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TECHNICAL & SERVICE MANUAL
OUTDOOR UNIT : CU-3KS19NBU
CU-4KS24NBU
CU-4KS31NBU
DC INVERTER MULTI-SYSTEM AIR CONDITIONER
Capacity at 230V Outdoor Model No. Product Code No.
19,700 BTU/h CU-3KS19NBU 1 852 361 24
25,400 BTU/h CU-4KS24NBU 1 852 361 25
30,600 BTU/h CU-4KS31NBU 1 852 361 26
< Applicable Indoor Units >
CU-3KS19NBU
Wall mounted type
CS-MKS7NKU
CS-MKS9NKU
CS-MKS12NKU
CS-MKS18NKU
CS-MKS24NKU
Semi-concealed type
CS-MKS9NB4U & CZ-18BT1U
CS-MKS12NB4U & CZ-18BT1U
CS-KS18NB4UW & CZ-18BT1U
CU-4K
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SAFETY PRECAUTIONS • Before doing repair work, please read the " SAFETY PRECAUTIONS" carefully and fully understand them. • The precautionary items here are divided into " Warning" and " Caution" items. Items in particular which may cause death or serious injury to the service personnel if the work is not performed correctly, are included in the " Warning" table. However, even precautionary items identified as " Caution" also have the potential for serious consequences if
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Warning If refrigerant gas blows off during the work, do not touch the refrigerant gas as it may cause frostbite. Prohibit If refrigerant gas leaks during the work, ventilate the room. If refrigerant gas catches fire, harmful gas may be generated. Do not mix any gas other than the specified refrigerant gas in the refrigerating cycle. If air or other contaminants mix with the gas, pressure will become extremely high in the refrigerating cycle, which may cause a unit breakdown." Prohibit When th
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Table of Contents Page SAFETY PRECAUTIONS .............................................................................................................. 2 TABLE OF CONTENTS ...................................................................................................................... 4 APPLICABLE INDOOR UNITS ..................................................................................................... 6 1. OPERATING RANGE .........................................
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Page 9. REFRIGERANT R410A: SPECIAL PRECAUTIONS WHEN SERVICING UNIT 9-1. Characteristics of New Refrigerant R410A ......................................................................... 79 9-2. Checklist before Servicing ................................................................................................... 80 9-3. Tools Specifically for R410A ................................................................................................ 81 9-4. Tubing Installat
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APPLICABLE INDOOR UNITS Wall Mounted Type Indoor Unit CS-MKS7NKU CS-MKS9NKU CS-MKS12NKU CS-MKS18NKU CS-MKS24NKU Multi-Outdoor Unit 3-Room CU-3KS19NBU YES YES YES YES NO 4-Room CU-4KS24NBU YES YES YES YES YES 4-Room CU-4KS31NBU YES YES YES YES YES Semi-Concealed Type CS-MKS9NB4U CS-MKS12NB4U CS-KS18NB4UW Indoor Unit & & & CZ-18BT1U CZ-18BT1U CZ-18BT1U Multi-Outdoor Unit 3-Room CU-3KS19NBU YES YES YES 4-Room CU-4KS24NBU YES YES YES 4-Room CU-4KS31NBU YES YES YES 6
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1. OPERATING RANGE Temperature Indoor Air Intake Temp. Outdoor Air Intake Temp. Maximum 95 °F DB / 71 °F WB 115 °F DB Cooling Minimum 67 °F DB / 57 °F WB 14 °F DB 7
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2. SPECIFICATIONS 2-1. Unit Specifications Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS9NKU × 2 < 230V > Duct Less Type Rated Type 3-Room Multi Outdoor Unit Number of Connectable Indoor Units 3 Number of Operatable Indoor Units 3 Voltage Rating 230V Single-Phase 60Hz Cooling Total Capacity BTU/h 17,000 ( 6,800 to 18,800 ) kW 5.00 ( 1.90 to 5.50 ) Sensible Capacity 14,300 BTU/h Latent Capacity BTU/h 2,700 3 3 Air Circulation (High) ft /min (m /h) 1,707 (2,900) Available Voltage Range V 187 to 2
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Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS9NKU × 3 < 230V > Type 3-Room Multi Outdoor Unit Number of Connectable Indoor Units 3 Number of Operatable Indoor Units 3 Voltage Rating 230V Single-Phase 60Hz Cooling Total Capacity BTU/h 18,800 ( 9,800 to 18,800 ) kW 5.50 ( 2.90 to 5.50 ) Sensible Capacity 16,000 BTU/h Latent Capacity BTU/h 2,800 3 3 Air Circulation (High) ft /min (m /h) 1,707 (2,900) Available Voltage Range V 187 to 253 Running Amperes A 6.7 Power Input W 1,500 Power Factor % 98 EE
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Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS9NKU × 3 < 208V > Type 3-Room Multi Outdoor Unit Number of Connectable Indoor Units 3 Number of Operatable Indoor Units 3 Voltage Rating 208V Single-Phase 60Hz Cooling Total Capacity BTU/h 18,800 ( 9,800 to 18,800 ) kW 5.50 ( 2.90 to 5.50 ) Sensible Capacity 16,000 BTU/h Latent Capacity BTU/h 2,800 3 3 Air Circulation (High) ft /min (m /h) 1,707 (2,900) Available Voltage Range V 187 to 253 Running Amperes A 7.4 Power Input W 1,500 Power Factor % 98 EE
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Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS7NKU + CS-MKS9NKU × 2 < 230V > Duct Less Type Rated Type 4-Room Multi Outdoor Unit Number of Connectable Indoor Units 4 Number of Operatable Indoor Units 4 Voltage Rating 230V Single-Phase 60Hz Cooling Total Capacity BTU/h 24,200 ( 9,800 to 25,400 ) kW 7.10 ( 2.90 to 7.50 ) Sensible Capacity 20,300 BTU/h Latent Capacity BTU/h 3,900 3 3 Air Circulation (High) ft /min (m /h) 1,707 (2,900) Available Voltage Range V 187 to 253 Running Amperes A 10.7 Power
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Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS9NKU × 3 < 230V > Type 4-Room Multi Outdoor Unit Number of Connectable Indoor Units 4 Number of Operatable Indoor Units 4 Voltage Rating 230V Single-Phase 60Hz Cooling Total Capacity BTU/h 25,400 ( 9,800 to 25,400 ) kW 7.50 ( 2.90 to 7.50 ) Sensible Capacity 21,400 BTU/h Latent Capacity BTU/h 4,000 3 3 Air Circulation (High) ft /min (m /h) 1,707 (2,900) Available Voltage Range V 187 to 253 Running Amperes A 11.3 Power Input W 2,560 Power Factor % 98 E
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Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS9NKU × 3 < 208V > Type 4-Room Multi Outdoor Unit Number of Connectable Indoor Units 4 Number of Operatable Indoor Units 4 Voltage Rating 208V Single-Phase 60Hz Cooling Total Capacity BTU/h 24,400 ( 9,800 to 24,400 ) kW 7.20 ( 2.90 to 7.20 ) Sensible Capacity 20,600 BTU/h Latent Capacity BTU/h 3,800 3 3 Air Circulation (High) ft /min (m /h) 1,707 (2,900) Available Voltage Range V 187 to 253 Running Amperes A 12.1 Power Input W 2,460 Power Factor % 98 E
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Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS7NKU × 3 + CS-MKS9NKU < 230V > Duct Less Type Rated Type 4-Room Multi Outdoor Unit Number of Connectable Indoor Units 4 Number of Operatable Indoor Units 4 Voltage Rating 230V Single-Phase 60Hz Cooling Total Capacity BTU/h 29,000 ( 9,800 to 29,000 ) kW 8.50 ( 2.90 to 8.50 ) Sensible Capacity 24,400 BTU/h Latent Capacity BTU/h 4,600 3 3 Air Circulation (High) ft /min (m /h) 1,942 (3,300) Available Voltage Range V 187 to 253 Running Amperes A 11.4 Power
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Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS9NKU × 4 < 230V > Type 4-Room Multi Outdoor Unit Number of Connectable Indoor Units 4 Number of Operatable Indoor Units 4 Voltage Rating 230V Single-Phase 60Hz Cooling Total Capacity BTU/h 30,600 ( 9,800 to 30,600 ) kW 9.00 ( 2.90 to 9.00 ) Sensible Capacity 25,800 BTU/h Latent Capacity BTU/h 4,800 3 3 Air Circulation (High) ft /min (m /h) 1,942 (3,300) Available Voltage Range V 187 to 253 Running Amperes A 12.3 Power Input W 2,800 Power Factor % 99 E
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Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS9NKU × 4 < 208V > Type 4-Room Multi Outdoor Unit Number of Connectable Indoor Units 4 Number of Operatable Indoor Units 4 Voltage Rating 208V Single-Phase 60Hz Cooling Total Capacity BTU/h 28,600 ( 9,800 to 28,600 ) kW 8.40 ( 2.90 to 8.40 ) Sensible Capacity 24,200 BTU/h Latent Capacity BTU/h 4,400 3 3 Air Circulation (High) ft /min (m /h) 1,942 (3,300) Available Voltage Range V 187 to 253 Running Amperes A 12.7 Power Input W 2,560 Power Factor % 99 E
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2-2. Major Component Specifications 2-2-1. Outdoor Unit Outdoor Unit CU-3KS19NBU Control PCB Part No. CB-CU-3KS19NBU Controls Microprocessor Control Circuit Fuse 250V 25A Compressor Type DC Twin Rotary (Hermetic) Compressor Model / Nominal Output 5KD240XAB21 / 1,700W Compressor Oil ... Amount Pints (cc) FV50S ... 1.91 (900) Coil Resistance (Ambient Temp. 68 °F (20 °C)) Ohm U - V : 0.720 V - W : 0.708 W - U : 0.726 Safety Device CT (Peak current cut-off control) Yes Compressor Discharge
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Outdoor Unit CU-4KS24NBU Control PCB Part No. CB-CU-4KS24NBU Controls Microprocessor Control Circuit Fuse 250V 25A Compressor Type DC Twin Rotary (Hermetic) Compressor Model / Nominal Output 5KD240XAB21 / 1,700W Compressor Oil ... Amount Pints (cc) FV50S ... 1.91 (900) Coil Resistance (Ambient Temp. 68 °F (20 °C)) Ohm U - V : 0.720 V - W : 0.708 W - U : 0.726 Safety Device CT (Peak current cut-off control) Yes Compressor Discharge Temp. Control Yes Operation cut-off control in abnormal am
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Outdoor Unit CU-4KS31NBU Control PCB Part No. CB-CU-4KS31NBU Controls Microprocessor Control Circuit Fuse 250V 25A Compressor Type DC Twin Rotary (Hermetic) Compressor Model / Nominal Output 5JD420XAB22 / 3,000W Compressor Oil ... Amount Pints (cc) FV50S ... 2.55 (1,200) Coil Resistance (Ambient Temp. 68 °F (20 °C)) Ohm U - V : 0.435 V - W : 0.441 W - U : 0.452 Safety Device CT (Peak current cut-off control) Yes Compressor Discharge Temp. Control Yes Operation cut-off control in abnormal
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2-3. Other Component Specifications Quantity of Sensor Model No. Sensor Name of sensor CU-3KS19NBU CU-4KS24NBU CU-4KS31NBU Outdoor air temp sensor TKS295B 1 1 1 Outdoor heat exchanger sensor TKS292B 1 1 1 AW / AN sensor TKS292B 1 / 1 1 / 1 1 / 1 BW / BN sensor TKS292B 1 / 1 1 / 1 1 / 1 CW / CN sensor TKS292B 1 / 1 1 / 1 1 / 1 DW / DN sensor TKS292B 0 1 / 1 1 / 1 40 35 30 25 20 15 10 5 0 -4 5 14 23 32 41 50 59 68 (-20)(-15)(-10) (-5) (0) (5) (10) (15) (20) Temperature F ( C) Quantity of Sensor
