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SM0001
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
ROOM AIR CONDITIONER
INDOOR UNIT + OUTDOOR UNIT
DECEMBER 2003
Hitachi Household Appliance (Wuhu) Co., Ltd.
SERVICE MANUAL
REFER TO THE FOUNDATION MANUAL
TECHNICAL INFORMATION
FOR SERVICE PERSONNEL ONLY
(W)
(A)
(kW)
(B.T.U./h)
(W)
(A)
(kW)
(B.T.U./h)
W
H
D
(kg)
RAS25YH4
RAC25YH4
DC INVERTER (WALL TYPE)
TYPE
MODEL
POWER SOURCE
TOTAL INPUT
TOTAL AMPERES
CAPACITY
TOTAL INPUT
TOTAL AMPERES
CAPACITY
DIMENSIONS
(mm)
NET WEIGHT
SPECIFICATIONS
780
280
205
9.5
RAS25YH4
RAS35YH4
CONTENTS
SPECIFICATIONS ------------------------------------------------------------------- 4
HOW TO USE ----------------------------------------------------------------------- 6
CONSTRUCTION AND DIMENSIONAL DIAGRAM --------------------- 25
MAIN PARTS COMPONENT --------------------------------------------------- 27
WIRING DIAGRAM ---------------------------------------------------------------- 29
CIRCUIT DIAGRAM --------------------------------------------------------------- 31
PRINTED WIRING BOARD LOCATION DIAGRAM --------------------- 37
BLOCK DIAGRAM ----------------------------------------------------------------- 41
BASIC MODE ----------------------------------------------------------------------- 43
REFRIGERATING CYCLE DIAGRAM --------------------------------------- 55
DESCRIPTION OF MAIN CIRCUIT OPERATION ----------------------- 56
SERVICE CALL Q & A ---------------------------------------------------------- 84
TROUBLE SHOOTING ----------------------------------------------------------- 87
PROCEDURE FOR DISASSEMBLY AND REASSEMBLY ---------- 113
PARTS LIST AND DIAGRAM ------------------------------------------------ 115
RAS25YH4 / RAC25YH4
RAS35YH4 / RAC35YH4
RAC25YH4
RAC35YH4
COOLING
HEATING
INDOOR UNIT
OUTDOOR UNIT
INDOOR UNIT
OUTDOOR UNIT
1 PHASE, 50Hz, 230V
560 (155 ~ 1,080)
2.86
2.50 (0.90 ~ 3.10)
8,530 (3,070 ~ 10,575)
770 (115 ~ 1,120)
3.72
3.40 (0.90 ~ 4.40)
11,601 (3,070 ~ 15,695)
750
548
288
35
780
280
205
9.5
750
548
288
35
1 PHASE, 50Hz, 230V
950 (155 ~ 1,300)
4.35
3.50 (0.90 ~ 4.00)
11,942 (3,070 ~ 13,650)
980 (115 ~ 1,300)
4.49
4.20 (0.90 ~ 5.00)
14,331 (3,070 ~ 17,745)
After installation
RAS35YH4
RAC35YH4
HITACHI
AW NO. 0001
RAS-25YH4/RAC-25YH4
RAS-35YH4/RAC-35YH4
RAS_25_35_AW_000cover
2003.12.31, 10:41 AM
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SAFETY DURING REPAIR WORK
First,
I must
disconnect
the
power
cord
plug
from
the
power
outlet.
1.
In order to disassemble and repair the unit
in question, be sure to disconnect the power
cord plug from the power outlet before
starting the work.
2.
If it is necessary to replace any parts, they should be replaced with respective genuine parts for the unit, and
the replacement must be effected in correct manner according to the instructions in the Service Manual of the
unit.
If the contacts of electrical
parts are defective, replace the
electrical parts without trying to
repair them.
3.
After completion of repairs, the initial state should
be restored.
4.
Lead wires should be connected and laid as in the
initial state.
5.
Modification of the unit by user himself should
absolutely be prohibited.
6.
Tools and measuring instruments for use in repairs or inspection should be accurately calibrated in advance.
7.
In installing the unit having been repaired, be careful to prevent the occurence of any accident such as
electrical shock, leak of current, or bodily injury due to the drop of any part.
8.
To check the insulation of the unit, measure the insulation resistance between the power cord plug and grounding
terminal of the unit. The insulation resistance should be 1M or more as measured b y 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
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2003.12.31, 10:41 AM
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­ 1 ­
WORKING STANDARDS FOR PREVENTING BREAKAGE OF SEMICONDUCTORS
1.
Scope
The standards provide for items to be generally observed in carrying and handling semiconductors in relative
manufacturers during maintenance and handling thereof. (They apply the same to handling of abnormal
goods such as rejected goods being returned).
2.
Object parts
(1) Micro computer
(2) Integrated circuits (IC)
(3) Field-effect transistors (FET)
(4) P.C. boards or the like on which the parts mentioned in (1) and (2) of this paragraph are equipped.
3.
Items to be observed in handling
(1) Use a conductive container for carrying and storing of parts. (Even rejected goods should be handled in
the same way).
Fig. 1. Conductive Container
IC
A conductive polyvinyl bag
IC
Conductive sponge
(2) When any part is handled uncovered (in counting, packing and the like), the handling person must always
use himself as a body earth. (Make yourself a body earth by passing one M ohm earth resistance through
a ring or bracelet).
(3) Be careful not to touch the parts with your clothing when you hold a part even if a body earth is being
taken.
(4) Be sure to place a part on a metal plate with grounding.
(5) Be careful not to fail to turn off power when you repair the printed circuit board. At the same time, try to
repair the printed circuit board on a grounded metal plate.
1M
Fig. 2. Body Earth
Body earth
(Elimik conductive band)
Clip for connection with a
grounding wire
RAS_25_35_AW_001-024
2003.12.31, 10:43 AM
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­ 2 ­
(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
Metal plate (of aluminium, stainless steel, etc.)
Staple
Screw stop at the screwed
part using a rag plate
Soldering iron
Grounding
wire
Fig. 4. Grounding a soldering iron
Use a high insulation mode (100V, 10M or higher) when ordinar y 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.
RAS_25_35_AW_001-024
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­ 3 ­
1.
In quiet operation or stopping the running, slight flowing noise of refrigerant in the refrigerating cycle is
heard occasionally, but this noise is not abnormal for the operation.
2.
When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from
the power outlet for safety.
3.
The room air conditioner does not start automatically after recovery of the electric power failure for prevent-
ing fuse blowing. Re-press START/STOP button after 3 minutes from when unit stopped.
4.
If the room air conditioner is stopped by adjusting thermostat, or missoperation, and re-start in a moment,
there is occasion that the cooling and heating operation does not start for 3 minutes, it is not abnormal and
this is the result of the operation of IC delay circuit. This IC delay circuit ensures that there is no danger of
blowing fuse or damaging parts even if operation is restarted accidentally.
5.
This room air conditioner should not be used at the cooling operation when the outside temperature is
below 10°C (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.
! CAUTION
RAS_25_35_AW_001-024
2003.12.31, 10:43 AM
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