Hitachi RAS-18YH6, RAS-25YH6 Service Manual

Download

Page 1

NO. 0019E

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

ROOM AIR CONDITIONER

INDOOR UNIT + OUTDOOR UNIT

DECEMBER 2006 Hitachi Household Appliances(Wuhu) Co.,Ltd.

SERVICE MANUAL

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)

(kg)

RAS-18YH6 RAC-18YH6

DC INVERTER (WALL TYPE)

TYPE

MODEL

POWER SOURCE

TOTAL INPUT

TOTAL AMPERES

CAPACITY

TOTAL INPUT

TOTAL AMPERES

CAPACITY

DIMENSIONS (mm)

NET WEIGHT

SPECIFICATIONS

780

280

210

9.5

RAS-18YH6 RAS-25YH6

CONTENTS

SPECIFICATIONS ------------------------------------------------------------------- 4

HOW TO USE ----------------------------------------------------------------------- 5

CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 15

MAIN PARTS COMPONENT --------------------------------------------------- 17

WIRING DIAGRAM ---------------------------------------------------------------- 19

CIRCUIT DIAGRAM --------------------------------------------------------------- 20

RAS-18YH6/RAC-18YH6 RAS-25YH6/RAC-25YH6

RAC-18YH6 RAC-25YH6

COOLING

HEATING

INDOOR UNIT

OUTDOOR UNIT

INDOOR UNIT

OUTDOOR UNIT

1 PHASE, 50 Hz, 220-230V

550 (155 ~ 1,010)

2.95-2.81

2.00 (0.90 ~ 2.50)

6,820 (3,070 ~ 8,530)

580 (115 ~ 970)

2.93-2.81

2.50 (0.90 ~ 3.20)

8,530 (3,070 ~ 10,920)

505

780

280

210

9.5

505

1 PHASE, 50 Hz, 220-230V

700 (155 ~ 1,290)

3.75-3.59

2.50 (0.90 ~ 3.10)

8,530 (3,070 ~ 10,580)

880 (115 ~ 1,250)

4.45-4.26

3.40 (0.90 ~ 4.40)

11,600 (3,070 ~ 15,010)

After installation

RAS-25YH6 RAC-25YH6

BLOCK DIAGRAM ----------------------------------------------------------------- 22

BASIC MODE ----------------------------------------------------------------------- 23

REFRIGERATING CYCLE DIAGRAM --------------------------------------- 29

DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 30

SERVICE CALL Q & A ---------------------------------------------------------- 60

TROUBLE SHOOTING ----------------------------------------------------------- 63

PROCEDURE FOR DISASSEMBLY AND REASSEMBLY ------------ 87

PARTS LIST AND DIAGRAM -------------------------------------------------- 89

700 (+68) 700 (+68)

258 (+48) 258 (+48)

Page 2

SAFETY DURING REPAIR WORK

First, I must disconnect the power cord plug

from the power outlet.

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 1MΩ 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

Page 3

– 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

A conductive polyvinyl bag

Conductive sponge

(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.

Fig. 2 Body Earth

Body earth (Elimik conductive band)

Clip for connection with a grounding wire

Page 4

– 2 –

(6)Use a three wire type soldering iron including a grounding wire.

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.

Bare copper wire (for body earth)

Working table

Resistor of 1 M

(1/2W)

Earth wire

Fig. 3 Grounding of the working table

Metal plate (of aluminium, stainless steel, etc.)

Staple

Screw stop at the screwed part using a rag plate

Soldering iron

Grounding wire

Fig. 4 Grounding a soldering iron

Page 5

– 3 –

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. The room air conditioner does not start automatically after recovery of the electric power failure for prevent-

ing 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 (14°F).

6. This room air conditioner (the reverse cycle) should not be used when the outside temperature is below

–15°C (5°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

Page 6

– 4 –

SPECIFICATIONS

MODEL

FAN MOTOR

FAN MOTOR CAPACITOR

FAN MOTOR PROTECTOR

COMPRESSOR

COMPRESSOR MOTOR CAPACITOR

OVERLOAD PROTECTOR

OVERHEAT PROTECTOR

FUSE (for MICROPROCESSOR)

POWER RELAY

POWER SWITCH

TEMPORARY SWITCH

SERVICE SWITCH

TRANSFORMER

VARISTOR

NOISE SUPPRESSOR

THERMOSTAT

REMOTE CONTROL SWITCH (LIQUID CRYSTAL)

40 W

ASC092CD

YES

3.0A

G4A

YES

450NR

YES

YES(IC)

WITHOUT REFRIGERANT BECAUSE

COUPLING IS FLARE TYPE.

UNIT

PIPES (MAX. 20m)

REFRIGERANT CHARGING VOLUME (Refrigerant 410A)

RAC-18YH6 RAC-25YH6

820g

RAS-18YH6 RAS-25YH6

PWM DC35V

–

YES

YES(IC)

YES

----------

YES

Page 7

– 2 –

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 signs indicate the following meanings. (The following are examples of signs.)

• Please keep this manual after reading.

This sign in the figure indicates prohibition. Indicates the instructions that must be followed.

WARNING

CAUTION

• 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.

• Be sure to use the specified piping set for R410A. Otherwise, this may result in

broken copper pipes or faults.

• 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 the unit near a location where there is flammable gas.

The outdoor unit may catch fire if flammable gas leaks around it. Piping shall be

suitable supported with a maximum spacing of 1m between the supports.

• Please ensure smooth flow of water when installing the drain hose. If any failure

is found in the drain path, water drops from the indoor and outdoor units, causing

wet household effects.

• Make sure that a single phase 230V power source is used.

The use of other power sources may cause electrical components to overheat

and lead to fire.

PROHIBITION

CONNECT EARTH LINE

PROHIBITION

• Should abnormal situation arise (like burning smell), please stop operating the

unit and remove plug from the socket or 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.

WARNING

PRECAUTIONS DURING INSTALLATION

PRECAUTIONS DURING SHIFTING OR MAINTENANCE

“OFF”

PROHIBITION

• Avoid an extended period of direct air flow for your health.

• Do not connect the power calbe with an extension cable or do not plug too many

leads of the other electric appliance into the socket where this cable is plugged.

In addition, wire the cable with some allowances to prevent the cable from stretching.

Not doing so will cause an electrical shock, heat generation or fire.

PROHIBITION

• Do not put objects like thin rods into the panel of blower and suction side

because the high-speed fan inside may cause danger.

• Do not bundle the power cable, pull it, put something on it, heat it, process it, or

put it between things. Breakage of the power cable may result.

Use of a damaged cable may cause an electrical shock or a fire.

PROHIBITION

HOW TO USE

– 3 –

WARNING

PRECAUTIONS DURING OPERATION

• Do not use any conductor as fuse wire, this could cause fatal accident.

PROHIBITION

• During thunder storm, disconnect the plug top or turn off the circuit breaker.

• Spray cans and other combustibles should not be located within a meter of the air

outlets of both indoor and outdoor units.

As a spray can’s internal pressure can be increased by hot air, a rupture may result.

“OFF”

CAUTION

PROHIBITION

• The product shall be operated under the manufacturer specification and not for

any other intended use.

PROHIBITION

DON’T WET

• Do not attempt to operate the unit with wet hands, this could cause fatal accident.

STRICTLY OBSERVE

PRECAUTIONS

PROHIBITION

• 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 wash the unit with water or place a water container such as a

vase on the indoor unit.

Electrical leakage could be present and cause electric shock.

• 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 place plants or animals directly under the air flow as it is bad for the plants or

animals.

• Do not climb on the outdoor unit or put objects on it.

PROHIBITION

DON’T TOUCH

• 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 automati-

cally 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.

• This appliance especially indoor unit cleaning must be performed by authorized

personnel only. Consult your sales agent.

Using a commercially available detergent or similar can damage the plastic parts

or clog the drain pipe, causing water to drip with potential electric shock hazard.

• Do not touch the air outlet, bottom surface and aluminum fin of the outdoor

unit.

You may get hurt.

• Do not touch the refrigerant pipe and connecting valve.

Burns may result.

• This appliance is not intended for use by young children or infirm persons unless they have been

adequately supervised by a responsible person to ensure that they can use this appliance safely.

• Young children should be supervised to ensure that they do not play with the appliance.

– 5 –

Page 8

– 4 –

NAMES AND FUNCTIONS OF EACH PART

INDOOR UNIT

Air filter

To prevent dust from coming into the indoor unit.

(Refer page 16)

Front panel

Indoor unit indicators

Light indicator showing the operating condition.

(Refer page 5)

Horizontal deflector Vertical deflector

(Air Outlet)

(Refer page 15)

Remote controller

Send out operation signal to the indoor unit. So as

to operate the whole unit.

(Refer page 6)

MODEL NAME AND DIMENSIONS

About the outdoor unit:

• When “Stop” is selected during operation

of the indoor unit, the fan of the outdoor

unit continues turning for 10 to 60

seconds to cool the electric parts down.

• In heating operation, condensate or

water due to defrosting will flow.

Do not cover the drain port of the outdoor

unit because such water may freeze in

the chilly area.

• When the outdoor unit is hung on the

ceiling, install the bush and drain pipe

on the drain port and drain water.

MODEL WIDTH (mm) HEIGHT (mm) DEPTH (mm)

RAS-18YH6, RAS-25YH6, RAS-35YH6 780 280 210

RAC-18YH6, RAC-25YH6 700 505 258

RAC-35YH6 750 548 288

Air outlet

When “ heating” operation is

performed, cool air blows and

when “cooling” or “dehumidifying”

operation is performed, warm air

blows.

Drain hose

Drains the dehumidified water from the indoor unit to the

outdoor during “cooling” or “dehumidifying” operation.

Piping and Wiring

Air inlets (Rear and left sides)

Drain port

(Bottom)

Earth terminal

(Lower section of the side)

Air outlet

When “ heating” operation is

performed, cool air blows and

when “cooling” or “dehumidifying”

operation is performed, warm air

blows.

Drain hose

Drains the dehumidified water from the indoor unit to the

outdoor during “cooling” or “dehumidifying” operation.

Piping and Wiring

Air inlets (Rear and left sides)

Drain port

(Bottom)

Earth terminal

(Lower section of the side)

RAC-35YH6

RAC-18YH6

RAC-25YH6

OUTDOOR UNIT

– 5 –

NAMES AND FUNCTIONS OF EACH PART

INDOOR UNIT INDICATIONS

TIMER LAMP (Orange)

This lamp lights when the timer is working.

FILTER LAMP (Green)

When the device is operated for a total of about 200

hours, the FILTER lamp lights indicates that it is time

to clean the filter.The lamp goes out when the

“

(AUTO SWING)” button is pressed while the

operation is stopped.

OPERATION LAMP (Yellow)

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.

TEMPORARY SWITCH

●

Use this switch to start and stop when the remote controller does not work.

●

This temporary operation will be at the most recent setting made. (The unit

will immediately go into automatic operation once power is switched on.)

CAUTION

Turn off the circuit breaker or pull out

the power plug if the unit is not be

operated for a long period.

✩ If the power stays on and the unit is not operated, power is slightly consumed in the control circuit.

The power is saved by turning off the power switch (or the circuit breaker when the power is supplied

from the outdoor unit).

Attaching the air cleansing and deodorizing filters (Accessories) to the filter frame.

• Attach the air cleansing and deodorizing filters to the frame by

gently compress its both sides and release after insertion into

filter frame.

• The cooling capacity is slightly weakened and the cooling speed

becomes slower when the air cleansing and deodorizing filters

are used.

• Air cleansing and deodorizing filters are washable and reusable up to 20 times by using vacuum

cleaner or water rinse under running tap water. When you want to renew it, please ask your sales

agent.

Frame

POWER SWITCH

– 6 –

Page 9

– 6 – – 7 –

● Signal emitting window/transmission sign

Point this window toward the indoor unit when controlling it.

The transmission sign blinks when a signal is sent.

● Display

This indicates the room temperature selected, current time, timer status,

function and intensity of circulation selected.

● START/STOP button

Press this button to start operation. Press it again to stop operation.

● AUTO SWING button

Controls the angle of the horizontal air deflector.

● FAN SPEED selector

This determines the fan speed. Every time you press this button, the intensity of

circulation will change from (AUTO) to (HI) to (MED) to (LOW).

(This button allows selecting the optimal or preferred fan speed for each

operation mode.)

● SLEEP button

Use this button to set the sleep timer.

● TEMPERATURE buttons

Use these buttons to raise or lower the temperature setting. (Keep pressed, and

the value will change more quickly.)

● TIME button

Use this button to set and check the time and date.

● RESET button

Press this button after the batteries are replaced or when some irregular

operation is found.

● FUNCTION selector

Use this button to select the operating mode. Every time you press it, the mode

will change from (AUTO) to (HEAT) to (DEHUMIDIFY) to (COOL) and

to (FAN) cyclically.

● FAN SPEED selector

● AUTO SWING button

● TIMER control

Use these buttons to set the timer.

● OFF-TIMER button Select the turn OFF time.

● ON-TIMER button Select the turn ON time.

● RESERVE button Time setting reservation.

● CANCEL button Cancel time reservation.

VARIOUS FUNCTIONS

■ Auto Restart Control

• If there is a power failure, operation will be automatically restarted when the power is resumed with

previous operation mode and airflow direction.

(As the operation is not stopped by remote controller.)

• If you intend not to continue the operation when the power is resumed, switch off the power supply.

When you switch on the circuit breaker, the operation will be automatically restarted with previous

operation mode and airflow direction.

Note: 1. If you do not require Auto Restart Control, please consult your sales agent.

2. Auto Restart Control is not available when Timer or Sleep Timer mode is set.

AUTOMATIC OPERATION

The device will automatically determine the mode of operation, HEAT or COOL depending on the

initial room temperature. The selected mode of operation will change when the room temperature

varies.

Press the FUNCTION selector so that the display indicates the

(AUTO) mode of operation.

• When AUTO has been selected, the device will automatically

determine the mode of operation, HEAT or COOL depending

on the current room temperature.

• When AUTO is first selected, the device will determine the

current room temperature and select the proper operation

mode accordingly.

• When the air conditioner has adjusted the room's temperature

to the near preset temperature, it will begin to monitor

operation. If the room temperature subsequently changes,

the air conditioner will once again select the appropriate

operation (heating or cooling) to adjust the temperature to

the preset temperature. The monitoring operation range is

3°C relative to the preset temperature.

• If the mode automatically selected by the unit is not

satisfactory, manually change the mode setting (heat,

dehumidify, cool or fan).

NAMES AND FUNCTIONS OF EACH PART

REMOTE CONTROLLER

• This controls the operation of the indoor unit.

The range of control is about 7 meters. If indoor lighting is controlled electronically, the range of

control may be shorter, in some cases, the control signal may not be received.

This unit can be fixed on a wall using the fixture provided. Before fixing it, make sure the indoor unit

can be controlled from the remote controller.

• Handle the remote controller with care.

Dropping it or getting it wet may compromise its signal transmission capability.

• After new batteries are inserted into the remote controller, the unit will initially require approximately

10 seconds to respond to commands and operate.

Precautions for Use

• Do not put the remote controller in the following places.

• In direct sunlight

• In the vicinity of a heater.

• Handle the remote controller carefully. Do not drop it on the floor, and

protect it from water.

• Once the outdoor unit stops, it will not restart for about 3 minutes (unless

you turn the power switch off and on or unplug the power cord and plug

it in again).

This is to protect the device and does not indicate a failure.

• If you press the FUNCTION selector button during operation, the device

may stop for about 3 minutes for protection.

AUTO

HEAT

DEHUMIDIFY

COOL

FAN

FAN SPEED

LOW

MED

SLEEPING

STOP (CANCEL)

START (RESERVE)

START/STOP

TIME

TIMER SET

TIMER SELECTOR

ON TIMER

OFF TIMER

AUTO SWING

Press the (START/STOP) button.

Operation starts with a beep.

Press the button again to stop operation.

Press the (FAN SPEED) button, AUTO and LOW is available.

■ As the settings are stored in memory in the remote controller, you

only have to press the

(START/STOP) button next time.

You can raise or lower the temperature setting as necessary by

maximum of 3°C.

Press the temperature button and the temperature

setting will change by 1°C each time.

• The preset temperature and the actual room temperature may

vary somewhat depending on conditions.

START

STOP

– 7 –

Page 10

– 8 –

Press the (START/STOP) button. Heating operation starts

with a beep. Press the button again to stop operation.

START

STOP

HEATING OPERATION

• Use the device for heating when the outdoor temperature is under 21°C.

When it is too warm (over 21°C), the heating function may not work in order to protect the device.

• In order to keep reliability of the device, please use this device above -15°C of the outdoor

temperature.

Press the FUNCTION selector so that the display indicates

(HEAT).

Set the desired FAN SPEED with the (FAN SPEED) button

(the display indicates the setting).

(AUTO) : The fan speed changes automatically according

to the temperature of the air which blows out.

(HI) : Economical as the room will become warm

quickly.

But you may feel a chill at the beginning.

(MED) : Quiet.

(LOW) : More quiet.

Set the desired room temperature with the TEMPERATURE

buttons (the display indicates the setting).

The temperature setting and the actual room temperature may

vary somewhat depending on conditions.

■ As the settings are stored in memory in the remote controller, you

only have to press the

(START/STOP) button next time.

■ Defrosting

Defrosting will be performed about once an hour when frost forms on the heat exchange of the outdoor unit,

for 5~10 minutes each time.

During defrosting operation, the operation lamp blinks in cycle of 3 seconds on and 0.5 second off.

The maximum time for defrosting is 20 minutes.

(If the piping length used is longer than usual, frost will likely to form.)

– 9 –

DEHUMIDIFYING OPERATION

Use the device for dehumidifying when the room temperature is over 16°C.

When it is under 15°C, the dehumidifying function will not work.

Press the (START/STOP) button.

START

STOP

Press the FUNCTION selector so that the display indicates

(DEHUMIDIFY).

The FAN SPEED is set at LOW automatically.

The FAN SPEED button does not work.

■ When you want to change the operation mode, please use the

FUNCTION selector.

■ Set the desired temperature is available.

■ You also can use the FUNCTION selector to select this operation.

■ Dehumidifying Function

• Dehumidifying takes place with a target temperature which is slightly lower than the room

temperature setting. (However, target temperature is 16°C for a temperature setting of 16°C.)

If the room temperature becomes lower than the target value, operation stops. If the room

temperature becomes higher than the target value, operation restarts.

• The preset room temperature may not be reached depending on the number of people present in

the room conditions.

– 8 –

Page 11

– 10 –

Press the (START/STOP) button. Cooling operation starts

with a beep. Press the button again to stop operation. The cooling

function does not start if the temperature setting is higher than

the current room temperature (even though the (OPERATION)

lamp lights).

The cooling function will start as soon as you set the temperature

below the current room temperature.

START

STOP

COOLING OPERATION

Use the device for cooling when the outdoor temperature is -10 to 42°C.

If humidity is very high (over 80%) indoors, some dew may form on the air outlet grille of the indoor

unit.

Press the FUNCTION selector so that the display indicates

(COOL).

Set the desired FAN SPEED with the (FAN SPEED) button

(the display indicates the setting).

(AUTO) : The FAN SPEED is HI at first and varies to MED

automatically when the preset temperature has

been reached.

(HI) : Economical as the room will become cool quickly.

(MED) : Quiet.

(LOW) : More quiet.

Set the desired room temperature with the TEMPERATURE

buttons (the display indicates the setting).

The temperature setting and the actual room temperature may

vary somewhat depending on conditions.

■ As the settings are stored in memory in the remote controller, you

only have to press the

(START/STOP) button next time.

– 11 –

Press the (START/STOP) button. Fan operation star ts with a

beep.

Press the button again to stop operation.

START

STOP

FAN OPERATION

You can use the device simply as an air circulator. Use this function to dry the interior of the indoor unit

at the end of summer.

Press the FUNCTION selector so that the display indicates

(FAN).

Press the (FAN SPEED) button.

(HI) : The strongest air blow.

(MED) : Quiet.

(LOW) : More quiet.

FAN SPEED (AUTO)

… When the AUTO fan speed mode is set in the cooling/heating operation:

For the heating operation

• The fan speed will automatically change according to the temperature of

discharged air.

• As room temperature reaches the preset temperature, a very light breeze

will blow.

• Operation starts in the “HI” mode to reach the preset temperature.

• As room temperature approaches the preset temperature, fan speed auto-

matically switches to “LOW”.

For the cooling operation

– 9 –

Page 12

– 12 –

HOW TO SET THE TIMER

Time, Day, Month

TIME, DAY,

MONTH (current

time, day, month)

OFF TIMER

ON TIMER

RESERVE

CANCEL

OFF-Timer

ON-Timer

ON/OFF-Timer

Set the current month and day

with the TIMER control button.

M D

After you change the

batteries;

Start

Stop

You can set the device to turn off at

the present time.

Press the (OFF-TIMER)

button. The (OFF) mar k blinks

on the display.

The device will turn on at the

designated times.

Press the (ON-TIMER)

button. The (ON) mark blinks on

the display.

Start Stop

• The device will turn on (off) and

off (on) at the designated times.

• The switching occurs first at the

preset time that comes earlier.

• The arrow mark appear ing on the

display indicates the sequence of

switching operations.

Press the (OFF-

TIMER) button so that

the (OFF) mark

blinks.

Set the turn-off time

with the TIMER control

button.

Press the (RESERVE)

button.

Press the (ON-

TIMER) button so that the

(OFF) mark lights and

the (ON) mark blinks.

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

You can set only one of the OFF-timer,

ON-timer and ON/OFF-timer.

Start

Stop

– 13 –

Set the

(TIME) button.

Set the current time with

the TIMER control button.

Press the (TIME)

button again. The time

indication starts lighting

instead of flashing.

• The time indication will

disappear automatically in 10

seconds.

• To check the current time

setting, press the (TIME)

button twice.

The setting of the current

time is now complete.

Example: The current time is 1:30p.m.

Set the turn-off time with

the TIMER control button.

Point the signal window of the remote controller toward the indoor unit,

and press the (RESERVE) button.

The (OFF) mark starts lighting instead of flashing and the (RESERVED)

sign lights. A beep occurs and the (TIMER) lamp lights on the indoor unit.

Example: The device will turn off at 11:00p.m.

The setting of turn-off time is now complete.

Set the turn-on time with

the TIMER control button.

Point the signal window of the remote controller toward the indoor unit,

and press the (RESERVE) button.

The (ON) mark starts lighting instead of flashing and the (RESERVED)

sign lights. A beep occurs and the (TIMER) lamp lights on the indoor unit.

Example:

The device will turn on early so that the preset

temperature be almost reached at 7:00 a.m.

The setting of the turn-on time is now complete.

Set the turn-on time with

the TIMER control button.

Point the signal window of the remote controller toward the indoor unit,

and press the (RESERVE) button.

The (ON) mark starts lighting instead of flashing and the (RESERVED)

sign lights. A beep occurs and the (TIMER) lamp lights on the indoor unit.

Example:

For heating, the device will turn off at 10:30 p.m.,

and then turn on early so that the preset

temperature be almost reached at 7:00 a.m.;

for cooling and dehumidifying, it will simply

turned on at 7:00 a.m. The settings of the turn

on/off times are now complete.

• The timer may be used in three ways: off-timer, on-timer and ON/OFF (OFF/ON)-timer. Set the

current time at first because it serves as a reference.

• As the time settings are stored in memory in the remote controller, you only have to press the

(RESERVE) button is order to use the same settings next time.

– 10 –

Page 13

– 14 –

HOW TO SET THE SLEEP TIMER

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.

●

SLEEP

Mode Indication

Sleep Timer

1 hour 2 hours 3 hours 7 hours

Sleep timer off

Sleep Timer: The device will continue working for the desired 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. When the sleep timer has

been set, the display indicates the turn-off time.

Example: If you set 3 hours sleep time at

11:38 p.m., the turn-off time is 2:38 a.m.

Sleep

timer

Start

The device will be turned off by the sleep timer

and turned on by on-timer.

Set the ON-timer.2 Press the (SLEEP) button and set the sleep timer.

For heating:

In this case, the device will turn off in

2 hours (at 1:38 a.m.) and turn on early

so that the preset temperature will be

almost reached at 6:00 next morning.

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-time or on/off-

timer has been set earlier, the sleep timer becomes

effective instead of the off - or on/off-timer set earlier.

– 15 –

ADJUSTING THE AIR DEFLECTORS

Adjustment of the conditioned air in the upward and downward

directions.

The horizontal air deflector is automatically set to the proper angle

suitable for each operation. The deflector can be swung up and

down continuously and also set to the desired angle using the

“

(AUTO SWING)” button.

• 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 dew may drop.

CAUTION

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.

HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER

Remove the cover as shown in the figure and take out

the old batteries.2Install 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.

CAUTION

Push and pull to the

direction of arrow.

Vertical

about 15°

about 60°

about 45°

about 30°

When cooling,

dehumidifying

When heating

•

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 in the right.

• When the operation is stopped, the horizontal air deflector

moves and stops at the position where the air outlet closes.

Left side: Hold the third

blade from the left end

of the air deflector to

adjust the direction. The

pull for the blade is

marked.

Right side: Hold the third

blade from the right end

of the air deflector to

adjust the direction. The

pull for the blade is

marked.

– 11 –

Page 14

– 16 –

MAINTENANCE

Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning,

stop operation and switch off the power supply.

CAUTION

1. AIR FILTER

When the filter indicator lamp comes on, be sure to clean the filter. By doing so, the power rates are

saved. 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

Open the front panel carefully and remove the filter.

Vacuum dust from the air filter using vacuum cleaner.

If there is too much dust, wash the filter with a detergent

and rinse it thoroughly. After that, dry it in the shade.

• Set the filter with “FRONT” mark facing front, and

slot them into the original state.

• After attaching the filters, push the front panel at

three arrow portions as shown in figure and close

it.

• 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.

• Don't operate the unit without filter. Fault may occur if you continue.

CAUTION

– 17 –

2. CLEANING OF FRONT PANEL

• Remove the front panel and wash with clean water.

Wash it with a soft sponge.

After using neutral detergent, wash thoroughly with

clean water.

• When front panel 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 water remains at indicators or signal receiver of

indoor unit, it causes trouble.

Method of removing the front panel.

Be sure to hold the front panel with both hands to

detach and attach it.

CAUTION

Removing the Front Panel Attaching the Front Panel

• When the front panel is fully opened with both

hands, push the right arm to the inside to

release it, and while closing the front panel

slightly, put it out forward.

• Move the shafts of the left and right arms into

the steps in the unit and securely insert them

into the holes.

Shaft

Step

Hole

CID

• 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.

3. MAINTENANCE AT BEGINNING OF LONG OFF PERIOD

• Run the unit by setting the operation mode to

(FAN) and the fan speed to HI for about half a day

on a fine day, and dry the whole of the unit.

• Switch off the power plug or turn off the circuit breaker.

Air

Blow

– 12 –

Page 15

– 18 –

INFORMATION

CAPABILITIES

Heating Capability

• This room air conditioner utilizes a heat pump system that absorbs

exterior heat and brings it into a room to be heated. As the ambient

temperature gets lower, heating capability will also lower. In such a

situation, the inverter work to increase compressor rpm to keep the

unit’s heating capability from decreasing. If the unit’s heating perfor-

mance is still unsatisfactory, other heating appliances should be used

to augment this unit’s performance.

• The air conditioner is designed to heat an entire room so that it may take some time before you feel warm.

Timer operation is recommended for effective preheating ahead of the desired time.

Cooling and Dehumidifying Capabilities

• If the heat present in a room exceeds the unit’s cooling capacity (for example, if there are many people in

the room or other heating appliances are used), the preset room temperature may not be reached.

CAUTION

Do not use a stove

or any other

hightemperature

devices in proximity

to the indoor unit.

• When fan speed, room temperature are set with the remote controller before starting manual operation and

the buttons are released, the indication of settings will go off in 10 seconds and only the operation mode

will be displayed.

• Pressing the button while the unit is in operation will let the protective circuit work so that the unit will

not operate for approximately 3 minutes.

• During heating operation, the indoor unit’s color indicator lamp may flash with no air emitted for a while.

• If you feel cold wind during heating operation with the (HI) fan speed or want to make the unit operation

quieter after the room is heated, use of (AUTO) setting is recommended.

• With the (LOW) setting, the unit’s cooling capability will lower slightly.

• With the (LOW) setting, the unit’s heating capacity will vary with the operating conditions.

VARIOUS FUNCTIONS

• When the timer has been programmed, the unit will not operate even if the set time is reached unless the

unit receives a signal from the remote controller. Confirm that timer programming is complete (beep) and

the TIMER lamp of the indoor unit lights.

• If the (SLEEP) button is pressed while the ON/OFF timer is programmed, the sleep timer takes priority.

• During sleep timer operation, the fan speed sets to (LOW) regardless of the preset speed. The remote

controller display indication will remain unchanged even with the (LOW) setting.

TIMER PROGRAMMING/SLEEP TIMER OPERATION

PROHIBITION

– 19 –

REGULAR INSPECTION

PLEASE CHECK THE FOLLOWING POINTS EVERY EITHER HALF YEARLY OR YEARLY. CONTACT

YOUR SALES AGENT SHOULD YOU NEED ANY HELP.

WARNING

Check to see if the unit’s earth line has been con-

nected correctly.

If the earth line is disconnected or faulty, unit failure or

electric shock hazard may result.

Check to see if the mounting frame has rusted ex-

cessively or if the outdoor unit has tilted or become

unstable.

It could collapse or fall, causing injury.

AFTER SALES SERVICE AND WARRANTY

WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS.

CONDITION CHECK THE FOLLOWING POINTS

• Do the batteries need replacement?

• Is the polarity of the inserted batteries correct?

• Is the fuse all right?

• Is the voltage extremely high or low?

• Is the circuit breaker “ON”?

• Is the power plug inserted?

• Do you have any power cut?

• Is the air filter blocked with dust?

• Is the set temperature suitable?

• Have horizontal air deflectors been adjusted to their correct

positions according to the operation mode selected?

• Are the air inlets or air outlets of indoor and outdoor units

blocked?

• Is the fan speed “LOW”?

When it does not operate.

When it does not cool well.

When it does not heat well.

If the remote controller is not

transmitting a signal.

(Remote controller display is

dim or blank.)

■ The following phenomena do not indicate unit failure.

The unit is preparing to blow warm air. Please wait.

The outdoor unit is defrosting. Please wait.

Refrigerant flow noise in the pipe or valve sound generated when flow rate is

adjusted.

Noise generated when the unit expands or contracts due to temperature changes.

Noise generated with the indoor unit fan’s rpm changing such as operation start

times.

Noise of the motorized valve when the unit is switched on.

During heating, the operation

indicator blinks and air blow stops

Hissing or fizzy sounds

Squeaking noise

Rustling noise

WARNING

Clicking noise

Check to see if the power plug is securely inserted

into the wall socket.

If the power plug is not inserted into the wall socket

securely or becomes hot, an electric shock or fire may result.

If dust or dirt is found on the power plug, clean the plug

and insert it into the wall socket.

– 13 –

Page 16

– 20 –

• If the unit still fails to operate

normally after performing the

above inspections, turn the

circuit breaker off, or pull the

power plug out, and contact

your sales agent immediately.

Contact your sales agent immediately if the

following phenomena should occur:

•

The circuit breaker switches off or the fuse blows

frequently.•The switch operation is not stable.•Foreign matter or water accidentally enters the unit interior.•The power cord gets excessively hot or its insulation is torn or stripped.•TIMER lamp on the indoor unit display blinks.

As the nature of the failure can be identified by the blinking cycle,

check the blinking cycle before turning off the circuit breaker.

(

)

Notes

• In quiet operation or stopping the running, the following phenomena may

occasionally occur, but they are not abnormal for the operation.

(1) Slight flowing noise of refrigerant in the refrigerating cycle.

(2) Slight rubbing noise from the fan casing which is cooled and then

gradually warmed as operation stops.

• The odor will possibly be emitted from the room air conditioner because

the various odor, emitted by smoke, foodstuffs, cosmetics and so on,

sticks to it. So please clean the air filter and the evaporator regularly to

reduce the odor.

Noise of the ventilation fan sucking in air present in the drain hose and blowing out

dehumidifying water that had accumulated in the condensed water collector. For

details, consult your sales agent.

Operation noise changes due to power variations according to room temperature

changes.

Mist is generated as the air within the room is suddenly cooled by conditioned air.

Water generated during defrosting operation evaporates and steam is emitted.

Caused as the smells and particles of smoke, food, cosmetics, etc. present in room

air become attached the unit and blown off into the room again.

Defrosting is underway (as the heating operation is stopped, the microcomputer

checks frost accumulated in the outdoor unit and instructs the unit to perform

automatic defrosting if necessary).

Shows preheating or defrosting operation is underway.

As the protective circuit or preheat sensor operates when unit operation is stopped

during preheating and then restarted, or when operation mode is switched from cooling

to heating, the lamp continues to blink.

Actual room temperature may deviate slightly from the remote controller's

temperature setting depending on the number of people in the room, indoor or

outdoor conditions.

• Please contact your sales agent immediately if the air conditioner still fails to operate normally after

the above inspections. Inform your agent of the model of your unit, production number, date of

installation. Please also inform him regarding the fault.

Please note:

On switching on the equipment, particularly when the room light is dimmed, a slight brightness

fluctuation may occur. This is of no consequence.

The conditions of the local Power Supply Companies are to be observed.

Does not reach the temperature

setting

Mist emission

Perking noise

Changing operation noise

Steam emitted from the outdoor unit

The outdoor unit continues to operate

even if operation is stopped.

Odors

The OPERATION lamp is blinking.

– 14 –

Page 17

– 15 –

About 70

Warning

About 108

(190)

190

400

81.5

210

280

780

About 370

CONSTRUCTION AND DIMENSIONAL DIAGRAM

MODEL RAS-18YH6, RAS-25YH6

Top air suction grill

147

56 17.5

When piping is drawn from the left side

, exchange the drain hose for the dr

ain cap

Mounting plate

Air outlet

Horizontal air diflector

Front panel

Cabinet

Drain

Drain cap connection port

Narrow pipe (ø6.35)

Wide pipe (ø9.52)

Drain hose

Power cord

Connecting cable

Vertical air deflector

INDOOR UNIT

Page 18

– 16 –

CONSTRUCTION AND DIMENSIONAL DIAGRAM

MODEL RAC-18YH6, RAC-25YH6

OUTDOOR UNIT

Page 19

– 17 –

MAIN PARTS COMPONENT

THERMOSTAT

Thermostat Specifications

FAN MOTOR

MAIN ELECTRIC COMPONENTS FOR OUTDOOR UNIT

Fan Motor Specifications

CONNECTION

TEMPERATURE

°C (°F)

INDICATION

MODEL RAS-18YH6, RAS-25YH6

THERMOSTAT MODEL IC

OPERATION MODE COOL HEAT

ON 16.7 (62.1) 18.7 (65.7)

OFF 16.0 (60.8) 19.3 (66.7)

ON 24.7 (76.5) 26.7 (80.1)

OFF 24.0 (75.2) 27.3 (81.1)

ON 32.7 (90.9) 34.7 (94.5)

OFF 32.0 (89.6) 35.3 (95.5)

RED

BLK

WHT

YEL

BLU

35V

0 - 5V

MODEL

NAME RATING APPLICABLE MODELS

REVERSING VALVE COIL 135 Ω (20 ˚C) RAC-18YH6, 25YH6

REACTOR L1 13 (mH), 0.224 Ω RAC-18YH6, 25YH6

REACTOR L2 25.5 (mH), 0.37 Ω RAC-18YH6, 25YH6

FILM CAPACITOR 45 (µF) RAC-18YH6, 25YH6

RAS-18YH6, RAS-25YH6

POWER SOURCE DC 5V, 35V

DC 140

- 350

OUTPUT 25W

40W

(Control circuit built in)

BLU : BLUE YEL : YELLOW BRN : BROWN WHT : WHITE GRY : GRAY ORN : ORANGE GRN : GREEN RED : RED BLK : BLACK PNK : PINK VIO : VIOLET

RED

140 350V

BLK

WHT

15V

YEL

0-6V

BLU

0-15V

RAC-18YH6, RAC-25YH6

Page 20

– 18 –

WHITE

COMPRESSOR

YELLOW

RED

FRONT SIDE OF OUTDOOR UNIT

MODEL

ITEM

COMPRESSOR TYPE

POWER SOURCE

OUTPUT

COMPRESSOR MOTOR

Compressor Motor Specifications

WINDING

20°C

75°

RESISTANCE

(Ω)

CAUTION

When the refrigerating cycle has been operated for a long time with the capillary tubes clogged or crushed or with too little refrigerant, check the color of the refrigerating machine oil inside the compressor. If the color has been changed conspicuously, replace the compressor.

2M=1.15

2M=1.40

(U)

(V)

(W)

WHITE

YELLOW

RED

RAC-18YH6, RAC-25YH6

ASC092CD

800W

DC 270 - 350 V

Page 21

– 19 –

WIRING DIAGRAM

RAS-18YH6 / RAC-18YH6 RAS-25YH6 / RAC-25YH6

CAUTION

The marked parts are very important ones for safety.

Page 22

– 20 –

CIRCUIT DIAGRAM

MODEL RAS-18YH6, RAS-25YH6

RAS_AW_020-021_A2 11/17/06, 11:18 AM20

Page 23

– 21 –

RAC-18YH6, RAC-25YH6

MODEL

RAS_AW_020-021_A2 11/17/06, 11:18 AM21

Page 24

Wireless receive circuit

Filter. Operation. Timer.

Auto sweep motor for Air deflector

Remote controller

Heat exchanger thermistor

Room temperature thermistor

Reset circuit

Initial setting circuit

Temporary switch

Outdoor microcomputer (AX-8V11)

RAS-18YH6 / RAC-18YH6MODEL RAS-25YH6 / RAC-25YH6

Indoor microcomputer (AX-7R13)

BLOCK DIAGRAM

INDOOR UNIT OUTDOOR UNIT

POWER RELAY

POWER

SWITCH

Inrush current

Protection circuit

HARMONICS

IMPROVEMENT

CIRCUIT

IPM

Rotor magnetic

pole position

detection circuit

Buzzer circuit

Indicating lamp

Indoor/Outdoor interface circuit

DC fan motor drive circuit

Microcomputer clock circuit

Indoor DC fan motor

Overheat thermistor

Defrost thermistor

Outdoor temperature thermistor

Indoor/Outdoor interface circuit

Reversing valve coil

Power circuit

Reset circuit

Outdoor DC fan motor

RECTIFIER

DC compressor

motor

Relay drive circuit

Electric expansion valve

Reversing valve

control circuit

Power source 1ø 50Hz 220-230V

– 22 –

Page 25

– 23 –

Page 26

– 24 –

Table 1 Mode data file

RAS-18YH6 RAS-25YH6

LABEL NAME VALUE

WMAX

3500 min

–1

4400 min

–1

WMAX2

3500 min

–1

4400 min

–1

WSTD

2950 min

–1

4200 min

–1

WBEMAX

2800 min

–1

3200 min

–1

CMAX

3200 min

–1

3200 min

–1

CMAX2

3200 min

–1

3200 min

–1

CSTD

2400 min

–1

2900 min

–1

CKYMAX

2300 min

–1

2700 min

–1

CJKMAX

2300 min

–1

2500 min

–1

CBEMAX

2300 min

–1

2300 min

–1

WMIN

2200 min

–1

2200 min

–1

CMIN

2200 min

–1

2200 min

–1

STARTMC

90 Seconds 90 Seconds

DWNRATEW

80% 80%

DWNRATEC

60% 60%

SHIFTW

2.00°C 2.00°C

SHIFTC

1.33°C 1.33°C

CLMXTP

30.00°C 30.00°C

YNEOF

25.00°C 25.00°C

TEION

2.00°C 2.00°C

TEIOF

9.00°C 9.00°C

SFTDSW

1.00°C 1.00°C

DFTIM1

43 Minutes 43 Minutes

DFTIM2

60 Minutes 60 Minutes

Page 27

Reversing valve (cooling “on” mode)

TE (9)

Notes: (1) Condition for entering into Cool Dashed mode. When fan set to “Hi” or “Auto mode” and temperature difference between indoor temperature and set temperature has a

corresponding compressor rpm (calculated value in Table 2) larger than CMAX.

(2) Cool Dashed will release when i) a maximum 25 minutes is lapsed and ii) room temperature is lower than set temperature –3°C (thermo off) and iii) when room temperature

has achieved setting temperature –1°C then maximum Cool Dashed time will be revised to 20 minutes. And iv) indoor fan is set to Lo and Med fan mode and v) change operation

mode. (3) During Cool Dashed operation, thermo off temperature is set temperature (with shift value) –3°C. After thermo off, operation continue in Fuzzy control mode. (4) Compressor minimum “ON” time and “OFF” time is 3 minutes. (5) During normal cooling mode, compressor maximum rpm CMAX will maintain for 60 minutes if indoor temperature is lower than CLMXTP. No time constrain if indoor temperature

is higher than CLMXTP. (6)

(7) When fan is set to “Med”, compressor rpm will be limited to CJKMAX. (8) When fan is set to “Lo”, compressor rpm will be limited to CBEMAX. (9) During Cool Dashed, when room temperature reaches set temperature –1°C compressor rpm is actual rpm x DWNRATEC.

Temperature

Calculated

difference

compressor rpm

1.66°C

2200 min

–1

2.00°C

2600 min

–1

2.33°C

3000 min

–1

CLMXTP

2min. 30sec.

(with shift value)

Table 2 Compressor rpm

Item

Temperature

Room temperature

Outdoor temperature

30°C 32°C 32°C 33°C

Thermo judgment (ON) Thermo judgment (OFF) Thermo judgment (ON) Thermo judgment (OFF)

Table 1 Thermo judgment

button

When fan speed setting on remote control is “Hi” or “Auto” mode, and both room and outdoor temperatures (data based on out door unit) meet temperature judgment (Off) shown in the table 1, the compressor rpm will be limited to CKYMAX.

– 25 –

Page 28

Sleep button

Notes:

(1) The sleep operation starts when the sleep button is pressed. (2) When the sleep button is set, the maximum compressor speed is limited to CBEMAX, and the

indoor fan is set to "sleep Lo". (3) The indoor fan speed does not change even when the fan speed mode is changed. (4)

If sleep operation is canceled by the cancel button or sleep button, all data is cleared.

1min.

Compressor speed

Horiz

ontal air

deflector

Shut

Horizontal

Facing down

Indoor fan

Outdoor fan

Timer lamp

Remote control (Sleep) ON

Med

Set to 7 hours

See basic operation

Notes:

(1) The sleep operation starts when the sleep button is pressed. (2) When the sleep button is set, the indoor fan is set to “sleep Lo”. (3) The indoor fan speed does not change even when the fan speed mode

is changed.

(4)

If sleep operation is canceled by the cancel button or sleep button, all data is cleared.

–1.33˚C

–0.66˚C

Notes:

(1) The operation is done assuming as the preset temperature

= (room temperature at the time) – (2°C).

(2) The indoor fan is operated in the “Lo” mode. During thermo OFF indoor fan will be OFF for 5

(3) When the operation is started by the themostat turning ON, the start of the indoor fan is

delayed 32 seconds after the start of compressor operation. (4) The compressor is operated forcedly for 3 minutes after operation is started. (5) The minimum ON time and OFF time of the compressor are 3 minutes.

minutes and ON for 1 minute.

Cooling Sleep Operation

Operation lamp

Cooling Defrost

Dehumidifying Operation

Start Stop

Dehumidifying Sleep Operation

Sleep button

Operation lamp

Timer lamp

Remote control (Sleep) ON

Indoor fan

See basic operation

Med

Sleep Lo

Outdoor fan

Horizontal air deflector

Shut

Horizontal

Facing down

Compressor speed

Set to 7 hours

SDMAX or SDRPM

7hr

STARCP

1hr

Sleep Lo

1 hr

7 hr

Room temperature

Reversing valve (cooling "on" model)

button

Min

2 min 30 sec.

– 26 –

Page 29

1.33˚C.

SFTDSW

0.66˚

Fan speed set to "auto"

1 min.

Basic Heating Operation

Start

Stop Start Start StopStop

Thermo

OFF

Thermo

OFF

Heating set temperature (remote control set temperature (+))

Start/stop button

Thermo judgment

Indoor fan

Ultra-Hi

Med

Ultra-Lo

Operation lamp

Max.

Rating

3000

Compressor speed

Outdoor fan

Reversing valve (cooling "on" model)

Ther

mo OFF

Dash period

TWMAX

Wtd

Defrost signal

Preheating judgment

30sec.

10sec.

15sec. 15sec.

15sec. 15sec. 15sec.

10sec.

15sec.

3min.

Max. 3 min.

Preheating released

Control by heat exchanger temperature

15sec.

Control by heat exchanger temperature

18˚C

10sec.

30sec.

10sec.

30sec.

30sec.30sec. 30sec. 30sec. 30sec.

10sec.

Preheat released

WMIN

(WSTD)

(WMAX)

NOTE (10)

WMAX2

Notes: (1) Condition for entering into Hot Dashed mode. When fan set to “Hi” or “Auto mode” and i) Indoor temperature is lower than 18°C, and ii) outdoor temperature is lower than 10°C,

and iii) Temperature difference between indoor temperature and set temperature has a corresponding compressor rpm (calculated value in Table 3) larger than WMAX. (2) Hot Dashed will release when i) Room temperature has achieved the set temperature + SFTDSW. ii) Thermo off. (3) During Hot Dashed operation, thermo off temperature is set temperature (with shift value) +3°C. After thermo off, operation continue in Fuzzy control mode. (4) Compressor minimum “ON” time and “OFF” time is 3 minutes. (5) During normal heating mode, compressor maximum rpm WMAX will maintain for 120 minutes if indoor temperature is higher than 18°C. No time limit constrain if outdoor temperature is

lower than 4°C. (6) During Hotkeep or Defrost mode, indoor operation lamp will blink at interval of 0.5 seconds “ON” and 0.5 second “OFF”. (7) When heating mode starts, it will enter into Hotkeep mode if indoor heat exchanger temperature is lower than YNEOF + 0.33°C. (8) When fan is set to “Lo”, compressor rpm will be limited to WBEMAX. When fan is set to "Med", compressor rpm will be limited to WJKMAX. (9) In “Ultra-Lo” fan mode, if indoor temperature is lower than 18°C, indoor fan will stop. If indoor temperature is higher than 18°C + 0.33°C, fan will continue in “Ultra-Lo” mode.

During Hotkeep or Defrost mode, fan will continue in “Ultra-Lo” mode.

(10) During Hot Dashed, when room temperature reaches set temperature + SFTDSW compressor rpm is actual rpm x DWNRATEW.

Temperature

Calculated

difference

compressor rpm

1.66°C2200 min

–1

2.00°C2600 min

–1

2.33°C3000 min

–1

2.66°C3400 min

–1

3.00°C3800 min

–1

3.33°C4200 min

–1

Table 3 Compressor rpm

Notes:

1. See the data in Table 1-Table 2 on page 47 & 49 for each constant in capital letters in the diagrams.

(with shift value)

– 27 –

Page 30

2min. 30sec.

Notes:

(1) The defrosting inhibit period is set as shown in the diagram below. When defrosting has finished once, the

inhibit period is newly set, based on the outdoor temperature when the compressor was started. During this period, the defrost signal is not accepted.

(2) If the difference between the room and outdoor temperature is large when defrosting is finished, the

maximum compressor speed (WMAX) or (WMAX2) can be continued for 120 minutes maximum. (3) The defrosting period is 12 minutes maximum. (4) When operation is stopped during defrosting, it is switched to auto refresh defrosting. (5) Auto refresh defrosting cannot be engaged within 15 minutes after operation is started or defrosting is

finished.

Sleep Lo

Notes:

(1) The sleep operation starts when the sleep button is pressed. (2) When the sleep button is set, the maximum compressor speed is limited to WBEMAX, and the indoor fan is

set to "sleep Lo". (3) The indoor fan speed does not change even when the fan speed mode is changed. (Sleep Lo) (4) When defrosting is to be set during sleep oepration, defrosting is engaged and sleep operation is restored

after defrosting. (5) If sleep operation is cancelled by the cancel button or sleep button, all data is cleared.

Reversing Valve Defrosting

Preheating released

Reversing valve (cooling "on" model)

Heating Sleep Operation

Upper limit WBEMAX

Sleep button

– 28 –

Page 31

– 29 –

Page 32

– 30 –

NORMAL : HI RESET : LO

RES

Microcomputer

C524

C522

C521

R551

IC521

R552

Power "OFF"

Power "ON"

Reset enter at 4.2V

Reset release at 4.4V

Voltage

Voltage supply to pin 2 of IC521

Voltage at pin 7 of microcomputer

5.0V

Fig. 1-2

Fig. 1-1

5.0V

DESCRIPTION OF MAIN CIRCUIT OPERATION

MODEL RAS-18YH6, RAS-25YH6

1. Reset Circuit

The reset circuit initializes the microcomputer program when power is ON or OFF. Low voltage at pin

7 resets the microcomputer and Hi activates the microcomputer.

When power “ON” 5V voltage rises and reaches 4.4V, pin

1 of IC521 is set to “Hi”. At this time the microcomputer

starts operation. When power “OFF” voltage drops and reaches 4.2V, pin

1 of IC521 is set to “Low”. This will RESET the

microcomputer.

Page 33

– 31 –

2. Receiver Circuit

IRR (light receiver unit) receives the infrared signal from the wireless remote controller. The receiver amplifies and shapes the signal and outputs it.

3. Buzzer Circuit

When the buzzer sounds, an approx 3.9kHz square signal is output from buzzer output pin

of the microcomputer. After the amplitude of this signal has been set to 12Vp-p by IC711, it is applied to the buzzer. The piezoelectric element in the buzzer oscillates to generate the buzzer’s sound.

Q141

L201

12V

IRR

VDD

Fig.2-1

Fig.3-1 Buzzer circuit

GND

OUT

C212

C211

R212

R211

ZD141

R141

R611

C611

RECEIVER I/P

Microcomputer

BZ1

R721

12V

IC711

Microcomputer

Buzzer output

16130

Sound wave

Metal diaphragm

Pizoelectric element

Fig. 3-2 Buzzer Operation

Page 34

– 32 –

Micro computer pins

Step width : 10ms

Horizontal air deflectors

123456 78

Fig.4-2 Microcomputer Output Signals

Table 4-1 Auto sweep Motor Rotation

crocompute

Roto

Auto sweep motor for horizontal air defectors

Fig.4-1

Rotation angle per step ) Time per step (ms.)

0.0882 10Horizontal air deflectors

4. Auto Sweep Motor Circuit

Fig. 4-1 shows the Auto sweep motor drive circuit; the signals shown in Fig.4-2 are output from pin

H of

microcomputer.

As the microcomputer’s outputs change as shown in Fig.4-2, the coils of the auto sweep motor is excite to turn the rotor. Table 4-1 shows the rotation angle of horizontal air deflectors.

Page 35

– 33 –

5. Initial Setting Circuit (IC401)

• When power is supplied, the microcomputer reads the data in IC401 or IC402 (E2PROM) and sets the preheating activation value and the rating and maximum speed of the compressor, etc. to their initial values.

• Data of self-diagnosis mode is stored in IC401 or IC402; data will not be erased even when power is turned off.

6. Power Supply

First, 35V power which operates the indoor unit is generated by the power source section of the outdoor unit and supplied to the indoor unit through the C and D lines of the connecting cable. Second, use the DC/DC converter and the 35 V power supply from the outdoor unit to generate 12 V control power, which drives the stepping motor during the operation. In addition, use the regulator IC 121 to generate 5 V power required for driving the micro computer and controlling fan motor. If the terminal block was overheated due to a connecting cable improper connection, the thermal fuse built in the terminal block will burnt to shut off the 12 V line and stop the operation of the indoor unit. Then, the outdoor unit cannot be communicated with the indoor unit and a communication error occurs (the outdoor LD301 will blink 9 times), stop all operations.

Fig. 6-1

Fig. 5-1

Microcomputer

External ROM

SCL SDA

5V 5V

C401

IC401 or IC402 (E

PROM)

R404

R403

27 26

}

Page 36

– 34 –

Micro computer

Fan motor

Fig. 7-1

DC fan motor output

DC fan motor Speed feedback

Voltage at point A Waveform

T2 T1

Voltage at point B Waveform

Voltage at point C Waveform

Fig. 7-2

Voltage at point B (V)

Fig. 7-3

7. Fan Motor Drive Circuit

• For the point A , 15.7 kHz PWM pulse will be output from the pin

N on the micro computer as shown in Fig. 7-2.

The pulse range will vary with different command speed.

• The pulse is converted into the analog voltage by the R751 and C751 and applied to the fan motor as the speed command voltage. Fig. 7-3 shows the relation between the voltage at the point B and the speed. (Some differences will occur due to the condition of the unit.)

• The fan motor outputs the feedback pulse of the speed, which is input into the pin

D on the micro computer. This

pulse is equivalent to a frequency of 12/60 speed. (Example: 1000 min-1 x 12/60 = 200 Hz) The micro computer monitors the frequency and adjusts the output pulse range of the pin

N so as to keep the

command speed.

• If the feedback pulse is 100 min-1 or less due to a locked fan motor or failure, the fan output will be stopped temporarily as fan lock error. After 10 seconds, restart the output of the pulse. If fan lock error is detected twice within 30 minutes, all units are stopped and the unit will come in the failure mode. (The timer lamp will blink 10 times.)

Page 37

– 35 –

MODEL RAC-18YH6 RAC-25YH6

1. Power circuit

This circuit is to convert the power from AC which is provided from the terminal A and B to DC voltage. And produces an AC current which does not exceed the harmonic amplitude limit of the IEC61000-3-2. When the compressor is stopped, the AC voltage becomes about 300 V and while the compressor operates, it is about 280 V.

Main parts (1) DB2

The DB2 rectifies the AC voltage. The possible causes for the DB2 failure are as follows. The 15 A fuse may be blown out or the IPM for the main P.W.B. may have a failure. In such a case, check the 15 A fuse for blowout and replace the main P.W.B. if necessary.

(2) DB3, L1, C023 and L2

The DB3, L1, C023 and L2 shape waveform of the input current. When the current runs through the L1 is taken for I1 and the current runs through the L2 is taken for I2 as shown in Fig. 1-2, I1 becomes an input current to the capacitor which peak value was crushed by the L1 and I2 becomes a resonance current which causes the LC resonance using the L2 and C023. By combining the I1 and I2, the input current from the main power shapes a waveform shown in the right side of Fig. 1-3, indicating that the waveform is similar to sine wave. The more the waveform is similar to the sine wave, the lower the harmonic current becomes. If the C023 has any failure, the protection unit activates and the C023 in open mode. In such a case, replace the failed parts.

1-2 1-3

DB3

C023

Page 38

– 36 –

Input

Voltage

Smoothed

Voltage

Fig. 1-4

(3) C021 and C022

This smoothes the voltage rectified for operating the compressor. When the input voltage is taken for the sine wave as shown in the top of Fig. 1-4, it is rectified by the DB2 and becomes the waveform as shown in the middle of Fig. 1-4. After that, the voltage is smoothed by the C021 and C022, and becomes the waveform shown in the bottom of Fig. 1-4.

(4) DB1 and C41

The DB1 rectifies the input voltage and the C41 smoothes it for the control power supply. If the units above have any failure, the control power supply won’t operate. In such a case, replace the main P.W.B.

(5) C001 to C003, C011, L101, and L102

They absorb electrical noise generated during operation of compressor, and also absorb external noise entering from power line to protect electronic parts. Be sure to connect the earth cable between the indoor unit and the outdoor unit. Otherwise, the noise filter circuit won’t operate properly.

(6) SA1 and VS1 to VS3

These surge absorber and varistors absorb external power surge such as induced thunder. Be sure to connect the earth cable between the indoor unit and the outdoor unit. Otherwise, the surge absorber and the varistors won’t operate.

(7) R002 and R007

The resistor R002 protects the rush current when the power is turned on while the resistor R007 protects the rush current when the compressor starts. When the R002 has any failure, the control power supply won’t operate. When the R007 has any failure and a strong rush current is generated, the DB2, C021 or C022 may be damaged.

Page 39

– 37 –

2. Indoor/Outdoor Interface Circuit

The interface circuit superimposes an interface signal on the DC 35V line to perform communications between indoor and outdoor units. This circuit consists of a transmitting circuit which superimposes an interface signal transmit from the microcomputer on the DC 35V line and a circuit which detects the interface signal on the DC 35V line. Communications are performed alternatively transmitting and receiving.

2-1 Communication signal from outdoor microcomputer to indoor microcomputer.

At first outdoor microcomputer will send a request signal (SDO) to indoor microcomputer. 38 KHz of carrier signal is generated and modulated by the request signal (SDO) from the outdoor microcomputer pin

This signal is superimposed to DC 35V line via C801 and L801. To prevent erroneous reception, the outdoor microcomputer is designed so that it cannot receive a signal while it is outputting a request signal. The receiving circuit in the indoor unit consists of a comparator and transistor. The interface signal from the outdoor unit on the DC 35V line is supplied to C821, where DC components are eliminated, and is then shaped by the comparator. The shaped signal is detected by diode, amplified by amp, and output to pin

i of the indoor microcomputer.

Fig. 2-2 shows the waveforms at each component when data is transferred from the outdoor microcomputer to the indoor microcomputer.

2-2 Communication signal from indoor microcomputer to outdoor microcomputer.

The request signal (SDO) generates by indoor microcomputer is output to pin

j , and amplifies by

Q801. I/F signal approx. 38 kHz is generated by comparator, then modulated by the signal from pin

j of

indoor microprocessor. This modulated I/F signal is then amplified and superimposed to DC 35V line via L801 and C802 of indoor interface circuit. Fig. 2-3 shows the waveforms at each component when data is transferred from outdoor microcomputer to indoor microcomputer. The circuit operation of the outdoor receiving circuit is same as indoor receiving circuit.

Page 40

– 38 –

Fig. 2-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate with each other.

(SDO)

I/F TRANSMISSION

(SDI)

I/F RECEPTION

C213

R255

R254

Q205

R256

R214

R257

D206

IC5(1/2)

R260

R261

R258

R259

R262

5V0V

R263

Q204

R268

6.5V

R803

Q801

R801

R802

C802

C801

L801

I / F0V

NF COIL 2

C808

L802

12V

(Communications from indoor microcomputer to outdoor microcomputer)

(Communications from outdoor microcomputer to indoor microcomputer)

Fig. 2-1 Indoor / Outdoor interface circuit

CONTROL P.W.B .

C807

C806

35V

Page 41

– 39 –

ms.

rame

.95ms.

ransmit/receive

witching time

V DC lin

Fig. 2-3 Voltages Waveforms of Indoor / Outdoor Microcomputers (Indoor to Outdoor Communications)

ms.

rame

ms.

eade

35V D

lin

Fig. 2-2 Voltages Waveforms of Indoor / Outdoor Microcomputers (Outdoor to Indoor Communications)

Page 42

– 40 –

Fig. 2-4

)

Outdoor microcomputer

(

HIC

)

to indoor microcompute

Serial Communications Format during Normal Communications

xampl

When the outdoor message is all 0s

and indoor message is all 1s:

)

Communications waveforms

eade

hen rese

approx.100ms.

)

hen rese

approx.10ms.

)

Bit No.=

it No.=

33.3ms.

)

33.3ms.

)

33.3ms.

)

ansmit

eceiv

witching tim

4.95ms.

)

33.3ms.

)

33.3ms.

)

Outdoor messag

ndoor messag

33.3ms.

)

33.3ms.

)

Character No

)

door microcomputer to outdoor microcomputer

(

HIC

)

Page 43

– 41 –

12126

123456

3 22

0202

3 22

01234

123

01234

123

Operation mode(0 LSB)

Operation mode(1)

Fan(0 LSB)

Fan(1)

Fan(2 MSB)

2-way valve

Reversing valve

Quick heating

Main power ON request

Operation mode(2 MSB)

Indoor in-operation bit

Capacity code(0 LSB)

Capacity code(1)

Capacity code(2)

Capacity code(3 MSB)

During forced operation

Defrost request signal

Self-diagnosis(1)

Self-diagnosis(0 LSB)

Outside temperature(0 LSB)

Actual compressor rotation speed(0 LSB)

Compressor command speed(0 LSB)

Compressor minimum rotation speed(0 LSB)

Compressor minimum rotation speed(1)

Compressor minimum rotation speed(2)

Compressor minimum rotation speed(3)

Compressor minimum rotation speed(4 MSB)

Compressor command speed(1)

Compressor command speed(2)

Compressor command speed(3)

Compressor command speed(4)

Compressor command speed(5)

Compressor command speed(6)

Compressor command speed(7 MSB)

15/20(A)

OVL up

Indoor new communication bit

Compressor ON

Actual compressor rotation speed(1)

Actual compressor rotation speed(2)

Actual compressor rotation speed(3)

Actual compressor rotation speed(4)

Actual compressor rotation speed(5)

Actual compressor rotation speed(6)

Actual compressor rotation speed(7 MSB)

Outdoor new communication bit

Rotary reversing valve being ON

Fast feed 1/1000 for commercial test

Fast feed 1/10000 for commercial test

Outside temperature(1)

Outside temperature(2)

Outside temperature(3)

Outside temperature(4)

Outside temperature(5)

Outside temperature(6)

Outside temperature(7 MSB)

Fan-7-step request

Self-diagnosis(3 MSB)

Self-diagnosis(2)

Page 44

– 42 –

Fig. 3-1 System power module circuit (U

is ON, V

is ON)

3. Intelligent power module circuit (IPM circuit)

Fig. 3-1 shows peripheral circuits of intelligent power

module (IPM).

In the diagram, U

and W

are called the

"upper arm", U

, V

and W

, the "lower arm".

Page 45

– 43 –

Fig. 3-3 Voltage waveform at each point

transistor chopped

hopping period (208µ sec.

)

hopping perio

transistor ON

80V-300

urrent a

pper ar

transistor

Lower arm trans

stor

Fig. 3-2 Switching order of power module

Intelligent power module switches power supply current according to position of the compressor motor rotor. The switching order is as shown in Fig. 3-2.

At point E: U+ is ON, V- is ON (circuit in Fig. 3-1) At point F: U+ is chopped (OFF), V- is ON (circuit in Fig. 3-4)

Upper arm transistor is controlled to ON/OFF by 2.5kHz-5kHz chopper signal. Rotation speed of the compressor is proportional to duty ratio (ON time/ ON time + OFF time) of this chopper signal. Time T in Fig. 3-2 shows the switching period, and relation with rotation speed (N) of the compressor is shown by formula below;

N = 60/2 X 1/T Fig. 3-3 shows voltage waveform at each point shown in Figs. 3-1 and 3-4. First half of upper arm is chopper, second half is ON, and first half of lower arm is chopper, second half is ON.

When power is supplied U+→ V- , because of that U+ is chopped, current flows as shown below;

(1) When U+ transistor is ON: U+ transistor → U coil → V coil → V- transistor → DC current detection

resistor → Point B (Fig. 3-3)

(2) When U+ transistor is OFF: (by inductance of motor coil) U coil → V coil → V-transistor →

U- diode → Point A (Fig. 3-4)

Page 46

Fig. 3-4 Power module circuit (U+ is OFF, V– is ON)

303

302

301

Since current flows at point B only when U

transistor and V– transistor are ON, the current waveform at point B becomes intermittent waveform as shown in Fig. 3-3. Since current at point B is approximately proportional to the input current of the air conditioner, input current is controlled by using DC current (Id) detection resistor.

<Reference> If power module is defected, self diagnosis lamps on the MAIN P.W.B. may indicate as shown below:

MAIN P.W.B

ICE SWITCH

Table 3-1

Fig. 3-5

– 44 –

Page 47

– 45 –

Page 48

– 46 –

Page 49

– 47 –

5. Power Circuit for P.W.B.

• Fig. 5-1 shows the power circuit for P.W.B.

• In the power circuit for P.W.B., power supply for microcomputer, peripheral circuits, and IPM driver

circuit and, as well as DC 35V, are produced by switching power circuit.

• Switching power circuit performs voltage conversion effectively by switching transistor IC1 to convert DC 330V voltage to high frequency of about 20kHz to 200kHz.

ig. 5-

AC220-230V

Page 50

– 48 –

Page 51

– 49 –

Page 52

– 50 –

Page 53

– 51 –

6-2. Overload control circuit (OVL control circuit)

Overload control is to decrease the speed of the compressor and reduce the load when the load on the air conditioner increases to an overload state, in order to protect the compressor, electronic components and power breaker. Overloads are judged by comparing the DC current level and set value. Fig.6-4 shows the overload control system configuration and Fig. 6-7 is a characteristic diagram on overload judgement values. There are two types of control which has named IS OVL and ID OVL. IS OVL is limiting the whole input of this room air conditioner system through the current sensor CT1 in order to keep the maximum rating of components by reading total operating current. ID OVL is watching and limits the compressor current through the detection resistor, which is built in IPM in order to control the compressor reliability. Since the compressor reliability is related with its speed, the ID OVL value is also linked with the compressor speed. Fig. 6-7 shows an ID OVL limitation curve. All of OVL operation values were programmed into EEPROM memory.

Compressor

Microcomputer EEPROM

Motor current (ID)

Whole current (IS)

Fig. 6-4 Overload Control System

Detection

resistor

A-D

converter

ID OVL

value

IS OVL

value

Motor

control

process

A-D

converter

Detection

transformer CT1

Amplifier

Smoother

Page 54

– 52 –

Page 55

– 53 –

IPM

DC current

DC Voltage

Detection resistor

---

UVW

U V

Compressor motor

Fig. 6-9

DC voltage : Low DC current : High

DC voltage : High DC current : Low

DC voltage : 260V

Rotation speed

DC current

Fig. 6-8

R003,R004,R608,R613, detect the DC voltage at the power circuit. The microcomputer receives a DC voltage and applies correction to the overload set value so the DC current will be low when the DC voltage is high. (Since the load level is indicated by the DC voltage multiplied by DC current, R247, R248, R249 are provided to perform the same overload judgement even when the voltage varies.)

(3) Start current control

It is required to maintain the start current (DC current) constant to smooth the start of the DC motor of the compressor. RAC-18YH6, RAC-25YH6 uses software to control the start current. The start current varies when the supply voltage varies. This control method copes with variations in the voltages as follows.

1. Turns on the power module’s U

and V- transistors so the current flows to the motor windings as

shown in Fig. 6-9.

2. Varies the turn-ON time of the U

transistor according to the DC voltage level and the start is

controlled so the start current is approx. 10A .

Page 56

– 54 –

Fig. 6-10

HIC

Microcomputer

RESET OUT.

RESET

C204

R252

IC5(1/2)

D208

R287

C215

R284

R286

C225

R285

C226

R292

R289

R288

0V 0V 0V 0V

12V

Fig. 6-11

12V line

5V line

Reset voltage

Time

10.9V

9.9V

Power is ON

Voltage (V)

Power is OFF

Voltage (V)

6-3. Reset Circuit

The reset circuit initializes the microcomputer program when Power is “ON” from “OFF” . Low voltage at pin 7 resets the microcomputer, and HI activates the microcomputer. Fig. 6-10 shows the reset circuit and Fig. 6-11 shows waveform at each point when power is turned on and off. When power is turned on, 12V line and 5V line voltages rise and 12V line voltage reaches 10.9V an reset voltage input to pin 7 of microcomputer is set to Hi. Reset voltage will be hold “Hi” until the 12V line voltage drops to 9.90V even though the power shuts down.

Page 57

– 55 –

Outdoor temperature

19.69.23

22.62

R303 Voltage (V

)

Table 6-2

Main P.W.B.

HIC

O.H. thermistor

DEF. thermistor

Outdoor temperature thermistor

Microcomputer AX-8V11

DEF

Outdoor temperature

C302

R303

R306

R302

R305

C303

C304

R304

R301

CN8

CN9

+5V

CN10

Fig. 6-12

6-4. Temperature Detection Circuit

The Over heat thermistor circuit detects the temperature at the surface of the compressor head, the Defrost. thermistor circuit detects the defrosting operation temperature. A thermistor is a negative resistor element which has the characteristics that the higher (lower) the temperature, the lower (higher) the resistance. When the compressor is heated, the resistance of the Over heat thermistor becomes low and voltage to a pin s of microcomputer is increased. Microcomputer compares the voltage at pin s with the internal set value, if it is exceeded the set value microcomputer judges that the compressor is overheated and stops operation. When frost forms on the outdoor heat exchanger, the temperature at the exchanger drops abruptly. Therefore the resistance of the Defrost. thermistor becomes high and the voltage at pin w of microcomputer drops. If this voltage becomes lower than the set value stored inside, the microcomputer starts defrosting control. During defrosting operation the microcomputer transfers the defrosting condition command to the indoor microcomputer via the circuit interface. The microcomputer always reads the outdoor temperature via a thermistor (microcomputer pin x ), an transfers it to the indoor unit, thus controlling the compressor rotation speed according to the value set at the EEPROM in the indoor unit, and switching the operation status (outdoor fan on/off, etc.) in the dehumidifying mode. The following shows the typical values of outdoor temperature in relation to the voltage:

<Reference> When the thermistor is open, in open status, or is disconnected, microcomputer pins s,w,x are approx. 0V; when the thermistor is shorted, they are approx. 5 V, and LD301 blinks seven times. However, an error is detected only when the OH thermistor is shorted; in such a case, the blinking mode is entered 12 minutes after the compressor starts operation.

Page 58

– 56 –

CN2

015V

IC2

6-5. Reversing valve control circuit

In this unit, reversing valve control circuit turns ON/OFF the power to the reversing valve coil by

opening/closing the reversing valve relay.

Opening/closing of relay will differ depending on the operation condition. (In the cooling cycle,

reversing valve relay is normally ON (close).)

Table 6-3 shows the circuit operation of each operation mode. If the following result is not obtained,

reversing valve control circuit may be defective.

Table 6-3

Point

Operation mode

Cooling

In normal cooling operation

In normal heating operation In defrosting operation

approx. 35 V

0VHi

12VLo 0V (not fixed)

Heating

Between Pin 29 of microcomputer and 0V

Between Pin 32 of HIC and 0V

Between 1 and 3 CN2

Main P.W.B.

Reversing

valve

Reversing valve

relay coil

(RL5)

HIC

Fig. 6-13

Microcomputer

Reversing valve relay

RL5

−

Page 59

– 57 –

IC6

HIC

6-6. Electric expansion valve control circuit

Electric expansion valve is driven by B-12V. Opening of the valve is controlled by feeding power to 1

or 2 phases of the 4-phase coil to switch the polarity of the coil.

The relation between the conducting phase switching direction and open/close direction is as shown

below. When the power is turned on, approx. 0.9 V is applied to CN15 pins 1 to 4 ; when no power is supplied, approx. 12 V is applied. When the power is reset, expansion valve performs initial operation for 5 to 10 seconds.During initial operation, measure pins 1 to 4 of CN15 using multimeter: If no change is found around 0.9 V or 12V, expansion valve or microcomputer is defective.

Fig. 6-15 shows logic waveform during the operation of expansion valve.

Page 60

– 58 –

6-7. Outdoor DC

an Motor contl circui

This model uses DC Fan Motor which has a controller circuit built in the Motor

This DC Fan Motor will rotate by control voltage apply to

sp input

(Voltage range: 1.7 to 7V DC

)

Motor will output FG pulse byollowing this motor reolution

indoor microcompute

This PWM control signal will convert to Vsp voltage by smoothing circuit. (R242 & C209)

otation speed

C Fan Motor circuit has to match the Fan Motor revolution with instructed revolution. Such as..

G feedback: Fasternstruction: Slower ... Decrease pulse width G

edback

Slowernstruction: Faster ... Increase pulse width

G pulse is also used for Fan Motor failure detection

Microcompute

ill monitorG pulse

econds aftera

thefan moto.

there is no

ignal detected

considerthat the

an Moto

malfunction and

op the operation.n this case,

302

on main

107 and IC4 are used for Fan Motorover curren

sp high

aster ;

lower ;

.W.B. will blink 12 times.

Fan Motor lock detected

)

G pulse will feed back to Outdoor microcomputer

Outdoor microcomputer will output PWM control signal from

by following the instruction from

an motor will start to rotate when Vsp was proceeding over than 1.7V, and generate FG pulse b

HIC

Page 61

– 59 –

< Reference > When operation stop with LD301 blinks 12 times, it may be caused by faulty DC fan motor. In this case, please check CN6 and CN12 connection first. It makes Fan Motor Lock also if those connectors are in misconnection. DC Fan Motor has broken invites 1A Fuse burned. Please replace both DC Fan Motor and 1A Fuse together. It will makes “Fan Lock Stop” when something has disturb the Fan rotation by inserting materials into propeller fan or ice has growing inside of outdoor unit by snowing. It may make “Fan Lock Stop” by strong wind (ex. 17m/sec or above) against the Fan rotation. In this case unit will be restart again after a while. In case of “ Fan Lock Stop” even though the DC Fan Motor is rotating correctly, the possible cause in Fan Motor problem or control board problem. Stop after the Fan motor runs 2 minutes, Fan Motor may be broken. < Caution > Please take care for the electrical shock by high voltage of DC Fan Motor power source which is common with compressor when you are servicing this unit. You can not confirm the coil and wiring of Motor directly due to the built in control circuit in Fan Motor.

Page 62

– 60 –

SERVICE CALL Q & A

Model RAS-18YH6 / RAC-18YH6

RAS-25YH6 / RAC-25YH6

COOLING MODE

The compressor has

Fan speed is not switched over during dehumidifying operation.

Cool air comes from the unit during dehumidifying operation.

Fans speed is normally set to LOW during dehumidifying operation.

To have an operation with high dehumidifying effect, the unit operates at low fan speed. As a result, cool air comes from the unit. This phenomenon is not a fault.

stopped suddenly during cooling operation.

The circulation stops occasionally during Heating mode.

When the fan speed is set at HIGH or MED, the flow is actually Weak.

Heating operation stops

When “Auto fan” mode is set, the indoor fan speed changes from HIGH through MED to LOW.

while the temperature is preset at "30".

Check if the indoor heat exchanger is frosted. Wait for 3-4 minutes until it is defrosted.

If the air conditioner operates in cooling mode when it is cold, the evaporator may get frosted.

It occurs during defrosting. Wait for 5-10 minutes until the condenser is defrosted.

At the beginning of heating, the fan speed remains LOW for 30 seconds. If HIGH is selected, it switches to LOW and again to MED after additional 30 seconds.

If temperature is high in

This is not an error. The anti cool air function shows this phenomenon.

In the fan “Auto” mode, the unit detects the heat exchange temperature. When the temperature becomes low, the fan speed changes from HIGH, through MED to LOW.

the outdoor, heating operation may stop to protect internal devices.

DEHUMIDIFYING MODE

HEATING MODE

Page 63

– 61 –

AUTO FRESH DEFROSTING

AUTO OPERATION

NICE TEMPERATURE RESERVATION

INFRARED REMOTE CONTROL

After the ON/OFF button is pressed to stop heating, the outdoor unit is still working with the OPERATION lamp lighting.

Fan speed does not change when fan speed selector is changed during auto operation.

When on-timer has been programmed, operation starts before the preset time has been reached.

Does Nice temperature reservation function operate during dehumidifying?

Even if the same time is preset, the operation start time varies.

Timer cannot be set.

The current time display disappears soon.

The timer has been programmed, but the preset time disappears.

Auto Fresh Defrosting is carried out : the system checks the outdoor heat exchanger and defrosts it as necessary before stopping operation.

At this point fan speed is automatic.

This is because Nice temperature reservation function is operating. This function starts operation earlier so the preset temperature is reached at the preset time. Operation may start maximum 60 minutes before the preset time.

It does not work. It works only during cooling and heating.

This is because Nice temperature reservation function is operating. The start time varies according to the load of room. Since load varies greatly during heating, the operation start time is corrected, so it will vary each day.

Has the clock been set? Timer cannot be set unless the clock has been set.

The current time disappears in approx. 10 seconds. The time set display has priority.

approx. 3 minutes.

Is the current time past the preset time? When the preset time reaches the current time, it disappears.

When the current time is set the display flashes for

Q10

A10

Q11

A11

A12

Q13

A13

Q14

A14

Q15

A15

Q12

Page 64

– 62 –

OTHERS

Q18

A18

Q19

A19

Q20

A20

Q21

A21

Q22

A22

The indoor fan varies among high air flow, low air flow and breeze in the auto fan speed mode. (Heating operation)

This is because the cool wind prevention function is operating, and does not indicate a fault.

The heat exchanger temperature is sensed in the auto speed mode. When the temperature is low, the fan speed varies among high air flow, low air flow and breeze.

Loud noise from the outdoor unit is

When the “Sleep” timer is set during operation, (1) The indoor fan won’t rotate. (No air comes from the unit) (2) The air speed won’t change.

The preset temperature is not indicated on the remote control.

(1) The temperature arrives at the preset indoor temperature and the air conditioner unit is temporarily stopped. Within about 3 minutes, the fan starts rotation. (2) When the unit operates at “LOW” air speed, it continues to operate at the same speed.

When automatic operation is performed, the preset temperature won’t be indicated. However, you can adjust the temperature within a range of ±3°C by pressing the “Room Temperature” button. If the temperature is 1°C higher than the auto preset temperature, 1°C will appear. If the temperature is 1°C lower than the auto preset temperature, 1°C will appear.

heard when operation is started.

When operation is started, the compressor rotation speed goes to maximum to increase the heating or cooling capability, so noise becomes slightly louder. This does not indicate a fault.

Noise from the outdoor unit occasionally changes.

The compressor rotation speed changes according to the difference between the thermostat set temperature and room temperature. This does not indicate a fault.

There is a difference between the set temperature and room temperature.

There may be a difference between the set temperature and room temperature because of construction of room, air current, etc. Set the temperature at a comfortable for the space.

Air does not flow immediately after operation is started.

Preliminary operation is performed for one minute when the power switch on and heating or dehumidifying is set. The operation lamp blinks during this time for heating. This does not indicate a fault.

Q16

A16

Q17

A17

Page 65

– 63 –

TROUBLE SHOOTING

RAC-18YH6, 25YH6 PRECAUTIONS FOR CHECKING

WARNING

Always keep your hands and metallic things away from the cabinet.

DANGER!

Donít install the ground line.

When using an oscilloscope, never ground it. Donít forget that high voltage as noted in the figure above may apply to the oscilloscope.

Remember that voltage of 175 V is applied to the 0V line on the P.W.B. or the like as shown in the right diagram.

Indoor Controller

Outdoor Controller

Power Switch

Point

400 F

I.P.M

Compressor motor

Point

line

Control P.W.B.

Main

P.W.B.

Voltage at point A

round voltage

Grounding

350V

Point B (0V line)

Power

inlet

Page 66

– 64 –

WARNING

Do not use a soldering iron with transformer: Otherwise, thermal fuse inside transformer will be blown.

DISCHARGE, PROCEDURE AND POWER SHUT OFF METHOD FOR POWER CIRCUIT

Caution

• Voltage of about 350 V is charged between the terminal of smoothing capacitors (375µF x 2).

• During continuity check for each circuit part of the outdoor unit, be sure to discharge the smoothing

capacitors.

Discharge Procedure

1. Turn off the power of the indoor unit or pull out the power supply plug.

2. After power is turned off, wait for 10 minutes or more. Then, remove electrical parts cover

and apply soldering iron of 30 to 75 W for 15 seconds or more to TAB05 and R001 terminals on the main P.W.B. as shown in the figure below, in order to discharge voltage in smoothing capacitor.

LEAD WIRE

Page 67

– 65 –

ELEC. COVER

FIXTURE SCREW

OFF

STRUCTURE OF AN INDOOR UNIT ELECTRIC PARTS

RAS-18YH6, 25YH6

Removing the indicating P.W.B.

1. Remove the connector from the CN2 on the control P.W.B.

2. Remove the upper hook from the indicating P.W.B. lock resin, pull the P.W.B. forward a little and remove it.

When installing the parts, use caution not to pinch any code between the part and cabinet.

Removing electrical parts

1. Remove the electrical parts cover.

2. Remove the connectors from the CN1 (heat exchange thermistor), CN4 (stepping motor) and CN10 (fan motor).

3. Remove two lock screws.

4. Remove the electrical parts in the direction of arrow.

Removing control P.W.B.

1. Remove the connectors from the CN2 and CN3.

2. Remove the P.W.B. from the P.W.B. support.

Page 68

– 66 –

ICP2

ICP1

12V

Power circuit

12V line

5V line

ZD121

20V

Zener Diode

Power circuit

35V line

ICP1

Q111

IC111

Lock

Press here

Unlock

Forbidden area (Gate (G) to 0 V)

35 V line

S: Source D: Drain G: Gate

Forbidden area

Indoor unit fan motor

Other Cautions

(1) Cautions concerning ICP (IC Protector)

1. Use due caution for short circuit in servicing.

Short circuit will open the ICP immediately.

2. When the ICP opens, remove the cause of this phenomenon and replace the ICP.

If the remedy is improper, the ICP may open again.

(2) The CN3 (power supply) and CN10 (fan motor) are the connectors with lock mechanism. Press

the lock with your fingers to unlock and remove the connector.

(3) When checking the voltage and waveform, do not connect the probes to the forbidden areas show

below. Touching them may cause the ICP1 blowout and Q111 failure.

The Q111 is a MOS-FET and its gate terminal is a high impedance. When a probe such as a multimeter is contacted with the gate G, the Q111 may have the continuous ON state to supply overcurrent in the circuit, causing the ICP1 blowout and Q111 failure.

When checking the switching waveform of the Q111, set the source S to the base and measure the gate G and drain D.

(4) During power feeding to the P.W.B., do not remove and insert the CN10 (fan motor connector).

Failure to do so may cause overcurrent to the fan motor and P.W.B.s (micro computer, IC and the like) and a failure may occur. To remove or insert the CN10, be sure to shut off the power.

Page 69

– 67 –

THE SUPPORT FUNCTION OF FAILURE DIAGNOSIS

No.

Function Name

Self-diagnosis indication function <Indicating a failure on the indoor unit side>

Description

• The “timer lamp” indicates a mode of failure detected on the indoor or outdoor unit side by blinking frequency.

• A failure detected on the outdoor unit side will be indicated by the “timer lamp” blinking 4 times after a retry operation has been performed several times.

Note: In some failure modes, only the retry operation is repeated without lamp indication.

OH thermistor temperature rise Outdoor unit communication error Power voltage abnormal Less frequent defects

• The “LD301” indicates a mode of failure detected on the outdoor unit side by blinking frequency. Upon failure detection, the outdoor unit will shut down and the LD301 continues to blink until the unit is reset. (In the event of communication errors, the LD301 continues to blink until communication is restored.)

Page 70

– 68 –

No. Blinking of Timer lamp Reason for indication Possible cause

Reversing valve defective When the indoor heat exchanger temperature is too low in the heating mode or it is too high in th

cooling

mode.

Outdoor unit is under forced operation

Outdoor unit electrical components defetive

When the outdoor unit is in forced operation or balancing operatio

after forced operation

Indoor/outdoor interface defective When the interface signal from th

outdoor

When the same error mode is detected 8 times within 30 minutes from outdoor unit electrical components. (However, when error is detected 8 times within two hours only for outdoor thermistor.)

unit is interrupted.

Room thermistor or heat exchanger thermistor is faulty When room thermistor or heat exchanger thermistor is

opened

circuit or short

circuit.

Over-current detection at the DC fan motor

when over-current is detected at th

DC fan motor of the indoor unit.

IC401 or IC402 data reading error When data read from IC401 or

IC402 is incorrect.

(1) Reversing valve defective (2) Heat exchanger thermistor

disconnected

(only in the heating mode) (Note) The malfunction mode is entered the 3rd time this abnormal indication appears (read every 3 minutes).

Electrical parts in the outdoor unit

(1) Indoor interface circuit (2) Outdoor

Outdoor unit electrical components (For details, operate again using remote comtroller and check from self-diagnosis display of outdoor unit.)

interface circuit

(1) Room thermistor (2) Heat exchanger thermistor

(1) Indoor fan locked (2) Indoor fan motor

IC401 or IC402 abnormal

( Lights for 0.35 sec. at interval of 0.35

sec.)

10 times

3 times

time

2 times

13 time

2 sec.

2sec.

2 sec.

9 times

2 sec.

(3) Indoor control P.W.B.

4 times

2sec.

(1) If the interface circuit is faulty when power is supplied, the self-diagnosis display will not be displayed.

(2) If the indoor unit does not operate at all, check if the connecting cable is connected to the outdoor unit.

(3) To check operation again when the timer lamp is blinking, you can use the remote control for operation

(except for mode mark

1).

TROUBLESHOOTING WHEN TIMER LAMP BLINKS.

Model RAS-18YH6, RAS-25YH6 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink.

SELF-DIAGNOSIS LIGHTING MODE Model: RAS-18YH6, RAS-25YH6

Page 71

– 69 –

SELF-DIAGNOSIS LIGHTING MODE

MODEL RAC-18YH6, RAC-25YH6

ELF-DIAGNOSIS LIGHTING MODE

MODEL RAC-E10H2

Page 72

– 70 –

1/ 2/ IPM (Intelligent Power Module) 3/ Service Switch 4/ Self-Diagnosis Lamp

Remove the compressor connector.

If your first attempt fails, wait 3 minutes (for the unit to restart) and check the self-diagnosis lamp status again.

Check outdoor electrical parts.

Check the refrigerating cycle.

Normal

Ye s

Check the drive

circuit (IPM) using the PRD checker.

Check the position

sensor circuit.

With the unit set in the operating state, press the start/stop button. Does the unit operate for approximately 2 seconds (the LD303 coming on) and then stop due to a failure of switching (the lamp blinking 4 times)?

OUTDOOR UNIT

303

D302

P.W.B.

ERICE SWIT

Page 73

– 71 –

Is the indoor unit "timer lamp" blinking?

Ye s

Trouble shoot according to the self-diagnosis lighting mode.

Open the indoor unit and check the voltage between pins Nos.1 and 3 of CN3 on the indoor unit control P.W.B. Normal: DC35V (32-38V)

Red

Brown

Is the voltage correct?

Is the compressor running?

Check if the connecting cable connected incorrectly? inserted incompletely? or disconnected?

Not runningRunning

Open the outdoor unit and observe the self-diagnosis lamp (LD301). Count how many times the lamp blinks.

Blinks other than 1 time. Blinks 1 time.

Can the unit be operated using the outdoor unit service switch? (See the nameplate on the outdoor unit for operating instructions.)

Check the outdoor electrical parts.

Check the indoor electrical parts.

Check the refrigerating cycle.

In the event of overload limit cut or OH thermistor temperature rise, use the self-diagnosis memory function because such failure may evade detection due to ambient temperature variations or other factors.

Ye s

CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING

Page 74

– 72 –

1. Power does not come on (no operation)

Is AC220-230V being generated between terminals A and B on the indoor unit terminal board?

Is AC220-230V being generated at AC outlet?

Check AC outlet and breaker, and repair any defective part.

Check the outdoor unit power circuit, and repair any defective part.

Check according to the proper method for checking the power circuit.

Check the reset circuit, and repair any defective section.

Replace the microcomputer and oscillator.

Is the control voltage being generated normally? 12V line: 12V or 7V 5V line: 5V

Do the air deflectors perform initial operation when the power supply is turned on after off?

Check the power cable, power switch, and terminal board, and repair any defective part.

Check the indoor/outdoor unit connection cable, and correct any defective section (wrong connection, incomplete insertion).

Is AC220-230V being generated between terminals A and B on the outdoor unit terminal board?

Is DC35V or 20V being generated between terminals C and D on the indoor unit terminal board?

Is the microcomputer reset input (pin7) "Hi"?

Is the microcomputer clock signal 10MHz at pins 0 and A being generated normally?

Is DC35V is being generated between terminals C and D on the outdoor unit terminal board?

Are C and D connection cables reversed?

Connect the cables correctly.

Check the wireless light receiving unit.

Replace the control P.W.B.

Perform final operation check.

: When not in operation, the unit will enter into a low-power standby state, possibly causing a voltage drop to the 12V and 35V lines as shown below.

25V - 20V

12V - 7V

Ye s

CHECKING THE INDOOR UNIT ELECTRICAL PARTS

Page 75

– 73 –

2. Indoor fan does not operate (others are normal)

Can the fan be stopped by remote control?

The microcomputer fan PWM output (at pin ) is 1-5V.

Replace the microcomputer.

Replace the fan motor.

Replace the microcomputer.

Perform final operation check.

3. Air deflector does not move (others are normal)

Are pulse signals output at microcomputer pins - when auto swing is turned on in the fan mode?

Replace the microcomputer.

Is a voltage over 15 or below 10V being generated on the 12V line?

Replace IC111.

Ye s

Check IC711. If it is normal, replace the air deflector motor.

Perform final operation check.

15 18

Page 76

– 74 –

1 2

4. Check the control P.W.B. (power circuit)

Is 35V or 20V being output at pin 5 relative to 0V at pin 3 of CN3?

Is 12V or 7V being output at (+) relative to 0V at (-) of C114?

Is ICP1 normal? Normal if it is less than 1

Blown (open) if it is 1

or more.

Replace ICP1. Check if the air deflector motor is shorted, and IC111, Q111, C114, ZD121 are defective. If shorted / defective, ICP1 will be open again.

Replace the terminal board. Insert the connection cable securely.

Replace IC121. Check if a short occurs in the 5V line. If the 5V line is shorted, ICP1 will be open again.

Check to see if the connection cables are disconnected or reversed. If normal, check the outdoor unit P.W.B.

Has the terminal board thermal fuse blown (open)?

Replace Q111 and IC111.

Is DC5V being generated?

Perform final operation check.

: When the unit is not in operation, the voltage across the 35V line may drop to 20V. : When the unit is not in operation, the voltage across the 12 V line may drop to 7V.

Ye s

(Normal)

Ye s

(Open)

Ye s

Page 77

– 75 –

Page 78

– 76 –

Is AC220-230V being generated at

terminals A and B?

Are the connections for

terminals C and D correct?

Is 5V being generated between

Pin 6 (0V) and Pin

(5V) at CN

Is the 15A

fuse normal?

[No operation or abnormal operation]

Be sure to turn the power off

before correcting the connection.

mainly, varistor (VS2), 3A fuse,

smoothing capacitors, IPM, etc.

The SW power supply s overcurrent protection is

activated, disabling the microcomputer.

Correct properly.

If the 15A

fuse has blown,

be aware that other parts

may also be defective.

Replace defective parts.

Is the power circuit normal?

See the description on power

circuit for details.

Is the switching power

circuit OK?

Has the 3A fuse blown?

Check to see if C and D cables are

connected correctly.

If reversed or incompletely inserted,

correct the cable connection.

Replace any defective parts.

If the 3A fuse has blown, the varistor 2, etc.

may also be defective.

With the piping and lines (A,

B, C, D) connected, operate

the unit in the forced cooling

mode using the outdoor unit

service switch.

How did the self-diagnosis

lamp (LD301) blink?

See the self-diagnosis

lamp mode.

Yes

Power is OK

Yes

(Fuse blown)

18 (test pin)?

CHECKING OUTDOOR UNIT ELECTRICAL PARTS

Page 79

– 77 –

LD301 blinks 12 times.

Fan lock error.

Is CN24 connected?

Is the propeller fan

locked?

Have the 1A fuse and

R107 blown?

Is +15V being generated?

Check voltage both between

CN18 3 and 6 on the main

P.W.B., and between +15V

and 15-0V (silk-screened) on

the main P.W.B.

Is the fan operating?

(An error occurs after the

fan operates for 2 minutes.)

Is the voltage between 4

and 6 at CN24 normal?

(Normally, the voltage is

above approx. DC1.7V

Connect the connector.

Remove any

obstructions.

Replace the fan motor

and main P.W.B.

Is the voltage between 4 and

7 at CN24 normal?

Check to see if the voltage is

within 2.5V

0.5V using a

tester.

(In effect, the output voltage

is alternately switched

between 5V and 0V.)

Replace the main

P. W. B .

Replace the fan motor.

Yes

Page 80

– 78 –

LD 301 blinks 10 times.

Defective power supply

voltage.

Is AC220-230V being output

at terminals A

and B on

the terminal board?

Apply AC220-230V.

Check the interior wiring.

TAB05, TAB11, reactor,

and C023 (yellow green)

connected properly?

Connect properly.

Replace the main P.W.B.

Possible causes include:

Power relay malfunction

Defective microcomputer

terminal

Yes

Page 81

– 79 –

Page 82

– 80 –

Page 83

– 81 –

Page 84

– 82 –

bli

cut

s t

nte

llig

ent power

module

(

)

normal

ace t

nte

llig

ent power

module

(

the main

.B.

)

bli

eset sto

, t

e un

t a

s r

sto

ust a

ter

ower

s su

ppli

does

dicate

fault

the

eset

cuit

al?

orma

lly

n 7 o

N18 is a

rox. 5V

ace t

e ma

e sure a

n t

ecto

ected

secure

orm

erat

Page 85

– 83 –

CHECKING THE REFRIGERATING CYCLE

1. Troubleshooting procedure (No operation, No heating, No cooling)

Connect U,V,W phase leads to the power module again and operate the air conditioner.

Gas leaks. Repair and seal refrigerant.

Is the self-diagnosis lamp mode as shown on the right?

YES

Error (Gas leaking)

Normal

Perform a final check of operation.

When the self-diagnosis lamp lights in the same condition as above.

The compressor is defective. Replace it and seal refrigerant.

If the compressor checker for an inverter type air conditioner is available, re-check using it.

( )

(JUDGING BETWEEN GAS LEAKAGE AND COMPRESSOR DEFECTIVE)

Blinking off

Time until the

lamp lights

Approx. 10 seconds

Within Approx. 30 seconds

Compressor

Gas leakage

Possible

malfunctioning

part

LD301

Selfdiagnosis lamp

Lighting mode

Blinks

2 times

Blinks

3 times

Blinks

4 times

Blinks

5 times

Blinks

6 times

Blinks

8times

Stop to operate and check the gas pressure in balancing mode.

Checking the IPM (main P.W.B.)

(R410 A) The values above are the theoretical ones.

Page 86

HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT

MODEL RAC-18YH6, RAC-25YH6

1. Turn off the power switch.

2. Remove the electrical box cover.

3. Turn on the power switch.

4. After waiting for 30 seconds, push the service switch for a second.

LD303 (red) will light and the unit will operate in the forced cooling mode at this time.

Never operate the unit for more than 5 minutes.

rvice switch

ERVICE SWIT

(Cautions) (1) If interface signal (DC 35V) terminals C and D are not connected when the outdoor unit is in forced cool mode,

the outdoor unit defect indicator (LD301) will blink 9 times during operation to indicate communication error.

(2) If checking is done with the compressor connector disconnected, the unit will stop and LD301 will blink 4 times.

Be sure to push the service switch for a second again to stop the forced cool operation.

HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY

1. Connect the large dia. pipe side and small dia. pipe side service valve using a pipe.

Connect the small diameter service value and the large diameter service valve using the reducing union and copper pipe as shown on the right.

Charge refrigerant of 300g after vacuuming (

)

Outdoor unit

Compressor

Reversing valve

Large dia. service valve

Reducing union (2/8” and 3/8”)

Copper pipe (2/8”)

Small diameter service valve

Parts to be prepared

(1) Reducing union 2/8” (6.35 mm) 3/8” (9.52 mm) (2) Copper pipe (2/8” and 3/8”)

Do not operate for more than 5 minutes

The operation method is the same as “How to operate using the connector to servicing the outdoor unit”.

The charging amount of 200g is equivalent to the load in normal operation.

– 84 –

Page 87

– 85 –

See next page for measuring value using multimeter

PS21564-C

Circuit of 1 device

Gate

Collector

Emitter

Internal circuit diagram of module

Terminal symbols of power module

Model

IPM (Intelligent Power Module) DIAGNOSIS

Page 88

– 86 –

PUV

Diagnosis procedure for power module using multimeter

[Inverter section] Set the multimeter to resistance range of 100. If 100 is not provided, measure with the range of

1 to 100.

If the pointer does not swing when the following continuity check is performed, it is normal. (When a digital multimeter is used, + and - terminals will be reversed, since the orientation of built-in battery is inverted.)

Note: If internal circuit of power module is disconnected (open) and pointer of the mutimeter does not swing, it may be assumed to be normal. If the pointer swings when + and - terminals are connected in reverse, it is normal. Compare swing statuses for U, V and W phases: If the statuses at all 3 points are the same, it is normal.

Page 89

– 87 –

Procedure for Disassembly and Reassembly

INDOOR UNIT RAS-18YH6, RAS-25YH6

1. Front Panel

(1)Pull up the washable panel by holding it at both

lower sides with both hands.

Fig. 1

(2)When the panel opens full, push the inner part

of the right arm into the inside and pull the panel forward while closing it gradually.

Fig. 2

2. Front cover

(1)After removing two screws, pull the center of

the front cover forward and release the claws.

(2)Hold the front cover at both lower sides and

pull them forward to remove.

Fig. 3

Indicating P.W.B.

Control P.W.B.

Support hook

3. Control P.W.B. and Indicating P. W. B .

(1)Remove each connector from the lead wire. (2)Remove the four P.W.B. supports from the

control P.W.B.

(3)Pull the support hook at the upper side of the

indication lamp of the indicating P.W.B. and pull out the P.W.B. forward.

Fig. 4

Page 90

– 88 –

MODEL RAC-18YH6, RAC-25YH6

. 5

. 7

. 9

. 10

. 1

. 8

. 6

Lower bearing cover

Cabinet

Upper bearing cover

(1) Remove two screws locking the drain pan.

2) Press to lower the hook at the center of theunit a little and pull the c

aw forward to removethe drain pan.

(5) Remove the electrical box fixin

screws and GND wire fixing

(6) Remove the terminal plate fixing screw

7) Remove

lock which binds lead wires

8) Set the electrical box upside down.

9) Remove P.W.B. fixing screws (2 locations) and radiation fin fixing screws

(

5 locations), and remove the P.B. from the support.

1. Electr

cal Part

emove the upper cover fixing screws and

lif

t the cover to remove it.

2) Remove the service valve cover

3) Remove the terminal plate cover

(4) Remove the right side cover

(3) Remove the screws from the upper and lowerbearing covers. (4) Remove the lockin

hook of the lower bearingcover from the

et.

5) Remove two lock screws from the fan motorholder

(6) Pull up the evaporator by holding it at the lowerside. Insert a

screw

dri

ver through the spacebetween the evaporator and drain

dloosen the fan lock screw to remove the fanand fa

oto

Radiation fin fixing screw

P.W.B. fixing screw

Page 91

– 89 –

PARTS LIST AND DIAGRAM

INDOOR UNIT MODEL: RAS-18YH6, RAS-25YH6

Page 92

– 90 –

PARTS NO.

RAS-18YH6 RAS-25YH6 Q'TY PARTS NAME

1 1 CABINET 2 1 VERTICAL AIR DEFLECTOR-L 3 1 VERTICAL AIR DEFLECTOR-R 4 1 FAN MOTOR 25W 1.1kg 6 HWRAS-25YH4 A07 1 TANGENTIAL AIR FLOW FAN 7 HWRAS-25YH4 A08 1 FAN SUPPORT ASS'Y 8 HWRAS-25YH4 A09 1 FAN COVER

9 HWRAS-25YH4 A10 1 FAN MOTOR SUPPORT 10 HWRAS-25YH5 A05 1 EVAPORATOR ASS'Y 11 HWRAS-25YH4 A12 1 PIPE SET(IN) 12 HWRAS-25YH4 A13 1 PIPE SET(OUT) 13 HWRAS-35YHA1 A10 1 UPPER COVER 14 HWRAS-25YH4 A15 1 SPRING 15 HWRAS-25YH4 A16 1 TERMINAL BOARD(2P) 16 HWRAS-25YH4 A17 1 TERMINAL BOARD(2P) 17 1 POWER SUPPLY CORD 18 HWRAS-25YH4 A19 1 THERMISTOR ASS'Y 19 HWRAS-25YH4 A20 1 POWER SWICHI 20 HWRAS-18YH6 A01 HWRAS-E10H2 A01 1 P.W.B.(MAIN) 21 HWRAS-25YH4 A22 1 P.W.B.(INDICATION) 22 HWRAS-25YH4 A23 1 CONNECTING CORD(12PIN) 23 HWRAS-25YH4 A24 1 ELECTRIC PARTS COVER 24 HWRAS-25YH4 A25 1 COVER(TERMINAL) 25 HWRAS-25YH5 A07 1 DRAIN PAN 26 HWRAS-25YH5 A08 1 HORIZONTAL AIR DEFLECTOR 27 HWRAS-25YH4 A28 2 DEFLECTOR SUPPORT 28 HWRAS-25YH4 A29 1 AUTO SWEEP MOTOR 29 HWRAS-25YH4 A30 1 DRAIN CAP 30 HWRAS-25YH4 A31 1 HEAT INSULATOR PIPE 31 1 DRAIN HOSE 32 1 FRONT COVER ASS'Y 33 1 COVER(EARTH) 34 1 COVER(SWICHI) 35 1 FRONT PANEL 36 1 AIR FILTER(R) 37 1 AIR FILTER(L) 38 1 COVER(LOWER)(R) 39 1 MOUNTING PLATE 40 HWRAS-25YH4 A41 1 REMOCON.

SUPPORT 41 HWRAS-25YH4 A42 1 SCREW ASS'Y 42 HWRAS-25YH4 A43 1 REMOTE CONTROL ASS'Y 43 HWRAS-25YH4 A06 1

COVER(ELECTRIC)

INDOOR UNIT

HWRAS-25YH5 A20 HWRAS-25YH5 A02 HWRAS-25YH5 A03 HWRAS-25YH5 A04

HWRAS-E08H A01

HWRAS-D10EX2 A02 HWRAS-25YH5 A09 HWRAS-25YH5 A10 HWRAS-25YH5 A11 HWRAS-25YH5 A12 HWRAS-25YH5 A13 HWRAS-25YH5 A14 HWRAS-35YHA1 A11 HWRAS-25YH5 A16

Page 93

OUTDOOR UNIT MODEL: RAC-18YH6, RAC-25YH6

– 91 –

Page 94

– 92 –

PARTS No.

NO RAC-18YH6 RAC-25YH6 Q'TY PARTS NAME

1 1 BASE 2

HWRAC-E10H2

A02

1 COMPRESSOR 800W 8.0kg 3 HWRAC-25YH4 A03 3 COMPRESSOR RUBBER 4 HWRAC-25YH4 A04 3 PUSH NUT 5 1 CONDENSER 6 1 REVERSING VALVE (WITH COIL) 7

HWRAC-E10H2

A05

1 SERVICE VALVE ASSEMBLY 8 1 ELECTRIC EXPANSION VALVE 9 1 SOUND PROOF COVER ASSEMBLY

HWRAC-E10H2

A08

1 O.L.R COVER

HWRAC-E10H2

A09

HWRAC-D10EX

A08

CONNECTING CORD (COMPRESSOR)

THERMISTOR (DEFROST)

HWRAC-E08H A09 1

THERMISTOR SUPPORT

HWRAC-E10H2 A10 1

COIL (ELECTRIC EXPANSION VALVE)

HWRAC-E10H2 A12 1

PARTITION (WITH HEAT INSULATOR)

HWRAC-E10H2 A13 1

REARCTOR COVER

HWRAC-E10H2 A14 1

REACTOR1

HWRAC-E10H2 A15 1

REACTOR2

FAN MOTOR SUPPORT

HWRAC-25YH4 A24 1

FAN MOTOR 47W 1.4kg

HWRAC-E10H2 A16 1

PROPELLER FAN

HWRAC-E10H2 A17 1

NUT(PROPELLER FAN)

HWRAC-E10H2 A18 1

SIDE COVER(L)

HWRAC-E10H2 A19 1

FRONT COVER

HWRAC-E10H2 A21 1

DISCHARGE GRILL

HWRAC-25YH4 A32 2

ELECTRIC PARTS PLATE

ELECTRIC PARTS COVER

HWRAC-E08H A11 1

TERMINAL PLATE

HWRAC-D10EX2 A09 1

TERMINAL BOARD(2P)

HWRAC-25YH4 A37 3

HEAT SINK(REGURATOR1)

FUSE(15A)

HWRAC-25YH4 A41

FUSE(3A)

HWRAC-25YH4 A42

VARISTOR

P.W.B.(MAIN)

HWRAC-E10H2 A25

FUSE(1A)

HWRAC-E10H2 A26

SUPPORT(P.W.B.)

HWRAC-E10H2 A27

HWRAC-E10H2 A28

COVER(OUTDOOR THERMISTOR)

THERMISTOR(OUTDOOR TEMP.)

SIDE COVER(R)

TERMINAL COVER TOP COVER SERVICE VALVE COVER

HWRAC-D10EX A17

DRAIN PIPE COVER(CAPACITOR)

OUTDOOR UNIT

CAPACITOR 45 F 200V

HWRAC-E10H2

A01

HWRAC-E10H2

A03

HWRAC-E10H2

A04

HWRAC-E10H2

A06

HWRAC-E10H2

A07

HWRAC-25YH4 A14

HWRAC-E10H2 A11

HWRAC-25YH4 A23

HWRAC-E10H2 A20

HWRAC-E10H2 A22

HWRAC-D10EX2 A11 HWRAC-E10H2 A24

HWRAC-18YH6 A01

HWRAC-25YH6 A01

HWRAC-25YH4 A50 HWRAC-E10H2 A29

13 14

35 36 37 38 39 40 41 42 43 44 45 46 47 50 51

16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33

Page 95

HITACHI

AW NO. 0019E

RAS-18YH6/RAC-18YH6 RAS-25YH6/RAC-25YH6

Hitachi RAS-18YH6, RAS-25YH6 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual