Sony AS18A6RC Service Manual

ROOM AIR CONDITIONER

INDOOR UNIT	OUTDOOR UNIT
AS24A2RC	US24A2RC
AS18A6RC	US18A6RC
AS18A0RCD	US18A0RCD

SERVICE Manual

AIR CONDITIONER

CONTENTS

1. Installation

2. Disassembly and Reassembly

3. Troubleshooting

4. Exploded Views and Parts List

5. Refrigerating Cycle Block Diagrams

6. PCB Diagrams

7. Wiring Diagrams

8. Schematic Diagrams

E DB81-00189A(3)

1. Installation

1-1 Refrigerant Refill Procedure

•Refill an air-conditioner with refrigerant when refrigerant has been leaked at installing or using

1.Purge air(for new installation only).

2.Turn the 3-way valve clockwise to close, connect the pressure gauge(low pressure side) to the service valve, and open the 3-way valve again.

3.Connect the tank to refill with Refrigerant

4.Set the unit to cool operation mode.

5.Check the pressure indicated by the pressure gauge(low pressure side).

*Standard pressure is should be 4.5~5.5kg/cm2 in a regular, high operation mode.

	Suspension hook
Compound	High
gauge	pressure
	gauge
	Hand
	wheel
	Finger tight
	fittings
For mounting	Connected to
other and of
hose when	high pressure
not in use	side

Charging line

6.Open the refrigerant tank and fill with refrigerant until the rated pressure is reached.

*It is recommended not to pour the refrigerant in too quickly, but gradually while operating a pressure valve.

R-22

7.Stop operation of the air conditioner.

8.Close the 3-way valve, disconnect the pressure gauge, and open the 3-way valve again.

9.Close the cap of each valve.

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1-2 “Pump down” Procedure

Pump down' shall be carried out when an evaporator is replaced or when the unit is relocated in

another area.

1.Remove the caps from the 2-way valve and the 3-way valve.

2.Turn the 3-way valve clockwise to close and connect

a pressure gauge(low pressure side) to the service valve, and open the 3-way valve again.

3. Set the unit to cool operation mode.	2-Way Valve
(Check if the compressor is operating.)

4. Turn the 2-way valve clockwise to close.

3-Way Valve

5.When the pressure gauge indicates "0" turn the 3-way valve clockwise to close.

6.Stop operation of the air conditioner.

7.Close the cap of each valve.

Relocation of the air conditioner

•Refer to this procedure when the unit is relocated.

1.Carry out the pump down procedure (refer to the details of 'pump down').

2.Remove the power cord.

3.Disconnect the assembly cable from the indoor and outdoor units.

4.Remove the flare nut connecting the indoor unit and the pipe.

At this time, cover the pipe of the indoor unit and the other pipe using a cap or vinyl plug to avoid foreign material entering.

5.Disconnect the pipe connected to the outdoor unit.

At this time, cover the valve of the outdoor unit and the other pipe using a cap or vinyl plug to avoid foreign material entering.

6.Make sure you do not bend the connection pipes in the middle and store together with the cables.

7.Move the indoor and outdoor units to a new locatioon.

8.Remove the mounting plate for the indoor unit and move it to a new location.

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2. Disassembly and Reassembly

Stop operation of the air conditioner and remove the power cord before repairing the unit.

2-1 Indoor Unit

No	Parts		Procedure	Remark
!	Front Grille	1)	Stop the air conditioner operation and block the
			main power.
		2)	Seperate tape of front panel upper.

3) Contract the second finger to the left, and right handle and pull to open the inlet grille.

4)Take the left and right filter out.

*Take the Deodorizing and Electrostatic filter out. (Optional)

5)Loosen one of the right fixing screw and seperate the terminal cover.

6)Loosen three fixing screws of front grille.

7)Pull the upper left, right and Center of discharge softly for the outside cover to be pulled out.

8)Pull softly the lower part of discharge and push it up.

Caution;

Assemble the front panel and fix the hooks of left, right and Center

3

No	Parts		Procedure	Remark
@	Ass’y Tray Drain.	1) Do “1” above.
			Separate the drain hose from the extension
			drain hose.
		2)	Take the display PCB out.
			(Center of indoor unit)
		3)	Loosen two fixing screws of left and right
		4)	Pull tray drain out from the back body.

#	Electrical Parts	1) Do “1”, “2”, above
	(Main PCB)	2)	Take all the connector of PCB upper side out.
			(Inclusion Power cord)
		3)	Separate the outdoor unit connection wire from
			the terminal block.
		4)	Pulling the Main PCB up. it will be taken out.
			(Separate the TRANS hook. it before).
$	Heat Exchanger	1) Do “1” and “2”, “3”, above
		2)	Loosen two fixing earth screws of right side.
		3)	Separate the connection pipe.
		4)	Separate the bush body at the upper side and
			holder at the rear side.
		5)	Loosen the two fixing screws of left side.
		6)	Lifting the heat exchanger up a little to push the
			up side for separation from the indoor unit.

4

No	Parts		Procedure		Remark
%	Fan Motor and	1) Do “1” “2” ”3” “4”, above.
	Cross Fan
		2)	Loosen the fixing three screws and separate the
			motor holder.
		3)	Loosen the fixing screw of fan motor.
			(By use of M3 wrench)
		4)	Separate the fan motor from the fan.
		5)	Separate the fan from the left holder bearing.

5

2-2 Outdoor Unit

No	Parts		Procedure		Remark
!	Cabinet	1)	Turn off the unit and remove the power cable
		2)	Remove the top cover.
		3)	Remove the control box cover.
		4)	Unplug the ass'y cable.
		5)	Remove the cabi-side.
		6)	Remove the cabi-front.
		* When you assemble the parts, check if the
			each parts and electric connectors are fixed
			firmly.
@	Fan Motor &	1)	Do Procedure 1 above.
	Propeller Fan	2)	Remove the nut flange.
			(Turn to the right to remove as it is a left turned
			screw)
		3)	Disassemble the propeller fan.

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3. Troubleshooting

3-1 Items to be checked first

1)The input voltage should be rating voltage 10% range.

The airconditioner may not operate properly if the voltage is out of this range.

2)Is the link cable linking the indoor unit and the outdoor unit linked properly? The indoor unit and the outdoor unit shall be linked by 6 cables.

Check the terminals if the indoor unit and outdoor unit are properly linked by the same number of cables.

Otherwise the airconditioner may not operate properly.

3)When a problem occurs due to the contents illustrated in the table below it is a symptom not related to the malfunction of the airconditioner.

NO	Operation of air conditioner			Explanation
1	The STD operation indication LED blinks when a	It indicates power is on. The LED stops blinking if the operation
	power plug of the indoor unit is plugged in for the first time.	ON/OFF button on the remote control unit is pushed.
2	In a COOL operation mode, the compressor does not	In happens after a delay of 3 minutes when the compressor is
	operate at a room temperature higher than the setting	reoperated. The same phenomenon occurs when a power is on.
	temperature that the INDOOR FAN should operate.	As a phenomenon that the compressor is reoperated after a delay of
		3 minutes, the indoor fan is adjusted automatically with reference
		to a temperature of the air blew
3	Fan speed setting is not allowed in AUTO or DRY mode.	The speed of the indoor fan is set to LL in DRY mode.
		Fan		speed is 5 steps is selected automatically in AUTO mode.
4	Compressor stops operation intermittently in DRY mode.	Compressor operation is controlled automatically in DRY mode
		depending on the room temperature and humidity.
5	The compressor stops intermittently in a COOL mode or DRY	The compressor stops intermittently or the fan speed of the indoor
	mode, and fan speed of the indoor unit decreases.	unit decreases to prevent inside/outside air frozen depending on the
		inside/outside air temperature.

4)Indoor unit observes operation condition of the air conditioner, and displays self diagnosis details on the display panel.

NO	Display	Self Diagnosis
1	STD LED blinking (1Hz)	Restore from power failure (input initial power)
2	TIMER LED blinking (1Hz)	Indoor unit Room sensor Error (open or short)
3	STD and TIMER LED blinking (1Hz)	Indoor unit heat exchanger temperature sensor Error (open or short)
4	BIO LED blinking (1Hz)	Indoor fan malfunctioning (for spead is Below 450rpm)
5	STD, BIO and TIMER LED blinking(1Hz)	EEPROM Error
6	All LED blinking(1Hz)	Option Error (option wasn’t setup or option data error)

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3-2 Fault Diagnosis by Symptom

3-2-1 No Power(completely dead)-Initial diagnosis

1)Checklist :

(1)Is input voltage normal? (rating voltage ±10% range)

(2)Is AC power linked correctly?

(3)Are connections between primary side, secondary side of the power transformer and PCB good.

(4)Is input voltage of DC regulator IC KA7805 (IC02) normal? (11VDC-12.5VDC)

(5)Is output voltage of DC regulator IC KA7805 (IC02) normal? (4.5VDC-5.5VDC)

2)Troubleshooting procedure

YES

Replace PCB

display

Remove power cord and plug in again

in approx. 5 seconds

NO

Is operation lamp blinking?

YES

Is DC voltage of PCB

Does operation start when

run/stop button on the remote

display normal?

controller unit pushed?

NO

NO

Is the rating Voltage ±10%

Is transmission display of the remote

controller unit blinking?

range applied to the

between #1 and #3 of CN78

YES

NO

Is "beep"sound heard from the main

unit?

NO

•Check linkage between

YES

power cord and

Is DC voltage of the PCB module

terminal tap

normal?

•Check fuse

YES

Are voltages of #8 (compressor), and#6

(outdoor fan) of the micom normal? ; 5VDC

Is 11~12.5VDC

appear in

Is voltage of #60 (indoor fan) of the micom

normal?

the input side of the DC

regulator IC KA7805(IC02)?

DC5V

NO

YES

10ms

NO

Is voltage at #33 terminal of the Micom normal?

refer to

; 0VDC

Is voltage at #18 terminal of the Micom normal?

replace

; 5VDC

PCB module

YES

Is voltage at #52 terminal of the micom

normal?

10ms

YES

Are voltage at #48 and #49 of the

NO

micom normal?

Replace resonator (X501)

100ns

YES

Is operation normal?

Replace

NO

YES

micom

OK

YES

NO

NO

YES

NO

NO

Normal

Refer to remote control unit fault diagnosis

Refer to Replace PCB module.

Are voltages at RY71(Compressor) and RY72 (Outdoor fan) normal? ; DC12V

Is voltage at SS71(indoor fan)

YES	NO
Check connections	Replace
compressor, outdoor	RY71, RY72
fan and indoor fan.	and SS71

Is output voltage of ICO2 normal?(DC5V)

YES

NO

Refer to replace PCB

Replace ICO2

module

Is voltage output terminal of

D101~D105(IN4007) normal?

YES	NO
OK	Replace IN4007

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3-2-2 When the Indoor Unit Fan Does Not Operate. (Initial Diagnosis)

1)Checklist :

(1)Is the indoor unit fan motor properly connected with the connector (CN73)?

(2)Is the AC voltage correct?

(3)Is HALL IC in indoor fan motor properly connected with the connector (CN43)?

(4)Is the running capacitor properly connected with the solder part of the PCB?

2)Troubleshooting procedure

After unplugging out the power cord should

be reconnected within five seconds.

YES

Does the operating lamp(Green) blink?

YES

Does the Solid State Relay(SS71) work properly?

Test rod location		Normal
+	-	Voltage
SS71+	SS71-	12V
	YES
Is the supply voltage of the fan
	motor sufficient?
Test rod location		Normal
PCB CN73	Condition	voltage
pin3, pin5	Fan operate	.
		=. AC 180V

YES

Check as in the procedur “NO power parts”

NO	Refer to page 8.

Microcomputer is out of order.

NO

PCB is	Refer to replace
out of order.	PCB module
NO

MF-C is out of order

Replace MFC

Fan motor	Fan motor
is out of order.	should be replaced.

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