Hitachi RAK-18NH6 User manual

NO. 0355E
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
INDOOR UNIT
MARCH 2007 Refrigeration & Air-Conditioning Division
SERVICE MANUAL
PM
REFER TO THE FOUNDATION MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
H
D
(kg)
DC INVERTER (WALL TYPE)
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
CAPACITY
TOTAL INPUT
TOTAL AMPERES
CAPACITY
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS
CONTENTS
SPECIFICATIONS ----------------------------------------------------- 5
HOW TO USE -------------------------------------------------------- 14
CONSTRUCTION AND DIMENSIONAL DIAGRAM ------- 38
MAIN PARTS COMPONENT ------------------------------------- 39
WIRING DIAGRAM -------------------------------------------------- 40
CIRCUIT DIAGRAM ------------------------------------------------- 43
PRINTED WIRING BOARD LOCATION DIAGRAM ------- 45
BLOCK DIAGRAM --------------------------------------------------- 47
BASIC MODE --------------------------------------------------------- 49
REFRIGERATING CYCLE DIAGRAM ------------------------- 63
AUTO SWING FUNCTION ---------------------------------------- 65
DESCRIPTION OF MAIN CIRCUIT OPERATION --------- 66
SERVICE CALL Q & A -------------------------------------------- 71
PARTS LIST AND DIAGRAM ------------------------------------ 81
RAK-18NH6
RAK-25NH6
RAK-35NH6
RAK-50NH6
COOLING
HEATING
780
280
220
RAK-18NH6
RAK-25NH6
RAK-35NH6
RAK-50NH6
RAK-35NH6
1 PHASE, 50 Hz, 220-240V
REFER TO THE SPECIFICATION PAGE (6)
INDOOR UNIT
RAK-18NH6 RAK-25NH6
NOTE:
This manual describes only points that differ from
RAF-25, 35NH5, RAD-25, 35NH5, RAI-25, 35NH5
and RAM-55QH5 (PM No. 0312E) for items not
described in this manual.
9.59.0
HITACHI
DC INVERTER
TEMPORARY
SWITCH
9.5 9.5
RAK-50NH6

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

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

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

–4 –
1. In quiet operation or stopping the running, slight flowing noise of refrigerant in the refrigerating cycle is
heard occasionally, but this noise is not abnormal for the operation.
2. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug
from the power outlet for safety.
3. 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 (14°F).
6. This room air conditioner (the reverse cycle) should not be used when the outside temperature is below
–15°C (5°F).
If the reverse cycle is used under this condition, the outside heat exchanger is frosted and efficiency falls.
7. When the outside heat exchanger is frosted, the frost is melted by operating the hot gas system, it is not
trouble that at this time fan stops and the vapour may rise from the outside heat exchanger.
!
CAUTION

–5 –
SPECIFICATIONS
MODEL
FAN MOTOR
FAN MOTOR CAPACITOR
FAN MOTOR PROTECTOR
COMPRESSOR
COMPRESSOR MOTOR CAPACITOR
OVERLOAD PROTECTOR
OVERHEAT PROTECTOR
FUSE (for MICROPROCESSOR)
POWER RELAY
POWER SWITCH
TEMPORARY SWITCH
SERVICE SWITCH
TRANSFORMER
VARISTOR
NOISE SUPPRESSOR
THERMOSTAT
REMOTE CONTROL SWITCH (LIQUID CRYSTAL)
RAK-18NH6, RAK-25NH6, RAK-35NH6, RAK-50NH6
35W
NO
NO
–
NO
NO
NO
NO
NO
NO
YES
NO
NO
NO
NO
YES(IC)
YES
----------
WITHOUT REFRIGERANT BECAUSE
COUPLING IS FLARE TYPE.
UNIT
PIPES
REFRIGERANT CHARGING
VOLUME
(Refrigerant 410A)

–6 –
SPECIFICATION OF ROOM AIR CONDITIONER
RAK-18NH6, RAK-25NH6, RAK-35NH6, RAK-50NH6
RAM-55QH5
TYPE
MODEL
PHASE/VOLTAGE/FREQUENCY
COOLING
(ONE UNIT)
COOLING
(2 UNITS)
RAK-25NH5+RAK-35NH5
........RAM-55QH5
HEATING
(ONE UNIT)
HEATING
(2 UNITS)
RAK-25NH5+RAK-35NH5
........RAM-55QH5
AUTOMATIC AIR DEFLECTORS
FAN SPEED
LINE CORD
REMOTE CONTROL SWITCH
MAXIMUM LENGTH OF PIPING
DIMENSIONS
inches (mm)
NET WEIGHT (kg)
PACKING
inches (mm)
GROSS WEIGHT (kg)
FLARE NUT SIZE (SMALL/LARGE)
1.8 (1.00 - 2.50)
6,150 (3,415 - 8,536)
560 (200 - 750)
3.21
2.57 - 2.36
99
35
7.3
OUTDOOR UNIT
CAPACITY (kW)
(BTU/h)
TOTAL INPUT (W)
COP
TOTAL AMPERE (A)
POWER FACTOR (%)
SOUND LEVEL (INDOOR)
AIR FLOW VOLUME (Hi)
CAPACITY (kW)
(BTU/h)
TOTAL INPUT (W)
COP
TOTAL AMPERE (A)
POWER FACTOR (%)
SOUND LEVEL (OUTDOOR)
CAPACITY (kW)
(BTU/h)
TOTAL INPUT (W)
COP
TOTAL AMPERE (A)
POWER FACTOR (%)
SOUND LEVEL (INDOOR)
AIR FLOW VOLUME (Hi)
CAPACITY (kW)
(BTU/h)
TOTAL INPUT (W)
COP
TOTAL AMPERE (A)
POWER FACTOR (%)
SOUND LEVEL (OUTDOOR)
COOLING/HEATING
WALL TYPE
INDOOR UNIT RAK-18NH6 RAK-25NH6 RAK-35NH6
RAM-55QH5
1ø/ 220V~240V / 50Hz
5.0 (0.9 - 5.2)
17,070 (3,070 - 17,740)
1,780 (155 - 2,200)
2.81
8.14 - 7.50
99
47
13.5
2.5 (1.00 - 3.10)
8,540 (3,415 - 10,585)
750 (200 - 880)
3.33
3.44 - 3.16
99
38
8.5
5.40 (1.50 - 5.90)
18,430 (5,120 - 20,130)
1,795 (200 - 1,980)
3.01
8.30 - 7.60
99
52
2.5 (1.10 - 3.20)
8,540 (3,756 - 10,927)
690 (200 - 970)
3.62
3.17 - 2.90
99
36
7.3
6.50 (0.9 - 8.1)
22,180 (3,070 - 27,640)
1,970 (155 - 2,100)
3.30
9.00 - 8.30
99
4.7
13.5
3.4 (1.10 - 4.40)
11,610 (3,756 - 15,024)
870 (200 - 1,120)
3.91
3.99 - 3.66
99
39
8.5
7.2 (1.50 - 7.20)
24,560 (5,120 - 24,560)
2,100 (200 - 2,100)
3.43
9.6 - 8.8
99
52
YES
4
YES
4
YES
4
NOT PROVIDED (POWER CORD SHOULD BE PREPARED AND CONNECTED TO
OUTDOOR UNIT WHEN INSTALLED)
YES (WIRELESS) YES (WIRELESS)YES (WIRELESS)
MAX 35m (TWO UNITS TOTAL)
W
H
D
(INSTALLED)
W
H
D
cu.ft
30-23/32 (780)
11-1/32 (280)
8-35/50 (220)
–
32-11/16 (830)
9-27/32 (250)
12-31/32 (330)
2.41
9
6.35/9.52
RAK-50NH6
3.5 (1.00 - 4.00)
11,950 (3,415 - 13,658)
1,090 (200 - 1,300)
3.21
5.00 - 4.59
99
41
10.1
4.2 (1.10 - 5.00)
14,340 (3,756 - 17,072)
1,080 (200 - 1,300)
3.89
4.96 - 4.55
99
41
10.1
YES (WIRELESS)
YES
4
HITACHI
DC INVERTER
TEMPORARY
SWITCH
30-23/32 (780)
11-1/32 (280)
8-35/50 (220)
–
32-11/16 (830)
9-27/32 (250)
12-31/32 (330)
2.41
9
6.35/9.52
30-23/32 (780)
11-1/32 (280)
8-35/50 (220)
–
32-11/16 (830)
9-27/32 (250)
12-31/32 (330)
2.41
9
6.35/9.52
30-23/32 (780)
11-1/32 (280)
8-35/50 (220)
–
32-11/16 (830)
9-27/32 (250)
12-31/32 (330)
2.41
9
6.35/12.7

–7 –
DUAL SYSTEM MULTI R.A.C. RAM-55QH5
COOL / HEAT CAPACITY SPEC. FOR INDOOR UNITS
COMBINATIONS TO BE ABLE TO OPERATE SIMULTANEOUSLY
Whichever indoor units are installed, cooling and heating capacity depends on how many and which indoor units
are operating at that time.
POSSIBLE
COMBINATIONS
TO OPERATE
CAPACITY RATING
(kW)
(RANGE)
POWER
CONSUMPTION
(W)
AMPERE
(A)
220-240V
OUTDOOR UNIT
C O O L I N G
CAPACITY RATING
(kW)
(RANGE)
POWER
CONSUMPTION
(W)
AMPERE
(A)
220-240V
OUTDOOR UNIT
H E A T I N G
ONE UNIT
TWO UNIT
1.8
2.5
3.5
5.0
1.8+1.8
1.8+2.5
1.8+3.5
1.8+5.0
2.5+2.5
2.5+3.5
1.80
(1.00-2.50)
2.50
(1.00-2.80)
3.50
(1.00-3.90)
5.00
(1.00-5.60)
1.80+1.80
(1.50-4.00)
1.80+2.40
(1.50-4.60)
1.70+3.30
(1.50-5.60)
1.40+4.00
(1.50-5.90)
2.50+2.50
(1.50-5.60)
2.17+3.03
(1.50-5.70)
560
(200-750)
780
(200-980)
1160
(200-1280)
1780
(200-1960)
1190
(200-1300)
1310
(200-1450)
1650
(200-1820)
1795
(200-1980)
1650
(200-1820)
1730
(200-1900)
2.6-2.4
3.6-3.3
5.3-4.9
8.2-7.5
5.5-5.0
6.0-5.5
7.6-6.9
8.2-7.6
7.6-6.9
7.9-7.3
2.50
(1.10-3.20)
3.90
(1.10-4.70)
4.80
(1.10-5.80)
6.50
(1.10-7.20)
2.50+2.50
(1.50-5.20)
2.40+3.80
(1.50-6.30)
2.30+4.50
(1.50-7.20)
2.00+5.00
(1.50-7.20)
3.40+3.40
(1.50-7.20)
3.15+3.85
(1.50-7.20)
750
(200-1050)
1145
(200-1380)
1550
(200-1870)
2400
(200-2660)
1460
(200-1550)
1820
(200-1920)
1995
(200-2100)
2050
(200-2100)
2015
(200-2110)
2070
(200-2110)
3.4-3.2
5.3-4.8
7.1-6.5
11.0-10.1
6.7-6.1
8.4-7.7
9.2-8.4
9.4-8.6
9.3-8.5
9.5-8.7
ONE UNIT : The values indicated are only for one unit opration when two indoor units are connected.
3.5+3.5 2.70+2.70
(1.50-5.90)
1795
(200-1980) 8.2-7.6 3.60+3.60 (1.50-7.20)
2110
(200-2110) 9.7-8.9
2.5+5.0 1.80+3.60
(1.50-5.90)
1795
(200-1980) 8.2-7.6 2.70+4.50 (1.50-7.20)
2110
(200-2110) 9.7-8.9
RATING CONDITON (DRY BLUB / WET BULB)
COOLING
HEATING
INDOOR OUTDOOR
27 / 19 ˚C
20 / –˚C
35 / –˚C
7 / 6˚C

–8 –
DUAL SYSTEM MULTI R.A.C. RAM-55QH5
INDOOR UNITS COMBINATIONS TO BE ABLE TO INSTALL
Two indoor units can be installed with one outdoor unit.
And total nominal cooling capacity should not be more than 7.5kW
INDOOR UNIT
MODEL
NOMINAL
COOLING
CAPACITY
(kW)
CAPACITY (kW)
at one unit operation
SUITABLE ROOM SIZE (m2)
at one unit operation
COOLING HEATING COOLING HEATING
RAK-18NH5
RAK-25NH5
RAF-25NH5
RAD-25NH5
RAI-25NH5
RAK-35NH5
RAF-35NH5
RAD-35NH5
RAI-35NH5
1.8
2.5
2.5
2.5
2.5
3.5
3.5
3.5
3.5
1.00 - 2.50
1.00 - 2.80
1.00 - 2.80
1.00 - 2.80
1.00 - 2.80
1.00 - 3.90
1.00 - 3.90
1.00 - 3.90
1.00 - 3.90
1.10 - 3.20
1.10 - 4.70
1.10 - 4.70
1.10 - 4.70
1.10 - 4.70
1.10 - 5.80
1.10 - 5.80
1.10 - 5.80
1.10 - 5.80
8 - 12
11 - 17
11 - 17
11 - 17
11 - 17
16 - 24
16 - 24
16 - 24
16 - 24
9 - 11
14 - 18
14 - 18
14 - 18
14 - 18
17 - 22
17 - 22
17 - 22
17 - 22
Be sure to connect two indoor units to this outdoor unit. If not, condensed water may drop, resulting in trouble.
RAK-50NH5 5.0 1.00 - 5.60 1.10 - 7.20 23 - 34 23 - 29
RAF-50NH5 5.0 1.00 - 5.60 1.10 - 7.20 23 - 34 23 - 29
RAI-50NH5 5.0 1.00 - 5.60 1.10 - 7.20 23 - 34 23 - 29

–9 –
DUAL SYSTEM MULTI R.A.C. RAM-55QH5
CONNECTING POSISION TO BE ABLE TO INSTALL
POSSIBLE COMBINATIONS
TO INSTALL
(kW)
CONNECTING POSITION ON
OUTDOOR UNIT
(VALVE DIAMETER)
(mm)
No.1 No.2
SUITABLE ROOM SIZE
TO INSTALL
(m2)
6.35/9.52D 6.35/9.52D
TWO UNITS
1.8+1.8
1.8+2.5
1.8+3.5
1.8+5.0
2.5+2.5
2.5+3.5
(8-12) + (8-12)
(8-12) + (10-16)
(7-9) + (15-22)
(6-9) + (18-27)
(12-15) + (12-15)
(11-14) + (14-18)
1.8
1.8
1.8
1.8
2.5
2.5
1.8
2.5
3.5
5.0
2.5
3.5
2.5, 3.5, 4.0, 5.0 means indoor units cooling capacity class.
(1) Marking
: needs flare adapter (9.52 12.7D): Part No. TA261D-4 001
(2) Suitable room size is determined based on the conditions below:
•Climate is in the temperate zone like Tokyo, Japan.
•For usual residential use.
•Smaller figure is for light construction which means light thermally sealed.
•Larger figure is for heavy constructions, which means well thermally sealed.
3.5+3.5 (13-16) + (13-16) 3.5 3.5
2.5+5.0 (10-12) + (18-20) 2.5 5.0

