SPLIT SYSTEM AIR CONDITIONER TECHNICAL & SERVICE ...

TECHNICAL & SERVICE MANUAL 

ADR518CW AE518SC 

AE518SC3 / AER518SCL3 

ADR518HW AE518SH 

AE518SH3 / AER518SH3 

INDOOR UNIT 

SPLIT SYSTEM AIR CONDITIONER 

0.8180.224.0 

OUTDOOR UNIT 

® 

OCTOBER 01

A 

B 

C 

D 

E 

F 

G 

H 

I 

L 

M 

N 

O 

P 

Q 

R 

H 

TABLE OF CONTENTS 

SPECIFICATIONS...........................................................................................................PAGE...3 

MAJOR COMPONENT SPECIFICATION.....................................................................................9 

OTHERS COMPONENT SPECIFICATIONS................................................................................16 

OPERATING RANGE....................................................................................................................21 

DIMENSIONALE DATA.................................................................................................................22 

FUNCTION.....................................................................................................................................24 

REFRIGERANT FLOW DIAGRAM................................................................................................31 

ELECTRIC WIRING DIAGRAM.....................................................................................................32 

TROUBLESHOOTING COOLING MODEL...................................................................................36 

SAME PARTS OF AIR CONDITIONER DO NOT OPERATE........................................................43 

AIR CONDITIONER OPERATES,BUT ABNORMALITIES OCCUR.............................................44 

TROUBLESHOOTING HEATING MODEL....................................................................................45 

SAME PARTS OF AIR CONDITIONER DO NOT OPERATE.......................................................52 

AIR CONDITIONER OPERATES,BUT ABNORMALITIES OCCUR............................................55 

IS SENSOR IS DEFECTIVE..........................................................................................................56 

CHECKING ELECTRICAL ...........................................................................................................59

A SPECIFICATIONS 

1)UNIT SPECIFICATIONS 

UNIT MODEL 

Power source 220 / 230 / 240V - 1 - 50 Hz 

Shipping volume m 3 0,33 0,3 

Shipping weight (approx.) kg 44 57 

NOTA. Rating conditions: 

INDOOR UNIT 

OUTDOOR UNIT 

W (Kcal/h) 4.950 (4,250) 

Cooling: Outside air temp.: 35°C DB, indoor unit entering air temp.: 27°C DB / 19°C WB 

3 

ADR518CW 

AE518SC 

PERFORMANCES COOLING 

Capacity 

BTU/h 16,900 

Air circulation (high - med - low) m 3 /h 780 

External static pressure (high speed) mm w.g. (Pa) 5 (49) at shipment - 10 (98) using the Booster cable 

Moisture removal (high speed) l/h 2,8 

Umidità ELECTRICAL asportata RATINGS (alta velocità) l/h 0,9 

Voltage rating V 230 

Available voltage range V 198 ÷ 264 

Running ampere A 9.5 

Power input W 2,06 

Power factor % 94 

Compressor locked rotor amperes A 46 

C.O.P. 

FEATURES 

W/W 2.4 

Controls Microprocessor 

Control unit Remote control 

Temperature control I.C. thermostat 

Timer ON/OFF 12 hours 

Fan speed indoor / outdoor 3 + auto / 2 auto 

Air filter Washable, easy access (accessory) 

Compressor Rotary (hermetic) 

Refrigerant / ref. control / amount charged at ship g R22 / capillary tube / 1.710 g 

Operation sound 

Indoor Hi / Me / Lo (1 m) dB-A 

Outdoor Hi / Lo (3 m) dB-A 

42 / 37 / 32 

51 / 44 

Max. tubing length m (with factory R22 charge) 10 

Max. allowable tubing length m ....(with.R22.addition)....................20 

Required amount of additional refrigerant g/m 25 

Limit of elevation difference 

m 

between the two units 7 

Refrigerant tube 

diameter 

Narrow tube mm (in.) 

Wide tube mm (in.) 

6.35 (1/4”) 

12.7 (1/2”) 

Accessory Booster cable 

DIMENSIONS AND WEIGTH INDOOR UNIT OUTDOOR UNIT 

Higth mm 316 630 

Width mm 750 830 

Depth mm 665 305 

Net weigth kg 42 52 

Data subject to change without notice.

UNIT MODEL 

Power source 400V - 3N - 50 Hz (4 wires) 

Shipping volume m 3 0,33 0,3 



INDOOR UNIT 

OUTDOOR UNIT 

W (Kcal/h) 4.950 (4250) 


4 

ADR518CW 

AE518SC3 


Capacity 

BTU/h 16,900 



Moisture removal (high speed) l/h 2,8 





Power input W 1.96 


Compressor locked rotor amperes A 21.5 

C.O.P. 

FEATURES 

W/W 2.5 












42 / 37 / 32 

51 / 44 

Max. tubing length m (with factory R22 charge) 10 

Max. allowable tubing length m ....(with.R22.addition).....................20 



between the two units 


diameter 

m 



6,35 (1/4”) 

12,7 (1/2”) 







7 


UNIT MODEL 


Shipping volume m 3 0.33 0.3 



INDOOR UNIT 

OUTDOOR UNIT 

W (Kcal/h) 5900 (5070) 


5 

ADR518CW 

AER518SCL3 


Capacity 

BTU/h 17.400 


External static pressure (high speed) mm w.g. (Pa) 5 (49 at shipment - 10 (98) using the Booster cable 

Moisture removal (high speed) l/h 2.8 



Available voltage range V 342 : 440 


Power input W 2.000 


Compressor locked rotor amperes A 21.5 

C.O.P. 

FEATURES 

W/W 2,3 








Refrigerant / ref. control / amount charged at ship g R407C / capillary tube / 1.710 g 




42 / 37 / 32 

51/ 44 

Max. tubing length m (with factory R407C charge) 10 

Max. allowable tubing length m (with R407C addition) 30 





diameter 

m 



6,35 (1/4”) 

12.7(1/2") 







7 


UNIT MODEL 

Power source 220 / 230 / 240V - 1 - 50 Hz 

Shipping volume m 3 0,33 0.3 



INDOOR UNIT 

OUTDOOR UNIT 

W (Kcal/h) 4.950 (4.257) 6000(5160) 

6 

ADR518HW 

AE518SH 

PERFORMANCES COOLING HEATING 

Capacity 

BTU/h 16.900 20500 



Moisture removal (high speed) l/h 2.8 --- 




Running ampere A 9.8 10.3 

Power input W 2.100 2.150 

Power factor % 93 90 


C.O.P. W/W 2.35 2.8 

FEATURES 












42 / 37 / 32 

51 / 44 

Max. tubing length m (standard refrigerant charge) 10 






diameter 

m 



6,35 (1/4”) 

12.7 (1/2”) 







Data subject to change without notice. 


7

UNIT MODEL 





INDOOR UNIT 

OUTDOOR UNIT 

W (Kcal/h) 4.700 (4.042) 5.800(6.744) 

7 

ADR518HW 

AE518SH3 


Capacity 

BTU/h 16.100 19.800 











C.O.P. W/W 2.35 2.76 

FEATURES 








Refrigerant / ref. control / amount charged at ship g R22 / capillary tube / 2.450g 




42 / 37 / 32 

51 / 44 







diameter 

m 



6,35 (1/4”) 

12.7 (1/2”) 









7

UNIT MODEL 





INDOOR UNIT 

OUTDOOR UNIT 

W (Kcal/h) 4.800 (4.128) 6300(5418) 

8 

ADR518HW 

AER518SH3 


Capacity 

BTU/h 16.400 21.500 











C.O.P. W/W 2.23 2.8 

FEATURES 








Refrigerant / ref. control / amount charged at ship g R407C / capillary tube / 1.600 g 




42 / 37 / 32 

51 / 44 


Max. allowable tubing length m ....(with.R407C.addition)................30 





diameter 

m 



6,35 (1/4”) 

12.7 (1/2”) 









7

B MAJOR COMPONENT SPECIFICATIONS 

INDOOR UNIT 

UNIT MODEL ADR518CW / ADR518HW 

Power source 220 / 230 / 240V -1 - 50 Hz 

REMOTE CONTROL UNIT RCS-U251G 

CONTROLLER P.C.B. POW-U186GH 


Control circuit fuse 250V - 3A 

FAN Centrifugal 

Number ... dia. / length mm 2 ... Ø 200 / L 230 

FAN MOTOR 

Model ... Number K48410M01526 ... 1 

Power source V 220 / 230 / 240-1-50 Hz 

No. di poli ... giri/min (230V-max) 4 ... 1040 

Nominal output W 70 

Coil resistance 

(Ambient temp. 20°C) 

SAFETY DEVICES Internal type 

Operating temp. 

Open 

Close 

°C 

°C 

130 ± 18 

179 ± 15 

Run capacitor 

Rated 

µF 5 

VAC 440 

Voltage AC 230V - 50 Hz 

Input 114.7 W 

Coil Aluminum plate fin / Copper tube 

Fin pitch mm 1,8 

Fase area m 2 0,125 

EXTERNAL FINISH 

Ω WHT - BRN :181,1 

9 

ORG - VLT :136,8 

YEL - ORG :151,4 

BLK - YEL :120,6 

WHT - VLT :112,7 

VLT - PNK :144,2 

DRAIN PUMP 

Model PC 

Total head capacity 0.4 m / 0.6 l/m 

HEAT EXCHANGER 

Rows 3 

Insulated galvanized metal sheet

Outdoor Unit AE518SC3 

Controller 

PCB 

Part No. POW-C181BL 

Control circuit fuse 250V – 5A 

Type Rotary (Hermetic) 

Compressor model C-2R173H8V- 80817C88D 

Source 380 – 400 V – 3N ~ 50 Hz 

Nominal output W 1,700 

Compressor oil ... Amount cc SUNISO 4GSD-T ... 800 

Coil resistance (Ambient temp. 25°C) Ω C – R : 6.369 

C – S : 6.073 

R – S : 6.217 

Type Internal protector External protector 

Safety 

devices 

Overload relay 


Open 

Close 

°C 

°C 

— 

125 ± 5 

Automatic reclosing 

HOE-10TB TH-5A 

— 

— 

Operating amp.(Ambient temp. 25°C) — 5A 

Run capacitor 

µF 

VAC 

— 

— 

Crank case heater 240V 30W 

Type Propeller 

Q´ty ... Dia. mm 1 ... ø400 

Fan motor model ... Q´ty SMEN 19 TFB6055 ... 1 

Source 220 – 230 V ~ 50 Hz 

No. of poles ... rpm (220 V, High) 6 ... 910 


Coil resistance (Ambient temp. 20°C) Ω WHT – BRN : 77.7 WHT - YEL : 366 

WHT – PNK : 211 

Safety 

devices 

Type 


Open 

Close 

°C 

Internal type 

130 ± 5 


Run capacitor 

µF 

VAC 

2.0 

400 


Rows 2 

Fin pitch mm 1.8 

Face area m 2 

0.508 

External Finish Acrylic baked-on enamel finish 

Compressor 

Fan & Fan Motor 

Heat 

Exch. Coil 

10 

DATA SUBJECT TO CHANGE WITHOUT NOTICE.

Outdoor Unit AE518SC 

Controller PCB — 

Compressor 


Compressor model PH36VTRT 


Compressor oil ... Amount cc DIAMOND... 900 


11 

C – S : 2.03 

Type Internal protector (OLR) 

Safety Overload relay — 

devices Operating temp. Open °C Automatic opening 155 ± 5 

Close °C Automatic reclosing 90 ± 10 

Operating amp. (Ambient temp. 25 C) Trip in 3 to 10 sec at 54A 

Run capacitor µF 55.0 

VAC 450 

Crank case heater — 


Number ... Dia. mm 1 ... ø 400 

Fan motor model ... Number Smen 19TFB6055 ... 1 



Coil resistance (Ambient temp. 20°C) Ω WHT – BRN : 77.7 ± 7% 

WHT – YEL : 366.0 ± 7% 

WHT – PNK : 211.0 ± 7% 

Safety Type Thermal protector 

devices Operating temp. Open °C 130 ± 5 

Close Automatic reclosing 


VAC 440 


Rows 2 


Face area m2 0.508 



Heat 

Exch. Coil 


Outdoor Unit AER518SCL3 

Controller 

PCB 

Part No. POW-C181BL 

Control circuit fuse 250V – 5A 


Compressor model C-2RN173H8W 80807088 

Source 380 – 400 V – 3N ~ 50 Hz 


Compressor oil ... Amount cc FV68S ... 800 


C – S : 6.073 

R – S : 6.217 

Type Internal protector External protector 

Safety 

devices 

Overload relay 


Open 

Close 

°C 

°C 

— 

Automatic opening 


HOE-10TB TH-5A 

— 

— 

Operating amp.(Ambient temp. 25°C) — 5A 

Run capacitor 

µF 

VAC 

— 

— 



Q´ty ... Dia. mm 1 ... ø400 

Fan motor model ... Q´ty SMEN 19 TFB6047 ... 1 

Source 220 – 230 V ~ 50 Hz 



Coil resistance (Ambient temp. 20°C) Ω WHT – BRN : 83.4 

WHT – PNK : 218.7 

Safety 

devices 

Type 


Open 

Close 

°C 

Internal type 

130 ± 5 


Run capacitor 

µF 

VAC 

2.0 

440 


Rows 2 


Face area m 2 

0.508 


Compressor 


Heat 

Exch. Coil 

12 


Outdoor Unit AE518SH 

Controller PCB POW–C186GH 

Compressor 


Compressor model SCI PH36VTRT 


Compressor oil ... Amount cc DIAMOND....900 


13 

C – S : 2.03 

Type Internal protector External (OLR) 

Safety Overload relay MRA-8967-9200 

devices Operating temp. Open °C 160 ± 5 

Close °C 84± 11 

Operating amp.(Ambient temp. 25°C) Trip in 6 to 16 sec. at 55 A 


VAC 450 



Number ... Dia. mm 1 ... ø 400 

Fan motor model ... Number Smen 19TFB6055 ... 1 



Coil resistance (Ambient temp. 20°C) Ω WHT – BRN : 77.7 ± 7% 

WHT – YEL : 366.0 ± 7% 

WHT – PNK : 211 ± 7% 

Safety Type Internal protector 

devices Operating temp. Open °C 130 ±8 

Close Automatic reclosing 


VAC 440 


Rows 2 


Face area m2 0.453 



Heat 

Exch. Coil 


Outdoor Unit AE518SH3 

Power source 

Control circuit 

CONTROLLER PCB 

COMPRESSOR 

Type 

Compressor model 

Source 

Nominal output W 

Compressor oil ... Amount cc 

Coil resistance (Ambient temp. 25°C) 

C - R Ω 

C - S Ω 

R - S Ω 

380 - 400 V - 3N ~ 50 Hz 

220 - 240 V ~ 50 Hz 

POW-C186GH 

Rotary (Hermetic) 

C-R173H8M-806-389-88 

380 - 400 V - 3N ~ 50 Hz 

1700 

SUNISO4CS ... 800 

5,62 

5,51 

5,62 

Safety devices: Type Internal protector External protector 

Overload relay // HOE-10TB TH-7A 


Open °C 120 ± 5 // 

Close °C Automatic reclosing // 

Operating amp. (Ambient temp. 25°C) // 5 A 

µF 

VAC 

Crank case heater 

FAN AND FAN MOTOR 

Type 

Number ... Dia. mm 

Fan motor model ... Number 

Source 

No. of poles ... rpm (220 V) 


WHT - BRN Ω 

WHT - YEL Ω 

Safety devices: Type 

Open 

Close 

°C 

HEAT EXCH. COIL 

µF 

VAC 

Coil 

Rows 

Fin pitch mm 

Face area m 2 

Run capacitor 

// 

// 

240 V - 30 W 

Propeller 

1 ... Ø400 

Smen 19TFB6055 ... 1 

220 - 240 V ~ 50 Hz 

6 ... 900 

50 

77,7 


366,0 

WHT - PNK Ω 

211,0 

Internal protector 


130 ± 8 


Run capacitor 

2 

440 

Aluminum plate fin / Copper tube 

2 

1,6 

0,453 


Acrylic baked-on enamel finish 

14 


Outdoor Unit AER518SH3 

Power source 

Control circuit 

CONTROLLER PCB 

COMPRESSOR 

Type 

Compressor model 

Source 


Compressor oil ... Amount cc 


C - R Ω 

C - S Ω 

R - S Ω 

380 - 400 V - 3N ~ 50 Hz 

220 - 240 V ~ 50 Hz 

POW-C186GH 

Rotary (Hermetic) 

C-2RN173H8A 80242088 

380 - 400 V - 3N ~ 50 Hz 

1700 

FV68S ... 800 

5,62 

5,51 

5,62 

Safety devices: Type Internal protector External protector 

Overload relay // HOE-10TB TH-7A 


Open °C 120 ± 5 // 

Close °C Automatic reclosing // 

Operating amp. (Ambient temp. 25°C) // 5 A 

µF 

VAC 

Crank case heater 

FAN AND FAN MOTOR 

Type 

Number ... Dia. mm 

Fan motor model ... Number 

Source 

No. of poles ... rpm (220 V) 


WHT - BRN Ω 

WHT - YEL Ω 

Safety devices: Type 

Open 

Close 

°C 

HEAT EXCH. COIL 

µF 

VAC 

Coil 

Rows 

Fin pitch mm 

Face area m 2 

Run capacitor 

// 

// 

240 V - 30 W 

Propeller 

1 ... Ø400 

Smen 19TFB6055 ... 1 

220 - 240 V ~ 50 Hz 

6 ... 900 

50 

77,7 


366,0 

WHT - PNK Ω 

211,0 

Internal protector 


130 ± 8 


Run capacitor 

2 

440 

Aluminum plate fin / Copper tube 

2 

1,6 

0,453 


Acrylic baked-on enamel finish 

15 


C OTHER COMPONENT SPECIFICATIONS 


Power Relay G7L-2A-TUB 

Coil rating AC 200–240V, 50/60Hz 

Coil resistance kΩ (at 23°C) ( 21 ± 15% ) 

Contact rating AC 220V, 25A 

Thermostat (Fan Speed Control 23S) MQT5S-27YZJ 

Switching temp. °C high ➞ LOW 23.5°C +0 

–2.5 

low ➞ HIGH 27.0°C +0 

–3 


Outdoor Unit AE518SC3 

Negative Phase Relay (47C) RDR-S400 

Rating AC 415V, 3-phase 50Hz 


Operation Positive phase: ON 

16 

Negative phase: OFF 

Electro Magnetic Contactor (MG) HOE-10TB TH-5A 

Magnetic contactor 

Coil rating AC 220–240V, 50Hz / AC 240–260V, 60Hz 

Coil resistance Ω (at 25°C) 1,260 ± 10% 

Contact rating (Main) AC 440V, 8A 

Thermal relay (Overcurrent relay) 

MQT5S-27YZJ 

Operating amperes 5A


Thermistor (Coil sensor TH3 / Air sensor TH4) PBC-41E-S4 / PBC-41E-S8 

Resistance kΩ –20°C 40.1 ± 5% 20°C 6.5 ± 5% 

Solid State Relay (SSR) G3L-205TL-TS1 

Input 

Rated voltage DC 12V 

Control voltage range DC 0V to 6.4V 

Load voltage range AC 75V to 264V, 50Hz 

Negative Phase Relay (47C) RDR-S400 

Rating AC 415V, 3-phase 50Hz 


Operation Positive phase: ON 

Negative phase: OFF 

Electro Magnetic Contactor (MG) HOE-10TB TH-5A 

Magnetic contactor 

Coil rating AC 220–240V, 50Hz / AC 240–260V, 60Hz 

Coil resistance Ω (at 25°C) 1,260 ± 10% 

Contact rating (Main) AC 440V, 8A 

Thermal relay (Overcurrent relay) 

–10°C 24.4 ± 5% 30°C 4.4 ± 5% 

Operating amperes 5A 

0°C 15.3 ± 5% 40°C 3.0 ± 5% 

10°C 9.9 ± 5% 50°C 2.1 ± 5% 

Transformer (TR2) ATR-J105-I 

Rating Primary AC 230V, 50Hz 

Secondary 19V, 0.526A 

Capacity 10VA 

Coil resistance Ω (at 22°C) Primary (WHT – WHT): 205 ± 10% 

Secondary (BRN – BRN): 2.0 ± 10% 

Thermal cut-off temp. 150°C 

17 

MQT5S-27YZJ 

Power Relay HH62S DC24V 

Coil rating DC 24V 

Coil resistance kΩ (at 23°C) 650 ± 10% 

Contact rating AC 250V, 10A


Power Relay (PR) DFU24D1-F 

Coil rating DC 24V 

Coil resistance Ω (at 20°C) 650 ± 10% 


Starting Relay (SR) AMVL300A 

Coil rating AC 300V, 50Hz 

Coil resistance kΩ (at 23°C) 13.3 ± 2% 

Contact rating 20A AC 

Operating voltage AC 185 – 217V, 50Hz 

Return voltage AC 60 – 120V, 50Hz 

Thermostat (Defrost thermo. 23D) TRS02-12MSR 

Operating temp. °C ON 12 ± 2 

Diff. 8 deg. below 

Thermostat (Fan Speed Control 23S) MQT5S-27YZJ 

Switching temp. °C high ➞ LOW 23.5°C ±1.5 

Coil rating 

low 

AC 220-240V, 

➞ HIGH 

50Hz, 

27.0°C 

6W 

+0 

–3 

Contact Coil resistance rating Ω (at 20°C) AC 1.740 220V, ± 7% 3A 

4-way Valve (20S) LB64012 (Coil), V26-110B (Valve) 

Coil rating AC 220-240V, 50Hz, 6W 

Coil resistance Ω(at 20°C) 1.740 ± 7% 

Starting Capacitor C4; C5 

Capacitor 125 µF - 165V 

Resistor 18KΩ - 2W 

18

D OPERATING RANGE 

Function Temperature 

Cooling 

Maximum 35°C BS / 22°C BU 50°C BS 

Minimum 19°C BS / 14°C BU,5 -15°C BS 

21 

INDOOR UNIT OUTDOOR UNIT 

Indoor air Outdoor air 

intake temp. intake temp. 

Maximum 35°C BS / 22.5°C BU 52°C BS 

Minimum 19°C BS / 14°C BU,5 19°C BS 

Referred to the systems - ADR518CW - AER518SCL3 only (3 phase and low ambient version) 

Function Temperature 

Cooling 

INDOOR UNIT OUTDOOR UNIT 

Indoor air Outdoor air 

intake temp. intake temp.

REMOTE CONTROL UNIT 

E DIMENSIONAL DATA 

Indoor unit ADR518SW 

256 

200 

(OVERALL 

DIM.) 

20 

60 

26 

29 

692 

(OVERALL DIM.) 

2 - ø3.3 

(HOLE) 

6 

310 

5 - ø3,3 

(HOLE 

OPPOSITE SIDE) 

160 

38 

46 150 150 150 150 46 

125 

25 

120 

7 

15 

15 

8 

175 

120 

3 

665 

38 590 

665 

117 50 

22 

285 

(SUSPENSION BOLT 

PITCH) 

4 - ø3.1 

(HOLE) 

4 

100 

2 

120 

5 

310 

145 

1 

20 

32 

280 

750 

830 

20 

32 

6 

30 

170 

252 

30 

(SUSPENSION BOLT PITCH) 

LEGEND 

42 

35 220 220 35 195 74 

480 

210 

Refrigerant liquid line (Narrow tube - ø 6.35) 

Refrigerant gas line (Wide tube - ø 12.70) 

1 

8 - ø3,1 

(HOLE) 

20 

13 

2 

Drain connection (outside diam. 32) 

Electrical junction box 

3 

107 

4 

200 

107 

Mounting for suspention 

Duct connection for discharge (ø 200) 

5 

6 

Duct connection for suction 

Fresh air intake (ø 150) 

7 

8 

Dimension: mm

Outdoor Unit 

Air discharge 

538 146 

Air intake 

830 

307 

337 

4 – ø12 holes 

19 

23 

630 

Wide tube service valve 

ø12.7 (1/2") 

Narrow tube service valve 

ø6.35 (1/4") 

305 

61 

95 

Unit : mm

F FUNCTION 

1)ROOM TEMPERATURE CONTROL 

Cooling 

• Room temperature control is obtained by cycling the compressor ON and OFF under control of the room 

temperature sensor in the remote control unit. 

SET T + 0,5 ϒC 

TEMPERATURE T ϒC 

NOTA 

COMPRESSOR 

OUTDOOR 

FAN 

INDOOR 

FAN 

MORE THAN 

5 MINUTES 

ON 

THERMO OFF 

MORE THAN 

3 MINUTES 

• The control circuit will not attempt to turn the compressor ON until the compressor has been OFF for at 

least 3 minutes. 

To protect the compressor from stalling out when trying to start against the high side refrigerant pressure, 

the control circuit has a built-in automatic time delay to allow the internal pressure to equalize. 

• As a protective measure, the control circuit switches the compressor OFF after 5 minutes or more of 

compressor operation. 

• Thermo ON: When the room temperature is above T + 1°C (T°C is set temperature). 

Compressor ➔ ON. 

• Thermo OFF: When the room temperature in equal to or below set temperature T°C. 

Compressor ➔ OFF. 

24 

ROOM TEMPERATURE 

THERMO 

ON THERMO 

OFF 

MORE THAN 

WITHIN 

3 MINUTES 

WITHIN 

5 MINUTES 

THERMO 

ON THERMO 

OFF 

5 MINUTES 3 MINUTES 5 MINUTES 

OFF 

ON 

OFF 

ON 

ON OFF 

ON 

OFF 

ON 

SET SPEED (MANUAL)

Heating 

SET TEMP. 

MORE THAN 

5 MINUTES 

T°C 

T-0.5°C 

COMPRESSOR 

OUTDOOR 

FAN 

INDOOR 

FAN 

STANDBY LAMP 

INDOOR HEAT 

EXCH. COIL 

TEMP. 35°C 

25°C 

SOLENOID COIL 

(4-WAY VALVE) 

OPERATION 

BUTTON 

OFF 

OFF 

OFF 

5 MINUTES 

THERMO 

OFF 

ON OFF 

ON OFF 

• The control circuit will not attempt to turn the compressor ON until the compressor has been OFF for at 

least 5 minutes. To protect the compressor from stalling out when trying to start against the high side 

refrigerant pressure, the control circuit has a built-in automatic time delay to allow the internal pressure to 

equalize. 

• As a protective measure, the control circuit switches the compressor OFF after 5 minutes or more of 

compressor operation. 

• Thermo ON: when the room temperature is below T -1°C (T°C is set temperature). 

Compressor ➔ ON. 

• Thermo OFF: when the room temperature is equal to or above set temperature T°C. 

Compressor ➔ OFF. 

25 

THERMO 

ON 

ROOM TEMP. 

THERMO 

OFF 

ON OFF 

ON OFF 

30 SECONDS 30 SECONDS 

LL SET SPEED LL SET SPEED LL 

❆ ❆ 

OFF ON OFF ON OFF ON 

OFF 

5 MINUTES 

ON (REVERSING CYCLE) 

OFF ON 

L L = Low low speed ❆ COLD DRAFT PREVENTION 

❆

2)FREEZE PREVENTION (COOLING) 

• This function prevents freezing of the indoor heat exchange coil. 

• When the compressor has been running for 10 minutes or more and the temperature of the indoor heat 

exchange coil falls below –1°C, the control circuit stops the compressor for at least 6 minutes. 

SET 

TEMP. 

INDOOR 

HEAT EXCH. 

COIL TEMP. 

T +0.5°C 

T°C 

–1°C 

COMPRESSOR 

INDOOR 

FAN 

ROOM TEMP. 

MORE THAN 

10 MINUTES 

3)OVERLOAD PREVENTION (HEATING) 

6 MINUTES 

ON OFF ON ON OFF ON 

SET SPEED SET SPEED 

26 

MORE THAN 

10 MINUTES 

• This function prevents overheating of the indoor heat exchange coil. 

For indoor units ADR518HW only 

INDOOR HEAT 

EXCH. COIL 

TEMP. °C 

61 

59 

52 

49 

OUTDOOR 

FAN 

INDOOR 

FAN 

COMPRESSOR 

ON OFF ON 

H o M o L H ➔ H, M ➔ M, L ➔ M 

THERMO OFF 

THERMO ON 

• When the temperature of the indoor heat exchange coil rises above 59°C, and if the indoor fan is L (low 

speed), then the fan speed changes from L (low speed) to M (medium speed). 

• When the temperature of the indoor heat exchange coil rises above 61°C, the outdoor fan stops. 

ON 

AFTER 

6 MINUTES 

H = High speed 

M = Medium speed 

L = Low speed

4)DEFROSTING OPERATION (Heating) 

• When the capacity of the unit has been decreesed due to frosting up of the outdoor heat exchanger during 

heating, the temperature drop gradient is detected by the microcomputer-controlled temperature sensing 

system, and defrosting operation is started. 

DEFROSTING FLOWCHART 

Temperature of indoor heat 

exchanger coil is lower than 

45°C 

YES 

Temperature in indoor heat 

exchanger coil drops 0.8 

deg/6 min. or more and 

repeats 3 times continuously. 

YES 

Integrated operating time of 

compressor is more than 

20 minutes. 

YES 

Compressor ON 

A B C 

Temperature of outdoor heat 

exchange coil is higher than 

12°C. 


compressor is longer than 

3 hours 

Compressor keeps running 

for 5 minutes 

Defrosting thermo in the 

outdoor unit is OFF. 

(Below 4°C) 

27 

YES 

Defrosting begins. 

Cold-draft prevention. 

Release of defrosting. 

NO 


compressor is longer than 

1.5 hours 

YES 

Thermo OFF 

(Compressor OFF) 

YES 

Temperature of indoor heat 

exchanger coil is lower than 

53°C. 

YES 

Thermo ON 

(Compressor ON) 

Defrosting time is over 

11.5 minutes.

5)DEFROSTING MODE TIMING CHART 

COMPRESSOR 

OUTDOOR 

FAN 

SOLENOID COIL 

(4-WAY VALVE) 

INDOOR 

FAN 

STANDBY LAMP 

INDOOR HEAT 

EXCH. COIL 

TEMP. 35°C 

L L = Low low speed 

START OF DEFROSTING RELEASE OF DEFROSTING 

32 SECONDS 

MAX. 11 MINUTES 32 SECONDS 

ON OFF 

ON ON OFF 

ON 

ON OFF 

ON 

2 SECONDS 

ON OFF 

ON 

SET SPEED OFF SET SPEED 

LL 

6)OUTDOOR FAN SPEED CONTROL (COOLING) 

OFF ON ON OFF 

28 

2 SECONDS 

• To optimize performance of the air conditioner, the outdoor fan speed is switched automatically according 

to the outdoor temperature. 

• If the outdoor air temperature falls below 28.5°C, the fan speed switches to LOW. 

• If the outdoor air temperature rises above 31.5°C for 5 minutes or longer, the fan speed switches to HIGH. 

• This function does not become active in heating operation. 

OUTDOOR AIR 

TEMPERATURE (°C) 

OUTDOOR FAN 

SPEED 

H = High speed 

L = Low speed 

31,5 

28,5 

H H 

L 

RELEASE OF 

COLD DRAFT PREVENTION

3) For AER518SCL3 only (3 phase and low ambient version) 

• When the outside ambient temperature decreases, the rotation speed of the outdoor fan is regulated by 

means of the outdoor heat-exchanger sensor to prevent liquid back. 

• The rotation speed varies with indoor temperature conditions (Hatching area). 

• The unit is protected against high pressure by means of the outside temperature sensor, and thus when 

the outside ambient temperature reaches 30°C respectively, the fan speed is forced to high. 

ROTATION SPEED OF FAN (rpm) 

1000 

800 

600 

400 

200 

0 

CONDITIONS: ROOM TEMPERATURE 19,4°C DB / 13,9°C WB 220V - 50 HZ 

▲ 

-10 -5 0 5 10 15 20 25 30 35 

OUTDOOR AMBIENT TEMPERATURE (°C) 

29 

▲ 

▲ 

900 rpm 

▲ 

▲ 

▲ 

▲ 

▲

G REFRIGERANT FLOW DIAGRAM 

COOLING MODE 

Indoor unit Outdoor unit 

HEAT PUMP MODE 

Indoor unit Outdoor unit 

30

H ELECTRIC WIRING DIAGRAMS WARNING 

TP1 

1 

2 

4 

5 

6 

7 

BLK 

WHT 

GRN/YEL 

BRN 

RED 

ORG 

YEL 

E 

FMI 

E 

GRY 

GRY 

WHT 

VLT 

ORG 

YEL 

BLK 

BRN 

PNK 

GRN/YEL 

LFS 

GRN/YEL 

1 2 3 4 

1 2 34 

11 

UNIT 

TH1 (COIL) 

2 2 

11 WHT 

SUP TH 

2 2 WHT 

9 9 GRY 1 1 

8 8 GRY 2 2 

TH2 (ROOM) 

77 

12P 

BODY 11 BLK 

66 VLT 66 VLT 4 THERMO 2 2 BLK 

55 ORG 55 ORG 9 

44 YEL 44 

YEL 1 

3 3 BLK 3 3 BLK 12 

11 WHT 

2 2 BRN BRN 2 2 BRN FMI PR 

2 2 WHT 

1 1 

11 

TR 235V P-O 

C1 

BLK 

BRN 

1 2 34 

1 2 34 

11 

22 UNIT 

TH1 (COIL) 

BLK 

SUP 11 WHT 

TH 

22 WHT 

9 9 GRY 11 

8 8 GRY 2 2 

TH2 (ROOM) 

77 

12P 

6 6 VLT 66 VLT 4 BODY 11 BLK 

5 5 ORG 55 ORG THERMO 2 2 BLK 

9 

4 4 YEL 4 4 YEL 1 

33 BLK 3 3 BLK 12 

2 2 BRN BRN 22 BRN 

1 1 WHT 

FMI PR 

2 2 WHT 

1 1 11 

TR 

235V P-C 

C1 

E 

DP 

PNK 

BLK 

BLK 

BLK 

BLK 

ADR518CW 

BLK 

11 BLK 

2 2 BLK 

1 1 BLU 

22 WHT 

GRY 

GRY 

WHT 

VLT 

ORG 

YEL 

BLK 

BRN 

PNK 

31 

RY 

PCB1 

1 

2 

FS 

PNK 

RED 

DP1 

DP2 

ADR518HW 

1 1 BLK 

SEC 

2 2 BRN 

REMOCON2 REMOCON1 

PCB1 

FMI 

1 1 

SS 

55 

1 1 

SS 

12 12 

E 

GRN/YEL 

19V 

S-O 

BLK 

BLK 

WHT 

GRN/YEL 

E 

GRN/YEL 

BLK 

BRN 

11 

2 2 

SEC 

TP1 

1 

2 

ORG 4 

S-0 

REMOTE 

CONTROL 

SWITCH 

19V 

11 

S S 

55 

BLK 11 BLK 

BLK 2 2 BLK 

LFS 

GRN/YEL 

E 

FS 

1 

2 

E 

REMOCON1 

To avoid electrical shock hazard, be 

sure to disconnect power before 

checking, servicing and/or cleaning 

any electrical parts 

REMOTE 

CONTROL 

SWITCH 

11 

SS 

1212 

REMOCON2 

DP1 

DP2 

BLU 

WHT 

11 

2 2 

GRN/YEL 

E DP BLK 

BLK


AE518SC3 

34 

WARNING 




any electrical parts


33 

WARNING 






34 

WARNING 





Outdoor unit AE518SH3 

WARNING 

To avoid electrical shock hazard, be sure to 

disconnect power before checking, servicing 

and/or cleaning any electrical parts. 

35

Outdoor unit AER518SH3 

WARNING 

To avoid electrical shock hazard, be sure to 

disconnect power before checking, servicing 

and/or cleaning any electrical parts. 

36

I TROUBLESHOOTING (cooling model) 

1)CHECK BEFORE AND AFTER “TROUBLESHOOTING” 

a) Check power supply wiring. 

•WARNING: 

If the following troubleshooting must be done with power being supplied, be careful about any uninsulated 

live part that can cause ELECTRIC SHOCK. 

b) Check inter-unit wiring. 

•Check that inter-unit wiring (both the power wiring and control wiring) is correctly connected to the 

indoor unit from the outdoor unit. 

ADR518CW- AE518SC 

POWER SUPPLY 

50 Hz - Single-phase 

220/230/240 V 

ADR518CW- AER/AE518SCL3 

POWER SUPPLY 

50 Hz - 3-phase 400V 

4 Wires 

(c) Check power supply 

POWER 

SUPPLY 

GROUND 

POWER 

SUPPLY 

GROUND 

OUTDOOR INTER-UNIT INDOOR 

WIRING 

UNIT UNIT 

➀ 

➁ 

➂ 

➃ 

➄ 


WIRING 

UNIT UNIT 

•Check that voltage is in specified range (± 10% of the rating). 

•Check that power is being supplied 

Single-phase systems Three-phase systems 

L 

N 

L1 

L2 

L3 

N 

230V 

➀ 

➁ 

➂ 

➃ 

➄ 

➅ 

➆ 

➇ 

37 

L1 

L2 

L3 

N 

400V 

400V 

➀ 

➁ 

➂ 

➃ 

➀ 

➁ 

➂ 

➃ 

➄ 

➅ 

➆ 

➇ 

400V 

230VV

2)SYSTEMATIC CHART OF “TROUBLESHOOTING” 

Air conditioner does not operate. 

Circuit breaker trips (or 

fuse blows). 

Neither indoor unit nor 

outdoor unit runs. 

38 

When circuit breaker is 

set to ON, it trips in a 

few moments. 

Circuit breaker trips in 

several minutes after 

turning air conditioner 

ON. 

Power is not supplied. 

Function of compressor 

winding protection 

works. 

Indoor unit sensor are 

defective. 

Open or short circuit. 

Limit float switch has 

operated “OPEN”. 

Indoor unit installed upside 

- down. 

Measure insulation 

resistance of power 

supply wires. 

Check capacity of circuit 

breaker. Meaure resistance 

of electrical components. 

Check power supply. 

Check drain pump and 

drain hose. 

Reposition the indoor 

unit.

3)AIR CONDITIONER DOES NOT OPERATE 

(a) Circuit breaker trips (or fuse blows) 

• When circuit breaker is set to ON, it trips in a few moments. (Resetting is not possible). 

• Measure insulation resistance there is a possibility of ground fault. If resistance value is 1MΩ or less, 

insulation is defective. 

ADR518CW - AE518SC 

Power 

supply 

Circuit 

breaker 

ADR518CW- AER/AE518SCL3 

Power 

sypply 

Unità 

esterna 

L1 

L2 

L3 

N 

5 

6 

7 

8 

Circuit 

breaker 

• Set circuit breaker to OFF. 

➀ Remove power supply wires 

from terminal plate in outdoor 

unit. 

• Measure insulation resistance of 

power supply wires. 

➁ Remove inter-unit wires from 

terminal plate in outdoor unit. 


outdoor unit. 

➂ Remove inter-unit wires from 

terminal plate in intdoor unit. 


intdoor unit. 

➃ Measure insulation resistance of 

inter-unit wires. 

� 

Unità Outdoor 

� 

Unità 

� 

esterna unit esterna 

� 

x 1 x x 

x 2 x x 

3 � 

4 4 x x 

5 

6 

5 

8 

7 

� 

Ground 

Inter-uni 

wiring 

x 

x 

x 

x 

5 

6 

�7 

8 Ground 

5 1 

6 

7 

8 2 

� 

4 

38 

1 

2 

� 

4 

5 

� 

Unità 

esterna 

Outdoor 

unit 

� � 

Unità 

esterna 

� 

x x 

x x 

OK 

OK 

x x 

x x 

Inter-unit 

wiring 

Do rewiring 

Insulation of outdoor 

unit is defective. 

Insulation of indoor unit 

is defective. 

Do rewiring. 

Indoor 

unit 

1 

2 

� 

4 

Indoor 

unit 

YES 

YES 

Measure insulation resistance 

of electrical parts in 

outdoor unit. 

Measure insulation resistance 

of electrical parts in 

indoor unit.

(b) Circuit breaker trips in several minutes after turning air conditioner ON. 

• There is a possibility of short circuit. 

Check capacity of circuit breaker. 

Capacity of circuit breaker is suitable? 

YES 

Measure resistance of compressor 

motor winding. 

OK 

Measure resistance of outdoor fan 


(c) Neither indoor unit nor outdoor unit runs 


Is power being supplied to wall 

receptacle? 

Leds of remote control unit are light 

Check is drain flow prevented? 

NO 

Check if the drain pump is working. 

Measure resistance of drain pump 


YES 

Check function of limit float switch. 

Float in high position: open circuit. 

Float in down position: short circuit. 

(Normal condition) 

YES 

Check installation of indoor unit is 

it installed upside - down? 

OK 

NO 

NO 

Replace it with suitable one. 

(larger capacity). 

40 

YES 

NO 

NO 

YES 

Circuit breaker is 

tripped. 

Power failure. 

Outdoor unit 

AE518SC3 

AER518SCL3ONLY 

Measure coil resistance of 

magnetic contactor. (MG or 

52C) 

Reset the breaker. 

Wait for recovery or contact 

power company. 

Check drain hose. 

Replace drain pump. 

Replace limit float switch. 

Reposition the indoor unit.

(d) Check fuse on PCB Ass’y in indoor unit 

Check fuse on PCB Ass’y in 

indoor unit for continuity. (F) 

Measure resistance of primary 

winding of transformer. 

(TR) 

Measure resistance of indoor 

fan motor winding. (FMI) 

Measure resistance of drain 

pump winding. 

If fuse blows, there is a possibility of short circuit. 

OK 

OK 

e) Check transformer in indoor unit 

Check whether transformere is detective. 

Measure resistance of primary and 

secondary winding. (TR) 

f) Check indoor fan motor protector 

Wait for 30 minutes and then try to run. 

Air conditioner does not run again. 

Indoor fan motor internal protector trips. 

Check fan rotation. Turn 

fan gently once or twice 

by hand. 

OK 

Air conditioner starts running. 

Fan cannot 

be turned 

4) ONLY OUTDOOR UNIT DOES NOT RUN 

39 

Measure coil resistance of power 

relay or magnetic contactor in outdoor 

unit. (PR - MG - 52C) 

PCB Ass’y in indoor unit is defective. 

Check fan casing for 

foreign matter on inside. 

Fan motor burnout or 

foreign matter in bearing. 

a) Outdoor unit does not run when air conditioner is in following conditions. 

• During thermo OFF. 

• During freeze prevention (for at least 6 minutes). 

• During drain pump works (for at least 12 minutes). 

b) PCB Ass’y in indoor unit is defective. 

Remove foreign matter 

or repair. 

Repair or replace.

•Check power relay in outdoor unit (only for AE518SC) 

• Check coil resistance of power 

relay. 

OK 

• PCB Ass’y defective. 

•Check negative phase relay (only for AE518SC/SCL3-AER/AE518SH3) 

• Check negative phase relay to 

see if it has operated. (47C) 

YES 

• Rewire power supply wires. 

5) COMPRESSOR MOTOR DOES NOT RUN (only for AE518SC) 

a) Single phase systems 230V - 1 - 50 Hz 

• Check compressor motor capacitor. 

(C1) 

OK 

• Measure resistance of compressor 


42 

• Check overload relay and/or 

compressor motor internal protector. 

(OLR - 49C) 

It has tripped 

• Is outdoor heat exchanger coil 

dirty or are there obstacles near 

air suction inlet of outdoor unit? 

NO 

• Check power supply voltage. Is 

voltage abnormally low? 

NO 

• Is temperature of compressor 

abnormally high? 

YES 

• Refrigerant gas shortage.

) Three - phase systems 400V - 3N - 50 Hz 

• Measure resistance of compressor 


Is outdoor heat exchanger coil dirty 

or are there obstacles near air suction 

inlet? 

YES 

Clean heat exchanger or remove 

obstacles. 

• Check compressor motor overcurrent 

relay (51C). 

It’s operated 

• Check power supply voltage. Is 

voltage abnormally low? 

NO 

• Check compressor. 

There is a possibility of locked 

rotor. 

NO 

90% or more of 

rated voltage 

Is temperature of compressor 

abnormally high? 

43 

YES 

Refrigerant gas shortage. 

YES 

Charge refrigerant gas.

L SOME PARTS OF AIR CONDITIONER DO NOT OPERATE 

1) ONLY INDOOR FAN DOES NOT RUN 

Check fan rotation. Turn fan gently 

once or twice by hand. 

Fan turn 

normal 

Check fan motor capacitor. 

OK 

Measure resistance of fan motor 

winding. 

OK 

Check output of fan motor terminals 

on PCB Ass’y. 

Fan cannot 

be turned 

NO 

NO 

44 

OK 





Replace capacitor. 

Replace fan motor. 

2) FUNCTION OF OUTDOOR FAN SPEED CONTROL DOES NOT WORK PROPERLY 

(only for SAP-C188E5) 

• Check thermostat in outdoor 

unit. (23S) 

3) ONLY OUTDOOR FAN DOES NOT RUN 



Measure the resistance of outdoor 

fan motor winding. 

OK 


Only for low ambient version 

units (AE518SCL3) 

Fan cannot 

be turned. 





Remove foreign 

matter or repair. 

Repair or replace. 

• Check electronic fan speed regulator 

(SSR) 




Defrost controller (POW-C92 GH) 

is defective in outdoor unit.

M AIR CONDITIONER OPERATES, BUT ABNORMALITIES OCCUR 

a) 

POOR COOLING 

Refrigerant 

flow failure 

Air circulation 

is a little 

b) Excessive cooling 

Is remote control unit installed at a 

place where it can detect room temperature 

properly! 

Check installation position of remote 

control unit. 

Does cool air from air conditioner 

reach position directly? 

Is cooling load too large? 

Measure temperatures of 

suction and discharge air 

of air conditioner. 

Check for clogging of air filter. 


Compressor is defective. 

Service valves are not fully open. 

Air filter is clogged. 

Is fan speed set to LOW? 

Long extension of ducts. 

Refrigerant tubes between indoor 

and outdoor units are not insulated. 

45 

YES 

Temperature difference 

is small 

Temperature difference between 

suction and discharge air is large 

enough (approx. 10°C or more). 

NO 

Change installation position of 

remote control unit. 

Review cooling load estimate. 

Possibility of 

gas shortage. 

Air filter is clogged 

Charge refrigerant gas. 

Replace. 

Open the valves fully. 

Charge refrigerant 

gas (R22 

R407C) 

Clean filter 

Clean filter in the air intake grille. 

Set the fan speed to either MEDIUM 

or HIGH. 

Use the booster cable. 

Insulate wide and narrow tubes 

separately. 

Change installation position of remote 

control unit.

N TROUBLESHOOTING (HEATING MODEL) 

1)CHECK BEFORE AND AFTER “TROUBLESHOOTING” 

a) Check power supply wiring. 

•WARNING: 

If the following troubleshooting must be done with power being supplied, be careful about any 

uninsulated live part that can cause ELECTRIC SHOCK. 

•Check that power supply wires are correctly connected to terminals: 

Single-phase system –No. 1 and No. 2 on the terminal plate in the outdoor unit. 

Three-phase system – ADR518HW/AE518SH - No. 1, 2, on the terminal 

plate in the outdoor unit. 

–ADR518HW / AE/AER518SH3 - No. 8, 9, 10 and 11 on terminal plate in the 

outdoor unit. 

b) Check inter-unit wiring. 

•Check that inter-unit wiring (both the power wiring and control wiring) is correctly connected to the 

indoor unit from the outdoor unit. 

ADR518HW - AE518SH 

POWER SUPPLY 

50 Hz - Single-phase 

220/230/240 V 

POWER 

SUPPLY 

ADR518HW - AE/AER518SH3 

POWER SUPPLY 

50 Hz - 3-phase 400V 

4 Wires 

POWER 

SUPPLY 

GROUND 

GROUND 

L1 

L2 

L3 

N 


UNIT POWER WIRING UNIT 

� 

� 

� 

� 

� 

� 

� 

GROUND 

INTER-UNIT 

CONTROL WIRING 

OUTDOOR POWER WIRING INDOOR 

UNIT UNIT 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

INTER-UNIT 

GROUND 

INTER-UNIT 

CONTROL WIRING 

46 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

� 

�

(c) Check power supply 

• Check that voltage is in specified range (± 10% of the rating). 

• Check that power is being supplied 

Single-phase systems Three-phase systems 

L 

N 

220V 

(d) Check lead wires and connectors in indoor and outdoor units. 

• Check that coating of lead wires is not damaged. 

• Check that lead wires and connectors are connected firmly. 

• Check that wiring is correct. 

L1 

L2 

L3 

N 

47 

400V 

400V 

400V 

230V

2)SYSTEMATIC CHART OF “TROUBLESHOOTING” 

Air conditioner does not operate. 

Circuit breaker trips (or 

fuse blows). 

Neither indoor unit nor 

outdoor unit runs. 

48 

When circuit breaker is 

set to ON, it trips in a 

few moments. 

Circuit breaker trips in 

several minutes after 

turning air conditioner 

ON. 

Power is not supplied. 

Function of compressor 

winding protection 

works. 

Indoor unit sensor are 

defective. 

Open or short circuit. 

Limit float switch has 

operated “OPEN”. 

Indoor unit installed 

upside - down. 


resistance of power 

supply wires. 

Check capacity of circuit 

breaker. Meaure 

resistance of electrical 

components. 


Check drain pump and 

drain hose. 

Reposition the indoor 

unit.

3)AIR CONDITIONER DOES NOT OPERATE 

(a) Circuit breaker trips (or fuse blows) 

•When circuit breaker is set to ON, it trips in a few moments. (Resetting is not possible). 

•Measure insulation resistance there is a possibility of ground fault. If resistance value is 1MΩ or less, 

insulation is defective. 

ADR518HW- AE518SH 

Power 

supply 

Circuit 

breaker 

ADR518CW - AE/AER518SH3 

Power 

supply 

L1 

L2 

L3 

N 

Circuit 

breaker 

� � � 

Unità Outdoor Unità 

esterna unit esterna 

� 

x x 

x x 

x 

x 

3 

4 

5 

� 

6 

Ground 

7 

8 

Unitx 

x 

x 

x 

49 

1 

2 

3 

4 

5 

6 

7 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

Inter-unit 

power wiring 

x x 

x x 

x x 

x x 

Inter-unit 

control wiring 

� � � 

Outdoor 

unit 

Unità 

esterna 

� 

x x 

x x 

� 

Ground 

Unità 

esterna 

8 

Inter-unit 

power wiring 

x x 

x x 

x x 

x x 

Inter-unit 

control wiring 

1 

2 

3 

4 

5 

6 

7 

1 

2 

3 

4 

5 

6 

7 

Indoor 

unit 

Indoor 

unit

• Set circuit breaker to OFF. 

➀ Remove power supply wires 

from terminal plate in outdoor 

unit. 


power supply wires. 

➁ Remove inter-unit wires from 

terminal plate in outdoor unit. 


outdoor unit. 

➂ Remove inter-unit wires from 

terminal plate in intdoor unit. 


intdoor unit. 

➃ Measure insulation resistance of 

inter-unit wires. 

OK 

OK 

50 

Do rewiring 

Insulation of outdoor 

unit is defective. 

Insulation of indoor unit 

is defective. 

Do rewiring. 

YES 

YES 


resistance of electrical parts 

in outdoor unit. 


resistance of electrical parts 

in indoor unit.

(b) Circuit breaker trips in several minutes after turning air conditioner ON. 

• There is a possibility of short circuit. 

Check capacity of circuit breaker. 

Capacity of circuit breaker is 

suitable? 

YES 

Measure resistance of outdoor fan 


OK 

Measure resistance of indoor fan 


(c) Neither indoor unit nor outdoor unit runs (leds of remote control unit are light) 


Is power being supplied to wall 

receptacle? 

Check is drain flow prevented? 

NO 

Check if the drain pump is working. 

Measure resistance of drain pump 


YES 

Check function of limit float switch. 

Float in high position: open circuit. 

Float in down position: short circuit. 

(Normal condition) 

YES 

Check installation of indoor unit it 

is installed upside - down? 

OK 

NO 

NO 

Replace it with suitable one. 

(larger capacity). 

In case of Heating 

operation: 

Measure resistance of 4-way 

valve’s winding. (20S or SC). 

51 

YES 

NO 

NO 

YES 

Circuit breaker is 

tripped. 

Power failure. 

Reset the breaker. 

Wait for recovery or 

contact power company. 

Check drain hose. 

Replace drain pump. 

Replace limit float switch. 

Reposition the indoor unit.

(d) Check fuse on PCB Ass’y in indoor unit 

Check fuse on PCB Ass’y in 

indoor unit for continuity. 

Measure resistance of 

primary winding of 

transformer. 


indoor fan motor winding. 

Measure resistance of drain 

pump winding. 

If fuse blows, there is a possibility of short circuit. 

OK 

OK 

e) Check transformer in indoor unit 

Check whether transformere is 

detective. 

Measure resistance of primary and 

secondary winding. 

f) Check indoor fan motor protector 

Wait for 30 minutes and then try to run. 

Air conditioner does not run again. 

Indoor fan motor internal protector trips. 

Check fan rotation. Turn 

fan gently once or twice 

by hand. 

OK 

Air conditioner starts running. 

Fan cannot 

be turned 

4) ONLY OUTDOOR UNIT DOES NOT RUN 

52 

Measure coil resistance of power 

relay or magnetic contactor in 

outdoor unit. 

PCB Ass’y in indoor unit is 

defective. 





a) Outdoor unit does not run when air conditioner is in following conditions. 

• During thermo OFF. 

• During freeze prevention (for at least 6 minutes). 

• During drain pump works (for at least 12 minutes). 

b) PCB Ass’y in indoor unit is defective. 

Remove foreign matter 

or repair. 

Repair or replace.

O SOME PARTS OF AIR CONDITIONER DO NOT OPERATE 

1) ONLY INDOOR FAN DOES NOT RUN 



Fan turn 

normal 


OK 

Measure resistance of fan motor 

winding. 

OK 

Check output of fan motor terminals 

on PCB Ass’y. 

Fan cannot 

be turned 

2) ONLY OUTDOOR FAN DOES NOT RUN 



Measure the resistance of outdoor 

fan motor winding. 

OK 


NO 

NO 

Fan cannot 

be turned. 

53 

OK 




foreign matter in 

bearing. 

Replace capacitor. 

Replace fan motor. 




foreign matter in 

bearing. 







Defrost controller (POW-C92 GH) 

is defective in outdoor unit.

3) ONLY COMPRESSOR DOES NOT RUN 

a) Single phase systems 230V - 1 - 50 Hz 


compressor motor winding. 

OK 

Check compressor motor 

capacitor. (Either C1 or BC). 

OK 

Check power supply voltage. 

Voltage is abnormally low. 

NO 

Check compressor. 

There is a possibility of 

locked rotor. 

Outdoor unit SAP-C188EH5 

Measure coil resistance of 

starting relay (SR) and 

power relay (PR). 


rated voltage. 

OK 

YES 

Either overload relay or 

internal protector is working. 

(Either OLR or 49C). 

54 

YES 

Temperature of compressor 

is abnormally high. 

YES 


NO 

Rotor may be locked up. 

Contact power utility company to 

have power voltage restored to 

normal 

YES 

YES 

Charge refrigerant gas 

(R22). 

Replace compressor.

) Three-phase systems 400V - 3N - 50 Hz 

Check negative phase relay (47C) 

to see if it has operated. 

NO 

Check magnetic contactor. (MG) 

O.K. 

Check thermal relay (51C) to see if 

it has operated. 

YES 

Check power supply voltage. 

Voltage is abnormally low. 

NO 


rated voltage. 

Check compressor. 

There is a possibility of locked 

rotor. 

Check compressor motor internal 

protector. (49C) 

YES 

YES 

Temperature of compressor is 

abnormally high. 

55 

YES 


NO 


Rewire power supply wires. 

Contact power utility company to 

have power voltage restored to 

normal 

Charge refrigerant gas.

P AIR CONDITIONER OPERATES, BUT ABNORMALITIES OCCUR 

a) 

POOR COOLING OR 

POOR HEATING 

Refrigerant 

flow failure 

Air 

circulation is 

a little 

Cold air is 

discharged 

Cold draft 

prevention is 

mal function 

b) Excessive cooling or heating 

Is remote control unit installed at a 

place where it can detect room 

temperature properly! 

Check installation position of 


Does cool or heat air from air 

conditioner reach position directly? 

Is heating or cooling load too 

large? 

4 way valve is defective. 

Measure temperatures of 

suction and discharge air 

of air conditioner. 

Check for clogging of air filter. 



Service valves are not fully open. 

Air filter is clogged. 

Is fan speed set to LOW? 

Long extension of ducts. 

Refrigerant tubes between indoor 

and outdoor units are not insulated. 

4 way valve is defective. 

“STANDBY” is displayed. 

Indoor coil sensor is defective. 

56 

YES 

Temperature 

difference is small 

Temperature difference between 

suction and discharge air is large 

enough (approx. 10°C or more). 

NO 



Review heating or cooling load 

estimate. 

Replace. 

Possibility of 

gas shortage. 

Air filter is clogged 

Charge refrigerant gas. 

Replace. 

Open the valves fully. 

Charge 

refrigerant gas 

(R22 or 407c) 

Clean filter 

Clean filter in the air intake grille. 

Set the fan speed to either MEDIUM 

or HIGH. 

Use the booster cable. 

Insulate wide and narrow tubes 

separately. 

Replace. 

Replace P.C.B. Ass’y in the indoor unit. 

Replace. 


remote control unit.

Q IF A SENSOR IS DEFECTIVE 

Indoor coil temp. thermistor (TH) is defective. 

Open 

Short 

When thermistor opens, the air conditioner will be in the following conditions as the controller tries to detect extremely 

low indoor coil temperature. 

IN COOLING MODE - Function of freeze prevention continues to work. That is the controller turns both compressor 

and outdoor fan motor periodically ON and OFF for several minutes. 

When thermistor is short, the air conditioner will be in the following conditions as the controller tries to detect extremely 

high indoor coil temperature. 

IN COOLING MODE - Function of freeze prevention will not work even when the frost builds up on indoor heat exchanger 

coil. 

Room temp. thermistors are defective (BTH and RTH). 

Open 

Short 

NOTE 

When thermistor opens, the air conditioner will be in the following conditions as the controller tries to detect extremely 

low room temperature. 

IN COOLING MODE - The air conditioner soon stops and will not start again. (Thermo. OFF). 

Neither outdoor fan nor compressor runs. 

When thermistor is short, the air conditioner will be in the following conditions as the controller tries to detect extremely 

high room temperature. 

IN COOLING MODE - The air conditioner continues to operate. (Thermo. ON). 

Both the outdoor fan and compressor do not stop. 

As a result, the room becomes too cold. 

Definition of Open or Short Circuit of Sensor (Thermistor) 

OPEN -A lead wire is broken or disconnected or the circuit inside the temperature sensor is open. 

SHORT -The protective cover of a lead wire has been damaged, and the exposed wire is touching another 

metal part, or both lead wires have become exposed and are touching each other. Alternatively, the 

circuit inside the temperature sensor is closed. 

57 

Thermistor Structure

S CHECKING ELECTRICAL COMPONENTS 

1) Measurement of Insulation Resistance 

• The insuration is in good condition if the resistance 

exceeds 1 MΩ. 

(a) Power Supply Wires 

Clamp the earthed wire of the power supply wires 

with the lead clip of the insulation resistance 

tester and measure the resistance by placing a 

probe on either of the power wires (Fig. 1). 

Then measure the resistance between the 

earthed wire and the other power wires (Fig. 1). 

(b) Indoor Unit 

Clamp an aluminium plate fin or copper tube with 

the lead clip of the insulation resistance tester 

and measure the resistance by placing a probe 

on ➀, and then ➁ on the terminal plate (Fig. 2). 

(c) Outdoor Unit 

Clamp a metallic part of the unit with the lead clip 

of the insulation resistance tester and measure 

the resistance by placing a probe on ➀, and then 

➁on the terminal plate (Fig. 2). 

(d) Measurement of Insulation Resistance for 

Electrical Parts 

Disconnect the lead wires of the disired electric 

part from terminal plate, PCB Ass’y, capacitor, 

etc. 

Similarly disconnect the connector. Then measure 

the insuration resistance. (Fig. 1 to 4). 

Refer to Electric Wiring Diagram. 

If the probe cannot enter the poles because the 

hole is too narrow then use a probe with a thinner 

pin. 

58

2) Checking Continuity of Fuse on PCB Ass’y 

• Remove PCB Ass’y from electrical component box. 

Then pull out the fuse from PCB Ass’y (Fig. 5). 

• Check continuity of fuse by the multimeter (Fig. 6). 

3) Checking Motor Capacitor 

Remove the lead wiers from the capacitor terminals, 

and then place a probe on the capacitor terminals 

as shown in Fig. 7. Observe the deflection 

of the pointer, setting the resistance measuring 

range of the multimeter to the maximum value. 

The capacitor is “good” if the pointer bounces to a 

great extent and then gradually returns to its original 

position. 

The range of deflection and deflection time deffer 

according to capacity of the capacitor. 

59

Via Varese, 90 - 21013 Gallarate - Va - Italy 

Tel. +39 0331 755111 - Fax +39 0331 776240 

www.argoclima.it 

Printed in italy

SPLIT SYSTEM AIR CONDITIONER TECHNICAL & SERVICE ...

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