Hitachi RAS-25CNH2 User manual

NO. 0081E
SERVICE MANUAL
PM
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
SPECIFICATIONS
CONTENTS
SPECIFICATIONS --------------------------------------------------------------5
HOW TO USE -------------------------------------------------------------------6
CONSTRUCTION AND DIMENSIONAL DIAGRAM ---------------- 22
MAIN PARTS COMPONENT --------------------------------------------- 23
PRINTED WIRING BOARD LOCATION DIAGRAM---------------- 25
BLOCK DIAGRAM ------------------------------------------------------------ 33
DESCRIPTION OF MAIN CIRCUIT OPERATION ------------------ 35
SERVICE CALL Q & A ----------------------------------------------------- 67
TROUBLE SHOOTING ------------------------------------------------------ 70
PARTS LIST AND DIAGRAM--------------------------------------------- 80
RAS-25CNH2
RAC-25CNH2
REFER TO THE FOUNDATION MANUAL
INDOOR UNIT
RAS-25CNH2
OUTDOOR UNIT
RAC-25CNH2
WALL TYPE
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
INDOOR UNIT + OUTDOOR UNIT
APRIL 1998
H.A.P.M.
TYPE
MODEL
1ø 220V – 240V 50HzPOWER SOURCE
910 (190 `1,150) [COOL] / 1,250 (160 `1,350) [HEAT]TOTAL INPUT
4.20 `3.85 [COOL] / 5.75 `5.25 [HEAT]TOTAL AMPERES (RATED / MAX.)
COOLING CAPACITY
HEATING CAPACITY
DIMENSIONS
NET WEIGHT
(W)
(A)
(kW)
(B.T.U./h)
(kW)
(B.T.U./h)
W
H
D
(kg)
(mm)
2.50 (0.90 `2.80)
8,870 (3,070 `9,550)
3.60 (0.90 `4.00)
12,280 (3,070 `13,650)
744
248
168
5.5
700
570
210
29
RAS-25CNH2
RAC-25CNH2

– 1 –
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.

– 2 –
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

– 3 –
(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
2
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

– 4 –
1. In quiet operation or stopping the running, 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 recommend to stop the operation and to disconnect the power cord plug from
the power outlet for safety.
3. If the room air conditioner is stopped by setting the temperature or mis-operation, and then re-started in a
moment, cooling 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.
4. This room air conditioner should not be used at the cooling operation when the outside temperature is below
20°C.
5. When the operation knob is set to “COOL” from another position, IC delay circuit functions and stops the
compressor for the first 3 minutes, which is not an abnormal phenomenon.
CAUTION

– 5 –
RAC-25CNH2
20 W
NO
NO
G920DP5H
NO
YES
YES
3.15A
G4A
NO
NO
YES
NO
450NR
NO
NO
NO
MODEL
FAN MOTOR
FAN MOTOR CAPACITOR
FAN MOTOR PROTECTOR
COMPRESSOR
COMPRESSOR MOTOR CAPACITOR
OVERLOAD PROTECTOR
OVERHEAT PROTECTOR
FUSE
POWER RELAY, STICK RELAY
POWER SWITCH
TEMPORARY SWITCH
SERVICE SWITCH
TRANSFORMER
VARISTOR
NOISE SUPPRESSOR
REMOTE CONTROL SWITCH (LIQUID CRYSTAL)
THERMOSTAT
FUSE CAPACITY
RAS-25CNH2
20 W
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
NO
NO
NO
NO
YES
YES (IC)
SPECIFICATIONS
NO
---------- ❈ 690g
UNIT
PIPES
❈690g for piping set of 5~8m.
REFRIGERANT
CHARGING VOLUME
(Refrigerant 22) WITHOUT REFRIGERANT BECAUSE
COUPLING IS FLARE TYPE.
P - 105 VK1 (5m), P - 108 VK1 (8m)

– 6 –
INDOOR UNIT
OUTDOOR UNIT
WIDTH (mm)
744
700
MODEL
RAS-25CNH2
RAC-25CNH2
HEIGHT (mm)
248
570
DEPTH (mm)
168
210
MODEL NAME AND DIMENSIONS
NAMES AND FUNCTIONS OF EACH PART
AIR FILTER
To prevent dust from coming into the indoor unit.
(Refer page 18)
POWER PLUG (NOT PROVIDED)
INDOOR UNIT INDICATORS
Light indicator showing the operating condition.
(Refer page 7)
SUCTION GRILL (AIR INLET)
HORIZONTAL DEFLECTOR ●VERTICAL
DEFLECTOR (AIR OUTLET)
(Refer page 14)
REMOTE CONTROL
Send out operation signal to the indoor unit. So as
to operate the whole unit.
(Refer page 8)
DRAIN PIPE
Condensed water drain to outside.
CONNECTING CORD
AIR INLET (BACK, LEFT SIDE)
AIR OUTLET

– 7 –
INDOOR UNIT INDICATORS
TEMPORARY SWITCH
Use this switch to start and stop when the remote
controller does not work.
●By setting the temporary switch, the operation is done
in previously set operation mode.
●When the operation is done using the temporary switch
after the power source is turned off and turn on again,
the operation is done in automatic mode.
OPERATION INDICATOR
OPERATION LAMP
This lamp lights during operation.
The OPERATION LAMP flashes in the following cases
during heating.
(1) During preheating
For about 2–3 minutes after starting up.
(2) During defrosting
Defrosting will be performed about once an hour
when frost forms on the heat exchanger of the
outdoor unit, for 5–10 minutes each time.
TIMER LAMP
This lamp lights when the timer is working.
SIGNAL RECEIVER
There will be a beep sound when this receiver receives
signal from remote controller.
POWER SWITCH

– 8 –
NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT
■This controls the operation function and timer setting of the room air conditioner. The range of
control is about 4 meters. If indoor lighting is controlled electronically, the range of control may be
shorter.
Precautions for Use
●Do not put the remote controller in direct
sunlight and high temperature.
●Do not drop it on the floor, and protect
it from water.
●If you press the FUNCTION button
during operation, the air conditioner may
stop for about 3 minutes for protection
before you can start it again.
You can use the remote controller by fixing it on the
wall with the accessory parts.
●Before fixing it,
make sure the
unit can be
controlled by the
remote control
unit at the fixing
position.
REMOTE
CONTROLLER
HOLDER
START/STOP Button
Press this button to start operation.
Press it again to stop operation.
SLEEP Button
Use this button to set the sleep timer.
(Page 12)
Reserve Button
Timer setting reservation.
OFF TIMER Button
Select the turn OFF time.
ON TIMER Button
Select the turn ON time.
Transmission Sign
The transmission sign blinks
when a signal has been send.
TEMPERATURE Button
Room temperuture setting.
Value will change more quickly
when keep pressing.
(Page 9)
FAN SPEED Button
Select the fan speed for
cooling and heating mode.
(Page 10)
AUTO SWING Button
Control the angle of the
horizontal air deflector.
( Page 14)
CANCEL Button
Cancel timer reservation.
Signal Transmission
FUNCTION Button
Select the operation mode.
(Page 10)
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–9 –
AUTOMATIC OPERATION
■The device will automatically determine the mode of operation, HEAT, COOL or DEHUMIDIFY,
depending on the initial room temperature. The selected mode of operation will not change when
the room temperature varies.
1
Press the (START/STOP) button
●Operation start with a “beep”sound.
Press the (START/STOP) button
●Make sure the (Automatic) mode have been selected by using
the (FUNCTION) button.
●The fan speed selector does not work at this operation.
STOP
Press the (ROOM TEMPERATURE) button
●Temperature setting change by 1°C for each 1 time press.
Up
Down
●You can raise or lower the temperature setting by a maximum of
3°C.
●The display does not indicate the preset temperature in the Automatic
mode. Device will receive the setting by a “beep”.
■You can slightly adjust the room temperature.
1
°C
°C
▲ ▲
■CONDITION OF AUTOMATIC OPERATION
●The selected mode of operation will not change during the operation even though the room
temperature change.
Over 27°C COOL
23 ~ 27°C
FUNCTION
27°C
Slightly lower than the
room temperature LOW
FAN SPEED
HIGH at start, LOW after
the preset temperature is
reached
-
DRY
-
INITIAL ROOM
TEMPERATURE (APPROX.)
TEMPERATURE
SETTING
Under 23°C HEAT 23°C
HIGH at start, MED or
LOW after the preset
temperature is reached
-
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–10 –
MANUAL OPERATION [Heating ●Dehumidify ●Cooling]
■Please use under below condition when you want to set the function mode, room temperature and
fan speed by manually.
1
OPERATION MODE SELECTION
●Every time you press the button, the mode will change as the below
sequence
(Auto) [(Heat) [(Dry) [(Cool)
2
ROOM TEMPERATURE SETTING
Up
Down
●The cooling operation does not start if the
temperature setting is higher than the current
room temperature.
3
FAN SPEED SETTING
●Every time you press the button, fan speed will change as the
below sequence.
●HEATING : AUTO [HIGH [MED [LOW
COOLING : ( [[[)
●DEHUMIDIFYING : LOW (FIXED)
: ( )
4
Press the (START/STOP) button
●Operation start with a signal received sound “beep”.
Press the (START/STOP) button
●As the settings are stored in memory in the remote control unit, you
only have to press the (Start/Stop) button in order to use the
same setting next time.
STOP
HEATING
Outdoor Temperature
21°C below
DEHUMIDIFYING
Room Temperature
16°C above
COOLING
Outdoor Temperature
22°C above
°C
Heating 20~24°C
Dehumidify 20~26°C
Cooling 25~28°C
■Recommend Temperature
▲ ▲
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–11 –
TIMER RESERVATION
■ON Timer and OFF Timer are available.
1
OFF TIME setting
●Select the OFF TIME by pressing the (OFF)
Button.
●Setting time will change according to the below
sequence when you press the button.
●The value change more quickly if you keep pressing
the button.
OFF Timer Reservation
■Operation stop at setting time
2
Press the (Reserve) button
●OFF TIMER reserved with a signal received sound
“beep”.
●The (OFF) Mark starts lighting instead of blinding.
0.5 1.0 1.5 9.5 10 11 12
0.5 hour interval 1 hour interval
1
ON TIME setting
●Select the ON TIMER by pressing the (ON)
Button.
●At the beginning of setting, time 6 hours was set.
●Setting time will change according to the below
sequence.
●The value change more quickly if you keep pressing
the button.
ON Timer Reservation
0.5 1.0 1.5 9.5 10 11 12
0.5 hour interval 1 hour interval
1
Press the (Cancel) button
●As the time settings are stored in remote controller
memory, you only have to press the (Reserve)
button in order to use the same setting next time.
CANCELLATION of Timer Reservation
2
Press the (Reserve) button
●ON TIMER reserved with a signal received sound
“beep”.
●The (ON) Mark starts lighting instead of blinding.
o
■Operation will start for setting
temperature at setting time (The starting
time may different depend on the room
temperature and set temperature).
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–12 –
Set the current time at first if it is not set before (see the pages for setting
the current time). Press the (SLEEP) button, and the display changes
as shown below.
HOW TO SET THE SLEEP TIMER
Mode
Sleep timer
Indication
1 hour 2 hours 3 hours 7 hours
Sleep timer off
44 44
1
Sleep Timer: The device will continue working for the designated
number of hours and then turn off.
Point the signal window of the remote controller toward the indoor
unit, and press the SLEEP button.
The timer information will be displayed on the remote controller.
The TIMER lamp lights with a beep from the indoor unit.
How to Cancel Reservation
Point the signal window of the remote controller toward the indoor unit, and press the (CANCEL)
button.
The (RESERVED) sign goes out with a beep and the (TIMER) lamp turns off on the indoor unit.
NOTE
If you set the sleep timer when the off-timer or
on/off-timer has been set earlier, the sleep timer
becomes effective instead of the off- or on/off-
timer set earlier.
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Example: Setting 3 hours
sleep time.

–13 –
Cooling
“”
and
dehumidifying
“”
Explanation of the sleep timer
The device will control the FAN SPEED and room temperature automatically
so as to be quiet and good for people’s health.
You can set the sleep timer to turn off after 1, 2, 3 or 7 hours. The FAN
SPEED and room temperature will be controlled as shown below.
Function Operation
The settings of room temperature and circulation are not varied.
The FAN SPEED will be set to
LOW immediately.
Fan
“”
Heating
“”
The room temperature will be
controlled 5°C below the
temperature setting 30 minutes
after the setting of the sleep
timer. The FAN SPEED will be
set to LOW immediately.
Operation with the sleep timer
The room temperature is kept
at about 12°C minimum.
The room temperature is kept
at about 25–28°C.
Sleep timer set
30 minutes later
1 hour later 3 hours later
7 hours
later
2 hours
later
5°C
Sleep
timer set
30 minutes later 3 hours later
7 hours later
2 hours
later
6 hours
later

–14 –
ADJUSTING THE AIR DEFLECTOR
1
Adjustment of the conditioned air in the upward and downward
directions.
According to operation, the horizontal air deflector is
automatically set to the proper angle suitable for each
operation. The deflector can be swing up and down and also
set to the desired angle using the “(AUTO SWING)”
button. (If the angle of the deflector is changed, it will not
return to the auto-set position after operations start unless
the operation mode is switched.)
2
Adjustment of the conditioned air to the left and right.
Hold the vertical air deflector as shown in the figure and adjust
the conditioned air to the left and right.
●If the “(AUTO SWING)”button is pressed once,
the horizontal air deflector swings up and down. If the
button is pressed again, the deflector stops in its current
position. Several seconds (about 6 seconds) may be
required before the deflector starts to move.
●Use the horizontal air deflector within the adjusting range
shown on the right.
●When the operation is stopped, the horizontal air deflector
moves and stops at the position where the air outlet
closes.
When cooling
dehumidifying
When heating
!
CAUTION
●In “Cooling”operation, do not keep the horizontal air
deflector swinging for a long time. Some dew may form
on the horizontal air deflector and some dew drops may
fall from it.

–15 –
HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER
1
Remove the cover as shown in the figure and take out the
old batteries.
=
2
Install the new batteries.
The direction of the batteries should match the marks in the
case.
1. Do not use new and old batteries, or different kinds of batteries
together.
2. Take out the batteries when you do not use the remote controller
for 2 or 3 months.
3. The batteries must be of the LR03 type.
CAUTION
Push and pull to the
direction of arrow
!

–16 –
Suitable Room Temperature Install curtain or blinds
Ventilation Effective Usage Of Timer
Do Not Forget To Clean The Air Filter Please Adjust Suitable Temperature
For Baby And Children
Warning
Freezing temperature
is bad for health and a
waste of electric power.
!
It is possible to
reduce heat
entering the
room through
windows.
At night, please use the “OFF or ON timer
operation mode”, together with your wake up
time in the morning. This will enable you to
enjoy a comfortable room temperature. Please
use the timer effectively.
Dusty air filter will reduce the air volume and
the cooling efficiency. To prevent from wasting
electric energy, please clean the filter every 2
weeks.
Please pay attention to the room temperature
and air flow direction when operating the unit
for baby, children and old folks who have
difficulty in movement.
Caution
Do not close the room for a long period of
time. Occasionally open the door and windows
to allow the
entrance of
fresh air.
!
THE IDEAL WAYS OF OPERATION

–17 –
FOR USER’S INFORMATION
The Air Conditioner And The Heat Source In The Room
After Power Failure
Not Operating For A Long Time
When Lightning Occurs
Caution
If the amount of heat in the room is above the cooling
capability of the air conditioner (for example: more
people entering the room, using heating equipments
and etc.), the preset room temperature cannot be
achieved.
!
When the power is resumed after a power failure,
the indoor unit will still remain “OFF”. To operate the
unit, please press the “ON/OFF”button again.
When the indoor unit is not to be used for a long
period of time, please switch off the power from the
mains. If the power from mains remains “ON”, the
indoor unit still consumes about 8W in the operation
control circuit even if it is in “OFF”mode.
Warning
To protect the whole unit during lightning, please
stop operating the unit and remove the plug from the
socket.
!
OFF
Operate
After power
failure

–18 –
MAINTENANCE
Before the cleaning, stop operation and disconnect the power supply.
1. AIR FILTER
Clean the air filter, as it removes dust inside the room. In case the air filter is full of dust, the air flow
will decrease and the cooling capacity will be reduced. Further, noise may occur. Be sure to clean the
filter following the procedure below.
PROCEDURE
!
CAUTION
Claws
Front cover
INSTALLATION METHOD
REMOVING METHOD
Suction grille
Air filter
1
Remove the filter
●Be sure to hold the button sides on the left
and right of the front grille with both hands
and pull up the grille forward.
●Slightly lift the filter and release the claws (4
locations) at the lower part of the front cover
and remove the filter from the lower side.
2
Remove dust from the filter using a
vacuumcleaner.
If there is too much dust, use neutral detergent.
After using neutral detergent, wash with clean
water and dry in the shade.
3
Install the filter. (Set them with “FRONT”mark
facing front.)
●Be sure to hold the front grille with both hands
and close it, then push the three sections
indicated by the arrows.
!
CAUTION
●Do not wash with hot water at more than 40°C. The filter may shrink.
●When washing it, shake off moisture completely and dry it in the shade; do not expose it directly to
the sun. The filter may shrink.
●Do not operate the air conditioner with the filter removed. Dust may enter the air conditioner and
cause trouble.

–19 –
2. Washable Suction Grille
●The suction grille remove and can wash with clean
water in whole.
Wash it with a soft sponge.
After using neutral detergent, wash thoroughly with
clean water.
●When it is not removed, wipe it with a soft dry
cloth. Wipe the remote controller thoroughly with a
soft dry cloth.
●Wipe the water thoroughly.
If the water remains at indicators or signal receiver
of indoor unit, it causes trouble.
Method to remove of the suction grille.
Be sure to hold the suction grille with both hands
to detach and attach it.
!
CAUTION
●Do not splash or direct water to the body of the unit when cleaning
it as this may cause short circuit.
●Never use hot water (above 40°C), benzine, gasoline, acid, thinner or
a brush, because they will damage the plastic surface and the coating.
Removing the Suction Grille
Arm
●When the suction grille is fully opened with
both hands, push the right arm to the inside
to release it, and while closing the suction
grille slightly, put it out forward.
Attaching the Suction Grille
●Move the projections of the left and right
arms into the Flanges in the unit and
securely insert them into the holes.
Projection
Hole
Flange