Hitachi 0174E Service Manual

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Page 1

NO. 0174E

RAK-25NH4/RAC-25NH4 RAK-35NH4/RAC-35NH4

SERVICE MANUAL

TECHNICAL INFORMATION

FOR SERVICE PERSONNEL ONLY

RAK-25NH4 RAK-35NH4 RAK-50NH4

RAC-25NH4 RAC-35NH4 RAC-50NH4

RAK-50NH4/RAC-50NH4

REFER TO THE FOUNDATION MANUAL

CONTENTS

SPECIFICATIONS ------------------------------------------------------------------- 5 HOW TO USE ------------------------------------------------------------------------ 6 CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 29 MAIN PARTS COMPONENT --------------------------------------------------- 31 WIRING DIAGRAM ---------------------------------------------------------------- 33 CIRCUIT DIAGRAM --------------------------------------------------------------- 35 PRINTED WIRING BOARD LOCATION DIAGRAM --------------------- 41 BLOCK DIAGRAM ----------------------------------------------------------------- 43 BASIC MODE ----------------------------------------------------------------------- 45 REFRIGERATING CYCLE DIAGRAM --------------------------------------- 59 AUTO SWING FUNCTION ------------------------------------------------------ 61 DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 62 SERVICE CALL Q & A ---------------------------------------------------------- 93 TROUBLE SHOOTING ----------------------------------------------------------- 96 PARTS LIST AND DIAGRAM ------------------------------------------------- 116

SPECIFICATIONS

TYPE

MODEL POWER SOURCE

TOTAL INPUT

COOLING

HEATING

DIMENSIONS (mm)

NET WEIGHT

TOTAL AMPERES

CAPACITY

TOTAL INPUT TOTAL AMPERES

CAPACITY

(W)

(A)

(kW)

(B.T.U./h)

(W)

(A)

(kW)

(B.T.U./h)

H D

(kg)

INDOOR UNIT

RAK-25NH4 RAC-25NH4

1 PHASE, 50 Hz, 220-230V

695 (155~1,050)

2.50 (0.90 ~ 3.00)

900 (115 ~ 1,400)

3.50 (0.90 ~ 5.00)

860 285 183

9.0

OUTDOOR UNIT

3.20-3.05

8,540

4.15-4.00

11,950

750 570 280

DC INVERTER (WALL TYPE)

INDOOR UNIT

RAK-35NH4 RAC-35NH4

1 PHASE, 50 Hz, 220-230V

1,080 (155~1,280)

3.50 (0.90 ~ 4.00)

1,320 (115 ~ 1,920)

4.80 (0.90 ~ 6.60)

860 285 183

9.0

OUTDOOR UNIT

4.94-4.72

11,950

6.04-5.77

16,390

750 570 280

INDOOR UNIT

RAK-50NH4 RAC-50NH4

1 PHASE, 50 Hz, 220-230V

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

OUTDOOR UNIT

1,780 (155~2,200)

8.17-7.82

5.00 (0.90 ~ 5.20) 17,070

1,970 (115 ~ 2,100)

9.04-8.65

6.50 (0.90 ~ 8.10) 22,200

860 285 183

9.0

After installation

850 650 298

MAY 2003

ROOM AIR CONDITIONER

INDOOR UNIT + OUTDOOR UNIT

Refrigeration & Air-Conditioning Division

Page 2

SAFETY DURING REPAIR WORK

1. In order to disassemble and repair the unit in question, be sure to disconnect the power cord plug from the power outlet before starting the work.

2. If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and the replacement must be effected in correct manner according to the instructions in the Service Manual of the unit.

If the contacts of electrical parts are defective, replace the electrical parts without trying to repair them.

First, I must disconnect the power cord plug

from the power outlet.

3. After completion of repairs, the initial state should be restored.

4. Lead wires should be connected and laid as in the initial state.

5. Modification of the unit by user himself should absolutely be prohibited.

6. Tools and measuring instruments for use in repairs or inspection should be accurately calibrated in advance.

7. In installing the unit having been repaired, be careful to prevent the occurence of any accident such as electrical shock, leak of current, or bodily injury due to the drop of any part.

8. To check the insulation of the unit, measure the insulation resistance between the power cord plug and grounding terminal of the unit. The insulation resistance should be 1M or more as measured by a 500V DC megger.

9. The initial location of installation such as window, floor or the other should be checked for being and safe enough to support the repaired unit again. If it is found not so strong and safe, the unit should be installed at the initial location reinforced or at a new location.

10. Any inflammable thing should never be placed about the location of installation.

DANGER

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.

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Page 3

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).

A conductive polyvinyl bag

Fig. 1. Conductive Container

(2) When any part is handled uncovered (in counting, packing and the like), the handling person must always

use himself as a body earth. (Make yourself a body earth by passing one M ohm earth resistance through a ring or bracelet).

(3) Be careful not to touch the parts with your clothing when you hold a part even if a body earth is being

taken. (4) Be sure to place a part on a metal plate with grounding. (5) Be careful not to fail to turn off power when you repair the printed circuit board. At the same time, try

to repair the printed circuit board on a grounded metal plate.

Conductive sponge

Body earth (Elimik conductive band)

Fig. 2. Body Earth

Clip for connection with a grounding wire

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Page 4

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

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

Staple

Bare copper wire (for body earth)

Fig. 3. Grounding of the working table

Working table

Resistor of 1 M (1/2W)

Earth wire

Soldering iron

Screw stop at the screwed part using a rag plate

Fig. 4. Grounding a soldering iron

Use a high insulation mode (100V, 10M or higher) when ordinary iron is to be used.

(7) In checking circuits for maintenance, inspection or some others, be careful not to have the test probes of the

measuring instrument shortcircuit a load circuit or the like.

Grounding wire

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Page 5

CAUTION

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 preventing fuse blowing. Re-press START/STOP button after 3 minutes from when unit stopped.

4. If the room air conditioner is stopped by adjusting thermostat, or missoperation, and re-start in a moment, there is occasion that the cooling and heating operation does not start for 3 minutes, it is not abnormal and this is the result of the operation of IC delay circuit. This IC delay circuit ensures that there is no danger of blowing fuse or damaging parts even if operation is restarted accidentally.

5. This room air conditioner should not be used at the cooling operation when the outside temperature is below 10°C (50°F).

6. This room air conditioner (the reverse cycle) should not be used when the outside temperature is below –10°C (14°F). If the reverse cycle is used under this condition, the outside heat exchanger is frosted and efficiency falls.

7. When the outside heat exchanger is frosted, the frost is melted by operating the hot gas system, it is not trouble that at this time fan stops and the vapour may rise from the outside heat exchanger.

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Page 6

SPECIFICATIONS

MODEL

RAK-25NH4 RAK-35NH4 RAK-50NH4

RAC-25NH4 RAC-50NH4RAC-35NH4

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

PWM DC35V

–

YES

40 W

JU1012D JU1013D

YES

3.0A

G4A

SERVICE SWITCH

TRANSFORMER

VARISTOR

NOISE SUPPRESSOR

THERMOSTAT

REMOTE CONTROL SWITCH (LIQUID CRYSTAL)

REFRIGERANT CHARGING VOLUME (Refrigerant 410A)

UNIT

PIPES (MAX. 20m)

YES(IC)

YES

----------

WITHOUT REFRIGERANT BECAUSE

COUPLING IS FLARE TYPE.

450NR

YES(IC)

1150g1150g

YES

1400g

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Page 7

SAFETY PRECAUTION

●

Please read the “Safety Precaution” carefully before operating the unit to ensure correct usage of the unit.

●

Pay special attention to signs of “ Warning” and “ Caution”. The “Warning” section contains matters which, if not observed strictly, may cause death or serious injury. The “Caution” section contains matters which may result in serious consequences if not observed properly. Please observe all instructions strictly to ensure safety.

●

The sign indicate the following meanings.

Make sure to connect earth line.

Indicates the instructions that must be followed.

●

Please keep this manual after reading.

PRECAUTIONS DURING INSTALLATION

●

Do not reconstruct the unit. Water leakage, fault, short circuit or fire may occur if you reconstruct the unit by yourself.

●

WARNING

CAUTION

Please ask your sales agent or qualified technician for the installation of your unit. Water leakage, short circuit or fire may occur if you install the unit by yourself.

●

Please use earth line. Do not place the earth line near water or gas pipes, lightning-conductor, or

the earth line of telephone. Improper installation of earth line may cause electric shock.

●

A circuit breaker should be installed depending on the mounting site of the unit. Without a circuit breaker, the danger of electric shock exists.

●

Do not install near location where there is flammable gas. The outdoor unit may catch fire if flammable gas leaks around it.

●

Please ensure smooth flow of water when installing the drain hose.

The sign in the figure indicates prohibition.

A R N

N G

A R N

PRECAUTIONS DURING SHIFTING OR MAINTENANCE

●

Should abnormal situation arises (like burning smell), please stop operating the unit

and turn off the circuit breaker. Contact your agent. Fault, short circuit or fire may occur if you continue to operate the unit under abnormal situation.

●

Please contact your agent for maintenance. Improper self maintenance may cause electric shock and fire.

●

Please contact your agent if you need to remove and reinstall the unit. Electric shock or fire may occur if you remove and reinstall the unit yourself improperly.

PRECAUTIONS DURING OPERATION

●

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

●

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 use any conductor as fuse wire, this could cause fatal accident.

●

During thunder storm, disconnect and turn off the circuit breaker.

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Page 8

PRECAUTIONS DURING OPERATION

●

The product shall be operated under the manufacturer specification and not for any other intended use.

●

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

●

When operating the unit with burning equipments, regularly ventilate the room to avoid oxygen insufficiency.

●

Do not direct the cool air coming out from the air-conditioner panel to face household heating apparatus as this may affect the working of apparatus such as the electric kettle, oven etc.

●

Please ensure that outdoor mounting frame is always stable, firm and without defect. If not, the outdoor unit may collapse and cause danger.

●

Do not splash or direct water to the body of the unit when cleaning it as this may cause short circuit.

●

C A

Do not use any aerosol or hair sprays near the indoor unit. This chemical can adhere on heat exchanger fin and blocked the evaporation water flow to drain pan. The water will drop on tangential fan and cause water splashing out from indoor unit.

U T

●

Please switch off the unit and turn off the circuit breaker during cleaning, the high-speed fan inside the unit may cause danger.

●

Turn off the circuit breaker if the unit is not to be operated for a long period.

●

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

●

Do not put water container (like vase) on the indoor unit to avoid water dripping into the unit. Dripping water will damage the insulator inside the unit and causes short-circuit.

●

Do not place plants directly under the air flow as it is bad for the plants.

●

When operating the unit with the door and windows opened, (the room humidity is always above 80%) and with the air deflector facing down or moving automatically for a long period of time, water will condense on the air deflector and drips down occasionally. This will wet your furniture. Therefore, do not operate under such condition for a long time.

●

If the amount of heat in the room is above the cooling or heating capability of the unit (for example: more people entering the room, using heating equipments and etc.), the preset room temperature cannot be achieved.

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Page 9

NAMES AND FUNCTIONS OF EACH PART

INDOOR UNIT

Air filter

To prevent dust from coming into the indoor unit. (Refer page 25)

Front panel

Indoor unit indicators

Light indicator showing the operating condition. (Refer page 9)

Horizontal deflector (Air Outlet)

(Refer page 20)

●

Vertical deflector

MODEL NAME AND DIMENSIONS

MODEL

RAK-25NH4, RAK-35NH4, RAK-50NH4

Remote controller

Send out operation signal to the indoor unit. So as to operate the whole unit. (Refer page 10)

WIDTH (mm)

860

HEIGHT (mm)

295

DEPTH (mm)

183

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Page 10

INDOOR UNIT INDICATORS

HITACHI

FILTER LAMP

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 POWER SWITCH set to OFF and ON again.

OPERATION LAMP

This lamp lights during operation. The OPERATION LAMP flashes in the following cases during heating.

(1) During preheating

For about 2–3 minutes after starting up.

(2) During defrosting

Defrosting will be performed about once an hour when frost forms on the heat exchanger of the outdoor unit, for 5–10 minutes each time.

TIMER LAMP

This lamp lights when the timer is working.

OPERATION INDICATOR

● This figure shows the opening condition of

front panel. Refer to page 24 in relation to how to open or close the front panel.

TEMPORARY SWITCH

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

● By pressing the temporary switch, the operation is done in automatic mode.

TEMPORARY SWITCH

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NAMES AND FUNCTIONS OF REMOTE CONTROL UNIT

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. 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.

● Signal emitting window/transmission sign

Point this window toward the indoor unit when controlling it.

RESET

AUTO HEAT DEHUMIDIFY COOL FAN

FAN SPEED LOW MED HI

SLEEPING STOP (CANCEL) START (RESERVE) START/STOP TIME TIMER SET

TIMER SELECTOR ON TIMER OFF TIMER

AUTO SWING

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.

● 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 buttons

● 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

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).

● AUTO SWING button

Controls the angle of the horizontal air deflector.

● TIMER control

Use this button 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.

Precautions for Use

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

● Under 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.

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Page 12

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, COOL or DEHUMIDIFY depending on the initial room temperature. The selected mode of operation will not 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, COOL or DEHUMIDIFY depending on the initial room temperature.

● If the mode automatically selected by the unit is not satisfactory, manually change the mode setting (heat, dehumidify, cool or fan).

RESET

START

STOP

Press the (START/STOP) button. Operation starts with a beep. Press the button again to stop operation.

■ 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.

°C

● The preset temperature and the actual room temperature may vary somewhat depending on conditions.

● The display does not indicate the preset temperature in the AUTO mode. If you change the setting, the indoor unit will produce a beep.

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

Press the temperature button and the temperature setting will change by 1°C each time.

■ Condition of Automatic Operation

Initial room temperature (approx.)

Function

Over 27°C COOL

23~27°C

DEHUMIDIFY

Under 23°C

HEAT

Temperature setting

27°C

Slightly lower than the room temperature

23°C

– 11 –

FAN SPEED

HI at start, MED or LOW after the preset temperature is reached

LOW

HI at start, MED or LOW after the preset temperature is reached

Page 13

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.

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 is HI at first and varies to MED

automatically when the preset temperature has been reached.

(HI) : Economical as the room will become warm

quickly.

But you may feel a chill at the beginning. (MED) : Fan speed slow. (LOW) : Fan speed slower.

RESET

Set the desired room temperature with the TEMPERATURE buttons (the display indicates the setting).

START

STOP

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

The temperature setting and the actual room temperature may vary somewhat depending on conditions.

Press the (START/STOP) button. Heating operation starts with a beep. Press the button again to stop operation.

have to press the (START/STOP) button next time.

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Page 14

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 FUNCTION selector so that the display indicates

(DEHUMIDIFY). The FAN SPEED is set at LOW automatically. The FAN SPEED button does not work.

Set the desired room temperature with the TEMPERATURE button (the display indicates the setting).

The range of 20-26˚C is recommended as the room temperature for dehumidifying.

RESET

■ Dehumidifying Function

START

STOP

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

Press the (START/STOP) button. Dehumidifying operation starts with a beep. Press the button again to stop operation.

only have to press the

(START/STOP) button next time.

When the room temperature is higher than the temperature setting: The device will dehumidify the room, reducing the room temperature to the preset level. When the room temperature is lower than the temperature setting: Dehumidifying will be performed at the temperature setting slightly lower than the current room temperature, regardless of the temperature setting. The function will stop (the indoor unit will stop emitting air) as soon as the room temperature becomes lower than the setting temperature.

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Page 15

COOLING OPERATION

Use the device for cooling when the outdoor temperature is 22-42°C. If in doors humidity is very high (80%), some dew may form on the air outlet grille of the indoor unit.

Press the FUNCTION selector so that the display indicates

(COOL).

RESET

Set the desired FAN SPEED with the (the display indicates the setting).

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

MED automatically when the preset temperature

(HI) : Economical as the room will become cool

(MED) : Fan speed slow. (LOW) : Fan speed slower.

Set the desired room temperature with the TEMPERATURE button (the display indicates the setting).

START

STOP

The temperature setting and the actual room temperature may vary some how depending on conditions.

Press the 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.

has been reached.

quickly.

(START/STOP) button. Cooling operation starts

(FAN SPEED) button

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

only have to press the

(START/STOP) button next time.

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Page 16

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).

RESET

FAN SPEED (AUTO)

For the heating operation

START

STOP

.....

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

● The fan speed will automatically change according to the temperature

of discharged air.

● When the difference of room temperature and setting temperature is

large, fan starts to run at HI speed.

● When the room temperature reaches setting temperature, fan speed

changes to LOW automatically.

Press the (FAN SPEED) button.

Press the (START/STOP) button. Fan operation starts with a beep. Press the button again to stop operation.

For the cooling operation

● When the difference of room temperature and setting temperature is

large, fan starts to run at HI speed.

● After room temperature reaches the preset temperature, the cooling

operation, which changes the fan speed and room temperature to obtain optimum conditions for natural healthful cooling will be performed.

– 15 –

Page 17

HOW TO SET THE TIMER

RESET

Time, Day, Month

TIME, DAY, MONTH

After you change the batteries;

(current time, day, month)

OFF TIMER

ON TIMER

OFF-Timer

RESERVE CANCEL

You can set the device to turn off at the present time.

ON-Timer

● The device will turn on

at the designated times.

Start

M D

STOP

Stop

Start

Set the current month and

day with the TIMER control button.

M D

Press the (OFF-TIMER)

button. The (OFF) mark blinks on the display.

Press the (ON-TIMER)

button the (ON) mark blinks on the display.

ON/OFF-Timer

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 appearing on the display indicates the sequence of switching operations.

Press the (ON-OFF)

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.

– 16 –

Page 18

Press the

(TIME) button.

AM PM PM

Set the turn-off time with the

TIMER control button.

Set the current time with the

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

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

Press the (TIME) button again.

The time indication starts lighting

instead of flashing.

● The time indication will disappear

● To check the current time setting,

automatically in 10 second.

press the (TIME) button twice. The setting of the current time is

now complete.

Set the turn-on time with the

TIMER control button.

Set the turn-on time with the

TIMER control button.

The setting of turn-off time is now complete.

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:

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.

The device will automatically turn on earlier so that the preset temperature can be reached at 7:00 a.m. The setting of the turn-on time is now complete.

Example: The device will turn off at 10:30 p.m. and then automatically turn on earlier so that the preset temperature can be reached at 7:00 a.m. The settings of the turn-on/off times are now complete.

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

● 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 in order to use the same settings next time.

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Page 19

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.

Mode

44 44

SLEEP

Sleep timer

Sleep Timer: The device will continue working for the designated number of hours and then turn off. Point the signal window of the remote controller toward the indoor unit, and press the SLEEP button. The timer information will be displayed on the remote controller. The TIMER lamp lights with a beep from the indoor unit. When the sleep timer has been set, the display indicates the turn-off time.

Sleep

timer

Set the ON-timer.

Start

1 hour 2 hours 3 hours 7 hours

The device will be turned off by the sleep timer and turned on by on-timer.

Indication

Sleep timer off

Example: If you set 3 hours sleep time at 11:38 p.m., the turn-off time is 2:38 a.m.

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.

– 18 –

Page 20

Explanation of the sleep timer

The device will control the FAN SPEED and room temperature automatically so as to be quiet and good for people’s health. You can set the sleep timer to turn off after 1, 2, 3 or 7 hours. The FAN SPEED and room temperature will be controlled as shown below.

Operation with the sleep timer

Function Operation

Heating

“ ”

Cooling

“ ”

and

dehumidifying

“ ”

Fan

“ ”

The room temperature will be controlled 5°C below the temperature and the FAN SPEED will be set to LOW setting 30 minutes after the setting of the sleep timer.

The room temperature will be

Sleep timer set

30 minutes later

2°C

2 hours later

1 hour later

controlled 2°C above the temperature and the FAN SPEED will be set to LOW setting 30 minutes after the setting of the sleep timer.

Sleep timer set

30 minutes later

2 hours later

6 hours later

3 hours later

The settings of room temperature and circulation are varied.

5°C

7 hours later

3 hours later

7 hours later

NOTE

● If date or current time is not set, sleep timer can not be set.

● If you set the sleep timer after the off-, on/off- or off/on-timer has been set, the sleep timer

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

● You can not set other timer during sleep timer operation.

● After sleep timer time is up and when press sleep button again, the sleep timer will be set as

last setting.

● Sleep timer effective only once.

– 19 –

Page 21

ADJUSTING THE AIR DEFLECTOR

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.

● If the “ (AUTO SWING)” button is pressed once,

the horizontal air deflector swings up and down. If the button is pressed again, the deflector stops in its current position. Several seconds (about 6 seconds) may be required before the deflector starts to move.

● Use the horizontal air deflector within the adjusting range

shown on the right.

● When the operation is stopped, the horizontal air deflector

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

RESET

CAUTION

● In “Cooling” operation, do not keep the horizontal air

deflector swinging for a long time. Some dew may form on the horizontal air deflector and dew may drop.

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.

When cooling dehumidifying

When heating

– 20 –

Page 22

HOW TO EXCHANGE THE BATTERIES IN THE REMOTE CONTROLLER

Remove the cover as shown in the figure and take out the

old batteries.

Install the new batteries.

The direction of the batteries should match the marks in the case.

CAUTION

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.

Push and pull to the direction of arrow

– 21 –

Page 23

THE IDEAL WAYS OF OPERATION

Suitable Room Temperature Install curtain or blinds

Warning

Freezing temperature is bad for health and a waste of electric power.

Ventilation Effective Usage Of Timer

It is possible to reduce heat entering the room through windows.

Caution

Do not close the room for a long period of time. Occasionally open the door and windows to allow the entrance of fresh air.

Do Not Forget To Clean The Air Filter

Dusty air filter will reduce the air volume and the cooling efficiency. To prevent from wasting electric energy, please clean the filter every 2 weeks.

At night, please use the “OFF or ON timer operation mode”, together with your wake up time in the morning. This will enable you to enjoy a comfortable room temperature. Please use the timer effectively.

Please Adjust Suitable Temperature

For Baby And Children

Please pay attention to the room temperature and air flow direction when operating the unit for baby, children and old folks who have difficulty in movement.

– 22 –

Page 24

FOR USER’S INFORMATION

OFF

The Air Conditioner And The Heat Source In The Room

Caution

If the amount of heat in the room is above the cooling capability of the air conditioner (for example: more people entering the room, using heating equipments and etc.), the preset room temperature cannot be achieved.

Not Operating For A Long Time

When the indoor unit is not to be used for a long period of time, please switch off the power from the mains. If the power from mains remains “ON”, the indoor unit still consumes about 8W in the operation control circuit even if it is in “OFF” mode.

When Lightning Occurs

Warning

To protect the whole unit during lightning, please stop operating the unit and remove the plug from the socket.

Interference From Electrical Products

Caution

To avoid noise interference, please place the indoor unit and its remote controller at least 1m away from electrical products.

To prevent interference, place at least 1m away.

Inverter-type fluorescent lamp.

– 23 –

Page 25

ATTACHING THE AIR CLEANSING AND DEODORIZING FILTERS

CAUTION

Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply.

Open the front panel.

● Pull up the front panel by holding it at both sides

with both hands.

Remove the filter.

● Push upward to release the claws and pull out the

filter.

Attaching the air cleansing and deodorizing filters to the filter.

● Attach the air cleansing and deodorizing filters to

the frame by gently compress its both sides and release after insertion into filter frame.

Claws

(4 places)

CAUTION

Do not bend the air cleansing and deodorizing filter as it may cause damage to the structure.

Attach the filters.

● Attach the filters by ensuring that the surface written

“FRONT” is facing front.

● After attaching the filters, push the front panel at

three arrow portion as shown in figure and close it.

NOTE

● In case of removing the air cleansing and deodorizing filters, please follow the above procedures.

● The cooling capacity is slightly weakened and the cooling speed becomes slower when the air cleansing

and deodorizing filters are used. So, set the fan speed to "HIGH" when using it in this condition.

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

or water rinse under running tap water. Type number for this air cleansing filter is <SPX-CFH7>. Please use this number for ordering when you want to renew it.

● Do not operate the air conditioner without filter. Dust may enter the air conditioner and fault may occur.

– 24 –

Page 26

MAINTENANCE

CAUTION

Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply.

1. AIR FILTER

Clean the air filter, as it removes dust inside the room. In case the air filter is full of dust, the air flow will decrease and the cooling capacity will be reduced. Further, noise may occur. Be sure to clean the filter following the procedure below.

PROCEDURE

Open the front panel and remove the filter

● Gently lift and remove the air cleansing and

deodorizing filter from the air filter frame.

Vacuum dust from the air filter and air cleansing and deodorizing filter using vacuum cleaner. If there is too much dust, rinse under running tap water and gently brush it with soft bristle brush. Allow filters to dry in shade.

● Re-insert the air cleansing and deodorizing

filter to the filter frame. 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.

NOTE:

● Air cleansing and deodorizing filter should be cleaned every month or sooner if noticeable loading

occurs. When used overtime, it may loose its deodorizing function. For maximum performance, it is recommended to replace it every 3-6 months depending on application requirements.

CAUTION

● Do not wash with hot water at more than 40°C. The filter may shrink.

● When washing it, shake off moisture completely and dry it in the shade; do not expose it directly to

the sun. The filter may shrink.

● Do not use detergent on the air cleansing and deodorizing filter as some detergent may deteriorate

the filter electrostatic performance.

– 25 –

Page 27

2. Washable 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.

Removing the Front Panel

Arm

● 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

● Move the projections of the left and right

arms into the Flanges in the unit and securely insert them into the holes.

Attaching the Front Panel

slightly, put it out forward.

CAUTION

● Do not splash or direct water to the body of the unit when cleaning

it as this may cause short circuit.

● Never use hot water (above 40°C), benzine, gasoline, acid, thinner or

a brush, because they will damage the plastic surface and the coating.

Projection

Hole

Flange

– 26 –

Page 28

CAUTION

Cleaning and maintenance must be carried out only by qualified service personal. Before cleaning, stop operation and switch off the power supply.

3. MAINTENANCE AT BEGINNING OF LONG OFF PERIOD

● Run the unit by setting the operation mode to

(COOL), the temperature to 32°C and the fan speed to HI for about half a day on a fine day, and dry the whole of the unit.

Air

● Switch off the power plug.

Blow

REGULAR INSPECTION

PLEASE CHECK THE FOLLOWING POINTS BY QUALIFIED SERVICE PERSONAL EITHER EVERY HALF YEARLY OR YEARLY. CONTACT YOUR SALES AGENT OR SERVICE SHOP.

Confirm

Is the earth line disconnected or broken?

Is the mounting frame seriously affected by rust and is the outdoor unit tilted or unstable?

Is the plug of power line firmly plugged into the socket? (Please ensure no loose contact between them).

– 27 –

Page 29

AFTER SALE SERVICE AND WARRANTY

WHEN ASKING FOR SERVICE, CHECK THE FOLLOWING POINTS.

CONDITION CHECK THE FOLLOWING POINTS

● Is the fuse all right?

When it does not operate

When it does not cool well When it does not hot well

Notes

● In quiet operation or stopping the operation, the following phenomena

may occassionally 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

● 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 the air filter and the evaporator regularly must be cleaned to reduce the odor.

● Is the voltage extremely high or low?

● Is the circuit breaker “ON”?

● Was the air filter cleaned?

● Does sunlight fall directly on the outdoor unit?

● Is the air flow of the outdoor unit obstructed?

● Are the doors or windows opened, or is there any source of

heat in the room?

● Is the set temperature suitable?

gradually warmed as operation stops.

●

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.

●

Power supply shall be connected at the rated voltage, otherwise the unit will be broken or could not reach the specified capacity.

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.

Note

● Avoid to use the room air conditioner for cooling operation when the outside temperature is below

21°C (70°F). The recommended maximum and minimum operating temperatures of the hot and cold sides should be as below:

Cooling Heating

Minimum Maximum Minimum Maximum

Indoor

Outdoor

Dry bulb °C21322027

Wet bulb °C15231219

Dry bulb °C21 43 2 21

Wet bulb °C15 26 1 15

– 28 –

Page 30

CONSTRUCTION AND DIMENSIONAL DIAGRAM

MODEL RAK-25NH4, RAK-35NH4, RAK-50NH4

Air suction grill

183

Mounting plate

860

Top air suction grill

Front panel

Cabinet

285

About

380

350

About

View from back

(Pipe lead-out)

6.5 60

31 120.5

60 60

240 170450

Drain outlet

Horizontal deflectorDischarge grill

Drain hose

Hole on the wall for ø 65mm pipe

Drain

Narrow pipe

Vertical deflector

7070140

Drain cap connection port

147

56 17.5

When piping is drawn horizontally, exchange the drain hose for the drain cap

6.5 60

Connecting cable

– 29 –

Wide pipe

Page 31

CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR

MODEL RAC-25NH4, RAC-35NH4

852

28 750

16556

559

570

195

2616 280

166

MODEL RAC-50NH4

10464

Handle

Air suction grille

955

26 850

Air outlet

638

650

340

201

280

2022 298

Handle

340

169.5

Fixing hole

Holes for anchor bolt (2-ø12)

507 198

Notch for anchor bolt (2-ø12 Notchs)

12 37

1010

320

More than

340

– 30 –

100

700

More than

100

More than

Service space

More than

100

Page 32

MAIN PARTS COMPONENT

RED

360V

BLK

WHT

15V

YEL

0~6V

BLU

0~15V

THERMOSTAT

Thermostat Specifications

MODEL RAK-25NH4, RAK-35NH4, RAK-50NH4 THERMOSTAT MODEL IC OPERATION MODE COOL HEAT

ON 15.6 (60.1) 20.0 (68.0) OFF 15.3 (59.5) 20.7 (69.3) ON 23.6 (74.5) 28.0 (82.4) OFF 23.3 (73.9) 28.7 83.7) ON 31.6 (88.9) 36.0 (96.8) OFF 31.3 (88.3) 36.7 (98.1)

TEMPERATURE °C (°F)

INDICATION

FAN MOTOR

Fan Motor Specifications

MODEL

RAK-25NH4, RAK-35NH4,

RAK-50NH4

POWER SOURCE DC: 0 ~ 35V OUTPUT 23W

RED BLK

WHT

YEL BLU

CONNECTION

35V

0V 5V

0 ~ 5V

RAC-25NH4, RAC-35NH4,

RAK-50NH4

DC360V

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

– 31 –

Page 33

COMPRESSOR MOTOR

Compressor Motor Specifications

MODEL COMPRESSOR MODEL

RAC-25NH4 RAC-50NH4RAC-35NH4

JU1012D JU1013D PHASE SINGLE RATED VOLTAGE AC 220 ~ 230 V RATED FREQUENCY 50 Hz POLE NUMBER 4

(U)

WHITE

CONNECTION

(W)

(V)

YELLOW

RESISTANCE VALUE

20°C

(68°F)

2M = 1.05

RED

75°C

(167°F)

YELLOW

2M = 1.28

WHITE

RED

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.

– 32 –

Page 34

WIRING DIAGRAM

BLU

POWER RELAY

COIL

NF COIL 1

C003

C001

C002

VARISTOR1

L001

CT1

VARISTOR3

SURGE

ABSORBER

DIODE STACK

R010

L002

R011

C011

C010

FAN

MOTOR

VARISTOR2

CN6 WHT

C008 C013 C015

WHT YEL

RED

WHT YEL

YEL

DIODE STACK

RED

UVW

REACTOR

SYSTEM POWER

MODULE 2

L2 L1

CN14

CN13

CN11

C503

C502C501

CN14

CN10 RED

CN9 BLU

CN8 WHT

CN15 WHT

CN13

CN11

CN12

RED

GRY

2A FUSE

ICP RELAY

R008R007

3A FUSE

25A FUSE

C006 R001

BLK GRN WHT

(WHT) (BRN) (RED)(BLK)

CONNECTING

CORD

BRN RED

BLK

GRN

RED BLK

WHT

YEL

BLU

POWER CIRCUIT

TERMINAL BOARD

(GRN+YEL)

LNCD

SINGLE PHASE

AC220~230V

50Hz

(GRN+YEL)

THERE ARE SOME LEAD WIRES WHICH HAVE SPIRAL STRIPES WITH WHITE IN ADDITION TO THE ORIGINAL COLOR

CN2 RED

MAIN P.W.B.

REVERSING VALVE

R002

C007 C012 C014

ELECTRIC EXPANSION VALVE

OH THERMISTOR

DEFROST THERMISTOR

OUTDOOR TEMPERATURE THERMISTOR

GRY GRY

RED RED

COMPRESSOR

MODEL RAK-25NH4 / RAC-25NH4

RAK-35NH4 / RAC-35NH4 RAK-50NH4 / RAC-50NH4

INDOOR UNIT

CONNECTING CORD

FROM OUTDOOR UNIT

(BROWN) (RED)

GREEN & YELLOW

INDOOR ROOM TEMPERATURE THERMISTOR

HEAT EXCHANGER THERMISTOR

TERMINAL

BOARD

C D

BLACK BLACK

GRAY GRAY

BROWN RED

CN1

CN5 CN9

EEPROM / TEST HA

1234 1 2 3 4

5678

CN12

MAIN P. W. B.

C1 C2 M1 M2

CN4 CN11

4 LINES 5 LINES

CN8

CN10

9 LINES

STEPPING

MOTOR

INDOOR

FAN MOTOR

WIRELESS

REMOTE CONTROLLER

RECEIVER

P. C. B.

CN3A

CN2A

OUTDOOR UNIT

CN2

LED

P. C. B.

– 33 –

Page 35

CIRCUIT DIAGRAM

Remote Control

Key matrix table

SEG5

SEG0

SEG1

SEG2

SEG3 SEG4

6 7

SEG5

SEG6

SEG7

COM3

COM2

COM1

COM0

SEG14

SEG13

SEG12

SEG11

SEG13

SEG9

SEG8

RB425D(1/2)

C8 50v/1u

LCD 1

K 1

K2K3

P10

P11

K7 K8

K9 K10

K11K12

SEG20 SEG19 SEG18 SEG17 SEG16 SEG21

SEG24

SEG25

SEG26 SEG27 SEG28

P12

40 39 38 37 36 35 34 33 32 31 30 29

K13 K14

K15 K16

K17

K18

65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

SEG20

SEG21 SEG22 SEG23 SEG24 SEG25 SEG26 SEG27 SEG28 SEG29 SEG30 SEG31 SEG32

SEG33

SEG34 SEG35

SEG19

P40

100k

SEG18

P42

P41

SEG17

SEG16

SEG14

SEG15

IC 1

SEG13

SEG12

SEG11

SEG10

SEG9

M3455OM6A-504FP

P43

P02

P00

P01

P10

P03

P11

P12

P13

SEG8

SEG7

SEG5

SEG6

48 47

SEG4

17 18

SEG2

SEG3

SEG1

Input

P10

P11

P12

SEG0

SEG42

SEG43

NCVL C1

XC OUT

SW1

SW-187-2P

Output

Door open Automatic swingFan speed selectionOperation selectionStart/Stop

Door shut ––Automatic swingStart/Stop

Door open Day

Door shut Fan speedRoom temperature downRoom temperature up–

Door open CancelReservation–Off timer

Door shut –––Sleep

SEG41

SEG40

P30 P31

39 38 37

VL C2 VL C3

36 35

XC IN

34 33

VDD

VSS

X OUT

X IN

30 29

RESET

CARR

P23

P22

P20

BEEP

P21

100k

330

100k

D1 D2

EL-1L7

D2D1

R6 R9

24(1/8W)

2SC3443

or 2SC2982

R10 12M

RB425D

(1/2)

K19

105

910kHz

R11

150k

32.768

kHz

104

• present timeHour downHour upOn timer

D3D2D1

R14 220k

220K

R13

104

R15

100k

R16 100k

334

220p

C3 220p

C4 18p

C5 22p

R12

220k

– 35 –

Page 36

CIRCUIT DIAGRAM

MODEL RAK-25NH4, RAK-35NH4, RAK-50NH4

– 37 –

Page 37

CIRCUIT DIAGRAM

MODEL RAC-25NH4/RAC-35NH4/RAC-50NH4

– 39 –

Page 38

PRINTED WIRING BOARD LOCATION DIAGRAM

MODEL RAK-25NH4, RAK-35NH4, RAK-50NH4

MAIN P.W.B.

Marking on P.W.B.

COMPONENT SIDE

SOLDERING SIDE

IVORY

CN5

8 4

CN1

WHT

C621

C751

C132

C131 R111

ICP2

IC402

J29

J30

J17

R631 L751

R751

R114

Q113

WHT

CN4

CN8 WHT

J31

J18

J19

J10

IVORY

ZD131

Q111

R122

R121 ICP1

IC111

R112 C112

C111

ZD111

R125

R126

CN6

RES1

J33

J32

J34

J20

J11

J12

HB-098-101A

Q131

R132

Q112

D111

R115

Q115

C103

D821

C823 R825 R823 C822

J39

C133

IVORY

CN14

J52 J46 J44

J51 J50

J45

J42

J43

J49 J48

J40

J41

J21 J22

J14 J13

J15

CN9

BLK

ZD211

R201

R131

ZD121

C123

Q114

C113 R117

R828

R829

Q821

R826

R824

R822

IC801

4 Q801

R812 J72

C763

R612

R764

R609

R830

C115

J78

C651

C825

R118

R651

Q803

R119

R761

R120

R658

C801

R804

C121

C116

R116 R124

Q116

R123

J79

R827

R821

C803 C804

J801

L801

R806 R805 R803

J23

J16

R811

J35

J24

R701

REG2

J37

J36

R606

R657

R610

C507

R807

R810

C631

R656

R503

J76

J47

R403

R605

R404

Q802

J53

J38

IC501

R500

R654

R763

R504

R813

CN11

J54

J25

C821

ICP3C762

R219

R653

WHT

J55

C114

J26

R742

R743

R604

R603

C601

R505

J71

AUTO RESTART CANCEL

C802

J83

R602

R601

J75

R652

J27

R745

R611

C122

Q722

R744R741

C506

R501

C824

R641

R506

L111

C611

R502

R514

R507

R508

L501

C501

IC711

R655

C524

R509

R746

C521

L101

J82

J81

R515

R510

R511

Q521

R650

J56

L743 L742 L741

C522

C302

R512

HB–098–101A

No. Lot

C102

J28

C101

D101

CN12

WHT

C711

J80

IC521

C401

R521

R522

C505 C304 R307

R305

R513

J74

R308

C104 R127

R301

C502

R128

C523

D402

IC401

J70

R401

R306 C303 R303 R302

R749 R748 R747

CN10

R402

J77

D403

IVORY

D401

J73

RECEIVING P.W.B.

Marking on P.W.B.

Lot No.

IR1

1 14

J57

IVORY

CN2A

IVORY CN3A

COMPONENT SIDE

SW1

HB-098-102A

– 41 –

SOLDERING SIDE

Page 39

MODEL RAC-25NH4, RAC-35NH4, RAC-50NH4 MAIN P.W.B. Marking on P.W.B

COMPONENT SIDE

– 42 –

Page 40

RAK-25NH4 / RAC-25NH4 RAK-35NH4 / RAC-35NH4 RAK-50NH4 / RAC-50NH4

LCD wireless

Room temperature thermistor

Wireless receive circuit

Filter. Operation. Timer.

Power source 1ø, 50Hz, 220~230V

L N

Outdoor unit Terminal board

SPM2

Trip signal synthesis circuit

Heat exchanger thermistor

Temporary switch

Initial setting circuit

Reset circuit

Auto sweep motor for Air deflector

Indoor microcomputer (AX-7R11)

Outdoor microcomputer / HIC (AX-8N00)

Electric Expansion valve drive circuit

Electric

Expansion

valve

– 43 –

Page 41

BASIC MODE

MODEL RAK-25NH4, RAK-35NH4, RAK-50NH4

Operation mode

Basic operation of start/stop switch

Off-timer

On-timer

Timer functions

Off -> On On -> Off timer

Auto

Med

Fan speed mode (indoor fan)

Basic operation of temperature controller

Sleep operation (with sleep button ON)

Operates at “Hi” regardless of the room temperature.

Operates at “Med” regardless of the room temperature.

Operates at “Lo” regardless of the room temperature.

Performs only fan operation at the set speed regardless of the room temperature.

• Enters sleep operation after set as on the left.

• Action during sleep operation Lo (sleep) operation

Fan

Start/stop switch Operation lamp

Hi Med

Fan

Speed

Hi Med Lo

Changes from “Hi” to “Med” or “Lo” depending on room temperature.

Temperature set for cooling

Thermo iudgment Compressor

Hi Med Lo

1. Runs at “Hi” until first thermo off after operation is started.

2. Runs at “Lo” when thermo is off.

Set to “ultra-Hi” when the compressor runs at maximum speed, and to “Hi” in other modes.

Same as at left.

See page 49.

• Same as at left

• See page 51.

(Compressor stopped forcibly for 3 minutes)

Dehumidifying

(dehumidifying operation by the function select button only, not including that engaged by the dehumidify button)

Start/stop switch Operation tamp

Cancel switch Operation temp Timer tamp

Timer memory

Srart/stop switch Reserve switch Cancel switch Operation temp Timer tamp

Timer memory

Start/stop switch Reserve switch Cancel switch Operation lamp Timer lamp

Timer memory

Start

(Change in reserved time)

Changes between “Lo” and “Med” depending on the room temperature.

Fan speedTemperature division Division 1 Division 2 Division 3 Division 4

Lo Med Med

1. The indoor fan also stops when the compressor is in stop status.

Set to “Hi” in modes other than when the compressor stops.

Set to “Med” in modes other than when the compressor stops.

Set to “Lo” in modes other than when the compressor stops.

See page 53.

• Same as at left

• See page 53.

Stop

Start Stop

(Off-timer during stop)

(On-timer during operation)

ON ONONOFF OFF OFF ONOFF

(Off->On timer) (On->Off timer) (On->Off timer)

(Change in reserved time)

during operation)

(Off->On timer)

during stop)

Set to “ultra-Lo”, “Lo”, “Med”, “Hi”, “ultra-Hi” or “stop” depending on the room temperature, time and heat exchange temperature. Set to “stop” if the room temperature is 18˚C in the “ultra-Lo” mode other than during preheating (cooling is recovered at 18.33˚C).

When the compressor is running at maximum speed during hot dash or when recovered from defrosting.

˚C

42. 66

37. 66

32. 66

29. 66

Hi or ultra-HI (fan speed set to “auto”)

Med Lo

In modes other than left

Heat exchanger temperature

Set to “ultra-Lo”, “Lo”, “Med”, “Hi”, “ultra-Hi” or “stop” depending on the room temperature, and time. Set to “stop” if the room temperature is 18˚C in the “ultra-Lo” mode other than during preheating (cooling is recovered at 18.33˚C). Set to “ultra-Hi” when the compressor is running at maximum speed during hot dash or when recovered from defrosting.

Set to “ultra-Lo”, “Lo”, “Med” or “stop” depending on the room temperature and time. Set to “stop” if the room temperature is 18˚C in the “ultra-Lo” mode other than during preseating (cooling is recovered at 18.33˚C).

Set to “ultra-Lo”, “Lo”, or “stop” depending on the room temperature and time. Set to “stop” if the room temperature is 18˚C in the “ultra-Lo” mode other than during preseating (cooling is recovered at 18.33˚C). The fan speed is controlled by the heat exchanger temperature; the overload control is executed as in the following diagram:

KAFON KAFOF

“Med” with overload

“Lo”

Heat exchanger temperature

See page 55.

• Same as at left

• See page 57.

N&F autoHeatingCooling

The neuro & fuzzy control allows device to determine optimum operation mode and set temperature. However, during auto cooling, the new cool rhythm starts when the room temperature is less than the set temperature plus 0.66˚C, after dash is finished.

Room temperature

Outdoor temperature

Calendar

Humidity

Neuro pattern recognition

Fuzzy control

Operation mode

Set temperature

Notes: (1) The set temperature can be varied ±3˚C using the

temperature setting buttons and .

(2) If operation is started by tele-control or by temporary switch

in status where remote control has not been used after power was supplied, the operation mode will be as follows (since there is no stored calendar data):

Cooling Dehumidifying

Heating

Room temparature at

operation start (˚C)

Set temperature: 28˚C Fan mode: Auto

Set temperature: Room temperature at operation Fan mode: Auto

Set temperature: 22˚C Fan mode: Auto

start

• Same as at left.

• Performs the sleep operation of each operation mode.

Special auto (not normally used)

The special auto mode is based on N&F auto, but the following is different:

Operation mode

N&F auto

Special auto

Mode change during operation

Does not change as long as outdoor temperature or calendar data does not change greatly.

The operation mode will be judged the same as at operation start every hour.

The special auto operation mode is entered when operation is started in the following status:

<Start condition> Power is supplied white the tele-control signal is being input. (Operation starts automatically.)

<End condition> The remote control restores the normal operation mode.

Note (1) Since there is no stored calendar

data, N&F control is not determined. See Note (2) of N&F auto.

– 45 –

Page 42

Table 1 Mode data file

RAK-25NH4 RAK-35NH4 RAK-50NH4

LABEL NAME VALUE

WMAX 4500 min WMAX2 4600 min WSTD 3250 min WBEMAX 2600 min CMAX 2900 min CMAX2 3000 min CSTD 2500 min CKYMAX 2200 min CJKMAX 2000 min CBEMAX 1800 min WMIN 1200 min CMIN 1500 min

–1

5500 min 5600 min 4350 min 2800 min 3700 min 3800 min 3550 min 2800 min 2500 min 2200 min 1200 min 1500 min

–1

6200 min 6250 min 5200 min 2600 min 5700 min 5800 min 5200 min 3550 min 2700 min 2000 min 1200 min 1500 min

–1

STARTMC 60 Seconds 60 Seconds 60 Seconds DWNRATEW 80% 80% 80% DWNRATEC 80% 80% 80% SHIFTW 3.33°C 3.33°C 3.33°C SHIFTC 1.00°C 1.00°C 0.33°C CLMXTP 30.00°C 30.00°C 30.00°C YNEOF 22.00°C 22.00°C 28.00°C TEION 5.00°C 5.00°C 2.00°C TEIOF 9.00°C 9.00°C 9.00°C SFTDSW 1.00°C 1.00°C 1.00°C DFTIM1 45 Minutes 45 Minutes 45 Minutes DFTIM2 60 Minutes 60 Minutes 60 Minutes

– 47 –

Page 43

NOTE (9)

Reversing valve (heating “on” mode)

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 7) larger than WMAX.

(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) When fan is set to “Hi”, compressor rpm will be limited to CKYMAX. (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.

Table 2 ∆TCMAX

Temperature Calculated

difference compressor rpm

1.66 2265 min 2 2435 min

2.33 2600 min

2.66 2765 min 3 2935 min

3.33 3100 min

3.66 3265 min 4 3435 min

4.33 3600 min

4.66 3765 min 5 3935 min

5.33 4100 min

5.66 4265 min 6 4435 min

6.33 4600 min

6.66 4765 min 7 4935 min

7.33 5100 min

7.66 5265 min 8 5435 min

8.33 5600 min

8.66 5765 min 9 5935 min

9.33 6100 min

9.66 6265 min

10 6435 min

10.33 6600 min

10.66 6765 min 11 6935 min

–1

Note:

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

– 49 –

Page 44

New Cool Rhythm

Cooling Sleep Operation

Final set temperature

(Cooling/dehumidifying set temperature (temperature set by remote control (+) SHIFTC)

Set temperature during rhythm (temperature set by remote control (+) SFTRZM)

Thermo judgment

Indoor fan

New cool rhythm

Outdoor fan

Rhythm Med

Rhythm Lo

Med

Room temperature

See basic operation.

Minimum 5min.

5 sec. 5 sec.

Minimum 5min. Minimum 5min.

5min.

1 cycle

2.5 sec. 2.5 sec.

4.5 sec.

2.5 sec.

5min.

Minimum

5min.

Minimum

5min.

Thermo OFF

15 sec.

Minimum

5min.5min.

5min.

Final set temperature (Cooling/dehumidifying set temperature (+) sleep shift)

(Cooling/dehumidifying set temperature = Remote control set temperature (+) SHIFTC)

Sleep key

Operation lamp

Timer lamp

Indoor fan

Outdoor fan

Horizontal air deflector

Med

Lo (sleep)

Shut

Horizontal

Facing down

See basic operation

Set to 7 hours

0.5hr

1.5hr

2.5hr 3.5hr 6hr 7hr

3hr

Maximum speed

Compressor speed

Notes:

(1) New cool rhythm is engaged when the fan speed is “auto” and the room temperature is less than

set one plus 0.66˚C in the “auto” operation mode or cooling mode. (2) The minimum new cool rhythm time is 10 minutes when the temperature falls and rises. (3) Cool rhythm is not engaged during Nice temperature, Sleep operation. (4) Pl control is engaged during new cool rhythm: the speed limit is the same as during normal operation. (5) The new cool rhythm set temperature is also shifted during thermo OFF.

Compressor speed

Notes:

(1) The sleep operation starts when the sleep key is pressed. (2) When the sleep key is set, the maximum compressor speed is limited, and the indoor fan is set to “sleep Lo”. (3) 30 minutes after the sleep key is set, the sleep shift of temperature starts, and upper shift is made at least 6 times. If 25˚C

is not reached after 6 shifts, shifts repeat unit 25˚C is reached. (4) The sleep shift upper value of set temperature is 28˚C. (5) After 6 hours, a shift down to the initial set temperature is made at a rate of 0.33˚C/5 min. (6) If the operation mode is changed during sleep operation, the set temperature is cleared, and shift starts from the point when

switching is made. (7) The indoor fan speed does not change even when the fan speed mode is changed. (8) When operation is stopped during sleep operation, the set temperature when stopped, as well as the time, continue to be

counted. (9) If the set lime is changed during sleep operation, all data including set temperature, time, etc. is cleared and restarted. (10) If sleep operation is canceled by the cancel key or sleep key, all data is cleared.

Reverse cycle period

MAX. 12min.

min–1

3000

fixed

– 51 –

Page 45

–1.33˚C

–0.66˚C

Delay

Notes:

(1) If the room temperature is (cooling preset temperature) - (1.33°C) or less after 30 seconds from starting the operation, 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 minutes and ON for 1 minute. (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.

– 53 –

Page 46

Basic Heating Operation

SFTDSW

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

Dash period

TWMAX

Fan speed set to "auto"

Ultra-Hi Hi Med

10sec.

Lo Ultra-Lo

Wtd

WMIN

Start

Max. 3 min.

Preheating released

30sec. 30sec.

1 min.

WMAX2

ultra Hi

Control by heat exchanger temperature

NOTE (11)

Lo Hi Hi Hi

Start/stop switch Thermo judgment Defrost signal Preheating judgment

Indoor fan

Operation lamp

Max.

(WMAX)

Rating

(WSTD)

Compressor speed

3000

Reversing valve (heating "on" model)

Outdoor fan

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 indoor temperature

is lower than 18°C and outdoor temperature is lower than 2°C. (6) During Hotkeep or Defrost mode, indoor operation lamp will blink at interval of 3 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 “Med” or “Lo”, compressor rpm will be limited to WBEMAX. (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 or outdoor temperature is lower than –5°C, compressor rpm is WMAX2. (11) During Hot Dashed, when room temperature reaches set temperature + SFTDSW compressor rpm is actual rpm x DWNRATEW.

1.33˚C.

0.66˚C.

Stop Start Start StopStop

Thermo

OFF

30sec. 30sec.

10sec.

15sec. 15sec. 15sec.

10sec. 15sec. 15sec.

Control by heat exchanger temperature

18˚C

Thermo OFF

Thermo

Preheat released

30sec. 30sec.30sec. 30sec. 30sec. 30sec. 10sec.

Control by

10sec.

150sec. Delay150sec. Delay

heat exchanger temperature

15sec.

Control by heat exchanger temperature

3min.

OFF

15sec.

150sec. Delay

Table 3 ∆TWMAX

Temperature Calculated

difference compressor rpm

1.66 1965 min 2 2135 min

2.33 2300 min

2.66 2465 min 3 2635 min

3.33 2800 min

3.66 2965 min 4 3135 min

4.33 3300 min

4.66 3465 min 5 3635 min

5.33 3800 min

5.66 3965 min 6 4135 min

6.33 4300 min

6.66 4465 min 7 4635 min

7.33 4800 min

7.66 4965 min 8 5135 min

8.33 5300 min

8.66 5465 min 9 5635 min

9.33 5800 min

9.66 5965 min

10 6135 min

10.33 6300 min

10.66 6465 min 11 6635 min

–1

Notes:

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

– 55 –

Page 47

WMIN

1 min

Notes: (1) The sleep operation starts when the sleep key is pressed. (2) When the sleep key is set, the maximum compressor speed is limited to WSTD+2000/2, and the indoor fan is set

to “sleep Lo”. (3) 30 minutes after the sleep key is set, the sleep shift of set temperature starts. (4) The maximum sleep shift of set temperature is 5°C, and the minimum is 12°C. (5) If the operation mode is changed during sleep operation, the changed operation mode is set and sleep control

starts. (6) The indoor fan speed does not change even when the fan speed mode is changed. (Lo) (7) When defrosting is to be set during sleep operation, defrosting is engaged and sleep operation is restored after

defrosting. (8) When operation is stopped during sleep operation, the set temperature when stopped, as well as the time, continue

to be counted. (9) If the set time is changed during sleep operation, all data including set temperature, time, etc. is cleared and

restarted. (10) If sleep operation is canceled by the cancel key or sleep key, all data is cleared.

– 57 –

Page 48

REFRIGERATING CYCLE DIAGRAM

MODEL RAK-25NH4 / RAC-25NH4

RAK-35NH4 / RAC-35NH4

COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT

STRAINER

CHARGING PIPE

ELECTRIC EXP ANSION VALVE

STRAINER

COMPRESSOR

REVERSING VALVE

SERVICE V ALVE

SUCTION TANK

(1/4)

SERVICE V ALVE

(3/8)

INDOOR UNIT

SINGLE-ENDED UNION (3/8)

SINGLE-ENDED UNION (1/4)

HEATING OUTDOOR UNIT

STRAINER

CHARGING PIPE

ELECTRIC EXP ANSION VALVE

STRAINER

COMPRESSOR

REVERSING VALVE

SERVICE V ALVE

SUCTION TANK

(1/4)

SERVICE V ALVE

(3/8)

INDOOR UNIT

SINGLE-ENDED UNION (3/8)

SINGLE-ENDED UNION (1/4)

– 59 –

Page 49

REFRIGERATING CYCLE DIAGRAM

MODEL RAK-50NH4 / RAC-50NH4

COOLING, DEHUMIDIFYING, DEFROSTING OUTDOOR UNIT

ELECTRIC EXP ANSION VALVE

STRAINER

COMPRESSOR

REVERSING VALVE

SERVICE V ALVE

(1/2)

SUCTION TANK

(1/4)

INDOOR UNIT

SINGLE-ENDED UNION (1/2)

SINGLE-ENDED UNION (1/4)

HEATING OUTDOOR UNIT

ELECTRIC EXP ANSION VALVE

STRAINER

COMPRESSOR

REVERSING VALVE

SERVICE V ALVE

(1/2)

SUCTION TANK

(1/4)

INDOOR UNIT

SINGLE-ENDED UNION (1/2)

SINGLE-ENDED UNION (1/4)

– 60 –

Page 50

REFERENCE

INITIALIZE AT NEXT

OPERATION.

OPERATING SPECIFICATION

STOP AT THE MOMENT.

START SWINGING

1 DOWNWARD

2 UPWARD

ONE SWING (CLOSING AIR DEFLECTOR)

1 DOWNWARD

2 UPWARD

3 DOWNWARD

STOP AT THE MOMENT.

START SWINGING

1 DOWNWARD

2 UPWARD

STOP AT THE MOMENT.

3 DOWNWARD

START SWING AGAIN.

STOP SWINGING TEMPORARILY.

(SWING MODE IS CLEARED IF SWING COMMAND IS

TRANSMITTED DURING TEMPORARY STOP.)

INITIALIZE

1 DOWNWARD

2 UPWARD

INITIALIZE AT NEXT

INITIALIZE

1 DOWNWARD

ONE SWING (CLOSING AIR DEFLECTOR)

1 DOWNWARD

OPERATION.

STOP SWINGING AND MODE BECOMES INITIALIZING

INITIALIZING CONDITION OF EACH MODE.

2 UPWARD

CONDITION.

STOP

DURING ONE SWING

PRESENT CONDITION

EACH MODE

OPERATION OPERATION MODE AIR DEFLECTOR

INPUT SIGNAL

AUTO SWING FUNCTION

MODEL: RAK-25NH4, RAK-35NH4, RAK-50NH4

STOP

KEY INPUT

STOP

AUTO COOL

COOL

FAN

AUTO DRY

DRY

DURING SWINGING

DURING

OPERATION

STOP

AUTO HEAT

HEAT

CIRCULATOR

DURING SWINGING

TEMPORARY STOP

AUTO DRY

THERMO. ON

(INTERNAL FAN

DURING SWINGING

DRY

AUTO HAET

HEAT

CIRCULATOR

DURING

OPERATION

ON)

THERMO. ON

(INTERNAL FAN

OFF)

STOP

DURING ONE SWING

STOP

DURING ONE SWING

STOP

COOL

FAN

DRY

HEAT

CIRCULATOR

STOP

MAIN SWITCH

DURING SWINGING

DURING

INITIALIZING

STOP

DURING SWINGING

EACH MODE

DURING

OPERATION

MAIN SWITCH

OFF

EACH MODE

DURING

OPERATION

CHANGE OF

OPERATION

– 61 –

Page 51

DESCRIPTION OF MAIN CIRCUIT OPERATION

MODEL RAK-25NH4, RAK-35NH4, RAK-50NH4

1. Reset Circuit

R522

C521

R521

C524

NORMAL : HI RESET : LO

RES

Microcomputer

C522

Voltage

Voltage supply to

of IC521

Reset release at 4.4V

IC521

Fig. 1-1

5.0V

Reset enter at 4.2V

voltage

Voltage at pin of microcomputer

5.0V

Fig. 1-2

● 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.

– 62 –

Page 52

2. Receiver Circuit

12V

▲

ZD211

IR1

VDD

GND

R2 R611

out

C611

13 RECEIVER I/P

Microcomputer

R201

Fig. 2-1

● The light receiver unit receives the infrared signal from the wireless remote control. The receiver amplifies

and shapes the signal and outputs it.

3. Buzzer Circuit

12V

Microcomputer

Buzzer output

● 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 a transistor, it is applied to the buzzer. The piezoelectric element in the buzzer oscillates to generate the buzzer’s sound.

R219

Fig. 3-1 Buzzer Circuit

Metal diaphragm

BZ1

Q722

Pizoelectric element

Sound wave

– 63 –

Fig. 3-2 Buzzer Operation

Page 53

4. Auto Sweep Motor Circuit

12V

IC711

Auto sweep motor for horizontal air defectors

Microcomputer

18 17 16 15

C711

7 6 5

11 12

Rotor

Fig.4-1

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

15 – 18 of microcomputer.

Microcomputer pins Step width

Horizontal air deflectors

12345678

Horizontal air

deflectors: 10ms.

Fig.4-2 Microcomputer Output Signals

● As the microcomputer’s outputs change as shown in Fig.4-2, the core of the auto sweep motor is excited

to turn the rotor. Table 4-1 shows the rotation angle of horizontal air deflectors.

Table 4-1 Auto sweep Motor Rotation

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

0.0882 10Horizontal air deflectors

– 64 –

Page 54

5. Room Temperature Thermistor Circuit

010

Room temperature (˚C)

Fig. 5-2

20 30 40

Room temperature thermistor

Fig. 5-1

R305

C302

Microcomputer

Room temp. input

Voltage at

(V)

R301

Heat exchanger temperature thermistor

Fig. 6-1

R306

C303

Microcomputer

Heat exchanger temperature input

R302

010

-10 Heat exchanger temperature (˚C)

Fig. 6-2

20 30 40

Voltage at

(V)A

● Fig. 5-1 shows the room temperature

thermistor circuit.

6. Heat exchanger temperature thermistor circuit

● The voltage at depends on the room

temperature as shown in Fig. 5-2.

● The circuit detects the indoor heat

exchanger temperature and controls the following.

(1) Preheating. (2) Low-temperature defrosting

during cooling and dehumidifying operation.

(3) Detection of the reversing valve non-operation or heat exchanger temperature thermistor open.

The voltage at depends on the

heat exchanger temperature as shown in Fig. 6-2.

– 65 –

Page 55

7. Initial Setting Circuit (IC401)

● When power is supplied, the microcomputer reads the data in IC401 or IC402 (E

PROM) 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.

5V 5V

1 2 3 4

IC401 or IC402 (E

8 7 6 5

PROM)

C401

R404

R403

27 26

SCL SDA

Microcomputer

External ROM

}

Fig. 7-1

– 66 –

Page 56

Model RAC-25NH4, RAC-35NH4, RAC-50NH4

1. Power Circuit

TERMINAL

BOARD

25A FUSE

SURGEABSORBER

VARISTOR3

L001

NF COIL1

C001

VARISTOR1

R001

C003

C002

CT1 C009

COIL

C004C005

C006

POWER RELAY

R007

R008

ICP RELAY

DIODE

STACK 1

(D25VB60)

SPM2

TB8

TB2

REACTOR

L1 L2

TB7 TB6

TB10

Vdba

TB11 TB12

V W

3A FUSE

VARISTOR2

STACK 2 (RC2)

C010

C011

POWER CIRCUIT

R010R011

DIODE

L002

C014 C015

C012 C013

C007 C008

JW6

R002

Fig. 1-1

● This circuit full-wave rectifies 220-230V AC applied between terminals L and N, and boosts it to a required

voltage with the active module, to create a DC voltage.

The voltage becomes 260-360V when the compressor is operated

(1) Active module

The active filter, consisting of a reactor and switching element, eliminates higher harmonic components contained in the current generated when the compressor is operated, and improves the power-factor.

< Reference >

● In case of malfunction or defective connection:

Immediately after the compressor starts, it may stop due to “abnormally low speed” active error, etc.

The compressor may continue to operate normally, but the power-factor will decrease, the operation current will increase, and the overcurrent breaker

(2) Diode stacks

These rectify the 220-230V AC from terminals L and N to a DC power supply.

of the household power board will probably activate.

● In case of active module faulty or defective

connection: Although the compressor continues to operate

normally, the power-factor will decrease, the operation current will increase, and the overcurrent breaker of the household power board will probably activate.

< Reference >

● If diode stack 1 is faulty, the compressor may stop

due to “lp”, “anbormally low speed”, etc. immediately after it starts, or it may not operate at all because no DC voltage is generated between the positive e and negative d terminals.

If diode stack 1 is faulty, be aware that the 25A fuse might also have blown.

● If diode stack 2 is faulty, DC voltage may not be

generated and the compressor may not operate at all. Also, be aware that the 3A fuse might have blown.

– 67 –

Page 57

(3) Smoothing capacitor (C501, C502, C503)

This smoothes (averages) the voltage rectified by the diode stacks. <Notes > Smoothing capacitor C501 is not available for model RAC-25NH4 and RAC-35NH4.

Smoothing Capacitors

SPM2

Fig. 1-2

DC voltage

(approx. 260-360V during operation)

Fig. 1-3

(4) Smoothing capacitor (C010, C011)

This smoothes (averages) the voltage rectified by the diode stack2. A DC voltage is generated in the same way as in Fig. 1-3. Voltage between + side of C010 and – side of C011 is about 330V.

(5) C001 to C003, C012 to C015, C007, C008, NF COIL1, COIL,

absorb electrical noise generated during operation of compressor, and also absorb external noise entering from power line to protect electronic parts.

(6) Surge absorber, Varistor 1, 2, 3,

absorbs external power surge.

(7) Inrush protective resistor (R007, R008)

This works to protect from overcurrent when power is turned on.

● Be careful to avoid an electric shock as a

high voltage is generated. Also take care not to cause a short-circuit through incorrect connection of test equipment terminals. The circuit board could be damaged.

< Reference >

● When inrush protective resistor is

defective, diode stack may malfunction. As a result, DC voltage is not generated and no operation can be done.

– 68 –

Page 58

2. Indoor/Outdoor Interface Circuit

● The interface circuit superimposes an interface signal on the DC 35V line supplied from the outdoor unit

to perform communications between indoor and outdoor units. This circuit consists of a transmiting circuit which superimposes an interface signal transmit from the microcomputer on the DC 35V line and a transmiting circuit which detects the interface signal on the DC 35V line and outputs it to the microcomputer.

● Communications are performed by mutually transmiting and receiving the 4-frame outdoor request signal

one frame of which consists of a leader of approx. 100 ms., start bit, 8-bit data and stop bit and the command signal with the same format transmit from the indoor unit.

● Communication signal from outdoor microcomputer to indoor microcomputer. At first outdoor microcomputer

will send a request signal (SDO) to indoor microcomputer. A high-frequency IF signal approx. 38 KHz is generated and modulated by the request signal (SDO) inside the outdoor microcomputer then output to pin 11 of microcomputer. This modulated IF signal is output to pin 30 of HIC and amplified by amp. 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 49 of the indoor microcomputer. Fig. 2-2 shows the voltages at each component when data is transferred from the outdoor microcomputer to the indoor microcomputer.

● Communication signal from indoor microcomputer to outdoor microcomputer. The request signal (SDO)

generates by indoor microcomputer is output to pin 50 , and amplifies by C801. IF signal approx. 38 kHz is generated by comparator, then modulate by the request signal from pin 50 of indoor microprocessor. This modulated IF signal is then amplified and superimposed to DC 35V line via L801 and C802 of indoor interface circuit. Fig. 2-3 shows the voltages 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.

– 69 –

Page 59

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

each other.

C802

I/F 0V

D101

L801

C803

C804

C821 R821

Terminal board

R813

R812

Q803

C822

R810

Q802

R811

5V 5V 5V

R822

R823

0V 0V0V

Indoor P.W.B.

Outdoor P.W.B.

35V

R824

3 2

IC801

R825

5V5V

R807

R805

IC801

R806

C823

R826 D821

R828

R803

R804

Q821

R829

R830

Q801

HIC

C824

IF transmit

output (SDO)

MICROCOMPUTER

IF receive

input (SDI)

C801

R827

Interface relay

L802

12V

C811

C812

C807

C808

L801

C801

C806

NF COIL2

C809

C810

I/F 0V

R801

R802 Q801

C802

IF transmit

output (SDO)

0V0V

R803

5V 5V

MICROCOMPUTER

IF receive input (SDI)

(Communications from outdoor microcomputer to indoor microcomputer)

(Communications from indoor microcomputer to outdoor microcomputer)

Fig. 2-1 Indoor/outdoor interface Circuit

– 70 –

Page 60

Outdoor HIC

0.7V 0V

5V 0V

Indoor microcomputer

DC 35V line

100ms. Leader

33ms. 1 frame

5V 0V

35V

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

Outdoor HIC

Indoor microcomputer

DC 35V line

4.95ms. Transmit / receive switching time

33ms. 1 frame

5V 0V

35V

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

– 71 –

Page 61

[Serial Communications Format during Normal Communications]

(1) Outdoor microcomputer (HIC) to indoor microcomputer

(2) Indoor microcomputer to outdoor microcomputer (HIC)

(3) Communications waveforms

1 frame = 100ms. + 33.3ms. x 8 + 4.95ms. = 371.35ms.

Outdoor message

Indoor message

[Example] When the outdoor message is all 0s

and indoor message is all 1s:

36 (V)

35 (V)

34 (V)

When reset

(approx. 10ms.)

Transmit/

receive

switching time

(4.95ms.)

Character No.

(33.3ms.)

Character No.

(33.3ms.)

Bit No = 0

0707077

07077

Leader

(100ms.)

When reset

(approx. 10ms.)

Leader

(100ms.)

Fig. 2-4

– 72 –

Page 62

7 6 5 4

3 2 1

Fan-7-step request 0 7

Actual compressor rotation speed (5 MSB) 6

Actual compressor rotation speed (4) 5

Actual compressor rotation speed (3) 4

Actual compressor rotation speed (2) 3

Actual compressor rotation speed (1) 2

Actual compressor rotation speed (0 LSB) 1

Compressor during operation 0

Compressor during operation 7

Outside temperature (7 MSB) 6

Outside temperature (6) 5

Outside temperature (5) 4

Outside temperature (4) 3

Outside temperature (3) 2

Outside temperature (2) 1

Outside temperature (1 0

Outside temperature (0 LSB) 7

Self-diagnosis (3 MSB) 6

Self-diagnosis (2) 5

Self-diagnosis (1) 4

Self-diagnosis (0 LSB) 3

Defrost request signal 2

During forced operation 1 0

Multi-bit

0 0 0 0 0 0 1 0

1/0 1/0 1/0 1/0

1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0

0 1/0

Compressor minimum rotation speed (4 MSB)

Compressor minimum rotation speed (3)

Compressor minimum rotation speed (2)

Compressor minimum rotation speed (1)

Compressor minimum rotation speed (0 LSB)

2 1

OVL up

15/20(A)

Compressor command speed (7 MSB)

Compressor command speed (6)

Compressor command speed (5)

Compressor command speed (4)

Compressor command speed (3)

Compressor command speed (2)

Compressor command speed (1)

Compressor command speed (0 LSB)

Compressor ON 6 5 4

Reversing valve 3

2-way valve 2

Fan (2 MSB) 1

Fan (1 0

Fan (0 LSB) 7

Capacity code (3 MSB) 6

Capacity code (2) 5

Capacity code (1) 4

Capacity code (0 LSB) 3

Indoor in-operation bit 2

Operation mode (2 MSB) 1

Operation mode (1) 0

Operation mode (0 LSB)

1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0 1/0

0 0 0 1/0 1/0 1/0 0 1/0 0 0 1/0 1/0 1/0 1/0 1/0 0

1/0 1/0 1/0 1/0

Bit No.

Character No.

(1) Outdoor message

[ Serial Communications Data ]

Contents

– 73 –

Data

Character No.

(2) Indoor message

Bit No.

Contents

Data

Page 63

3. Power Module Circuit

–

Compressor

motor

U coil

V coil

W coil

System Power module 2

–

C501

–

C502

–

C503

R24

0.35

Power relay

Coil

R007

R008

Inrush current

protection

relay

C006

R001

Noise filter

coil

Terminal

board

FUSE (25A)

is ON)

–

is ON, V

Fig. 3-1 shows the system power module and its peripheral circuit.

The three transistors on the positive e side are called the upper arm, and the three transistors on the negative d side, the lower arm.

●

– 74 –

Fig. 3-1 Power module circuit (U

Page 64

● DC 260-360V is input to system power module and system power module switches power supply current

according to rotation position of magnet 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

++T+

UVVW

Lower arm transistor

–

Time

Fig. 3-2 Switching order of power module

● Upper arm transistor is controlled to ON/OFF by 3.3kHz chopper signal. Rotation speed of the compress

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.

Voltage at

260V-360V

U transistor chopped

U transistor ON

Upper arm transistor

Current at

Chopping period

Fig. 3-3 Voltage waveform at each point

● When power is supplied U

[ U–, 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 (Fig. 3-1)

(2) When U+ transistor is OFF: (by inductance of motor coil) U coil [ V coil [ V– transistor [ Return

diode [ Point (Fig. 3-4)

– 75 –

Page 65

260V-360V

System Power Module 2

—

R24

—

A U V

U coil

V coil

DC compressor motor

W coil

DC current (Id) detection resistor

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

● Since current flows at point only when U+ transistor is ON, the current waveform at point becomes

intermittent waveform as shown in Fig. 3-3. Since current at point is approximately proportional to the

B B

input current of the air conditioner, input current is controlled by using DC current (Id) detection resistor.

If power module is detective, self diagnosis lamps on the control P.W.B. may indicate as shown below:

Table 3-1

Self-diagnosis lamp and mode

LD301

Blinks 2 times

Blinks 3 times

Blinks 4 times

P.W.B (Main)

Self diagnosis lamps (LD303, 302, 301)

Self-diagnosis

lp (peak current cut)

Abnormal low speed

rotation

Switching incomplete

Fig. 3-5

● Simplified check of power module (Lighting mode when operated with compressor leads disconnected)

(1) Disconnect connector of 3-pole (WHT, YEL, RED) lead wire connecting to compressor located at the

lower part of electric parts box.

(2) Set to compressor operation state (other than FAN mode) and press Start/stop switch of remote

control.

(3) If normal operation continues for more than 1 minute (LD303 lights), power module is considered

normal.

❈ Refer to other item (troubleshooting on page 94) for independent checking of power module.

– 76 –

Page 66

4. Power Circuit for P.W.B.

D908

R917

R915

D909

R918

L903

REG1

C911

20 21

D907

C910

R914

C912

C903

C907

C914

R916

L902

35V

17V

FM–15V

I/F0V

FM–0V

C913

D910

REG2

Q706

C924

R920

R921

R922

PQ2

4 3

PQ1

VR1

R923

C906

C918

R911

D906

C908

PQ1

D904

R908

R909

D903

D905

D911

R910

R901

C901

R902

R903

R002

Diode stack 2

(RC2)

R904

2 5

3 4

IC901

C011

C010

R011

R010

C905

D902

R906

L901

R907

Switching transformer (T1)

Fig. 4-1 Power circuit for P.W.B.

C919

C921

C920

12V

D912

R919

R925

R924 ZD904

C909

1 2

JW8

4 3

● Fig. 4-1 shows the power circuit for P.W.B. and waveform at each point.

● In the power circuit for P.W.B., power supply for microcomputer, peripheral circuits, and system power

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

● Switching power circuit performs voltage conversion effectively by switching transistor IC901 to convert

DC 330V voltage to high frequency of about 20kHz to 200kHz.

● Transistor IC901 operates as follows:

(1) Shifting from OFF to ON

● DC about 330V is applied from smoothing capacitors C010 Œ and C011 œ in the control power circuit.

With this power, current flows to pin of IC901 via R903 and R904 and IC901 starts to tum ON. Since voltage in the direction of arrow generates at point at the same time, current passing through R910 and D903 is positive-fed back to IC901.

– 77 –

Page 67

(2) During ON

● The drain current at IC901 increases linearly. During this period, the gate voltage and current become

constant because of the saturation characteristics of the transformer.

(3) Shifting from ON to OFF

● This circuit applies a negative feedback signal from the 12V output. When the voltage across C919

reaches the specified value, REG2 turns on and current flows to PQ2 1-2. This turns the secondary circuits on, sets IC901 pin 1 to “Hi”, and turns IC901 off.

(4) During OFF

● While IC901 is on, the following energy charges the primary windings of the transformer:

Energy=LI2/2. Here, L : Primary inductance

I : Current when IC1 is off

This energy discharges to the secondary windings during power off. That is, C910, C911, C912, C914 is charged according to the turn ratio of each winding.

● At the start, an overcurrent flows to IC901 because of the charged current at C910, C911, C912, C914.

● The drain current at IC901 generates a voltage across R906. If it exceeds the IC901 base voltage, it sets

the IC901 gate voltage to “HI”.

● R906 limits the gate voltage to prevent excessive collector current from flowing to IC901.

If the power circuit for P.W.B. seems to be faulty: (1) Make sure that 5V and 12V on the control P.W.B., upper arm U, V and W, and the lower arm power

voltage are the specified values.

(2) When only the 5V output is low:

REG 1 (regulator) faulty, 5V-0V shorted, output is too high, or REG 1 is abnormal.

(3) When 12V and 5V are abnormal:

The following defects can be considered:

1 Fan, operation, power, rush prevention relay (shorting in relay, etc.) 2 Microcomputer is abnormal. 3 REG 1 (regulator is abnormal), etc.

Shorting on primary circuits. When shorting occurs in the secondary circuits, there is no abnormality in the primary circuits because of overcurrent protection. The voltage rises when an opening occurs in the primary circuits, or the feedback system is abnormal.

(4) When 15V and 17V are abnormal:

D908, D909 or drive circuit is abnormal.

(5) When all voltage are abnormal:

IC901, R906, etc. are possibly abnormal.

* If IC901 is abnormal, be aware that other components, such as the power module, REG (regulator), etc.

are possibly defective.

[When the switching power supply seems to be abnormal, the voltage between IC901 pin 4 (to be measured at the leads of R904 and R903) and IC901 pin 5 (to be measured at R906 lead) may be between 11 and 16V. This is because the protection circuit of IC901 is operating.]

– 78 –

Page 68

5. Reversing valve control circuit

I/F 35V

Reversing valve

DC voltmeter or tester

CN2

I/F 0V

FUSE RESISTOR

D702

Q701

R701

R702

PQ701

R703

Q705

HIC

R219

MICROCOMPUTER

Fig. 5 – 1

● Reversing valve control circuit can switch reversing valve ON/OFF according to instruction from indoor

microcomputer depending on the operation condition shows in Table 5-1. Voltage at each point in each operation condition is approximately as shown below when measured by

tester. (When collector voltage of Q701 is measured)

Table 5-1

Operation condition Collector voltage of Q701

Cooling

General operation of Cooling In normal heating operation

About 35V

About 0.8V

MAX. rotation speed instructed

Heating

by indoor microcomputer after

About 0.8V

defrost is completed

Dehumidifying

Defrosting Sensor dry

About 35V About 35V

– 79 –

Page 69

6. Rotor magnetic pole position detection circuit

0V 0V 0V

R601

C605 C606 C607

18 19 20

Outdoor microcomputer

R602

C501

+5V

R603

D E

C502

C608

C503

+12V

HIC

System power module

R604 R605 R606

R607

R604

R603

R602

WV U

R608

R611

DC brushless motor for compressor

R610

R609

U phase terminal voltage

Spike voltage

Pole position detection signal

Drive signal

No power supplied

60 120 60 120

Upper armONNo power

(B) reference voltage (1/2Vd)

Detection point

—

supplied

Induced voltage

Comparing process

—

Lower arm

—

No power supplied

Vd 150~330

—

Fig. 6-1 Rotor magnetic pole position detection circuit and voltage waveform at each point

 To detect U phase, voltage at point C is produced by driving motor induced voltage signal (voltage at point A ) and

1/2 voltage of Vd (voltage at point B ), and comparing with comparator.

 For V phase and W phase, voltage at point

and voltage at point E are produced in the same way as above. Voltage at point C is taken into indoor unit microcomputer, switching timing to U+ transistor from W+ transistor is produced by delaying 30° from rise waveform, ignoring spike voltage. In addition, switching timing to U-transistor from W-transistor is produced by delaying 30° from fall waveform.

 For V phase and W phase, in the same way as above, drive signals are produced from voltages at point

. Phases are shifted by 120° and 240°, respectively, comparing with U phase.

and point

– 80 –

Page 70

7. Drive Circuit

MICROCOMPUTER

R512

R521

R511

R510

R509

R508

R507

IP CUTTER Id CONTROL CIRCUIT

17V

R501

C404

CN14

17V

PWB (MAIN)

SPM2

17V

–

IC1

VCC

VCU

PGU

VCV

PGV

VCW

PGW

NGU

NGV

NGW

SVT

SWT

SUB

SVB

SWB

–

GL1

GL2

SUT

R502

R503

R504

R505

R506

Q506

R536

R535

R525

Q504

R534

Q503

R524

R533

Q502

Q501

R522

R532

R531

R526

Q505

R523

HIC

–

GRY

R24

COMPRESSOR MOTOR

Fig. 7-1 shows the drive circuit. The circuits for U phase, V phase and W phase have the same Configuration.

ignal

nsistor

drive

Fig.. 7-1

In low speed rotation mode (PWM range), as shown in Fig. 7-2, 0-5V chopper signal is ouput from microcomputer for each phase. S

output from microcomputer is ouput to IC1 and is inverted by active Lo to become 0-15V chopper signal; it is then drive the tra

of each phase.

●

In high speed rotation mode (PWM range), as shown in Fig. 7-3, 0-5V drive signal is ouput from microcomputer for each phase (wi

no chopper because of full duty). Signal output from microcomputer is input to IC1 and is inverted by active Lo to become 0-15V

signal; it is then drive the transistor of each phase.

●

– 81 –

Page 71

[Low speed rotation mode]

15V

Drive signal at point B Drive signal at point A

Fig. 7-2

[High speed rotation mode]

Drive signal at point

15V

Drive signal at point

Fig. 7-3

– 82 –

Page 72

8. HIC and Peripheral Circuits

● Fig. 8-1 shows the micro computer and its peripheral circuits, Table 8-1, the basic operations of each

circuit block, and Fig. 8-2, the system configuration.

Detection Resistor

R24

R41

R43

DC Current

C34

0V0V

SPM2 – HIC

F 8

IC1

R42

Direct Current DC260-380V

3938

–

R222

R247

IC4

C225

R245

12V

R221

R284

R292

C217

R286

C2260VR285

CT1

D104

R005

C009

0V0V

R006

C107

C105

JW10

Fig. 8-1 Microcomputer and Peripheral Circuits

–

R288

IC5

CN13CN14

C205

R249

R248

C215

D205

R252

521

C218

R289

R500

R253

D204

SPM2

MAIN P.W.B

HIC

C222

C224

C204

IC1

MICROCOMPUTER

RESET

Table 8-1

Circuit block

Peak current cutoff circuit

Set value circuit

Voltage amplifier circuit

Reset circuit Trip signal

synthesis circuit

Basic operation

Detects DC current flowing power module and during overcurrent (instantaneous value) flows, stops upper/lower arm drive circuits and also produces lp signal by which drive signal output is stopped.

Compares voltage detected, amplified and input to HIC with set voltage value in microcomputer, and controls overload when set value exceeds input voltage.

Voltage-amplifies DC current level detected by the detection resistor and inputs this to microcomputer. Internal or external overload is judged in microcomputer.

Produces reset voltage. Modulates chopper signal to drive signal and stops according to presence/ab-

sence of lp signal or reset signal.

– 83 –

Page 73

Reset Voltage

Chopper

signal

Chopper

Trip signal

synthesis circuit

signal

DC 260V

Reset circuit

Over-load external

setting circuit

-360V

IP signal

Current amplified

circuit

DC Current level

Outdoor microcomputer

Fig. 8-2

● The following describes the operations of each circuit in detail.

(1) Peak current cut off circuit Fig.8-3 Peak Current Cut off Circuit and Waveforms at Each Section.

Drive

Circuit

Peak current cut off circuit

Detection

resistor

Drive

signal

DC current

Compressor

motor

Power module

DC current Id

21A (27A, for RAC-50NH4)

Voltage at point

1.05V (1.35V for RAC-50NH4)

Voltage at point

SPM2

–

Negative Terminal

DC current

R41

Detection

resistor

9 9

SPM2 – HIC

R43

IC1

R43

R42

20 9 2 39 17

Main P.W.B

CN14

Fig.8-3

● The Ip cut off circuit detects an instantaneous excessive current and stops inverter to protect parts such

as SPM2, etc.

● As shown in diagram, if current exceeding 21A (27A for RAC-50NH4) flows, voltage at point recognized

by detecting resistor is input to pin of SPM2 – HIC, and voltage divided by R41 and R43 is input to pin

of IC1. Since threshold of IC1 is exceeded in this case, Lo signal is input from pin (Voltage at point

. When Lo signal is input to pin of microcomputer, microcomputer stops drive output.

● When drive output from microcomputer is stopped, all drive output goes Hi, and microcomputer is initialized

to enter drive signal standby mode. 3 minutes later, microcomputer outputs drive signal again, to start operation.

HIC

IP Outdoor microcomputer

– 84 –

Page 74

(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. 8-4 shows the overload control system configuration and Fig. 8-5 is a characteristic diagram of

overload judgement values. There are two judgement methods-external judgement which compares the externally set value with the DC current value regardless of the rotation speed and internal judgement which compares the set value that varies according to the rotation speed programmed in the microcomputer software with the DC current value.

Microcomputer

To power module negative terminal

(R24)

DC current

Detection

resistor

Voltage amp

circuit

(Internal judgement)

DC voltage

OVL judgement with respect to externally set value

A/D

converter

A/D

converter

Judgement OVL according to the rotation speed

Selects data according to the rotation speed and DC voltage

Motor control process

Rotation speed data

OVL start current data

Fig. 8-4 Overload Control System Configuration

DC current

Judgement value according to the rotation speed

(internal judgement value)

Rotation speed

Fig. 8-5

1. Overload external judgement circuit

● Fig. 8-1. The filter consisting of R245 and C217 removes high harmonic components from the voltage

generated by the current flowing to Detection resistor; R245 and C217 average the voltage. This voltage is then input to IC4 pin is then amplified and supplied to microcomputer pin . The microcomputer

compares this input with the internally set value, and if the input exceeds the set value, it enters overload control status.

● Fig. 8-7 shows the rotation speed control. When the voltage at pin of the microcomputer exceeds the

set value, the microcomputer decreases the rotation speed of the compressor and reduces the load regardless of the rotation speed commanded by the indoor microcomputer.

– 85 –

Page 75

Detection Resistor

R24

CT1

C009

0V0V

D104

R006

R005

DC Current

C105

373938

C218

Direct Current DC 260-380V

R500

SPM2

MAIN P.W.B.

R253

C222

0V0V

D204

C224

0V0V

HIC

IC1

Microcomputer

R245

R221

CN14

C217

R222

–

R247

CN13

C205

R249

R248IC4

D205

Fig. 8-6

Voltage at microcomputer pin

Rotation speed of compressor

Commanded rotation speed Actual rotation speed

Deceleration DecelerationAcceleration Acceleration

Fig. 8-7

2. Voltage amp. circuit

● The voltage amp. circuit amplifies the DC current level detected by the detection resistor after being

converted to a voltage and supplies it to the microcomputer. Receiving this, the microcomputer converts it to a digital signal and compares it with the internal data to judge whether or not overload control is required.

< During overload control >

● The filter consisting of R245 and C217 removes high harmonic components from the voltage generated

from the DC current flowing to the detection resistor, and supplies it to IC4 pin 5 IC4 forms a non-inverting voltage amp. circuit together with the peripheral elements.

● The microcomputer stores the set values which vary according to the rotation speed. When the DC current

level exceeds the set value, the microcomputer enters the overload control state.

● The set Value is determined by the amplification of the voltage amp. circuit.

● Amplification : high [ DC current : low

{

● Amplification : low [ DC current: high

– 86 –

Page 76

● R500, R253, detect the DC voltage at the power circuit. The microcomputer receives a DC voltage (260-

380V) via HIC U and applies correction to the overload set value so the DC current is low (high) when the DC voltage is high (low).

(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.)

Amplification : low DC voltage : low DC current : high

Amplification : 8.5 times DC voltage : 260V

Amplification : high

DC current

Rotation speed

DC voltage : high DC current : low

Fig. 8-8

< During start current control >

● It is required to maintain the start current (DC current) constant to smooth the start of the DC motor for

the compressor.

● RAC-25NH4, RAC-35NH4, RAC-50NH4 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 Fig8-9. (2) Varies the turn-ON time of the W+ transistor according to the DC voltage level and the start is

controlled so the start current is approx. 10A as shown in Fig. 8-10.

DC 260-360V

Detection

resistor

Chopper duty: high

ON-time

W transistor

20 15 10

DC current (A)

DC current

Power module

—

Compressor motor

U V W

Fig. 8-9

DC voltage: low DC voltage: 280V DC voltage: high

DC voltage (start current)

Start

Set value

Time

Fig. 8-10

– 87 –

Page 77

9. Temperature Detection Circuit

+5V

O.H. thermistor

CN8

Normal 2.7V or less Over heat 2.7V or more Reset 2.3V or less

HIC

O.H.

627

Microcomputer

DEF.

636

Outdoor

645

temperature

DEF. thermistor

CN9

Outdoor temperature thermistor

CN10

+5V

Normal 2.4V or more Over heat 2.4V or less Reset 2.9V or more

+5V

Refer to the table 10-1

Fig. 9-1

● 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 at

pin 62 of microcomputer is increased.

● Microcomputer compares the voltage present at pin

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

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

), and 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 dry mode.

The following shows the typical values of outdoor temperature in relation to the voltage:

Table 9-1

Outdoor temperature (°C)

Microcomputer pin 5 voltage (V)

-10

1.1901.69102.23

2.75

3.22403.62

When the thermistor is open, in open status, or is disconnected, microcomputer pins 62 – 64 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.

– 88 –

Page 78

10. Reset Circuit

Main

HIC

P.W. B

12V

Microcomputer

C107

R284

R286

JW10

R292

C226

R285

2 3

IC5 (1/2)

C225

R288

C215

–

R289

R252

C204

0V0V

RESET

Fig. 10-1

● The reset circuit initializes the microcomputer program when Power is “ON” or “OFF”.

● Low voltage at pin

● Fig. 10-1 shows the reset circuit and Fig. 10-2 shows waveform at each point when power is turned on

resets the microcomputer, and HI activates the microcomputer.

and off.

● When power is turned on, 12V line and 5V line voltages rise and 12V line voltage reaches 10.9V and

reset voltage input to pin 48 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.

Voltage (V)

Power is ON

Voltage (V)

Power is OFF

12V line

5V line

Reset voltage

Time

12V line

5V line

Reset voltage

Time

Fig. 10-2

– 89 –

Page 79

11. Outdoor DC Fan Motor control circuit.

System power module

PQ102

FM-15V

C103

R114

R106

Main P.W.B

R115

ZD101

R105

C106

R104

R103

FM-15V

Q101

D101

R101

FM-0V

Ap 7V

33.3KHz

T/2

R102

+++

Smoothing Capacitor

123 4 5321

CN12

321

2A-FUSE

C101

R107

FM-0V

R108

Fig. 11-1

U V W

Vcc

PWM control voltage

FG Pulse

CN6

C104

D105

61 60 59

Power supply for DC fan motor from smoothing capacitor in system power module

RC Filter

VSD

BOARD

DC Fan motor with control board

IC4

R246 0V

C208

2 3

12V

–

Q201

HIC

R283

R242

C219

C209

ONE CHIP DRIVER IC

Microcomputer

R243

R244

R298

R297

Motor coil

FM–60˚ el FG Pulse input

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

● This DC Fan Motor will rotate by control voltage apply to Vsp input. (Voltage range: 1.7 to 7V DC)

Vsp high : Faster ; Vsp low : slower ; Vsp lower than 1.7V : stop

● Motor will output FG pulse by following this motor revolution.

● Outdoor Microprocessor will output PWM control signal from FMCHOP terminal by following the instruction

from indoor Microprocessor.

● This PWM control signal will convert to Vsp voltage by smoothing circuit (Q101 & RC filter)

● Fan motor will start to rotate when Vsp was proceeding over than 1.7V, and generate FG pulse by rotation

speed.

● FG pulse will feed back to Outdoor Microprocessor through PQ102.

● PQ102 is the isolator between Microprocessor circuit and DC Fan Motor circuit, which has to match the Fan

Motor revolution with instructed revolution. Such as...

FG feedback: Faster – Instruction: Slower ... Decrease pulse width FG feedback: Slower – Instruction: Faster ... Increase pulse width

● FG pulse is also used for Fan Motor failure detection

● Microprocessor will monitor FG pulse 30 seconds after start the fan motor. If there is no signal detected, it

will consider that the Fan Motor was malfunction and stop the operation. In this case, LD302 on control PWB will blink 12 times. (Fan Motor lock detected)

● R107 and IC4 are used for Fan Motor over current

– 90 –

Page 80

< 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 when 2A Fuse was burned. Please replace both DC Fan Motor and 2A 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 casue is

Fan Motor problem or PQ102 on board 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 due to the built in control circuit in Fan Motor.

– 91 –

Page 81

12. Power Factor Control Circuit

Power factor is controlled to almost 100%. (Effective use of power) With IC in ACT module, control is performed so that input current waveform will be similar to waveform of input

voltage

I (input current)

V (input voltage)

Effective

voltage

area

Invalid power area

(Even if voltage is applied. current does not flow)

input voltage

input current

Effective

voltage area

* Assuming the same current capacity (20A), power can be used about 10% effective, comparing with curent use (power factor of 90%), and maximum capacity is thereby improved.

– 92 –

Page 82

SERVICE CALL Q & A

Model RAK-25NH4 / RAC-25NH4

RAK-35NH4 / RAC-35NH4 RAK-50NH4 / RAC-50NH4

COOLING MODE

The compressor has stopped suddenly during cooling operation.

DEHUMIDIFYING MODE

Sound of running water is heard from indoor unit during dehumidifying.

Compressor occasionally does not operate during dehumidifying.

HEATING MODE

The circulation stops occasionally during Heating mode.

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

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

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

Normal sound when refrigerant flows in pipe.

Compressor may not operate when room temperature is 10°C or less. It also stops when the humidity is preset humidity or less.

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

Heating operation stops while the temperature is preset at "30".

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

– 93 –

Page 83

AUTO FRESH DEFROSTING

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

AUTO OPERATION

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

NICE TEMPERATURE RESERVATION

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

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.

Q10

Q1 1

Does “Nice temperature reservation” function operate during dehumidifying?

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

INFRARED REMOTE CONTROL

Q12

Q13

Q14

Timer cannot be set.

The current time display disappears soon.

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

A10

A11

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.

A12

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

The current time disappears

A13

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

A14

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 approx 3 minutes.

– 94 –

Page 84

OTHERS

The indoor fan varies among

Q15

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

Q16

Q17

Q18

Q19

Loud noise from the outdoor unit is heard when operation is started.

Noise from the outdoor unit occasionally changes.

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

Air does not flow immediately after operation is started.

A15

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

A16

A17

A18

A19

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.

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

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.

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.

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.

– 95 –

Page 85

TROUBLE SHOOTING

Model RAK-25NH4 / RAC-25NH4

RAK-35NH4 / RAC-35NH4 RAK-50NH4 / RAC-50NH4

PRECAUTIONS FOR CHECKING

DANGER

1. Remember that the 0V line is biased to 155-170V in reference to the ground level.

2. Also note that it takes about 10 minutes until the voltage fall after the power switch is turned off.

Power source

Indoor unit electric parts

Control P.W.B.

System power module 2

ACT Module

DC35V

+–+

–

(0V)

MAIN P.W.B.

Across a – b (0V line)....................

Across a – ground..........................

Across b (0V line)– ground............

–

Power module

Compressor motor

approx 260-360V approx 155-170V approx 155-170V

DANGER

When using an oscilloscope, never ground it. Don't forget that high voltages as noted above may apply to the oscilloscope.

Outdoor unit P.W.B.

Always keep your hands and metallic things away from the enclosure of the oscilloscope.

Oscilloscope

DANGER!

Don’t install

the ground

line.

– 96 –

Page 86

DISCHARGE PROCEDURE AND POWER SHUT OFF METHOD FOR POWER CIRCUIT

Caution

●

Voltage of about 300-330V is charged between both ends of smoothing capacitors

WARNING

1. Turn OFF the Power supply to the outdoor unit.

2. After power is turned off, wait for 10 minutes or more. Then, remove electrical parts cover and apply soldering iron of 30 to 75W for 15 seconds or more to P2 and N1 terminals on system power module, in order to discharge voltage in smoothing capacitor.

3. Remove receptable of red/gray lead wire connected to system power module from diode stack before performing operation chech of each circuit.

●

During continuity check for each part of circuit in indoor unit electrical parts, disconnect red/gray lead wire connected from diode stack to system power module (SPM2) to prevent secondary trouble. (Be sure to discharge smoothing capacitor)

System power module

RAC-25NH4, RAC-35NH4

Smoothing capacitors

SPM2

Soldering iron

Do not use a soldering iron with transformer: If one is used, thermal fuse inside transformer will be blown

As shown above, apply soldering iron to metal parts (receptable) inside the sleeve corresponding to P1 and N1 terminals of system power module: Do this with smoothing capacitors kept connected. By removing red/ gray lead wire from diode stack, power supply can be shut off. (corresponding to + and – terminals of system power module)

RAC-50NH4

SPM2

Smoothing capacitors

– 97 –

Page 87

CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE

Model RAK-25NH4 / RAC-25NH4

RAK-35NH4 / RAC-35NH4 RAK-50NH4 / RAC-50NH4

Timer lamp

Does the timer lamp on the indoor unit blink?

See “Troubleshooting when the timer lamp blinks”.

Remove the terminal cover and check the voltage between terminal (C) and terminal (D)

Does the operation lamp on the indoor unit start to light or blink?

Yes

Is the compressor in the outdoor unit operating?

Yes No

Remove the outdoor unit cover and electrical parts cover, and check self-diagnosis lamp LD301

CN17

022527

IC3

P.W.B

Service switch

Self diagnosis lamps (LD303, 302, 301)

Does LD301 blink one time ? * Repeats 0.25-second on and 2-second off.

Terminal C (+35V)

Terminal D (0V)

Is approx. DC 33 to 37V being generated? Is the polarity correct?

Yes

Check to see whether the Fcable is connected incorrectly or disconnected

Normal

Blinking other than one time

Press the service switch for 1 sec. Does the compressor operate? (After checking, be sure to press the service switch to stop the operation).

See “Out door unit self-diagnosis lamp lighting mode”.

Check the refrigerating cycle.

One-time blinking

Yes

Check the outdoor electrical parts.

– 98 –

Check the indoor electrical parts.

Page 88

TROUBLESHOOTING WHEN TIMER LAMP BLINKS.

sec.

Model RAK-25NH4, RAK-35NH4, RAK-50NH4 Perform troubleshooting according to the number of times the indoor timer lamp and outdoor LD301 blink.

SELF-DIAGNOSIS LIGHTING MODE Model: RAK-25NH4, RAK-35NH4, RAK-50NH4

No. Blinking of Timer lamp Reason for indication Possible cause

Reversing valve defective When the indoor heat exchanger

5sec.

– ––––––– 1 time

temperature is too low in the heating mode or it is too high in the cooling mode.

(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).

Outdoor unit forced operation

5sec.

– –––––– 2 time

5sec.

– ––––– 3 times

5sec.

–– 9 times

–– 10 times

–– 13 times

When the outdoor unit is in forced operation or balancing operation after forced operation

Indoor/outdoor interface defective When the interface signal from the outdoor 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 the DC fan motor of the indoor unit.

IC401 or IC402 data reading error When data read from IC401 or IC402 is incorrect.

Electrical parts in the outdoor unit

(1) Indoor interface circuit (2) Outdoor interface circuit

(1) Room thermistor (2) Heat exchanger thermistor

(1) Indoor fan locked (2) Indoor fan motor (3) Indoor control P.W.B.

IC401 or IC402 abnormal

( – – Lights for 0.5 sec. at interval of 0.5 sec..)

(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 to see if the F-cable is connected or disconnected. (3) To check operation again when the timer lamp is blinking, you can use the remote control for operation

(except for mode mark 1).

– 99 –

Page 89

SELF-DIAGNOSIS LIGHTING MODE

MODEL: RAC-25NH4, RAC-35NH4 & RAC-50NH4

– 100 –

Page 90

CHECKING INDOOR UNIT ELECTRICAL PARTS

1. Power does not come on (no operation)

No No Is DC 35V being generated between terminals C and D on the terminal board?

Is AC 220-240V AC being generated between terminals L and N on the outdoor unit terminal board?

Yes

Is DC 35V being generated between terminals C and D on the outdoor unit terminal board?

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

Yes

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

Are control voltages (12V, 5V) being generated normally?

Yes

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

Is the microcomputer reset input (pin 7 )“Hi”?

Yes

Is the microcomputer clock signal 10MHz at pin generated normally?

10 11

being

Yes

Check the outdoor unit power circuit, and repair the defective section.

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

Check the indication P.W.B. connection cord and light receiving unit.

Check the reset circuit, and repair any defective section.

Replace the microcomputer and oscillator.

Replace the control P.W.B

Perform final operation check.

– 101 –

Page 91

2. Outdoor unit does not operate (but receives remote infrared signal)

Set to room temperature 16°C in the cooling mode or to 32°C in the heating mode, and press the start/stop button.

Remove the outdoor unit cover and electrical parts cover, and check selfdiagnosis lamp LD301.

Self diagnosis lamps (LD303, 302, 301)

Does LD301 blink one time? *Repeats 0.25-second on and 2-second off.

Yes Does outdoor electrical part LD301 blink nine times?

Yes

Is the indoor/outdoor unit communication signal superimposed on 35V DC of connection wires C and D?

Approx.

35V

38kHz Approx. 2Vp-p

Yes

Check the room temperature thermistor; if it is defective, replace it. <Normal values>

10°C ➞ approx. 20kΩ 25°C ➞ approx. 10kΩ 30°C ➞ approx. 8kΩ

Check the heat exchanger thermistor; if it is defective, replace it. <Normal values>

10°C ➞ approx. 20kΩ 25°C ➞ approx. 10kΩ 30°C ➞ approx. 8kΩ

Check outdoor electrical parts, and repair any defective parts (around the outdoor interface transmitting circuit).

Does LD303 switch off several second after it lights?

Is the indoor transmitting signal being generated at Q801’s collector?

38kHz Approx. 2Vp-p

Approx.

35V

Transmission waveform

Yes

Perform final operation check.

– 102 –

Yes

Check the indoor interface transmitting circuit. Replace IC801.

Check outdoor electrical parts, and repair any defective parts (around the outdoor interface transmitting circuit).

Check outdoor electrical parts, and repair any defective parts.

Page 92

3. Only indoor fan does not operate (other is normal)

Can the fan be stopped by remote control?

Yes Yes

The microcomputer fan PWM output (pin) is “Hi”

Perform final operation check.

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

Are pulse signals output at microcomputer pin swing is turned on in the fan mode?

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

Yes

when auto

Yes

Replace IC111

Replace the microcomputer.

Replace the indoor fan motor.

Replace the microcomputer.

Replace the microcomputer

Yes

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

Perform final operation check.

5. All systems stop from several seconds to several minutes after operation is started (all indicators are also off)

Set to the “Hi” fan mode.

The operation lamp lights once and goes out in 5-10 seconds.

Yes

Disconnect CN10 and set to the fan mode again.

The operation lamps lights once and goes out in 5-10 seconds.

Can the indoor fan be lightly turned by hand? (Switch of main power before check)

Yes

Replace the indoor fan motor.

Yes

Check to see if shorting etc. has occurred in the P.W.B pattern

Check to see if the indoor fan is touching the chassis, etc. If it does repair

– 103 –

Page 93

6. Check the main P.W.B (power circuit)

Is DC 35V being output between cathode and anode of D101?

Yes

Is DC 12V being output?

Is DC 5V being output?

Is ICP2 normal? Normal if it is less than 1Ω. Blown (open) if it is 1Ω or more

Is ICP1 normal? Normal if it is less than 1Ω. Blown (open) if it is 1Ω or more

YesYes

Replace IC111.

Replace ICP2. Check if shorting has occurred in fan motor circuit and 35V interface circuit. If these are defective, ICP2 will be open again.

Replace ICP1. Check if shorting has occurred in the air deflector motor. If these are defective, ICP1 will be open again.

Replace REG2. Check the 5V line: if the 5V line is shorted, ICP1 will be open again.

Perform final operation check.

– 104 –

Page 94

Turn on an AM radio, bring

the remote control switch within

15 cm of the radio, and press

the ON/OFF button.

Check the indoor unit signal

receiving P. W. B..

If it is good, check the main P. W. B..

You can check the remote control switch by other methods as explained below.

Using the test card

The sensible area should flash in orange when you operate the remote control unit if it is good.

Ultra redray test card

Sensible area

Within 2 cm

Check functions again.

If it does not work, replace

the remote controller.

“Buzz”

Within 15 cm

[AM radio]

Check the LED (D1) with

a multimeter.

Replace the battery.

Install the battery in the correct polarity.

Yes

Does the radio buzz noisily?

Is battery polarity correct?

Is the battery check sign + –

flashing?

CHECKING THE REMOTE CONTROLLER

– 105 –

Page 95

CHECKING THE OUTDOOR UNIT ELECTRICAL PARTS

MODEL RAC-25NH4, RAC-35NH4, RAC-50NH4

Check to see whether the

connected C and D cable

Replace any defective parts.

If the 25A fuse has blown, be aware

that other parts may also be

defective (mainly, varistor 2, diode

stack, smoothing capacitors, system

power module, etc.).

correctly? If reversed, correct the

If the 3A fuse has blown, the

switching transformer (T1),

R906, etc. may also be

cable connection.

Replace any defective parts.

Yes

Is the switching power circuit OK?

Has the 3A fuse blown?

defective.

()

See the self-diagnosis lamp

lighting mode.

Yes

Is AC220-240V being

supplied to terminal L and N?

[No operation or abnormal operation]

Is the 25A fuse normal?

Yes

Is the power circuit normal?

See the description on

power circuit for details.

Is 5V being generated

between Pin 4 (0V) and pin

3 (5V) at CN 18 (test pin)?

– 106 –

Yes

”.

Operate the outdoor unit

according to the instruction

“How to operate the outdoor

unit independently

How did the self-diagnosis

lamp (LD301) light?

Page 96

There is a defective section between the

12V output of switching power supply on

the main P .W .B. and interface relay (also,

D907 and C910 may be defective.

check for contact with solder, etc.).

Repalce the interface relay.

Yes

Is DC 35V being output at

terminals C and D? (Normally,

DC 33-38.5V is output.)

Yes

Is DC 35V being output across R914?

Is DC 12V being supplied across

Yes

the control side (coil terminal) of

interface relay?

Coil terminal

Interface relay

Yes

Is a voltage (at least 10V) being

generated between the contact

terminals of interface relay?

Contact terminal

Check the interface curcuit.

LD301 blinks 9 time.

Communication error.

– 107 –

Page 97

Yes No

Yes

Check continuity of pattern and

lead wires according to the

P.W.B. and schematic diagrams.

Replace the power module.

Replace any defective parts.

Connect the thermistor.

”.

“forgetting

Check continuity of pattern and

lead wires according to the

P.W.B. and schematic diagrams.

Replace parts in the

Replace the thermistor.

thermistor circuit.

Is the power module normal?

LD301 blinks 8 time.

Acceleration defect.

Is the drive circuit normal?

Is the thermistor connector

to connect after servicing

❈ The problem may be

disconnected?

Thermistor abnormal.

LD301 blinks 7 time.

Is the continuity of thermistor normal?

Is the thermistor circuit normal?

– 108 –

Page 98

Check continuity of new parts.

Check continuity of pattern and

lead wires according to the

P.W.B. and schematic diagrams.

Replace parts in the

thermistor circuit.

Is the thermistor circuit normal?

Replace system power

module or defective parts.

Are R503, R541, R542, R549

and peripheral circuits of

system power module normal?

Replace the system power

module.

Yes

Replace the main P.W.B.

Is the system power module

normal?

Yes

Replace any defective

parts.

Is the drive circuit normal?

The temperature at the

OH thermistor rises.

LD301 blinks 6 time.

LD301 blinks 5 time.

Overload lower limit cut.

– 109 –

LD301 blinks 4 time.

Failure of switching.

LD301 blinks 3 time.

Abnormal low speed.

Page 99

LD301 blinks 2 time.

Peak current-cut.

LD301 blinks 1 time.

Reset stop.

However, the unit always resets and

stops just after power is supplied:

this does not indicate a fault.

Is the system power module

normal?

Is the drive circuit normal?

•

Are R503, R541, R542, R549

and peripheral circuits of system

power module normal?

•

Is the microcomputer IP input

signal normal?

(Normally, pin

is approx. 5V.)

Is the reset circuit normal?

(Normally, microcomputer

is approx. 5V.)

Replace any defective parts.

Operate the unit again.

is it normal?

Make sure again that

connectors are connected

securely.

Perform final operation check.

Replace the system power

module.

Yes

()

– 110 –

Page 100

POWER CIRCUIT

Phenomenon 1 <Rotation speed does not increase>

Is the DC voltage at least 350V?

Yes

Is the OVL lamp lit? If the lamp is lit, it does not indicate fault, but the unit is overload status.

Overvoltage defect: system power module faulty (15-times blinking)

Recheck cord, etc. of the system power module. If they are disconnected, connect them securely.

If abnormality continues, replace the system power module.

– 111 –

Hitachi 0174E Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual