Mitsubishi Electric PU(H)Y-P250YGM-A How to use

Models
Service Handbook
AIR CONDITIONERS
PU(H)Y-P250YGM-A
PUHY-P500YGM-A
PFD-P250VM-E
PFD-P500VM-E

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 ser-
vices.
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 withstand the
weight of the unit.
Unit installed on an unstable surface may fall and cause in-
jury.
Only use specified cables. Securely connect each cable 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.
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 electri-
cian according to the local regulations and instructions 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.
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.

WARNING
When installing the unit in a small room, exercise caution
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 reinstall-
ing 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.

Precautions for handling units for use with R410A
CAUTION
Do not use the existing refrigerant piping.
A large amount of chlorine that may be contained in the re-
sidual refrigerant and refrigerating machine oil in the exist-
ing piping may cause the refrigerating machine 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 cop-
per. 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 brazing. (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 alkylbenzene 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 refriger-
ant) 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 conventional
refrigerant (gauge manifold, charging hose, gas leak detec-
tor, reverse-flow check valve, refrigerant charge base, vac-
uum 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 de-
tect 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.

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, ar-
tifacts, 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 remark-
able drop in performance, electric shock, malfunctions,
smoke, and/or fire.
The presence of organic solvents or corrosive gas (i.e. am-
monia, sulfur compounds, and acid) may cause gas leak-
age or water leakage.
When installing the unit in a hospital, take appropriate mea-
sures 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.

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.
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 instructions
in the installation manual. Keep them insulated 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 children.
Tear plastic bags into pieces before disposing of them.

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 during
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 op-
eration.
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
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 ............................................................................................................ 11
[10] Remedies to be taken in case of a Refrigerant Leak............................................................ 11
[11] Characteristics of the Conventional and the New Refrigerants ............................................ 12
[12] Notes on Refrigerating Machine Oil...................................................................................... 13
II Restrictions
[1] System configuration ............................................................................................................ 17
[2] Types and Maximum allowable Length of Cables ................................................................ 18
[3] Switch Settings and Address Settings.................................................................................. 20
[4] An Example of a System to which an MA Remote Controller is connected ......................... 22
[5] Restrictions on Pipe Length.................................................................................................. 30
III Outdoor Unit Components
[1] Outdoor Unit Components and Refrigerant Circuit............................................................... 33
[2] Control Box of the Outdoor Unit ........................................................................................... 37
[3] Outdoor Unit Circuit Board ................................................................................................... 39
IV Indoor Unit Components
[1] External Dimensions............................................................................................................. 45
[2] Indoor Unit Components and Internal Structure ................................................................... 47
[3] Control Box of the Indoor Unit ..............................................................................................51
[4] Indoor Unit Circuit Board ...................................................................................................... 52
[5] Separating the top and bottom of the unit ............................................................................ 53
V Electrical Wiring Diagram
[1] Electrical Wiring Diagram of the Outdoor Unit...................................................................... 59
[2] Electrical Wiring Diagram of the Indoor Unit......................................................................... 61
VI Refrigerant Circuit
[1] Refrigerant Circuit Diagram .................................................................................................. 65
[2] Principal Parts and Functions...............................................................................................68
VII Control
[1] Functions and Factory Settings of the Dipswitches.............................................................. 75
[2] Controlling the Outdoor Unit ................................................................................................. 80
[3] Controlling the Indoor Unit.................................................................................................... 88
[4] Operation Flow Chart ........................................................................................................... 92
VIII Test Run Mode
[1] Items to be checked before a Test Run................................................................................ 99
[2] Test Run Method ................................................................................................................ 100
[3] Operating Characteristic and Refrigerant Amount.............................................................. 101
[4] Adjusting the Refrigerant Amount....................................................................................... 102
[5] Refrigerant Amount Adjust Mode ....................................................................................... 104
[6] The following symptoms are normal................................................................................... 106
[7] Standard Operation Data (Reference Data) ....................................................................... 107
IX Troubleshooting
[1] Error code Lists .................................................................................................................. 111
[2] Responding to Error Display on the Remote Controller ..................................................... 114
[3] Investigation of Transmission Wave Shape/Noise ............................................................. 144
[4] Troubleshooting Principal Parts.......................................................................................... 147
[5] Refrigerant Leak ................................................................................................................. 167
[6] Compressor Replacement Instructions (Only P500 type) .................................................. 168
[7] Collecting the Cooling Liquid from the Accumulator (Only P500 type)............................... 169
[8] Maintenance/Inspection Schedule...................................................................................... 170
X LED Monitor Display on the Outdoor Unit Board
[1] How to Read the LED on the Service Monitor.................................................................... 175

- 1 -
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 ....................................................................................................... 11
[10] Remedies to be taken in case of a Refrigerant Leak....................................................... 11
[11] Characteristics of the Conventional and the New Refrigerants ....................................... 12
[12] Notes on Refrigerating Machine Oil................................................................................. 13

- 2 -

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[ I Read Before Servicing ]
I Read Before Servicing
[1] Read Before Servicing
1. Check the type of refrigerant used in the system to be serviced.
Refrigerant Type New refrigerant series split-type air-conditioners for computer rooms: R410A
2. Check the symptoms exhibited by the unit to be serviced.
Refer to this service handbook for symptoms relating to the refrigerant cycle.
3. Thoroughly read the safety precautions at the beginning of this manual.
4. Preparing necessary tools: Prepare a set of tools to be used exclusively with each type of refrigerant.
Refer to next page for information on the use of tools.
5. For new refrigerant series split-type air-conditioners for computer rooms, it is necessary to replace a dryer
when the refrigerant circuit is open (e.g. repairing refrigerant leak).
Prepare a dryer dedicated for new refrigerant series split-type air-conditioners for computer rooms. Using a dryer other
than the dedicated one may cause a malfunction.
Replace a dryer after the refrigerant circuit has been repaired. (If the dryer is left in the air, it absorbs moisture. Replace
the dryer immediately.)
6. Verification of the connecting pipes: Verify the type of refrigerant used for the unit to be moved or replaced.
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.
7. If there is a leak of gaseous refrigerant and the remaining refrigerant is exposed to an open flame, a poisonous
gas hydrofluoric acid may form. Keep workplace well ventilated.
CAUTION
Install new pipes immediately after removing old ones to keep moisture out of the refrigerant circuit.
The use of refrigerant that contains chloride, such as R22, will cause the refrigerating machine oil to deteriorate.

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[ I Read Before Servicing ]
[2] Necessary Tools and Materials
Prepare the following tools and materials necessary for installing and servicing the unit.
Tools for use with R410A (Adaptability of tools that are for use with R22 or R407C)
1. To be used exclusively with R410A (not to be used if used with R22 or R407C)
2. Tools and materials that may be used with R410A with some restrictions
3. Tools and materials that are used with R22 or R407C that may also be used with R410A
4. Tools and materials that must not be used with R410A
Tools for R410A must be handled with special care to keep moisture and dust from infiltrating the cycle.
Tools/Materials Use Notes
Gauge Manifold Evacuation and refrigerant charging Higher than 5.09MPa on the high-pres-
sure side
Charging Hose Evacuation and refrigerant charging The hose diameter is larger than the
conventional model.
Refrigerant Recovery Cylinder Refrigerant recovery
Refrigerant Cylinder Refrigerant charging The refrigerant type is indicated. The
cylinder is pink.
Charging Port on the Refrigerant Cylinder Refrigerant charging The charge port diameter is larger than
that of the current port.
Flare Nut Connection of the unit with the pipes Use Type-2 Flare nuts.
Tools/Materials Use Notes
Gas Leak Detector Gas leak detection The ones for use with HFC refrigerant
may be used.
Vacuum Pump Vacuum drying May be used if a check valve adapter is
attached.
Flare Tool Flare processing Flare processing dimensions for the pip-
ing in the system using the new refriger-
ant differ from those of R22. Refer to
next page.
Refrigerant Recovery Equipment Refrigerant recovery May be used if compatible with R410A.
Tools/Materials Use Notes
Vacuum Pump with a Check Valve Vacuum drying
Bender Bending pipes
Torque Wrench Tightening flare nuts Only the flare processing dimensions for
pipes that have a diameter of
ø12.70 (1/2") and ø15.88 (5/8") have
been changed.
Pipe Cutter Cutting pipes
Welder and Nitrogen Cylinder Welding pipes
Refrigerant Charging Meter Refrigerant charging
Vacuum Gauge Vacuum level check
Tools/Materials Use Notes
Charging Cylinder Refrigerant charging Prohibited to use

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[ I Read Before Servicing ]
[3] Piping Materials
1. Copper pipe materials
The distinction between O-materials (Annealed) and 1/2H-materials (Drawn) is made based on the strength of the pipes
themselves.
O-materials (Annealed) can easily be bent with hands.
1/2H-materials (Drawn) are considerably stronger than O-material (Annealed) at the same thickness.
2. Types of copper pipes
3. Piping materials/Radial thickness
Use refrigerant pipes made of phosphorus deoxidized copper.
The operation pressure of the units that use R410A is higher than that of the units that use R22.
Use pipes that have at least the radial thickness specified in the chart below.
(Pipes with a radial thickness of 0.7 mm or less may not be used.)
The pipes in the system that uses the refrigerant currently on the market are made with O-material (Annealed), even if the
pipe diameter is less than ø19.05 (3/4"). For a system that uses R410A, use pipes that are made with 1/2H-material
(Drawn) unless the pipe diameter is at least ø19.05 (3/4") and the radial thickness is at least 1.2t.
The figures in the radial thickness column are based on the Japanese standards and provided only as a reference. Use
pipes that meet the local standards.
O-material (Annealed) Soft copper pipes (annealed copper pipes). They can easily be bent with hands.
1/2H-material (Drawn) Hard copper pipes (straight pipes). They are stronger than the O-material (Annealed)
at the same radial thickness.
Maximum working pressure Refrigerant type
3.45 MPa R22, R407C etc.
4.30 MPa R410A etc.
Pipe size (mm[in]) Radial thickness (mm) Type
ø6.35 [1/4"] 0.8t
O-material (Annealed)
ø9.52 [3/8"] 0.8t
ø12.7 [1/2"] 0.8t
ø15.88 [5/8"] 1.0t
ø19.05 [3/4"] 1.0t
1/2H-material,
H-material (Drawn)
ø22.2 [7/8"] 1.0t
ø25.4 [1"] 1.0t
ø28.58 [1-1/8"] 1.0t
ø31.75 [1-1/4"] 1.1t
NOOK
New Piping Existing Piping
Do not use the existing piping!

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[ I Read Before Servicing ]
4. Thickness and refrigerant type indicated on the piping materials
Ask the pipe manufacturer for the symbols indicated on the piping material for new refrigerant.
5. Flare processing (O-material (Annealed) and OL-material only)
The flare processing dimensions for the pipes that are used in the R410A system are larger than those in the R22 system.
If a clutch-type flare tool is used to flare the pipes in the system using R410A, the length of the pipes must be between 1.0
and 1.5 mm. For margin adjustment, a copper pipe gauge is necessary.
6. Flare nut
The flare nut type has been changed to increase the strength. The size of some of the flare nuts have also been changed.
The figures in the radial thickness column are based on the Japanese standards and provided only as a reference. Use
pipes that meet the local standards.
Flare processing dimensions (mm[in])
Pipe size (mm[in])
A dimension (mm)
R410A R22, R407C
ø6.35 [1/4"] 9.1 9.0
ø9.52 [3/8"] 13.2 13.0
ø12.7 [1/2"] 16.6 16.2
ø15.88 [5/8"] 19.7 19.4
ø19.05 [3/4"] 24.0 23.3
Flare nut dimensions (mm[in])
Pipe size (mm[in])
B dimension (mm)
R410A R22, R407C
ø6.35 [1/4"] 17.0 17.0
ø9.52 [3/8"] 22.0 22.0
ø12.7 [1/2"] 26.0 24.0
ø15.88 [5/8"] 29.0 27.0
ø19.05 [3/4"] 36.0 36.0
Dimension A
Dimension B

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[ I Read Before Servicing ]
[4] Storage of Piping
1. Storage location
Store the pipes to be used indoors. (Warehouse at site or owner's warehouse)
If they are left outdoors, dust, dirt, or moisture may infiltrate and contaminate the pipe.
2. Sealing the pipe ends
Both ends of the pipes should be sealed until just before brazing.
Keep elbow pipes and T-joints in plastic bags.
The new refrigerator oil is 10 times as hygroscopic as the conventional refrigerating machine oil (such as Suniso) and, if
not handled with care, could easily introduce moisture into the system. Keep moisture out of the pipes, for it will cause the
oil to deteriorate and cause a compressor failure.
[5] Pipe Processing
Use a small amount of ester oil, ether oil, or alkylbenzene to coat flares and flanges.
1. Notes
Use a minimum amount of oil.
Use only ester oil, ether oil, and alkylbenzene.
OK
OK
NO
NO
OK
OK
NO
NO

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[ I Read Before Servicing ]
[6] Brazing
No changes have been made in the brazing procedures. Perform brazing with special care to keep foreign objects (such as
oxide scale, water, and dust) out of the refrigerant system.
Example: Inside the brazed connection
1. Items to be strictly observed
Do not conduct refrigerant piping work outdoors if raining.
Use non-oxidized solder.
Use a brazing material (BCuP-3) that requires no flux when brazing between copper pipes or between a copper pipe and
copper coupling.
If installed refrigerant pipes are not immediately connected to the equipment, then braze and seal both ends.
2. Reasons
The new refrigerating machine oil is 10 times as hygroscopic as the conventional oil and is more likely to cause unit failure
if water infiltrates into the system.
Flux generally contains chloride. Residual flux in the refrigerant circuit will cause sludge to form.
3. Notes
Do not use commercially available antioxidants because they may cause the pipes to corrode or refrigerating machine
oil to deteriorate.
Use of oxidized solder for brazing Use of non-oxidized solder for brazing

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[ I Read Before Servicing ]
[7] Air Tightness Test
No changes have been made in the detection method. Note that a refrigerant leak detector for R22 will not detect an R410A
leak.
1. Items to be strictly observed
Pressurize the equipment with nitrogen up to the design pressure (4.15MPa), and then judge the equipment's air tight-
ness, taking temperature variations into account.
When using refrigerant instead of a leak detector to find the location of a leak, use R410A.
Refrigerant R410A must be charged in its liquid state (vs. gaseous state).
2. Reasons
Oxygen, if used for an air tightness test, poses a risk of explosion. (Only use nitrogen to check air tightness.)
Refrigerant R410A must be charged in its liquid state. If gaseous refrigerant in the cylinder is drawn out first, the compo-
sition of the remaining refrigerant in the cylinder will change and become unsuitable for use.
3. Notes
Procure a leak detector that is specifically designed to detect an HFC leak. A leak detector for R22 will not detect an
HFC(R410A, R407C) leak.
Halide torch R22 leakage detector
NO NO

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[ I Read Before Servicing ]
[8] Vacuum Drying (Evacuation)
1. Vacuum pump with a reverse-flow check valve (Photo1)
To prevent the vacuum pump oil from flowing into the refrigerant circuit during power OFF or power failure, use a vacuum
pump with a reverse-flow check valve.
A reverse-flow check valve may also be added to the vacuum pump currently in use.
2. Standard of vacuum degree (Photos 2)
Use a vacuum pump that attains 65Pa or lower degree of vacuum after 5 minutes of operation, and connect it directly to
the vacuum gauge. Use a pump well-maintained with an appropriate lubricant. A poorly maintained vacuum pump may not
be able to attain the desired degree of vacuum.
3. Required precision of vacuum gauge
Use a vacuum gauge that registers a vacuum degree of 650Pa and measures at intervals of 130Pa. (A recommended vac-
uum gauge is shown in Photo2.)
Do not use a commonly used gauge manifold because it cannot register a vacuum degree of 650Pa.
4. Evacuation time
After the degree of vacuum has reached 650Pa, evacuate for an additional 1 hour. (A thorough vacuum drying removes
moisture in the pipes.)
Verify that the vacuum degree has not risen by more than 130Pa 1hour after evacuation. A rise by less than 130Pa is ac-
ceptable.
If the vacuum is lost by more than 130Pa, conduct evacuation, following the instructions in section 6. Special vacuum dry-
ing.
5. Procedures for stopping vacuum pump
To prevent the reverse flow of vacuum pump oil, open the relief valve on the vacuum pump side, or draw in air by loosening
the charge hose, and then stop the operation.
The same procedures should be followed when stopping a vacuum pump with a reverse-flow check valve.
6. Special vacuum drying
When 650Pa or lower degree of vacuum cannot be attained after 3 hours of evacuation, it is likely that water has penetrated
the system or that there is a leak.
If water infiltrates the system, break the vacuum with nitrogen. Pressurize the system with nitrogen gas to
0.05MPa and evacuate again. Repeat this cycle of pressurizing and evacuation either until the degree of vacuum below
650Pa is attained or until the pressure stops rising.
Only use nitrogen gas for vacuum breaking. (The use of oxygen may result in an explosion.)
(Photo1) 15010H (Photo2) 14010
Recommended vacuum gauge:
ROBINAIR 14010 Thermistor Vacuum Gauge

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[ I Read Before Servicing ]
[9] Refrigerant Charging
1. Reasons
R410A is a pseudo-azeotropic HFC blend (boiling point R32=-52°C, R125=-49°C) and can almost be handled the same
way as a single refrigerant, such as R22. To be safe, however, draw out the refrigerant from the cylinder in the liquid
phase. If the refrigerant in the gaseous phase is drawn out, the composition of the remaining refrigerant will change and
become unsuitable for use.
2. Notes
When using a cylinder with a siphon, refrigerant is charged in the liquid state without the need for turning it upside down.
Check the type of the cylinder on the label before use.
[10] Remedies to be taken in case of a Refrigerant Leak
If the refrigerant leaks out, it may be replenished. The entire refrigerant does not need to be replaced. (Charge refrigerant in
the liquid state.)
Refer to "9. (5) Refrigerant leak".
Cylinder with a siphon
Cylinder color R410A is pink. Refrigerant charging in the liquid state
Cylin-
der
liquid
Valve Valve
liquid
Cylin-
der
Cylinder without a siphon