Hitachi RAK25NH4, RAK35NH4, RAK50NH4, RAC25NH4, RAC35NH4 Service manual

SM0174

RAK25NH4 RAC25NH4
RAK35NH4 RAC35NH4

SERVICE MANUAL

TECHNICAL INFORMATION

FOR SERVICE PERSONNEL ONLY

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

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

RAK50NH4 RAC50NH4

REFER TO THE FOUNDATION MANUAL

CONTENTS

SPECIFICATIONS ------------------------------------------------------------------- 5

CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 6

MAIN PARTS COMPONENT --------------------------------------------------- 8

WIRING DIAGRAM ---------------------------------------------------------------- 10

CIRCUIT DIAGRAM --------------------------------------------------------------- 12

PRINTED WIRING BOARD LOCATION DIAGRAM ---------------------

BLOCK DIAGRAM ----------------------------------------------------------------- 20

BASIC MODE ----------------------------------------------------------------------- 22

REFRIGERATING CYCLE DIAGRAM --------------------------------------- 35

AUTO SWING FUNCTION ------------------------------------------------------ 37

DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 38

SERVICE CALL Q & A ---------------------------------------------------------- 69

TROUBLE SHOOTING ----------------------------------------------------------- 72

PARTS LIST AND DIAGRAM ------------------------------------------------- 92

18

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)

W

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

38

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

38

INDOOR UNIT

RAK-50NH4 RAC-50NH4

1 PHASE, 50 Hz, 220-230V

1,780 (155~2,200)

5.00 (0.90 ~ 5.20)

1,970 (115 ~ 2,100)

6.50 (0.90 ~ 8.10)

860

285

183

9.0

OUTDOOR UNIT

8.17-7.82

17,070

9.04-8.65

22,200

850

650

298

60

After installation

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

ROOM AIR CONDITIONER

MAY 2003

Refrigeration & Air-Conditioning Division

INDOOR UNIT + OUTDOOR UNIT

FOR SERVICE PERSONNEL ONLY

●

Carefully read through the procedures of proper
installation before starting installation work.

●

The sales agent should inform customers regarding
the correct operation of installation.

SPLIT UNIT AIR CONDITIONER

INSTALLATION MANUAL

Outdoor Unit RAC-35NH4

HFC

R410A

SAFETY PRECAUTION

●

Read the safety precautions carefully before operating the unit.

●

The contents of this section are vital to ensure safety. Please pay special attention to the following sign.

WARNING ........ Incorrect methods of installation may cause death or serious injury.

!

!

CAUTION ......... Improper installation may result in serious consequence.

Be sure that the unit operates in proper condition after installation. Explain to customer the proper way of operating
the unit as described in the user’s guide.

RAC-25NH4
RAC-50NH4

Tools Needed For Installation Work

●

+ – Screwdriver

●

Saw ● ø 65mm Power Drill ● Hexagonal Wrench

Key ( 4mm)

●

Gas Leakage Detector ● Pipe Cutter

●

Vinyl Tape ● Pliers ● Flare Tool

●

Measuring Tape

●

Wrench (14, 17, 22, 26, 27mm)

●

Knife

●

Putty

!

WARNING

●

Please request your sales agent or qualified technician to install your unit. Water leakage, short circuit or fire may occur if you
do the installation work yourself.

●

Please observe the instructions stated in the installation manual during the process of installation. Improper installation may
cause water leakage, electric shock and fire.

●

Make sure that the units are mounted at locations which are able to provide full support to the weight of the units. If not, the
units may collapse and impose danger.

●

Observe the rules and regulations of the electrical installation and the methods described in the installation manual when
dealing with the electrical work. Use power cables approved by the authorities of your country.

●

Be sure to use the specified wire for connecting the indoor and outdoor units. Please ensure that the connections are tight
after the conductors of the wire are inserted into the terminals. Improper insertion and loose contact may cause over-heating
and fire.

●

Please use the specified components for installation work. Otherwise, the units may collapse or water leakage, electric shock
and fire may occur.

●

Be sure to use the specified piping set for R-410A. Otherwise, this may result in broken copper pipes or faults.

●

When installing or removing an air conditioner, only specified refrigerant (R410A) shall be allowed, do not allow air or moisture
to remain in the refrigeration cycle. Otherwise, pressure in the refrigeration cycle may become abnormally high so that a rupture
may be caused.

●

Be sure to ventilate fully if a refrigerant gas leak while at work. If the refrigerant gas comes into contact with fire, a poisonous
gas may occur.

●

After completion of installation work, check to make sure that there is no refrigeration gas leakage. If the refrigerant gas leaks
into the room, coming into contact with fire in the fan-driven heater, space heater, etc., a poisonous gas may occur.

●

Unauthorized modifications to the air conditioner may be dangerous. If a breakdown occurs please call a qualified air conditioner
technician or electrician. Improper repairs may result in water leakage, electric shock and fire, etc.

!

CAUTION

●

A circuit breaker or fuse (16A time delay) must be installed. Without a circuit breaker or fuse the danger of electric shock exists.
A main switch with a contact gap of more than 3mm has to be installed in the power supply line to the outdoor unit.

●

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

●

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

●

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

<

I477: A

>

THE CHOICE OF MOUNTING SITE (Please note the following matters and obtain permission from customer before installation).

!

WARNING

●

The Outdoor unit must be mounted at a location which can support heavy weight. Otherwise, noise and vibration will increase.

!

CAUTION

●

Do not expose the unit under direct sunshine or rain. Besides, ventilation must be good and clear of obstruction.

●

The air blown out of the unit should not point directly to animals or plants.

●

The clearances of the unit from top, left, right and front are specified in figure below. At least 3 of the above sides must be open air.

●

Be sure that the hot air blown out of the unit and noise do not disturb the neighbourhood.

●

Do not install at a location where there is flammable gas, steam, oil and smoke.

●

The location must be convenient for water drainage.

OUTDOOR UNIT

●

Place the Outdoor unit and its connecting cord at least 1m away from the antenna or signal line of television, radio or telephone. This is to
avoid noise interference.

Names of Outdoor Components

QtyNo. Item

Bush

0

(RAC-25NH4,
RAC-35NH4)

(RAC-50NH4)

2

3

Figure showing the Installa­tion of Outdoor Unit.

Drain Pipe

!

1

Bush

#

1

Dimension of Mounting Stand

of the Outdoor unit

(unit: mm)

mounting stand

Dimension of Mounting Stand

of the Outdoor unit

(unit: mm)

mounting stand

●

Please mount the Outdoor unit on stable ground to prevent

12
35

500

12
35

508

(RAC-25NH4,
RAC-35NH4)

57

10

320

340

20

(10)

124

(RAC-50NH4)

57

10

320

340

35

(10)

198

above 100mm

above 700mm

vibration and increase of noise level.

●

Decide the location for piping after sorting out the different types
of pipe available.

●

When removing side cover, please pull the handle after undoing
the hook by pulling it downward.

Please face this side (suction
side) of the unit to the wall.

Please remove side cover
when connecting the piping
and connecting cord.

Pull downward

above 200mm

above 50mm when
installed on the

(

ceiling of balcony

CONDENSED WATER DISPOSAL OF OUTDOOR UNIT

 There are holes on the base of Outdoor unit for condensed
 In order to flow condensed water to the drain, the unit is installed on

 At first insert one portion of the hook to the base (Portion A), then

When Using and Installing In Cold Areas

When the air conditioner is used in low temperature and in snowy
conditions, water from the heat exchanger may freeze on the base
surface to cause poor drainage. When using the air conditioner in such
areas, do not install the bushings. Keep a minimum of 250mm between
the drain hole and the ground. When using the drain pipe, consult your
sales agent.

For more details, refer to the installation Manual for Cold Areas.

● The difference in height

between the indoor and
outdoor unit should be
kept max 5m.

● The connecting pipe, no

matter big or small,
should all be insulated
with insulation pipe and
then wrapped with vinyl
tape. (The insulator will
deteriorate if it is not
wrapped with tape).

The connection of insulated
drain hose.

inner diameter ø 16mm

Maximum pipe length 20m

)

above 100mm

Please use insulated drain
hose for the indoor piping
(commercial product).

give clearance as
wide as possible

above 200mm

water to exhaust.
a stand or a block so that the unit is 100mm above the ground as

shown figure. Join the drain pipe to one hole.
pull the drain pipe in the direction shown by the arrow while inserting

the hook into the base. After installation, check whether the drain
pipe cling to the base firmly.

A

BASE

DRAIN PIPE

100 mm ABOVE

10

BUSH

12

11

DRAIN PIPE

BUSH

Preparation of Pipe1

●

Use a pipe cutter to cut the copper pipe.

Trimming tool

Copper pipe

!

CAUTION

●

Jagged edge will cause leakage.

●

Point the side to be trimmed downwards during trimming to prevent copper
chips from entering the pipe.

●

Before flaring, please put on the flare nut.

Die

Outer
Diameter (mm)

6.35

9.52

12.7

Die

Copper pipe

For R410A tool

0.0

0.5mm

~

0.0

0.5mm

~

0.5mm

0.0

~

A

A (mm)

●

Recommend to use
R410A flaring tool.

For R22 tool

1.0mm

1.0mm

1.0mm

INSTALLATION OF REFRIGERATING PIPES AND AIR REMOVAL

Pipe Connection2

In case of removing flare nut of an Indoor unit, first remove a nut

!

CAUTION

Wrench

Gas Leakage Inspection

Please use gas leakage detector to check if
leakage occurs at the connection of Flare
nut as shown on the right.

If gas leakage occurs, further tighten the
connection to stop leakage. (Use the detector
provided for R410A)

of small diameter side, or a seal cap of big diameter side will fly
out. Prevent water from entering into the piping when working.

Torque
wrench

Small dia. side
Large dia. side

Small dia. side

Valve

head cap

Valve core cap

Large dia. side

Flare nut

Outer

dia.of pipe

6.35 (1/4")

9.52 (3/8")

12.7 (1/2")

6.35 (1/4")

9.52 (3/8")

12.7 (1/2")

Torque N·m

(kgf · cm)

13.7 – 18.6 (140 – 190)

34.3 – 44.1 (350 – 450)

44.1 – 53.9 (450 – 550)

19.6 – 24.5 (200 ~ 250)

19.6 – 24.5 (200 ~ 250)

29.4 – 34.3 (300 – 350)

12.3 – 15.7 (125 ~ 160)

Removal Of Air From The Pipe And Gas Leakage Inspection

3

Procedures of using Vacuum Pump for Air Removal

As shown in right figure, remove the cap
of valve core. Then, connect the charge
hose. Remove the cap of valve head.

1

Connect the vacuum pump adapter to
the vacuum pump and connect the
charge hose to the adapter.

Fully tighten the “Hi” shuttle of the

When the meter reaches - 101KPa
(-76cmHg) during pumping, fully
tighten the shuttle.

Valve

Meter showing pressure

Charge hose

Lo Hi

Valve

Vacuum pump
adapter

manifold valve and completely unscrew
the “Lo” shuttle. Run the vacuum pump

2

for about 10–15 minutes, then completely

AIR REMOVAL

tighten the “Lo” shuttle and switch off
the vacuum pump.

Completely unscrew the spindle of the
service valve (at 2 places) in anti-

3

clockwise direction to allow the flow of
coolant (using Hexagonal Wrench key).

Remove the charge hose and tighten the
cap of valve head. Check the cap’s

4

periphery if there is any gas leakage.
The task is then completed.

When pumping starts, slightly loosen the
flare nut to check of air sucked in. Then
tighten the flare nut.

The body of
service valve

Cap of
valve core

Hexagonal

Cap of valve head

Wrench Key

Cap of valve head

Closed
R410A

Manifold valve

Vacuum
pump

●

WARNING

!

THIS APPLIANCE MUST BE EARTHED.

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

Procedures of Wiring

In case that power is supplied from Outdoor Unit

Indoor Unit Outdoor Unit

1.6 or

2.0

Connecting Cord

Strip wires

Outdoor

Unit

GRN + YEL

25mm

10mm

10mm

25mm

10mm

35mm

Power line Control line

!

WARNING

●

The naked part of the wire core should be 10 mm and fix it to the terminal
tightly. Then try to pull the individual wire to check if the contact is tight. Improper

CONNECTION OF POWER CORD

insertion may burn the terminal.

●

Be sure to use only power cables approved from the authorities in your country.
For example in Germany: Cable type: NYM 3x1.5mm

●

Please refer to the installation manual for wire connection to the terminals of the
units. The cabling must meet the standards of electrical installation.

●

There is a AC voltage of 230V between the L and N terminals. Therefore,
before servicing, be sure to remove the plug from the AC outlet or switch off
the main switch.

<

I477: A

>

DCNLDC

Connecting Cord

2.0
AC 220 - 230V

2

.

Wiring of The Outdoor Unit

●

Please remove the side cover for wire connection.

●

If you cannot attach the side cover due to the connecting cord,

!

WARNING

press the connecting cord in direction to the front panel to fix it.

●

Be sure that the hooks of the side cover is fixed in certainly.
Otherwise water leakage may occur and this causes short circuit
or faults.

●

The connecting cord should not touch to service valve and pipes.
(It becomes high temperature in heating operation.)

Checking for the electric source and the
voltage range

●

Before installation, the power source must be checked and necessary wiring work
must be completed. To make the wiring capacity proper, use the wire gauges list
below for the lead-in from a pole transformer and for the wiring from a switch board
of fuse box to the main switch and outdoor unit in consideration of the locked rotor
current.

IMPORTANT

Cable length

up to 16m
up to 15m
up to 25m

●

Investigate the power supply capacity and
other electrical conditions at the installation
location.
Depending on the model of room air
conditioner to be installed, request the
customer to make arrangements for the
necessary electrical work etc.
The electrical work includes the wiring work
up the outdoor. In localities where electrical
conditions are poor, use of a voltage
regulation is recommended.

Wire cross-section

2

1.5mm

2

2.5mm

2

4.0mm

CD

N

L

Use 16A Time
Delay Fuse

Earth terminal

1

Insulation And Maintenance Of Pipe Connection

●

The connected terminals should be completely sealed with heat insulator and
then tied up with rubber strap.

●

Please tie the pipe and power line together with vinyl tape as shown in the figure
showing the installation of Indoor and Outdoor units. Then fix their position with
holders.

●

To enchance the heat insulation and to prevent water condensation, please
cover the outdoor part of the drain hose and pipe with insulation pipe.

●

Completely seal any gap with putty.

Sleeve of

Insulation material for pipe connection

2

Power Source And Operation Test

protection pipe

Putty

Power Source

!

CAUTION

●

Please use a new socket. Accident may occur due to the use of old socket
because of poor contact.

●

Please plug in and then remove the plug for 2 – 3 times. This is to ensure that
the plug is completely plugged into the socket.

●

Keep additional length for the power cord and do not render the plug under

FINAL STAGE OF INSTALLATION

external force as this may cause poor contact.

●

Do not fix the power cord with U-shape nail.

Operation Test

●

Please ensure that the air conditioner is in normal operating condition during
the operation test.

●

Explain to your customer the proper operation procedures as described in the
user’s manual.

Putty

above 50mm

above 100mm

above

0.45m

above 300mm

must not bend

above 100mm

2

7

4

5

3

9

Maximum pipe length 20m

Plug

2,300mm or more

1

!

!

!

!

FOR SERVICE PERSONNEL ONLY

!

!

0.9m

1.6m

!

Connection

Horizontally
perpendicular
to the unit

inner diameter ø 16mm

HFC

R410A

●

Carefully read through the procedures of proper
installation before starting installation work.

●

The sales agent should inform customers regarding
the correct operation of installation.

SPLIT UNIT AIR CONDITIONER

INSTALLATION MANUAL

RAK-25NH4

Indoor Unit

SAFETY PRECAUTION

●

Read the safety precautions carefully before operating the unit.

●

The contents of this section are vital to ensure safety. Please pay special attention to the following sign.

WARNING ........ Incorrect methods of installation may cause death or serious injury.

CAUTION ......... Improper installation may result in serious consequence.

Be sure that the unit operates in proper condition after installation. Explain to customer the proper way of operating
the unit as described in the user’s guide.

RAK-35NH4
RAK-50NH4

Tools Needed For Installation Work

●

+ – Screwdriver

●

Saw ● ø 65mm Power Drill ● Hexagonal Wrench

Key ( 4mm)

●

Gas Leakage Detector ● Pipe Cutter

●

Vinyl Tape ● Pliers ● Flare Tool

●

Measuring Tape

●

Wrench (14, 17, 22, 26, 27mm)

●

Knife

●

Putty

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

WARNING

Please request your sales agent or qualified technician to install your unit. Water leakage, short circuit or fire may occur if you
do the installation work yourself.

Please observe the instructions stated in the installation manual during the process of installation. Improper installation may

cause water leakage, electric shock and fire.

Make sure that the units are mounted at locations which are able to provide full support to the weight of the units. If not, the

units may collapse and impose danger.

Observe the rules and regulations of the electrical installation and the methods described in the installation manual when

dealing with the electrical work. Use power cables approved by the authorities of your country.

Be sure to use the specified wire for connecting the indoor and outdoor units. Please ensure that the connections are tight

after the conductors of the wire are inserted into the terminals. Improper insertion and loose contact may cause over-heating
and fire.

Please use the specified components for installation work. Otherwise, the units may collapse or water leakage, electric shock

and fire may occur.
Be sure to use the specified piping set for R-410A. Otherwise, this may result in broken copper pipes or faults.
When installing or removing an air conditioner, only specified refrigerant (R410A) shall be allowed, do not allow air or moisture

to remain in the refrigeration cycle. Otherwise, pressure in the refrigeration cycle may become abnormally high so that a rupture

may be caused.
Be sure to ventilate fully if a refrigerant gas leak while at work. If the refrigerant gas comes into contact with fire, a poisonous

gas may occur.
After completion of installation work, check to make sure that there is no refrigeration gas leakage. If the refrigerant gas leaks

into the room, coming into contact with fire in the fan-driven heater, space heater, etc., a poisonous gas may occur.
Unauthorized modifications to the air conditioner may be dangerous. If a breakdown occurs please call a qualified air conditioner

technician or electrician. Improper repairs may result in water leakage, electric shock and fire, etc.

A circuit breaker or fuse (16A time delay) must be installed. Without a circuit breaker or fuse the danger of electric shock exists.
A main switch with a contact gap of more than 3mm has to be installed in the power supply line to the outdoor unit.

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

Please ensure smooth flow of water when installing the drain hose.
Piping shall be suitable supported with a maximum spacing of 1m between the supports.

CAUTION

above 50mm

above 100mm

above

0.45m

above 300mm

must not bend

above 100mm

2

7

4

5

3

9

Maximum pipe length 20m

Plug

2,300mm or more

1

THE CHOICE OF MOUNTING SITE (Please note the following matters and obtain permission from customer before installation).

!

!

0.9m

1.6m

!

Connection

Horizontally
perpendicular
to the unit

inner diameter ø 16mm

WARNING

●

The unit should be mounted at stable, non-vibratory location which can provide full support to the unit.

CAUTION

●

No nearby heat source and no obstruction near the air outlet is allowed.

●

The clearance distances from top, right and left are specified in figure below.

●

The location must be convenient for water drainage and pipe connection with the Outdoor unit.

●

To avoid interference from noise please place the unit and its remote controller at least 1m from the radio, television and inverter

INDOOR UNIT

type fluorescent lamp.

●

To avoid any error in signal transmission from the remote controller, please put the controller far away from high-frequency
machines and high-power wireless systems.

●

The installation height of indoor unit must be 2.3m or more in a non public area.

Names of Indoor Components

QtyNo. Item

Hanger

1

Screw for Hanger

2

Holder for Remote
Controller

3

AAA Size Battery

4

Screw for holder of
Remote Controller

5

Insulation pipe

6

Remote Controller

7

Purifying Filter

8

(4.1x32)

(3.1x16)

1

6

1

2

2

1

1

1

The Length of Indoor Unit

Connecting Cord

Figure showing the Installation of Indoor Unit.

Be sure to
completely
seal any
gap with
putty.

Direction of Piping

There are 4 directions allowed, namely,
horizontally perpendicular to the unit,
vertically down from right, horizontally out
from right and horizontally out to left.
Don’t form the piping downward at the
left of the unit.

CAUTION

The installation height of indoor

•

unit must be 2.3m or more in
a non public area.

Holder

9

● The difference in height between the indoor and outdoor

unit should be kept max 5m.

● The connecting pipe, no matter big or small, should all

be insulated with insulation pipe and then wrapped with
vinyl tape. (The insulator will deteriorate if it is not wrapped
with tape).

1

The connection of insulated drain hose.

Please use insulated drain hose for the
indoor piping (commercial product).

The indoor piping should be
insulated with the enclosed
insulation pipe. (If the
insulator is insufficient,
please use commercial
products).

above 50mm

above 100mm

above

0.45m

above 300mm

must not bend

above 100mm

2

7

4

5

3

9

Maximum pipe length 20m

Plug

2,300mm or more

1

!

!

!

!

!

!

0.9m

1.6m

1

!

!

!

!

!

!

!

External dimension of

indoor unit

160mm

160mm

80mm

860mm

40mm

45mm

30mm

Drain Hose

45mm

298mm

Level

Line

Hole for
pipe

Mark

Weight

Screw for Hanger

Please use more
than 4 screws.

Hanger

32mm

20mm

ø4.8mm

ø4.4mm

Wall

1 Hanger

2 Screw

Plug

Wall

above 50mm

Ceiling

4.1 x 32 Screw

Wall

Remote
Control
Holder

5 Screw

Plug

3

Sleeve of
protection
pipe

WALL

Protection
pipe

Seal with
putty

Seal with
putty

2 ~ 5mm

OutdoorIndoor

Connecting cords,
pipe and drain hose
must be tied together
with Vinyl tape.

Hanger

Hook

Refrigerating
Pipe

Connecting
Cord

Drain Hose

Protection
Pipe

Lift the body
of the unit
upwards and
then force
it downwards.

Hanger

Projection

Screw driver

Claw of indoor unit

Circle hole

2

1

!

Drain hoseDrain cap

Drain cap

Please insert
until here

Drain hose

Please insert
until here

Pipe
support

Pull up the pipe after
bending downward

Openings

Pipe

Connecting cord

Drain hose

Insulation pipe (must be wrapped with
vinyl tape at every 120mm).

Holder

9

Insulation pipe

6

Pipe

Rubber strap tied with great force

below
5mm

Please bend at a small
radius to form an arc

about 15cm

Projection

Temporary stand

Connected
section

Holder

Connecting cord

Drain hose

Protection

pipe

Bending
upwards

Condensed
water pond

Ditch

Condensed
water pond

!

Connection

Horizontally
perpendicular
to the unit

inner diameter ø 16mm

HFC

R410A

Installation of Hanger, Wall Penetration and Installation of Protection Pipe

CAUTION

●

The draining of the water container inside the indoor unit can be done from the left.
Therefore the hanger must be fixed horizontally or slightly tilted towards the side of
drain hose. Otherwise, condensed water may overflow the water container.

Direct Mounting On The Wall

●

Please use hidden beams in the wall to hold the hanger.

Procedures of Installation and Precautions

●

Procedures to fix the hanger.

1. Drill holes on wall. 2. Push plug into the holes. 3. Fix the hanger on wall
(As shown below) (As shown below) with 4.1 x 32 screw

(As shown in figure below)

INDOOR UNIT

●

Procedures to fix the holder of remote control.

1. Drill holes on wall. 2. Push plug into the holes.
(As shown below) (As shown below)

2

Installation of the Indoor Unit

VERTICALLY DOWNWARD PIPING

Preparation

●

Connect connecting cord.

●

Pull out the pipe, connecting cord and drain hose.

Installation

●

The upper part of the Indoor unit is hanged on the hanger.

●

The projection at the lower part of the Indoor unit is hooked onto the hanger.

CAUTION

Please pull the lower part of
the Indoor unit outwards to
check if the unit is hooked
onto the hanger. Improper
installation may cause
vibration and noise.

HOW TO REMOVE INDOOR UNIT FROM HANGER

●

Pull down PULL section on the bottom of indoor
unit and pull it towards you, then claws are
released from hanger. (Indicated by 2 arrows in
the drawing on the right.)

●

When bottom face of indoor unit cannot be
pulled due to obstacles, etc. Remove front cover,
insert screw driver into circle hole, pull claws
down and pull indoor unit towards you.

●

Please check how to remove and attach front
cover in this instruction manual.

HORIZONTAL PIPING

Preparation

Change of Drain Hose and Installation Procedures.

●

Exchange the location of drain hose and drain cap during horizontal piping as shown in
figure below. Be sure to plug in the drain hose until the insulating material folds upon itself.

●

Please use pliers to pull out the drain cap.
(This is an easier way to remove the drain cap).

INSTALLATION OF REFRIGERATING PIPES AFTER CONNECTION

●

The refrigerating pipes should be adjusted to fit into
the hole on the wall and then ready for further
connection.

●

The terminals of 2 connected pipes must be covered
with insulator used for terminal connection. Then the
pipes are wrapped with insulation pipe.

●

Connect the connecting cord after removing electrical
cover. (Refer to “CONNECTION OF POWER CORD”)

●

After adjustment, fit the connecting cord and pipes
into the space available under the indoor unit. Use
holder to hold them tight.

CAUTION

●

The rubber strap used for
fixing the insulator should
not be tied with great force.
Otherwise, this will damage
heat insulation and causes
water condensation.

●

Holder can be attached at the either of 2 places.
Please select the easier position.

THE CONNECTION OF REFRIGERATING PIPE DURING THE
INSTALLATION OF INDOOR UNIT

Preparation To Install Refrigerating Pipes

●

The refrigerating pipes and connecting cord
transform and are attached.

●

The end of the refrigerating pipes are at locations
marked with “

 ” symbol.

Installation

Hang the Indoor unit onto the hanger. Use the temporary stand
at the back of the Indoor unit to push its lower part 15cm
forwards.

●

Place the drain hose through the hole on the wall.

●

Wrap the refrigerating pipes with insulation pipe after
connecting refrigerating pipe.

●

Connect the connecting cord after removing electrical cover.
(Refer to “Connection of Power Cord”)

●

After adjustment, the connecting cord and refrigerating pipes
are placed into the space available under the Indoor unit.

●

The projection of Indoor unit must hook to the hanger.

CAUTION

●

Please fix in the plastic core
after flaring to avoid plastic
chips entering the pipes.

Wall Penetration and Installation of Protection Pipe

●

Drill a ø 65mm hole on
wall which is slightly tilted
towards the outdoor side.
Drill the wall at a small
angle.

●

Cut the protection pipe
according to the wall
thickness.

●

Empty gap in the sleeve
of protection pipe should
be completely sealed
with putty to avoid
dripping of rain water into
the room.

<

I477: A

>

WARNING

Be sure that the wire is not
in contact with any metal
in the wall. Please use the
protection pipe as wire
passing through the hollow
part of the wall so as to
prevent the possibility of
damaged by mouse.
Unless it seals completely,
any air with high humidity
flows from outdoor and
any dew may drop.

CAUTION

Condensed water may leak out if not inserted properly.

HORIZONTAL & DOWNWARD PIPING – MAKING OPENINGS

●

During horizontal or downward piping, use a knife to cut
openings as shown in figure. Then smoothen the edges of
openings with a file.

●

Turn the piping while holding down the lower
portion of pipe-support by hand.

Heat insulation pipe

Connecting
cord

Refrigerating pipe

3

Installation of Drain Hose

Pull this to the front
during the connection
of refrigerating pipes
to ease task.

You are free to choose the side (left or right) for the installation of drain

CAUTION

hose. Please ensure the smooth flow of condensed water of the Indoor
unit during installation. (Carelessness may result in water leakage.)

CAUTION

Be sure that the
drain hose is not
loosely connected
or bend.

1

!

!

Copper pipe

Trimming tool

A

Die

Die

Copper pipe

Wrench

Torque
wrench

Flare nut

!

Lo Hi

The body of
service valve

Cap of

valve core
Hexagonal
Wrench Key

Cap of valve head

Cap of valve head

30mm

10mm

10mm

70mm

!

CD

AUTO
RESTART
SWITCH

Preparation of Pipe

●

Use a pipe cutter to cut the copper pipe.

CAUTION

●

Jagged edge will cause leakage.

●

Point the side to be trimmed downwards during trimming to
prevent copper chips from entering the pipe.

●

Before flaring, please put on the flare nut.

●

Recommend to use
R410A flaring tool.

Outer
Diameter (mm)

INSTALLATION OF REFRIGERATING PIPES AND AIR REMOVAL

6.35

9.52

12.7

For R410A tool

0.0

0.5mm

~

0.0

0.5mm

~

0.0

0.5mm

~

A (mm)

For R22 tool

1.0mm

1.0mm

1.0mm

2

Pipe Connection

CAUTION

Small dia. side
Large dia. side

Small dia. side

Valve

head cap

Valve core cap

Large dia. side

In case of removing flare nut of an
Indoor unit, first remove a nut of small
diameter side, or a seal cap of big
diameter side will fly out. Prevent
water from entering into the piping
when working.

Outer

dia.of pipe

6.35 (1/4")

9.52 (3/8")

12.7 (1/2")

6.35 (1/4")

9.52 (3/8")

12.7 (1/2")

Torque N·m

(kgf · cm)

13.7 – 18.6 (140 – 190)

34.3 – 44.1 (350 – 450)

44.1 – 53.9 (450 – 550)

19.6 – 24.5 (200 ~ 250)

19.6 – 24.5 (200 ~ 250)

29.4 – 34.3 (300 – 350)

12.3 – 15.7 (125 ~ 160)

3

Removal Of Air From The Pipe And Gas Leakage Inspection

Procedures of using Vacuum Pump for Air Removal

As shown in right figure, remove the cap of valve core. Then, connect the charge
hose. Remove the cap of valve head. Connect the vacuum pump adapter to the

1

vacuum pump and connect the charge hose to the adapter.

Fully tighten the “Hi” shuttle of the manifold valve and completely unscrew the
“Lo” shuttle. Run the vacuum pump for about 10–15 minutes, then completely

2

tighten the “Lo” shuttle and switch off the vacuum pump.

Completely unscrew the spindle of the service valve (at 2 places) in anti-clockwise

3

AIR REMOVAL

direction to allow the flow of coolant (using Hexagonal Wrench key).

Remove the charge hose and tighten the cap of valve head. Check the cap’s

4

periphery if there is any gas leakage. The task is then completed.

Gas Leakage Inspection

Please use gas leakage detector to check if leakage
occurs at the connection of Flare nut as shown on
the right.

If gas leakage occurs, further tighten the connection
to stop leakage. (Use the detector provided for
R410A).

When the meter reaches - 101KPa
(-76cmHg) during pumping, fully
tighten the shuttle.

Valve

When pumping starts, slightly loosen the
flare nut to check of air sucked in. Then
tighten the flare nut.

Meter showing pressure

Charge hose

Vacuum pump
adapter

Valve

Closed
R410A

Manifold valve

Vacuum
pump

●

WARNING

THIS APPLIANCE MUST BE EARTHED.

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

Procedures of Wiring

In case that power is supplied from Indoor Unit

Indoor Unit

GRN + YEL

Strip wires

WARNING

●

The naked part of the wire core should be 10 mm and fix it to the terminal tightly. Then try to pull the
individual wire to check if the contact is tight. Improper insertion may burn the terminal.

●

Be sure to use only power cables approved from the authorities in your country. For example in Germany:
Cable type: NYM 3x1.5mm

CONNECTION OF POWER CORD

●

Please refer to the installation manual for wire connection to the terminals of the units. The cabling must
meet the standards of electrical installation.

●

There is a AC voltage of 230V between the L and N terminals. Therefore, before servicing, be sure to
remove the plug from the AC outlet or switch off the main switch.

2

.

Wiring Of The Indoor Unit

●

For wire connection of the Indoor unit, you need to remove front panel and electrical cover.

Method to remove front panel

●

Refer to “FINAL STAGE OF INSTALLATION – How to Remove The Front Cover”.

Method to remove electrical cover

●

Remove the screw and electrical cover.

●

Insert the connecting cord (C, D) from the bottom of
unit.

●

Fixed the wire to terminal wires firmly as shown in
figure at right side.

Electrical cover

Screw

Connect the
earth cord

After remove the screw
and band, put the
connecting cords and fix
the band with screw.

Checking for the electric source and the voltage range

●

Before installation, the power source must be checked and necessary wiring work must be completed. To make the wiring capacity proper, use the wire
gauges list below for the lead-in from a pole transformer and for the wiring from a switch board of fuse box to the main switch and outdoor unit in
consideration of the locked rotor current.

IMPORTANT

Cable length

up to 16m
up to 15m
up to 25m

Wire cross-section

2

1.5mm

2

2.5mm

2

4.0mm

1

!

!

!

Copper pipe

Trimming tool

A

Die

Die

Copper pipe

Wrench

Torque
wrench

Flare nut

Sleeve of
protection pipe

Putty

Putty

Insulation material for pipe connection

Remote

Controller

Holder for
Remote Controller

Screw (2 pieces)

1

2

!

Lo Hi

The body of
service valve

Cap of

valve core
Hexagonal
Wrench Key

Cap of valve head

Cap of valve head

30mm

10mm

10mm

70mm

!

CD

AUTO
RESTART
SWITCH

Insulation And Maintenance Of Pipe Connection

●

The connected terminals should be completely sealed with
heat insulator and then tied up with rubber strap.

●

Please tie the pipe and power line together with vinyl tape as
shown in the figure showing the installation of Indoor and
Outdoor units. Then fix their position with holders.

●

To enchance the heat insulation and to prevent water
condensation, please cover the outdoor part of the drain hose
and pipe with insulation pipe.

●

Completely seal any gap with putty.

3

Power Source And Operation Test

Power Source

FINAL STAGE OF INSTALLATION

●

Please use a new socket. Accident may occur due to the use of old
socket because of poor contact.

●

Please plug in and then remove the plug for 2 – 3 times. This is to
ensure that the plug is completely plugged into the socket.

●

Keep additional length for the power cord and do not render the
plug under external force as this may cause poor contact.

●

Do not fix the power cord with U-shape nail.

CAUTION

2

Installation Of Remote Controller

●

The remote controller can be placed in its holder which is
fixed on wall or beam.

●

To operate the remote controller at its holder, please ensure
that the unit can receive signal transmitted from the controller
at the place where the holder is to be fixed. The unit will beep
when signal is received from the remote controller. The signal
transmission is weaken by the fluorescent light. Therefore,
during the installation of the remote control holder, please
switch on the light, even during day time, to determine the
mounting location of the holder.

The controller must
be hooked onto the
hook at the lower
part of the holder.
Push in the remote
controller in the
direction as shown
in figure below.

Operation Test

●

Please ensure that the air conditioner is in normal
operating condition during the operation test.

●

Explain to your customer the proper operation
procedures as described in the user’s manual.

How to Remove The Front Cover

1 Remove the front panel.

●

Please remove and attach the front panel by both hands.

●

After opening the front panel by both hands.

11

Undo the right arm while pushing it inside.

1

11
22

2

Slide the front panel to right as shown in figure. Then

22

remove while pulling it to front.
2 Remove the filters.
3 Remove the caps and screws at the lower portion of the

front cover.

Cap

Screw

4 Pull the front cover upward as far as the location where

the lower portion of the front cover is on the deflector.

Lower portion of front cover

5 Remove while pulling the front cover in direction to arrow

as shown in figure to hold the both sides of front cover.

Deflector

How to Attach the Front Cover

11

1

After covering the front cover to the unit, certainly hook at

11

the upper portion (three places). Then, check that the drain
pan is certainly attached. Push the center of front cover in
the direction of arrow.

22

2

Fix the front cover at lower portion by screws and attach

22

the caps.

33

3

Attach the front panel.

33

●

Certainly insert the left shaft of the front panel to the hole
of the front cover. Next insert the right shaft as same as
the left.

44

4

Attach the filters which are placed the surface written

44

“FRONT” up.

●

After attaching the filters, push the front panel at three
arrow portion as shown in figure and close it.

Hole

Shaft

Guide

<

I477: A

>

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.

– 1 –

WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS

1. Scope
The standards provide for items to be generally observed in carrying and handling semiconductors in relative
manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal goods
such as rejected goods being returned).

2. Object parts
(1) Micro computer

(2) Integrated circuits (IC)
(3) Field-effect transistors (FET)
(4) P.C. boards or the like on which the parts mentioned in (1) and (2) of this paragraph are equipped.

3. Items to be observed in handling
(1) Use a conductive container for carrying and storing of parts. (Even rejected goods should be handled in

the same way).

A conductive polyvinyl bag

IC

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.

IC

Conductive sponge

Body earth
(Elimik conductive band)

1M

Fig. 2. Body Earth

Clip for connection with a
grounding wire

– 2 –

(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

2

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

– 3 –

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.

– 4 –

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

NO

NO

–

NO

NO

NO

NO

NO

NO

YES

40 W

NO

NO

JU1012D JU1013D

NO

YES

YES

3.0A

G4A

NO

NO

SERVICE SWITCH

TRANSFORMER

VARISTOR

NOISE SUPPRESSOR

THERMOSTAT

REMOTE CONTROL SWITCH (LIQUID CRYSTAL)

REFRIGERANT CHARGING
VOLUME
(Refrigerant 410A)

UNIT

PIPES (MAX. 20m)

NO

NO

NO

NO

YES(IC)

YES

----------

WITHOUT REFRIGERANT BECAUSE

COUPLING IS FLARE TYPE.

450NR

YES(IC)

1150g1150g

YES

NO

YES

NO

1400g

– 5 –

CONSTRUCTION AND DIMENSIONAL DIAGRAM

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

Air suction grill

Mounting plate

183

860

Top air suction grill

Front panel

Cabinet

285

About

380

350

About

View from back

(Pipe lead-out)

6.5 60

47

47

31 120.5

Drain outlet

60 60

240 170450

Horizontal deflectorDischarge grill

Drain hose

Hole on the wall
for ø 65mm pipe

P

47

Drain

Narrow pipe

Vertical deflector

7070140

Drain cap
connection port

147

56 17.5

28

47

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

6.5 60

Connecting cable

– 6 –

Wide pipe

CONSTRUCTION AND DIMENSIONAL DIAGRAM FOR OUTDOOR

MODEL RAC-25NH4, RAC-35NH4

852

28 750

16556

76

559

570

195

95

2616 280

166

MODEL RAC-50NH4

10464

Handle

Air suction
grille

955

26 850

Air outlet

79

638

650

340

201

280

2022 298

Handle

96

340

169.5

Fixing hole

Holes for anchor bolt
(2-ø12)

507 198

Notch for anchor bolt
(2-ø12 Notchs)

12
37

57

10

1010

320

340

– 7 –

More than

100

700

More than

100

More than

Service space

More than

100

MAIN PARTS COMPONENT

RED

360V

BLK

0V

WHT

15V

M

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

16

INDICATION

24

INDICATION

32

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

FG

RAC-25NH4, RAC-35NH4,

RAK-50NH4

DC360V

40W

M

(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

– 8 –

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

M

M

M

(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.

– 9 –

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

M

WHT YEL

RED

WHT YEL

YEL

YEL

YEL

DIODE
STACK

RED

UVW

REACTOR

SYSTEM POWER

MODULE 2

L2
L1

CN14

CN13

CN11

C503

C502C501

10

CN14

CN10
RED

CN9
BLU

CN8
WHT

CN15
WHT

CN13

CN11

5

5

CN12

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

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

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

M

M

INDOOR

FAN MOTOR

WIRELESS

REMOTE CONTROLLER

RECEIVER

P. C. B.

CN3A

CN2A

OUTDOOR UNIT

CN2

LED

P. C. B.

– 10 –

CIRCUIT DIAGRAM

Remote Control

Key matrix table

1

SEG5

2

SEG0

3

SEG1

4

SEG2

5

SEG3
SEG4

6
7

SEG5

8

SEG6

9

SEG7

10

COM3

11

COM2

12

COM1

13

COM0

14

SEG14

15

SEG13

16

SEG12

17

SEG11

18

SEG13

19

SEG9

20

SEG8

D3
RB425D(1/2)

C8

50v/1u

LCD 1

K 1

K2K3

K4

K5

P10

P11

K6

K7 K8

K9 K10

K11K12

SEG20
SEG19
SEG18
SEG17
SEG16
SEG21

SEG27
SEG28

P12

SEG24
SEG25
SEG26

NC
NC
NC
NC
NC
NC
NC

NC

NC

K13 K14

K15 K16

K17

K18

40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21

D0

D1

D2

D3

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

64

SEG20
SEG21
SEG22
SEG23
SEG24
SEG25
SEG26
SEG27
SEG28
SEG29
SEG30
SEG31
SEG32
SEG33
SEG34
SEG35

1

62

63

SEG19

SEG18

P41

P40

3

2

R1

100k

60

61

SEG17

SEG16

P42

P43

5

4

59

58

57

54

SEG14

SEG15

IC 1

56

SEG13

SEG12

55

SEG11

SEG10

SEG9

53

52

51

SEG8

SEG7

50

49

SEG5

SEG6

M3455OM6A-504FP

D2

P00

6

P01

7

P02

8

P03

9

P10

10

P11

11

P12

12

P13

13

D0

14

D1

15

16

48 47

SEG4

D3

17 18

SEG3

D5

D4

45

46

SEG1

SEG2

D6

20

19

Input

P10

P11

P12

43

44

42

SEG0

SEG42

SEG43

NCVL C1

XC OUT

D7

D9

D8

BEEP

22

21

23

SW1

SW-187-2P

Output

D0

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

41

SEG41

SEG40

40

P30
P31

39
38
37

VL C2
VL C3

36
35

XC IN

34
33

VDD

32

VSS

X OUT

31

X IN

30
29

RESET

28

CARR

27

P23

26

P22

25

24

P21

P20

R2

100k

R3

100k

R5

330

P

R4

100k

R6

D1 D2

EL-1L7

D2D1

R8

R7

R6 R9

24(1/8W)

Q1

2SC3443

or 2SC2982

R9

R10
12M

D3

RB425D

(1/2)

K19

X1

910kHz

C9

105

R11

150k

X2

32.768

kHz

C6

104

• present timeHour downHour upOn timer

D3D2D1

R14
220k

220K

R13

C7

104

R15

100k

R16
100k

C1

334

C2

220p

C3

220p

C4

18p

C5
22p

R12

220k

– 11 –

CIRCUIT DIAGRAM

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

– 12 –

CIRCUIT DIAGRAM

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

– 13 –

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

1

IVORY

CN5

8
4

1

CN1

WHT

C621

C751

C132

C131 R111

ICP2

1

1

IC402

J29

J30

J17

R631
L751

R751

R114

Q113

R121
ICP1

WHT

CN4

CN8
WHT

J31

J18

J19

J10

5

IVORY

ZD131

Q111

R122

IC111

R112 C112

C111

ZD111

R125

R126

J20

CN6

4

5

BZ

J39

RES1

J33

J32

J34

J11

J12

1

1

HB-098-101A

Q131

C133

R132

Q112

D111

R115

Q115

C103

D821

C823
R825
R823
C822

IVORY

1

CN14

1

J52
J46
J44

J51
J50

J45

J42

J43

J49
J48

J40

J41

J21
J22

J14
J13

J15

CN9

4

BLK

ZD211

R201

R131

ZD121

C123

Q114

C113 R117

R828

R829

R826

R824

R822

1

IC801

4
Q801

R812
J72

Q821

C763

R612

R764

R609

R830

C115

J78

C651

C825

R118

R651

Q803

R119

R761

R120

R658

ID

8

C801

R804

C121

C116

R116
R124

Q116

R123

J79

R827

R821

C803
C804

J801

L801

R806
R805
R803

J16

J23

R811

4

J35

J24

R701

REG2

J37

J36

R606

32

33

R657

R610

C507

R807

R810

C631

R656

R503

J76

R403

J47

R605

R404

Q802

J53

J38

IC501

R500

R654

5

R763

R504

R813

J54

J25

C821

ICP3C762

R219

R653

WHT

CN11

J55

R743

R604

R603

17

C601

R505

1

C114

C122

J26

J27

C802

J83

Q722

R745

R742

R744R741

R611

C506

16

R501

R602

C824

R641

R601

J75

R652

J71

AUTO RESTART
CANCEL

L111

R506

R508
L501

R502

C501

C611

R514

R507

R655

IC711

C524

R746

C521

R509

J82

1

R515

R510

HB–098–101A

J56

L101

C101

D101

13

L743 L742 L741

16

J81

1

C522

IC521

R521

R522

C505
C304
R307

C302

R511

R512

R513

J74

R308

C104
R127

C502

Q521

D402

R650

C102

CN12

WHT

C711

R305

C523

C401

R128

F

No.
Lot

J28

J80

R301

1

CN10

IVORY

6

9

R749

8

R748
R747

IC401

R401

R402

J77

D403

D401

R306
C303
R303

J73

R302

J70

RECEIVING P.W.B.

Marking on P.W.B.

Lot No.

IR1

1 14

J57

C1

IVORY

CN2A

IVORY
CN3A

COMPONENT SIDE

F

SW1

9

HB-098-102A

– 14 –

R1

R2

SOLDERING SIDE

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

COMPONENT SIDE

– 15 –

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

– 16 –

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

Hi

Med

Fan speed mode (indoor fan)

Lo

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

Lo

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.

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

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

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 .

v

v

(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):

Room temparature at

operation start (˚C)

Cooling
Dehumidifying

Heating

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.

– 17 –

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

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–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

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–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

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–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

– 18 –

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

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

Note:

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

– 19 –

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

Hi

Indoor
fan

New cool rhythm

Outdoor fan

Lo

Rhythm Med

Rhythm Lo

Med

Room temperature

See basic operation.

Lo

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.

5min.

Minimum

5min.

Thermo OFF

15 sec.

Minimum

5min.5min.

5min.

Lo

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

Hi

Med

Lo (sleep)

Shut

Horizontal

Facing down

See basic operation

Lo

Set to 7 hours

0.5hr

1.5hr

2.5hr 3.5hr 6hr 7hr

3hr

Maximum speed

P1

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

– 20 –

+

+

–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.

– 21 –

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

0

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

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.

15sec.

Control by
heat exchanger temperature

3min.

Hi

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

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

–1

Notes:

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

– 22 –

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.

– 23 –

REFRIGERATING CYCLE DIAGRAM

MODEL RAK-25NH4 / RAC-25NH4

RAK-35NH4 / RAC-35NH4

COOLING, DEHUMIDIFYING, DEFROSTING
OUTDOOR UNIT

STRAINER

CHARGING PIPE

ELECTRIC
EXP ANSION VAL VE

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 VAL VE

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)

– 24 –

REFRIGERATING CYCLE DIAGRAM

MODEL RAK-50NH4 / RAC-50NH4

COOLING, DEHUMIDIFYING, DEFROSTING
OUTDOOR UNIT

ELECTRIC
EXP ANSION VAL VE

STRAINER

STRAINER

COMPRESSOR

REVERSING
VALVE

SERVICE V ALVE

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 VAL VE

STRAINER

STRAINER

COMPRESSOR

REVERSING
VALVE

SERVICE V ALVE

SERVICE V ALVE

SUCTION
TANK

(1/4)

(1/2)

INDOOR UNIT

SINGLE-ENDED
UNION (1/2)

SINGLE-ENDED
UNION (1/4)

– 25 –

AUTO SWING FUNCTION

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

PRESENT CONDITION

INPUT SIGNAL

OPERATION OPERATION MODE AIR DEFLECTOR

OPERATING SPECIFICATION

REFERENCE

ONE SWING (CLOSING AIR DEFLECTOR)

KEY INPUT

STOP

DURING
OPERATION

– 26 –

THERMO. ON
(INTERNAL FAN
ON)

THERMO. ON
(INTERNAL FAN
OFF)

DURING
OPERATION

EACH MODE

AUTO COOL
COOL
FAN
AUTO DRY
DRY

AUTO HEAT
HEAT
CIRCULATOR

AUTO DRY
DRY
AUTO HAET
HEAT

CIRCULATOR

STOP

DURING ONE SWING

STOP

DURING SWINGING

STOP

DURING SWINGING

TEMPORARY STOP

DURING SWINGING

1 DOWNWARD
2 UPWARD

STOP AT THE MOMENT.

START SWINGING
1 DOWNWARD
2 UPWARD
3 DOWNWARD

STOP AT THE MOMENT.

START SWINGING
1 DOWNWARD
2 UPWARD
3 DOWNWARD

STOP AT THE MOMENT.

START SWING AGAIN.

STOP SWINGING TEMPORARILY.
(SWING MODE IS CLEARED IF SWING COMMAND IS
TRANSMITTED DURING TEMPORARY STOP.)

INITIALIZE AT NEXT
OPERATION.

MAIN SWITCH
ON

MAIN SWITCH
OFF

CHANGE OF
OPERATION

STOP

DURING
OPERATION

DURING
OPERATION

COOL
FAN

DRY
HEAT

CIRCULATOR

EACH MODE

EACH MODE

STOP
DURING ONE SWING

STOP
DURING ONE SWING

STOP
DURING SWINGING

DURING
INITIALIZING

STOP

DURING SWINGING

INITIALIZE
1 DOWNWARD
2 UPWARD

INITIALIZE
1 DOWNWARD

ONE SWING (CLOSING AIR DEFLECTOR)
1 DOWNWARD
2 UPWARD

INITIALIZING CONDITION OF EACH MODE.
STOP SWINGING AND MODE BECOMES INITIALIZING

CONDITION.

INITIALIZE AT NEXT
OPERATION.

DESCRIPTION OF MAIN CIRCUIT OPERATION

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

1. Reset Circuit

5V

2

R522

1

C521

R521

5

C524

NORMAL : HI
RESET : LO

RES

7

Microcomputer

C522

Voltage

Voltage supply to

2

pin

of IC521

Reset release at 4.4V

3

IC521

0V

Fig. 1-1

5.0V

Reset enter at 4.2V

voltage

Voltage at pin
of microcomputer

7

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.

– 27 –

2. Receiver Circuit

12V

C1

▲

ZD211

0V

R1

IR1

VDD

GND

R2 R611

V

out

C611

0V

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

30

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

30

Fig. 3-1 Buzzer Circuit

Metal diaphragm

BZ

0V

BZ1

Q722

Pizoelectric element

Sound wave

– 28 –

V

Fig. 3-2 Buzzer Operation

V

4. Auto Sweep Motor Circuit

12V

IC711

Auto sweep motor for
horizontal air defectors

9

Microcomputer

18
17
16

15

C711

7
6
5

4

10

11
12

13

Rotor

8

0V

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

15

16

17

18

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

– 29 –

5. Room Temperature Thermistor Circuit

5

4

3

2

1

0

010

Room temperature (˚C)

Fig. 5-2

20 30 40

0V

Room
temperature
thermistor

0V

5V

Fig. 5-1

62

A

R305

C302

Microcomputer

Room
temp. input

Voltage at

(V)

R301

0V

Heat exchanger
temperature thermistor

0V

5V

Fig. 6-1

61

A

R306

C303

Microcomputer

Heat
exchanger
temperature
input

R302

A

5

4

3

2

1

0

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

A

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

A

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

– 30 –

7. Initial Setting Circuit (IC401)

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

2

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 5V

1
2
3
4

IC401 or IC402 (E

0V

8
7
6
5

2

0V

PROM)

C401

0V

R404

R403

27
26

SCL
SDA

Microcomputer

External ROM

}

Fig. 7-1

– 31 –

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

1. Power Circuit

TERMINAL

BOARD

L

N

25A FUSE

SURGE­ABSORBER

VARISTOR3

L001

NF COIL1

C001

VARISTOR1

C003

C002

CT1
C009

0V

0V

COIL

C004C005

R001

C006

POWER RELAY

R007

R008

ICP RELAY

DIODE

STACK 1

(D25VB60)

SPM2

TB8

TB2

REACTOR

L1 L2

TB7 TB6

TB10

U

Vdba

N1

P1

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.

– 32 –

(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

a

b

DC voltage

Vd

(approx. 260-360V during operation)

OV

OV

OV

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.

– 33 –

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.

– 34 –

● 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

5V

C804

0V

C821 R821

Terminal board

CD

CD

Terminal board

R813

R812

Q803

C822

0V

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

1

R805

IC801

7

R806

C823

R826
D821

5V

R828

5V

0V

0V

R803

R804

Q821

5V

0V

R829

R830

Q801

0V

HIC

C824

IF transmit

50

output (SDO)

MICROCOMPUTER

IF receive

49

input (SDI)

5

6

C801

0V

R827

0V

Interface
relay

0V

L802

12V

C811

C812

C807

C808

0V

L801

C801

0V

C806

NF COIL2

5V

C809

C810

I/F 0V

R801

R802 Q801

29

C802

IF transmit

11

output (SDO)

0V

0V0V

0V

30

R803

5V

0V

5V 5V

0V

0V

0V

5V

0V

MICROCOMPUTER

68

0V

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

– 35 –

Outdoor HIC

Pin

Pin

0.7V

30

29

0V

5V
0V

Indoor microcomputer

DC 35V line

Pin

Pin

50

49

100ms.
Leader

33ms.
1 frame

5V
0V

5V
0V

35V

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

Outdoor HIC

Pin

30

0V

29

Indoor microcomputer

DC 35V line

Pin

Pin

Pin

50

49

4.95ms.
Transmit / receive
switching time

33ms.
1 frame

5V
0V

5V
0V

5V
0V

35V

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

– 36 –

[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.

0

(33.3ms.)

1

(33.3ms.)

2

(33.3ms.)

3

(33.3ms.)

Character No.

0

(33.3ms.)

1

(33.3ms.)

2

(33.3ms.)

3

(33.3ms.)

Bit No = 0

Bit No = 0

07

0707077

07077

Leader

(100ms.)

When reset

(approx. 10ms.)

Leader

(100ms.)

– 37 –

Fig. 2-4

[ Serial Communications Data ]

(1) Outdoor message

Character No.

Bit No.

Contents

– 38 –

Data

(2) Indoor message

Character No.

Bit No.

1

0

Multi-bit

1/0

Operation mode (0 LSB)

1/0

0

1

0

Operation mode (1)

0

0

7

6

5

4

3

2

Outside temperature (0 LSB)

Self-diagnosis (3 MSB)

Self-diagnosis (2)

Self-diagnosis (1)

Self-diagnosis (0 LSB)

Defrost request signal

During forced operation

1/0

1/0

3

2

Indoor in-operation bit

Operation mode (2 MSB)

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

0

7

6

5

4

Fan (0 LSB)

Capacity code (3 MSB)

Capacity code (2)

Capacity code (1)

Capacity code (0 LSB)

1

6

5

4

3

2

1

Outside temperature (6)

Outside temperature (5)

Outside temperature (4)

Outside temperature (3)

Outside temperature (2)

Outside temperature (1

1

6

5

4

3

2

1

Reversing valve

2-way valve

Fan (2 MSB)

Fan (1

2

7

6

5

4

3

2

1

0

7

Actual compressor rotation speed (5 MSB)

Actual compressor rotation speed (4)

Actual compressor rotation speed (3)

Actual compressor rotation speed (2)

Actual compressor rotation speed (1)

Actual compressor rotation speed (0 LSB)

Compressor during operation

Compressor during operation

Outside temperature (7 MSB)

1/0

1/0

1/0

1/0

2

7

6

5

4

3

2

1

0

7

Compressor command speed (0 LSB)

Compressor ON

Compressor command speed (1)

Compressor command speed (2)

Compressor command speed (3)

Compressor command speed (4)

Compressor command speed (5)

Compressor command speed (6)

Compressor command speed (7 MSB)

3

2

1

0

Fan-7-step request

0

0

1

0

3

2

1

0

OVL up

15/20(A)

Compressor minimum rotation speed (0 LSB)

3

7

6

5

4

0

0

0

0

3

7

6

5

4

Compressor minimum rotation speed (4 MSB)

Compressor minimum rotation speed (3)

Compressor minimum rotation speed (2)

Compressor minimum rotation speed (1)

Contents

Data

1/0

1/0

1/0

1/0

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

1/0

1/0

1/0

1/0

1/0

1/0

1/0

1/0

1/0

1/0

1/0

1/0

3. Power Module Circuit

+

W

U
V
W

W

–

+

V

V

–

+

U

U

–

A

+

DC
Compressor
motor

U coil

V coil

W coil

System Power module 2

+

–

C501

+

–

C502

+

–

C503

R24

0.35mH

Power relay

Coil

R007

R008

Inrush current
protection
relay

C006

R001

Noise filter
coil

L

N

Terminal
board

FUSE (25A)

●

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.

– 39 –

Fig. 3-1 Power module circuit (U

+

is ON, V

–

is ON)

● 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)

[]

E

F

+

Upper arm
transistor

++T+

UVVW

Lower arm
transistor

–

U

–

V

–

W

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

A

-

U transistor ON

Upper arm transistor

Current at

B

Chopping period

ON

T

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)

B

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

diode [ Point (Fig. 3-4)

A

B

– 40 –

260V-360V

+

System Power Module 2

+

U

B

R24

_

—

U

+

V

—

V

+

W

—

W

A

U
V
W

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

B

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

<Reference>

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

LD301

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.

– 41 –

4. Power Circuit for P.W.B.

22

18

19

+

D908

R917

R915

D909

R918

L903

REG1

C911

20

21

+

D907

C910

R914

C912

16

17

+

C903

C907

+

+

C914

14

13

R916

L902

35V

17V

5V

FM–15V

I/F0V

0V

0V

0V

FM–0V

C913

D910

REG2

Q706

C924

R920

R921

R922

PQ2

1

1

2

4
3

4

3

1

2

2

3

PQ1

VR1

R923

C906

C918

R911

D906

C908

PQ1

12

C

11

D904

R908

R909

D903

D905

D911

R910

R901

C901

R902

R903

R002

Diode stack 2

(RC2)

R904

2

5

3

4

1

+

+

IC901

C011

C010

R011

R010

C905

D902

R906

L901

R907

Switching transformer (T1)

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

1

9

+

C919

+

C921

C920

12V

D912

R919

R925

R924 ZD904

C909

15

1

2

JW8

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.

4

C

– 42 –

(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.

<Reference>

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.]

– 43 –

5. Reversing valve control circuit

I/F 35V

Reversing
valve

DC voltmeter
or tester

5V

CN2

3

1

V

I/F 0V

FUSE RESISTOR

D702

Q701

R701

R702

4

1

PQ701

23

R703

Q705

16

0V

HIC

R219

24

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

– 44 –

6. Rotor magnetic pole position detection circuit

0V
0V
0V

R601

C605
C606
C607

18
19
20

Outdoor microcomputer

R602

C501

+5V

R603

C

D
E

C502

C608

0V

C503

+12V

HIC

System power module

B

36

R604
R605
R606

R607

R604

R603

R602

WV U

33

34

R608

R611

DC brushless
motor for compressor

A

0V

47

35

R610

R609

U phase
terminal voltage

Spike voltage

Pole position
detection signal

Drive signal

No power
supplied

60 120 60 120

A

C

D

E

+

W

Upper armONNo power

(B) reference
voltage (1/2Vd)

Detection point

+

U

—

V

W

supplied

Induced voltage

Comparing process

+

V

—

Lower arm

ON

—

U

No power
supplied

60

+

W

Vd 150~330

+

U

—

V

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

D

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

E

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

D

and point

– 45 –

7. Drive Circuit

6

5

4

3

2

1

MICROCOMPUTER

A

R512

R521

R511

R510

R509

R508

R507

10

9

4

3

2

1

8

7

6

5

1

13

14

15

16

17

18

1

23

11

8

7

5

4

10

6

3

9

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

19

20

21

2

3

4

5

6

7

8

9

10

12

22

B

B

B

45

44

43

42

41

38

39

40

46

IP CUTTER Id CONTROL CIRCUIT

0V

17V

R501

C404

CN14

17V

0V

PWB (MAIN)

SPM2

0V

17V

U

+

V

+

W

+

U

–

V

–

W

–

IP

Id

IC1

VCC

VCU

PGU

U

VCV

PGV

V

VCW

PGW

W

NGU

NGV

NGW

SVT

SWT

SUB

SVB

SWB

F

OC

CB

A

0

A

–

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

P2

N1

HIC

–

+

GRY

R24

U

COMPRESSOR MOTOR

V

W

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

th

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.

●

– 46 –

[Low speed rotation mode]

+

U

-

V

5V

+

U

0V

+

V

+

W

-

U

-

V

-

W

15V

+

U

0V

+

V

+

W

-

U

-

V

-

W

Drive signal at point B Drive signal at point A

W

-

+

V

-

U

W

+

-

V

+

U

W

-

+

V

Fig. 7-2

[High speed rotation mode]

5V

+

A

U

0V

+

V

+

W

-

U

-

V

-

W

Drive signal at point

15V

+

U

0V

+

B

V

+

W

-

U

-

V

-

W

Drive signal at point

+

U

-

V

W

-

+

V

-

U

W

+

-

V

+

U

W

-

+

V

Fig. 7-3

– 47 –

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

N1

R41

R43

DC Current

C34

0V0V

SPM2 – HIC

OC

99

F

8

20

IC1

R42

P2

Direct Current
DC260-380V

10

3938

6

+

C217

R286

C2260VR285

0V

R222

–

+

5

R247

0V

IC4

C225

R245

L

Is

N

CT1

D104

R005

0V

C009

0V0V

R006

+

C107

0V

+

C105

58

62

JW10

0V

12V

0V

R221

R284

R292

Fig. 8-1 Microcomputer and Peripheral Circuits

7

0V

2

–

+

3

R288

0V

IC5

CN13CN14

C205

R249

R248

C215

1

+

D205

37

0V

5V

R252

19

521

5V

C218

R289

R500

R253

D204

0V

SPM2

MAIN P.W.B

HIC

59

Vd

C222

0V

17

Ip

60

Id

C224

0V

C204

0V

IC1

MICROCOMPUTER

61

Is

48

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.

– 48 –

5V

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

Terminal

0V

–

R41

9 9

SPM2 – HIC

R43

0V

B

R42

IC1

QC

R43

0V

20 9 2 39 17

8

F

Negative

DC
current

A

A

Detection

resistor

B

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

9

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

B

. 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

10

17

A

8

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

HIC

IP
Outdoor
microcomputer

– 49 –

(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

5

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

60

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.

60

– 50 –

Detection Resistor

R24

N1

L

Is

N

0V

CT1

C009

0V0V

D104

R006

R005

DC Current

58

+

C105

1

5

373938

5V

5V

C218

Direct Current
DC 260-380V

R500

SPM2

MAIN P.W.B.

R253

C222

0V0V

D204

C224

0V

0V0V

59

Vd

60

Id

61

Is

HIC

IC1

Microcomputer

P2

10

1

R245

0V

R221

CN14

+

C217

R222

6

–

+

5

R247

CN13

+

C205

0V

R249

7

R248IC4

D205

Fig. 8-6

Voltage at microcomputer pin

Rotation speed of compressor

60

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

– 51 –

● 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

0

G

0

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

5

DC current (A)

0

DC current

Power module

+

U

—

U

+

V

—

V

+

W

—

W

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

– 52 –

9. Temperature Detection Circuit

+5V

O.H. thermistor

CN8

HIC

Normal 2.7V or less
Over heat 2.7V or more

7

Reset 2.3V or less

62

O.H.

Microcomputer

DEF.

63

Outdoor

64

temperature

DEF. thermistor

CN9

Outdoor temperature
thermistor

CN10

+5V

0V

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

6

+5V

0V

Refer to the table 10-1

5

0V

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

62

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

63

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

64

), 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

20

2.75

30

3.22403.62

<Reference>

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.

– 53 –

10. Reset Circuit

Main

HIC

P.W.B

12V

5V

Microcomputer

C107

0V

R284

R286

62

+

JW10

R292

C226

R285

0V

0V

0V

2
3

IC5 (1/2)

C225

R288

8

C215

–

1

+

R289

R252

C204

0V0V

48

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

48

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.

12

6

Voltage (V)

Power is ON

0

12

6

Voltage (V)

Power is OFF

0

12V line

5V line

Reset voltage

Time

12V line

5V line

Reset voltage

Time

Fig. 10-2

– 54 –

11. Outdoor DC Fan Motor control circuit.

System power module

PQ102

FM-15V

C103

5V

0V

14

23

R114

R106

Main P.W.B

R115

+

ZD101

R105

C106

R104

R103

FM-15V

Q101

D101

R101

FM-0V

Ap 7V

33.3KHz

5V

T/2

R102

5V

t

T

+++

Smoothing Capacitor

123 4 5321

CN12

321

2A-FUSE

C101

R107

FM-0V

1

2

3

4

5

6

7

R108

0V

Fig. 11-1

U
V
W

RC Filter

0V

Vcc

PWM control voltage

FG Pulse

CN6

C104

D105

0V

61
60
59

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

ONE CHIP DRIVER IC

VSD

BOARD

DC Fan motor with control board

IC4

R246
0V

C208

2
3

12V

0V

8

–

1

+

Q201

0V

HIC

R283

R242

0V

C219

+

C209

R298

R243

R244

R297

Microcomputer

65

75

FM–60˚ el

15

FG Pulse
input

Motor coil

● 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

– 55 –

< 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.

– 56 –

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.

– 57 –

SERVICE CALL Q & A

Model RAK-25NH4 / RAC-25NH4

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

COOLING MODE

Q1

The compressor has
stopped suddenly during
cooling operation.

DEHUMIDIFYING MODE

Q2

Q3

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

Compressor occasionally does not
operate during dehumidifying.

HEATING MODE

Q4

The circulation stops
occasionally during
Heating mode.

A1

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

A2

A3

A4

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.

Q5

Q6

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".

A5

A6

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.

– 58 –

AUTO FRESH DEFROSTING

Q7

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

AUTO OPERATION

Q8

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

NICE TEMPERATURE RESERVATION

Q9

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

A7

A8

A9

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.

– 59 –

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.

– 60 –

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

L

Indoor unit
electric parts

Control
P.W. B.

System power module 2

a

N

+

~

~

ACT Module

DC35V

C

0V

D

+–+

–

(0V)

b

MAIN P.W.B.

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

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

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

+

–

Power module

M

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.

– 61 –

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)

P1

N1

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

– 62 –

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?

No

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.

No

Terminal C
(+35V)

Terminal D
(0V)

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

No

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

No

Check the outdoor electrical parts.

– 63 –

Check the indoor electrical parts.

TROUBLESHOOTING WHEN TIMER LAMP BLINKS.
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

1

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

2

3

4

5

1

6

5sec.

– –––––– 2 time

5sec.

– ––––– 3 times

5sec.

5sec.

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..)

<Cautions>

(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).

– 64 –

SELF-DIAGNOSIS LIGHTING MODE

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

– 65 –

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?

No

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

Yes

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

10 11

being

Yes

No

Yes

No

No

No

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.

– 66 –

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.

No

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

0V

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

No

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

No

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

0V

Transmission waveform

Yes

Perform final operation check.

– 67 –

Yes

No

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.

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

Can the fan be stopped by
remote control?

No

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

15

Yes

-

18

when auto

No

Yes

Replace IC111

Replace the microcomputer.

No

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.

No

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

Yes

Replace the indoor fan motor.

Yes

No

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

– 68 –

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?

No

No

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.

No

No

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.

– 69 –

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

Yes

No

No

No

Yes

Does the radio buzz noisily?

Is battery polarity correct?

Is the battery check sign + –

flashing?

CHECKING THE REMOTE CONTROLLER

– 70 –

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.).

No

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

No

Is the switching power circuit OK?

Has the 3A fuse blown?

No

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)?

– 71 –

Yes

”.

Operate the outdoor unit

according to the instruction

“How to operate the outdoor

unit independently

How did the self-diagnosis

lamp (LD301) light?

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.

No

Yes

Is DC 35V being output at

terminals C and D? (Normally,

DC 33-38.5V is output.)

No

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

No

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.

– 72 –

Yes No

No

Yes

Yes

Yes

No

No

No

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?

– 73 –

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.

No

Is the thermistor circuit normal?

Replace system power

module or defective parts.

No

Are R503, R541, R542, R549

and peripheral circuits of

system power module normal?

Replace the system power

module.

No

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.

– 74 –

LD301 blinks 4 time.

Failure of switching.

LD301 blinks 3 time.

Abnormal low speed.

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

17

is approx. 5V.)

Is the reset circuit normal?

(Normally, microcomputer

pin

48

is approx. 5V.)

Replace any defective parts.

Replace any defective parts.

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.

No

Yes

Yes

No

No

No

()

– 75 –

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)

No

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

If abnormality continues,
replace the system
power module.

– 76 –

CHECKING THE REFRIGERATING CYCLE

(JUDGING BETWEEN GAS LEAKAGE AND
COMPRESSOR DEFECTIVE)

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

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

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

YES

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

Normal
(0.39-0.98 MPaG)
(4-10 kg/cm

2

G)

Lighting mode

Self­diagnosis lamp

LD301

Time until the

lamp lights

Possible

malfunctioning

part

Blinks

Blinks

Blinks

Blinks

2 times

3 times

4 times

Approx. 10 seconds

Compressor

Blinking off

5 times

Approx.
10
seconds

Blinks

6 times

Within
Approx.
30
seconds

Gas
leakage

Checking the system power module

Blinks

8times

Approx.
10
seconds

Compressor

Gas leaking
(less than 4kg/cm
(less than 0.39 MPaG)

Gas leaks.
Repair and seal refrigerant.

2

G)

The compressor is defective. Replace it
and seal refrigerant.

Perform a final check of operation.

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

If the compressor checker for an
inverter type air conditioner is

( )

available, re-check using it.

– 77 –

HOW TO CHECK SYSTEM POWER MODULE

Checking system power module using tester

Set tester to resistance range (X 100)
If indicator does not swing in the following conductivity check, the system power module is normal.
(In case of digital tester, since built-in battery is set in reverse direction, + and – terminals are reversed.)

CAUTION

If inner circuit of system power module is disconnected (open), the indicator of tester will not swing and this may
assumed as normal. In this case, if indicator swings when + and – terminals are connected in reverse of diagram
below, it is normal. Furthermore, compare how indicator swings at U, V and W phases. If indicator swings the same way
at each point, it is normal.

– +

+–

P1 P2 U

L2 L1

N1

+

–

+

WV

+

– +

+

P1 P2 U

L2 L1

N1

+

–

–

–

WV

–

– 78 –

HOW TO OPERATE USING THE SERVICE SWITCH THE OUTDOOR UNIT

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

1. Turn off the power supply to outdoor unit and then turn on again.

2. Remove the electrical box cover.

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

Never operate the unit for
more than 5 minutes.

Electrical Box Cover

RAC-25NH4, RAC-35NH4

Electrical Box Cover

Service switch

(forced-cooling mode is set by
pressing for 1 second or more,
and stopped by pressing again.)

Self diagnosis lamps
(LD303, 302, 301)

RAC-50NH4

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

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

(2) If checking is done with the compressor connector disconnected, the unit will continue normal operation when the

electrical parts are normal, or it will repeat operating for approx. one minute and stop due to overload power limit cut,
or it will operate in the overload status.

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

HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY

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

Outdoor unit

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

Compressor

Reversing
valve

Large dia. service valve

Reducing union
(2/8” and 3/8”)

Copper pipe
(2/8”)

Charge refrigerant of 300g
after vacuuming ( 1 )

Small diameter
service valve

Parts to be prepared

(1) Reducing union

2/8” (6.35mm)

1/2” (12.7mm)
(2) Copper pipe (2/8” and 1/2”)
(3) Shorting leads

2 leads approx. 10 cm long

with alligator clip or IC clip

Do not operate for more than 5
minutes

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

1 The charging amount of 300g is equivalent to the load in normal operation.

– 79 –

SYSTEM POWER MODULE DIAGNOSIS

Circuit diagram of
the device
(excepting the
reflux diode)

Circuit diagram of
the module

Collector

BASE

Emitter

+

PGU PGV PGW

UVW

NGU NGV NGW

–

P1 P2 UN1

Terminals symbol
mark of the module

See next page
for measuring

value using
tester

L2 L1 W V

+ –

– 80 –

PARTS LIST AND DIAGRAM
INDOOR UNIT

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

1

7

8

4

5

2

9

10

12

14

15

13

24

6

19

3

20

11

22

16

17

22

18

– 81 –

THE UPDATED PARTS LIST

FOR THIS MODEL IS

AVAILABLE ON ESTA

OUTDOOR UNIT
MODEL : RAC-25NH4, RAC-35NH4

30

28

31

16

20

21

29

23

17

22

35

24

27

5

26

11

10

15

3

1

12

6

2

4

7

38

14

32

33

9

– 83 –

8

8

9

33

4

32

14

3

1

27

24

35

26

13

7

5

22

17

30

29

23

21

20

16

36

28

31

34

11

12

10

15

6

2

38

PARTS LIST AND DIAGRAM
OUTDOOR UNIT

MODEL : RAC-50NH4

– 84 –

THE UPDATED PARTS LIST

FOR THIS MODEL IS

AVAILABLE ON ESTA

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