Hitachi RAS-18CH7 User manual

NO. 0346E
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
INDOOR UNIT + OUTDOOR UNIT
DECEMBER 2006 Refrigeration & Air-Conditioning Division
SERVICE MANUAL
PM
REFER TO THE FOUNDATION MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
H
D
(kg)
(WALL TYPE)
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
CAPACITY
TOTAL INPUT
TOTAL AMPERES
CAPACITY
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS
RAS-18CH7
RAS-24CH7
CONTENTS
SPECIFICATIONS ----------------------------------------------------- 4
HOW TO USE ---------------------------------------------------------- 7
CONSTRUCTION AND DIMENSIONAL DIAGRAM ------- 31
MAIN PARTS COMPONENT ------------------------------------- 33
WIRING DIAGRAM -------------------------------------------------- 35
CIRCUIT DIAGRAM ------------------------------------------------- 37
PRINTED WIRING BOARD LOCATION DIAGRAM ------- 39
BLOCK DIAGRAM --------------------------------------------------- 41
BASIC MODE --------------------------------------------------------- 43
REFRIGERATING CYCLE DIAGRAM ------------------------- 49
DESCRIPTION OF MAIN CIRCUIT OPERATION --------- 51
AUTO SWING FUNCTION ---------------------------------------- 55
SERVICE CALL Q & A -------------------------------------------- 56
TROUBLE SHOOTING --------------------------------------------- 62
PARTS LIST AND DIAGRAM ------------------------------------ 65
RAS-18CH7/RAC-18CH7
RAS-24CH7/RAC-24CH7
COOLING
HEATING
OUTDOOR UNIT
RAC-18CH7
INDOOR UNIT
RAS-18CH7
1030
295
191
11
1 Ø, 50 Hz, 220 - 240V
1680 - 1730
7.8 - 7.40
5.10
17,410
1700 - 1750
8.00 - 7.50
5.7
19,460
After installation
RAC-18CH7
RAC-24CH7
OUTDOOR UNIT
RAC-24CH7
INDOOR UNIT
RAS-24CH7
850
650
298
55
1030
295
191
12
1 Ø, 50 Hz, 220-240V
2270-2400
10.9-10.5
6.30
21,500
2370-2400
11.20-10.40
7.05
24,060
850
650
298
50

– i –
SAFETY DURING REPAIR WORK
1. In order to disassemble and repair
the unit in question, be sure to
disconnect the power cord plug
from the power outlet before starting
the work.
2. If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and
the replacement must be effected in correct manner according to the instructions in the Service Manual of
the unit.
If the contacts of electrical parts
are defective, replace the
electrical parts without trying to
repair them.
3. After completion of repairs, the initial state
should be restored.
4. Lead wires should be connected and laid as
in the initial state.
5. Modification of the unit by user himself should
absolutely be prohibited.
6. Tools and measuring instruments for use in repairs or inspection should be accurately calibrated in advance.
7. In installing the unit having been repaired, be careful to prevent the occurence of any accident such as
electrical shock, leak of current, or bodily injury due to the drop of any part.
8. To check the insulation of the unit, measure the insulation resistance between the power cord plug and
grounding terminal of the unit. The insulation resistance should be 1M or more as measured by a 500V
DC megger.
9. The initial location of installation such as window, floor or the other should be checked for being and safe
enough to support the repaired unit again.
If it is found not so strong and safe, the unit should be installed at the initial location reinforced or at a new
location.
10. Any inflammable thing should never
be placed about the location of
installation.
11. Check the grounding to see whether
it is proper or not, and if it is found
improper, connect the grounding
terminal to the earth.
DANGER
First, I must disconnect
the power cord plug
from the power outlet.

– 1 –
WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS
1. Scope
The standards provide for items to be generally observed in carrying and handling semiconductors in relative
manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal
goods such as rejected goods being returned).
2. Object parts
(1) Micro computer
(2) Integrated circuits (IC)
(3) Field-effect transistors (FET)
(4) P.C. boards or the like on which the parts mentioned in (1) and (2) of this paragraph are equipped.
3. Items to be observed in handling
(1) Use a conductive container for carrying and storing of parts. (Even rejected goods should be handled in
the same way).
Fig. 1. Conductive Container
(2) When any part is handled uncovered (in counting, packing and the like), the handling person must always
use himself as a body earth. (Make yourself a body earth by passing one M ohm earth resistance through
a ring or bracelet).
(3) Be careful not to touch the parts with your clothing when you hold a part even if a body earth is being
taken.
(4) Be sure to place a part on a metal plate with grounding.
(5) Be careful not to fail to turn off power when you repair the printed circuit board. At the same time,
try to repair the printed circuit board on a grounded metal plate.
1M
Fig. 2. Body Earth
Body earth
(Elimik conductive band)
Clip for connection with a
grounding wire
IC
A conductive polyvinyl bag IC
Conductive sponge

– 2 –
(6) Use a three wire type soldering iron including a grounding wire.
Bare copper wire (for body earth)
Working
table
Resistor of 1 M (1/2W)
Earth wire
Fig. 3. Grounding of the working table
Screw stop at the screwed
part using a rag plate
Soldering iron
Grounding
wire
Fig. 4. Grounding a soldering iron
Use a high insulation mode (100V, 10M or higher) when ordinary iron is to be used.
(7) In checking circuits for maintenance, inspection or some others, be careful not to have the test probes of the
measuring instrument shortcircuit a load circuit or the like.
Metal plate (of aluminium, stainless steel, etc.)
Staple

– 3 –
1. In quiet or stopping operation, slight flowing noise of refrigerant in the refrigerating cycle is heard occasionally,
but this noise is not abnormal for the operation.
2. When it thunders near by, it is recommended to stop the operation and to disconnect the power cord plug
from the power outlet for safety.
3. The room air conditioner does not start automatically after recovery of the electric power failure for preventing
fuse blowing. Re-press START/STOP button after 3 minutes from when unit stopped.
4. If the room air conditioner is stopped by adjusting thermostat, or missoperation, and re-start in a moment,
there is occasion that the cooling and heating operation does not start for 3 minutes, it is not abnormal
and this is the result of the operation of IC delay circuit. This IC delay circuit ensures that there is no
danger of blowing fuse or damaging parts even if operation is restarted accidentally.
5. This room air conditioner should not be used at the cooling operation when the outside temperature is
below 10°C (50°F).
6. This room air conditioner (the reverse cycle) should not be used when the outside temperature is below
–10°C (14°F).
If the reverse cycle is used under this condition, the outside heat exchanger is frosted and efficiency falls.
7. When the outside heat exchanger is frosted, the frost is melted by operating the hot gas system, it is not
trouble that at this time fan stops and the vapour may rise from the outside heat exchanger.
!
CAUTION

– 4 –
SPECIFICATIONS
MODEL
FAN MOTOR
FAN MOTOR CAPACITOR
FAN MOTOR PROTECTOR
COMPRESSOR
COMPRESSOR MOTOR CAPACITOR
OVERLOAD PROTECTOR
OVERHEAT PROTECTOR
FUSE (MICRO COMPUTER CIRCUIT)
POWER RELAY
POWER SWITCH
TEMPORARY SWITCH
SERVICE SWITCH
TRANSFORMER
VARISTOR
NOISE SUPPRESSOR
THERMOSTAT
REMOTE CONTROL SWITCH (LIQUID CRYSTAL)
FUSE CAPACITY
RAS-18CH7
20 W
NO
NO
–
NO
NO
NO
3.15A
G4A
YES
NO
YES
NO
450NR
NO
YES(IC)
YES
RAC-18CH7
40 W
2.5 F,450V
YES (INTERNAL)
SHX33SC4-U
50 F, 440VAC
YES (INTERNAL)
YES (INTERNAL)
NO
NO
NO
NO
YES
NO
NO
NO
YES(IC)
NO
20 A TIME DELAY FUSE
---------- 1400gUNIT
REFRIGERANT CHARGING
VOLUME
(Refrigerant R22) ADDITIONAL REFRIGERANT R22
AT 25g PER EVERY METER IF
PIPE LENGTH MORE THAN 8m
PIPES (MAX. 15m)
PIPES (MIN. 5m)

– 5 –
SPECIFICATIONS
MODEL
FAN MOTOR
FAN MOTOR CAPACITOR
FAN MOTOR PROTECTOR
COMPRESSOR
COMPRESSOR MOTOR CAPACITOR
OVERLOAD PROTECTOR
OVERHEAT PROTECTOR
FUSE (MICRO COMPUTER CIRCUIT)
POWER RELAY
POWER SWITCH
TEMPORARY SWITCH
SERVICE SWITCH
TRANSFORMER
VARISTOR
NOISE SUPPRESSOR
THERMOSTAT
REMOTE CONTROL SWITCH (LIQUID CRYSTAL)
FUSE CAPACITY
RAS-24CH7
20 W
NO
NO
–
NO
NO
NO
3.15A
G4A
YES
NO
YES
NO
450NR
NO
YES(IC)
YES
RAC-24CH7
40 W
2.5 F,450V
YES (INTERNAL)
SHV33YC6-U
50 F, 450VAC
YES (INTERNAL)
YES (INTERNAL)
NO
NO
NO
NO
NO
NO
NO
NO
YES(IC)
NO
30 A TIME DELAY FUSE
---------- 1700gUNIT
REFRIGERANT CHARGING
VOLUME
(Refrigerant R22) ADDITIONAL REFRIGERANT R22
AT 25g PER EVERY METER IF
PIPE LENGTH MORE THAN 8m
PIPES (MAX. 15m)
PIPES (MIN. 5m)

– 6 –
above 50mm
above 100mm
above 0.45m
above 300mm
must not bend
above 100mm
2,300mm or more
Maximum pipe length 15m Minimum pipe length 5m
above 200mm
above 700mm
above 200mm
above 50mm when
installed on the
ceiling of balcony
()
above 100mm
above 100mm
give clearance as
wide as possible
Plug
Figure showing the installation of Indoor anf Outdoor unit
The installation height of indoor unit must be 2.3m or more.
CAUTION
!
The indoor piping should be
insulated with the enclosed
insulation pipe. (If the
insulator is insufficient,
please use commersial
products).
inner diameter ø16mm
The connection of insulated
drain hose.
Please use insulated drain
hose for the indoor piping
(commercial product).
The difference in height
between the indoor and
outdoor unit should be
kept max 10m.
The connecting pipe, no
matter big or small,
should all be insulated
with insulation pipe and
then warapped with vinyl
tape. (The insulator will
deteriorate if it is not
wrapped with tape).

– 7 –
!
SAFETY PRECAUTION
●
Please read the “Safety Precaution” carefully before operating the unit to ensure correct usage of the unit.
●
Pay special attention to signs of “ Warning” and “ Caution”. The “Warning” section contains matters which,
if not observed strictly, may cause death or serious injury. The “Caution” section contains matters which may
result in serious consequences if not observed properly. Please observe all instructions strictly to ensure safety.
●
The sign indicate the following meanings.
●
Please keep this manual after reading.
WARNING
PRECAUTIONS DURING INSTALLATION
●Do not reconstruct the unit.
Water leakage, fault, short circuit or fire may occur if you reconstruct
the unit by yourself.
●Please ask your sales agent or qualified technician for the installation
of your unit. Water leakage, short circuit or fire may occur if you install
the unit by yourself.
●Please use earth line.
Do not place the earth line near water or gas pipes, lightning-conductor,
or the earth line of telephone. Improper installation of earth line may
cause electric shock.
●A circuit breaker should be installed depending on the mounting site of
the unit. Without a circuit breaker, the danger of electric shock exists.
●Do not install near location where there is flammable gas. The outdoor
unit may catch fire if flammable gas leaks around it.
●Please ensure smooth flow of water when installing the drain hose.
CAUTION
!
!
PRECAUTIONS DURING SHIFTING OR MAINTENANCE
PRECAUTIONS DURING OPERATION
●Avoid an extended period of direct air flow for your health.
W
A
R
N
I
N
G
!
●Should abnormal situation arises (like burning smell), please stop operating the unit
and turn off the circuit breaker. Contact your agent. Fault, short circuit or fire may
occur if you continue to operate the unit under abnormal situation.
●Please contact your agent for maintenance. Improper self maintenance may cause
electric shock and fire.
●Please contact your agent if you need to remove and reinstall the unit. Electric
shock or fire may occur if you remove and reinstall the unit yourself improperly.
●If the supply cord is damaged, it must be replaced by the special cord obtainable
at authorized service/parts centers.
●Do not put objects like thin rods into the panel of blower and suction side
because the high-speed fan inside may cause danger.
●During thunder storm, disconnect and turn off the circuit breaker.
●Do not use any conductor as fuse wire, this could cause fatal accident.
!
Make sure to connect earth line.
Indicates the instructions that must be followed.
The sign in the figure indicates prohibition.
W
A
R
N
I
N
G
!

– 8 –
PRECAUTIONS DURING OPERATION
●Do not attempt to operate the unit with wet hands, this could cause fatal
accident.
●When operating the unit with burning equipments, regularly ventilate the
room to avoid oxygen insufficiency.
●Do not direct the cool air coming out from the air-conditioner panel to face
household heating apparatus as this may affect the working of apparatus
such as the electric kettle, oven etc.
●Do not place plants directly under the air flow as it is bad for the plants.
●Please ensure that outdoor mounting frame is always stable, firm and
without defect. If not, the outdoor unit may collapse and cause danger.
●Do not splash or direct water to the body of the unit when cleaning it as this
may cause short circuit.
●When operating the unit with the door and windows opened, (the room humidity is always above
80%) and with the air deflector facing down or moving automatically for a long period of time,
water will condense on the air deflector and drips down occasionally. This will wet your furniture.
Therefore, do not operate under such condition for a long time.
●If the amount of heat in the room is above the cooling or heating capability of the unit (for
example: more people entering the room, using heating equipments and etc.), the preset room
temperature cannot be achieved.
●Do not climb on the outdoor unit or put objects on it.
●Please switch off the unit and turn off the circuit breaker during cleaning, the
high-speed fan inside the unit may cause danger.
●Turn off the circuit breaker if the unit is not to be operated for a long period.
C
A
U
T
I
O
N
!
●The product shall be operated under the manufacturer specification and
not for any other intended use.
●Do not put water container (like vase) on the indoor unit to avoid water
dripping into the unit. Dripping water will damage the insulator inside the unit
and causes short-circuit.
●Do not use any aerosol or hair sprays near the indoor unit. This chemical
can adhere on heat exchanger fin and blocked the evaporation water flow
to drain pan. The water will drop on tangential fan and cause water splashing
out from indoor unit.