following symptoms are normal. ...................................................................................... 56
[4] Standard Operation Data (Reference Data) ........................................................................... 57
VIII Troubleshooting
[1] Error Code Lists...................................................................................................................... 65
[2] Responding to Error Display on the Remote Controller.......................................................... 66
[3] Troubleshooting Principal Parts.............................................................................................. 87
[4] Servicing the WCB.................................................................................................................. 97
IX LED Monitor Display on the Outdoor Unit Board
[1] How to Read the LED on the Service Monitor ...................................................................... 101

HWE09070 GB

- 1 -
HWE09070 GB
I Read Before Servicing
[1] Read Before Servicing ....................................................................................................... 3
[2] Necessary Tools and Materials.......................................................................................... 4
[3] Piping Materials .................................................................................................................5
[4] Storage of Piping ............................................................................................................... 7
[5] Pipe Processing................................................................................................................. 7
[6] Brazing............................................................................................................................... 8
[7] Air Tightness Test..............................................................................................................9
[8] Vacuum Drying (Evacuation) ........................................................................................... 10
[9] Refrigerant Charging........................................................................................................ 12
[10] Remedies to be taken in case of a Refrigerant Leak ....................................................... 12
[11] Characteristics of the Conventional and the New Refrigerants ....................................... 13
[12] Notes on Refrigerating Machine Oil ................................................................................. 14