Mitsubishi Electric CITY MULTI PUHY-400YMF-C How to use

AIR CONDITIONERS CITY MULTI
Models PUHY-400YMF-C, 500YMF-C
PUHY-P400YMF-C, P500YMF-C
PUHY-600YSMF-C, 650YSMF-C, 700YSMF-C, 750YSMF-C
PUHY-P600YSMF-C, P650YSMF-C, P700YSMF-C, P750YSMF-C
Service Handbook
Service Handbook PUHY-400YMF-C, 500YMF-C
PUHY-P400YMF-C, P500YMF-C
PUHY-600YSMF-C, 650YSMF-C, 700YSMF-C, 750YSMF-C
PUHY-P600YSMF-C, P650YSMF-C, P700YSMF-C, P750YSMF-C
HEAD OFFICE MITSUBISHI DENKI BLDG. MARUNOUCHI TOKYO 100-0005 TELEX J24532 CABLE MELCO TOKYO
Issued in May 2003 MEE02K140
Printed in Japan
New publication effective Jan 2003
Specifications subject to change without notice.
Service Handbook PUHY-400·500YMF-C/PUHY-P400·P500YMF-C/PUHY-600·650·700·750YSMF-C/PUHY-P600·P650·P700·P750YSMF-C

Contents
1 PRECAUTIONS FOR DEVICES
THAT USE R407C REFRIGERANT ......................................... 1
[1] Storage of Piping Material ............................................. 2
[2] Piping Machining ........................................................... 3
[3] Brazing ........................................................................... 4
[4] Airtightness Test ............................................................. 5
[5] Vacuuming ..................................................................... 5
[6] Charging of Refrigerant ................................................. 6
[7] Dryer .............................................................................. 6
2 COMPONENT OF EQUIPMENT ............................................. 7
[1] Appearance of Components .......................................... 7
[2] Refrigerant Circuit Diagram and Thermal Sensor ........ 18
[3] Electrical Wiring Diagram ............................................. 22
[4] Standard Operation Data ............................................. 24
[5] Function of Dip SW and Rotary SW ............................ 36
3 TEST RUN ............................................................................. 42
[1] Before Test Run ........................................................... 42
[2] Test Run Method .......................................................... 48
4 GROUPING REGISTRATION OF INDOOR UNITS WITH
M-NETREMOTE CONTROLLER ........................................... 49
5 CONTROL.............................................................................. 55
[1] Control of Outdoor Unit ................................................ 55
[2] Operation Flow Chart ................................................. 106
[3] List of Major Component Functions ........................... 111
[4] Resistance of Temperature Sensor ............................ 115
6 REFRIGERANT AMOUNT ADJUSTMENT ......................... 116
[1] Operating Characteristics and Refrigerant Amount ... 116
[2] Adjustment and Judgement of Refrigerant Amount ... 116
[3] Refrigerant Volume Adjustment Mode Operation....... 119
7 TROUBLESHOOTING ......................................................... 125
[1] Principal Parts ............................................................ 125
[2] Self-diagnosis and Countermeasures Depending
on the Check Code Displayed ................................... 153
175
[3] LED Monitor Display ..................................................
8
.............................. 199
[1]
........................................................... 199
[2] ......... 200
[3]
.......................................................... 200
[4] .......... 201
9 ...... 202
PREPARATION, REPAIRS AND REFRIGERANT
REFILLING WHEN REPAIRING LEAKS
Location of leaks: Extension piping or indoor units
(when cooling)
Location of leaks: Outdoor unit (Cooling mode)
Location of leaks: Extension piping or indoor units
(Heating mode)
Location of leaks: Outdoor unit (when heating)
CHECK THE COMPOSITION OF THE REFRIGERANT

Safety precautions
This equipment may not be applicable to
EN61000-3-2: 1995 and EN61000-3-3: 1995.
Please report to or take consent by the supply
authority before connection to the system.
Symbols used in the text
Warning:
Describes precautions thatshould be observed to
prevent danger of injury or death to the user.
Caution:
Describes precautionsthat should be observed to
preventdamage to the unit.
Symbols used in the illustrations
: Indicates an action that must be avoided.
: Indicates important instructions must be followed.
: Indicates a part which must be grounded.
: Beware of electric shock (This symbol is displayed on the
main unit label.) <Color: Yellow>
Warning:
Carefully read the labels affixed to the main unit.
Warning:
•Use the specified cables for wiring.Make the connections
securely so that the outside force of the cable is not
applied to the terminals.
- Inadequate connection and fastening may generate heat and
cause a fire.
•Have all electric work done by a licensedelectrician
according to “Electric Facility Engineering Standard”and
“Interior Wire Regulations”and the instructions given in
this manual and always use a dedicated circuit.
- If the power source capacity is inadequate or electric work is
performed improperly, electric shock and fire may result.
•Securely install the cover of control box and the panel.
- If the cover and panel are not installed properly, dust or water
may enter the outdoor unit and fire or electric shock may
result.
•After completing service work, make sure that refrigerant
gas is not leaking.
- If the refrigerant gas leaks and is exposed to a fan heater,
stove, oven, or other heat source, it may generate noxious
gases.
•Do not reconstruct or change the settings of the protection
devices.
- If the pressure switch, thermal switch, or other protection
device is shorted and operated forcibly, or parts other than
those specified by Mitsubishi Electric are used, fire or
explosion may result.
Before installing the unit, make sure you read all
the “Safety precautions”.
The “Saftey precautions” provide very important
points regarding safety. Make sure you follow
them.
This equipment may have an adverse effect on
equipment on the same electrical supply system.
Before installation and electric work

-1-
¡PRECAUTIONS FOR DEVICES THAT USE R407C REFRIGERANT
Caution
Do not use the existing refrigerant piping.
•The old refrigerant and refrigerator oil in the existing
piping contains a large amount of chlorine which may
cause the refrigerator oil of the new unit to deterio-
rate.
Use refrigerant piping made of phosphorus deoxi-
dized copper and copper alloy seamless pipes and
tubes”. In addition, be sure that the inner and outer
surfaces of the pipes are clean and free of hazardous
sulphur, oxides, dust/dirt, shaving particles, oils,
moisture, or any other contaminant.
•Contaminants on the inside of the refrigerant piping
may cause the refrigerant residual oil to deteriorate.
Store the piping to be used during installation indoors
and keep both ends of the piping sealed until just
before brazing. (Store elbows and other joints in a
plastic bag.)
•If dust, dirt, or water enters the refrigerant cycle,
deterioration of the oil and compressor trouble may
result.
Use ester oil, ether oil or alkylbenzene (small
amount) as the refrigerator oil to coat flares and
flange connections.
•The refrigerator oil will degrade if it is mixed with a
large amount of mineral oil.
Use liquid refrigerant to seal the system.
•If gas refrigerant is used to seal the system, the com-
position of the refrigerant in the cylinder will change
and performance may drop.
Do not use a refrigerant other than that specified.
•If another refrigerant is used, the chlorine in the
refrigerant may cause the refrigerator oil to
Use a vacuum pump with a reverse flow check valve.
•The vacuum pump oil may flow back into the refriger-
ant cycle and cause the refrigerator oil to deteriorate.
Do not use the following tools that have been used
with conventional refrigerants.
(Gauge manifold, charge hose, gas leak detector, re-
verse flow check valve, refrigerant charge base,
vacuum gauge, refrigerant recovery equipment)
•If the conventional refrigerant and refrigerator oil are
mixed in the R407C, the refrigerant may deterio-
rated.
•If water is mixed in the R407C, the refrigerator oil
may deteriorate.
•Since R407C does not contain any chlorine, gas
leak detectors for conventional refrigerants will not
react to it.
Do not use a charging cylinder.
•Using a charging cylinder may cause the refrigerant
to deteriorate.
Be especially careful when managing tools.
•If dust, dirt, or water that gets in the refrigerant cycle,
may cause the refrigerant to deteriorate.
If the refrigerant leaks, recover the refrigerant in the
refrigerant cycle, then recharge the cycle with the
specified amount of the liquid refrigerant indicated
on the air conditioner.
•Since R407C is a nonazeotropic refrigerant, if addi-
tionally charged when the refrigerant leaked, the com-
position of the refrigerant in the refrigerant cycle will
change and result in a drop in performance or abnor-
mal stopping.
deteriorate.

-2-
[1] Storage of Piping Material
(1) Storage location
Store the pipes to be used indoors. (Warehouse at site or owner’s warehouse)
Storing them outdoors may cause dirt, waste, or water to infiltrate.
(2) Pipe sealing before storage
Both ends of the pipes should be sealed until immediately before brazing.
Wrap elbows and T’s in plastic bags for storage.
* The new refrigerator oil is 10 times more hygroscopic than the conventional refrigerator oil (such as Suniso). Water
infiltration in the refrigerant circuit may deteriorate the oil or cause a compressor failure. Piping materials must be
stored with more care than with the conventional refrigerant pipes.

-3-
[2] Piping Machining
Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator oil to coat flares and flange connections.
Use only the necessary minimum quantity of oil !
Reason:
1. The refrigerator oil used for the equipment is highly hygroscopic and may introduce water inside.
Notes:
•Introducing a great quantity of mineral oil into the refrigerant circuit may also cause a compressor failure.
•Do not use oils other than ester oil, ether oil or alkylbenzene

-4-
[3] Brazing
No changes from the conventional method, but special care is required so that foreign matter (ie. oxide scale, water, dirt,
etc.) does not enter the refrigerant circuit.
Example : Inner state of brazed section
When non-oxide brazing was not used When non-oxide brazing was used
Items to be strictly observed :
1. Do not conduct refrigerant piping work outdoors on a rainy day.
2. Apply non-oxide brazing.
3. Use a brazing material (Bcup-3) which requires no flux when brazing between copper pipes or between a copper pipe
and copper coupling.
4. If installed refrigerant pipes are not immediately connected to the equipment, then braze and seal both ends of them.
Reasons :
1. The new refrigerant oil is 10 times more hygroscopic than the conventional oil. The probability of a machine failure if
water infiltrates is higher than with conventional refrigerant oil.
2. A flux generally contains chlorine. A residual flux in the refrigerant circuit may generate sludge.
Note :
•Commercially available antioxidants may have adverse effects on the equipment due to its residue, etc. When
applying non-oxide brazing, use oxygen free nitrogen (OFN).

-5-
[4] Airtightness Test
No changes from the conventional method. Note that a refrigerant leakage detector for R22 cannot detect R407C
leakage.
Halide torch R22 leakage detector
Items to be strictly observed :
1. Pressurize the equipment with nitrogen up to the design pressure and then judge the equipment’s airtightness,
temperature variations into account.
taking
2. When investigating leakage locations using a refrigerant, be sure to use R407C.
3. Ensure that R407C is in a liquid state when charging.
Reasons :
1. Use of oxygen as the pressurized gas may cause an explosion.
2. Charging with R407C gas will lead the composition of the remaining refrigerant in the cylinder to change and
refrigerant can then not be used.
this
Note :
•A leakage detector for R407C is sold commercially and it should be purchased.
[5] Vacuuming
1. Vacuum pump with check valve
A vacuum pump with a check valve is required to prevent the vacuum pump oil from flowing back into the
circuit when the vacuum pump power is turned off (power failure).refrigerant
It is also possible to attach a check valve to the actual vacuum pump afterwards.
2. Standard degree of vacuum for the vacuum pump
Use a pump which reaches 0.5 Torr (500 MICRON) or below after 5 minutes of operation.
In addition, be sure to use a vacuum pump that has been properly maintained and oiled using the specified oil. If
vacuum pump is not properly maintained, the degree of vacuum may be too low.
the
3. Required accuracy of the vacuum gauge
Use a vacuum gauge that can measure up to 5 Torr. Do not use a general gauge manifold since it cannot
vacuum of 5 Torr.
measure a
4. Evacuating time
•Evacuate the equipment for 1 hour after –755 mmHg (5 Torr) has been reached.
•After envacuating, leave the equipment for 1 hour and make sure that the vacuum is not lost.
5. Operating procedure when the vacuum pump is stopped
In order to prevent a backflow of the vacuum pump oil, open the relief valve on the vacuum pump side or loosen
charge hose to drawn in air before stopping operation.
the
The same operating procedure should be used when using a vacuum pump with a check valve.

-6-
Cylin-
der
Cylin-
der
Valve Va l ve
Liquid Liquid
[6] Charging of Refrigerant
R407C must be in a liquid state when charging, because it is a non-azeotropic refrigerant.
For a cylinder with a syphon attached For a cylinder without a syphon attached
Cylinder color identification R407C-Gray Charged with liquid refrigerant
R410A-Pink
Reasons :
1. R407C is a mixture of 3 refrigerants, each with a different evaporation temperature. Therefore, if the equipment
charged with R407C gas, then the refrigerant whose evaporation temperature is closest to the outside temperature
is
charged first while the rest of refrigerants remain in the cylinder.
Note :
•In the case of a cylinder with a syphon, liquid R407C is charged without turning the cylinder up side down. Check the
type of cylinder before charging.
[7] Dryer
1. Replace the dryer when the refrigerant circuit is opened (Ex. Change the compressor, full gas leakage). Be sure to
replace the dryer with a CITY MULTI Series Y (For use with R407C).
If any other product is used, the unit will be damaged.
2. Opening the refrigerant circuit after changing to a new dryer is less than 1 hour. The replacement of the dryer
be the last operation performed.
should
is

-7-
[1] Appearance of Components
Heat Exchanger
Sub-cool Coil
Heat Exchanger of CS circuit
(PUHY-P-YMF-C only)
Solenoid Valve
(SV5b)
Solenoid Valve
(SV7)
(PUHY-P-YMF-C only)
Solenoid Valve
(SV8)
(PUHY-P-YMF-C only)
Four-way Valve
(21S4b)
Four-way Valve
(21S4a)
Heat ExchangerAmbient temperature Sensor
Accumlator
Constant Capacity Compressor
(No. 2 Compressor)
Crank Case HeaterOil Equalization Pipe
Variable Capacity
Compressor
(No. 1 Compressor)
Oil Separator
1Variable capacity unit
Rear