Panasonic CU-4KS31NBU Protective Functions, Current Control, Description of function

Page 69

7-2. Protective Functions

NOTE The numerical values such as temperature, frequency, time and current in parentheses are an example

of CU-4KS31NBU and the values are different from the other models.

7-2-1. Current Control

The operating current may rise as a result of causes including increasing cooling loads or decreases in power voltage. In these cases, the operating frequency is automatically reduced, or operation is stopped, in order to control the operating current so that it is (20 A) or less.

As a result:

Power breakers and fuses will not be tripped.

Operation can continue during this period with somewhat reduced cooling capacity.

Operation at normal capacity is restored when the cause of the current rise is eliminated.

Description of function

 

 

Example of operation for cooling

 

Current

(20A)

Power Point C

(16.6A)

Point A

 

(17A)

Point B

 

Target

 

frequency

 

Frequency

Frequency

 

 

Stops operation

 

 

Approx.3 minutes

 

Operates at the target frequency at Point A and below.

Stops increases to the frequency between Points A and B.

Reduces the frequency by 1 Hz per 0.5 seconds when Point B is exceeded.

Stops operation, and restarts it appoximately 3 minutes later, if Point C is exceeded. (May operate when sudden voltage fluctuations occur. Indicates trouble.)

(1)Automatic frequency control

The operating frequency is reduced automatically, or operation is stopped, in order to control the operating current so that it is at or below the values shown in the table below.

 

(20A)

 

COOL

 

 

Point C (peak cut trip)

(20.0)

 

 

Point B (Hz reduction)

(17.0)

 

 

Point A (Hz increase prohibit)

(16.6)

 

 

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Contents DC Inverter MULTI-SYSTEM AIR Conditioner Safety Precautions Prohibit Table of Contents Appendix a Semi-Concealed Type Wall Mounted TypeOperating Range Outdoor Unit CU-3KS19NBU Unit SpecificationsIndoor Unit CS-MKS9NKU × Duct Less Type RatedIndoor Unit Outdoor Unit208V CU-4KS24NBU BTU/h/W Compressor Locked Rotor Amperes 20,600 CU-4KS31NBU Indoor Unit CS-MKS9NKU 4units Outdoor Unit CU-4KS31NBU 1unit 24,200 Outdoor Unit Major Component SpecificationsOutdoor Unit CU-4KS24NBU Outdoor Unit CU-4KS31NBU CU-3KS19NBU CU-4KS24NBU CU-4KS31NBU Other Component SpecificationsDimensional Data Unit inchmm 852-0-0010-20500-0 Unit inchmm 852-0-0010-20600-0 Insulation of Refrigerant Tubing Refrigerant Flow DiagramIndoor unit Outdoor unitIndoor unit Outdoor unit 1/4 Strainer Header Sub Main Compressor Accumulator Temperature Charts Temperature Charts CU-3KS19NBUOutdoor Unit CU-3KS19NBU Indoor Unit CS-MKS7NKU × Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS9NKU × Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS12NKU × Cooling CharacteristicsOutdoor Unit CU-3KS19NBU Indoor Unit CS-MKS18NKU × Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS9NB4U × Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS12NB4U × Outdoor Unit CU-3KS19NBU Indoor Unit CS-KS18NB4UW × Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS7NKU × Temperature Charts CU-4KS24NBUOutdoor Unit CU-4KS24NBU Indoor Unit CS-MKS9NKU × Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS12NKU × Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS18NKU × Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS24NKU × Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS9NB4U × Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS12NB4U × Outdoor Unit CU-4KS24NBU Indoor Unit CS-KS18NB4UW × Temperature Charts CU-4KS31NBU Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS9NKU × Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS12NKU × Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS18NKU × Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS24NKU × Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS9NB4U × Outdoor Unit CU-4KS31NBU Indoor Unit CS-MKS12NB4U × Outdoor Unit CU-4KS31NBU Indoor Unit CS-KS18NB4UW × Indoor Outdoor Cooling CapacityCS-MKS12NB4U × Power Supply 230V Single Phase 60Hz Cooling CapacityCS-MKS9NKU × CS-KS18NB4UW + CS-MKS12NB4U + CS-MKS12NB4U 30,600 BTU/h CS-MKS9NB4U × Cooling Capacity Low Ambient 15,180 18,570 19,250 25,420 19,410 19,360 24,830 19,520 24,260 30,760 22,560 28,790 22,730 Outdoor Unit CU-3KS19NBU 8FA2-5251-11800-1 Electric Wiring DiagramsOutdoor Unit CU-4KS24NBU 8FA2-5251-11600-1 Outdoor Unit CU-4KS31NBU 8FA2-5251-11400-1 Explanation of Functions FunctionsCool DRY Fluctuation fanLow Ambient Cooling Operation Current Control Protective FunctionsDescription of function Automatic frequency controlCompressor Temperature Control Low Start CurrentCurrent control Precautions before Performing Inspection or Repair Troubleshooting Before Calling for ServiceTrouble Diagnosis by Error Monitor Lamps Location of the Error Monitor LampsDisplay of the Error Monitor Lamps Work procedure Check items unit operation Checking the Outdoor SystemChecking the outdoor unit Trouble Diagnosis of Each Part Problems of Each Part and Inspection PointsOutdoor control circuit board Inspection Points for Each PartFuse CompressorCU-3KS19NBU MV0 MV1 MV2 CU-4KS24NBU MV3 CU-4KS31NBU Electric expansion valveBranch tubing temperature sensor BreakerRefrigerant gas pressure Diagnostic results Diagnostic procedureRemedy for symptom 3 to Trouble Diagnosis of Fan MotorWhat is New Refrigerant R410A? Characteristics of New Refrigerant R410ACharacteristics Components mixing proportionsChecklist before Servicing Tools Specifically for R410A Tubing Installation ProceduresCase of Compressor Malfunction Procedure for Replacing CompressorExample Amount in the charging cylinder is less than 20%To prevent the composition R410A from changingCase Refrigerant is Leaking Welding leaking pointsRecharging Charging Additional Refrigerant When Tubes are ExtendedRetro-Fitting Existing Systems Use of Existing Units852-6-4190-581-00-1 For Outdoor Unit ContentsPlease Read Before Starting ‡ 8VHWKHIODUHPHWKRGIRUFRQQHFWLQJWXELQJ Fins of the outdoor unit. You may get injuredGeneral Installation Site Selection For wall-mounted unitsFor ceiling-mounted cassette units H1, H2, H3, H4 Connecting Indoor Units Connecting indoor unit for CU-3KS19NBUConnecting indoor unit for CU-4KS24NBU 815.88mm Locally purchased Connecting indoor unit for CU-4KS31NBU CS-MKS24NKU It is recommended to use baffle plates Baffle Plate for the Outdoor UnitFront BackAir Discharge Baffle Air Intake BafflePrecautions for installation CU-3KS19NBU Outer Dimensions of Outdoor UnitCU-4KS24NBU CU-4KS31NBUNever install only a single indoor unit Diagram of Outdoor Unit InstallationInstallation Process Flaring Procedure with a Flare ToolUse of the Flaring Method Tubing Connections To 0.5 mm Adjust so that the amount of tubeTo prevent heat loss and wet floors due to dripping of con Insulation of Refrigerant Tubing For wall-mounted units  For ceiling-mounted cassette unitsFinishing the Installation Air Purging Air Purging with a Vacuum Pump for Test Run Adapter manual, and use the adapter correctly External diameter of service port R410A 5/16Pump-down procedure What is pump-down? Pump Down If pump-down is not possibleWiring Instructions General Precautions on WiringRecommended Wire Length and Diameter Disconnect switch may be required by national or local codes For Outdoor Unit  For solid core wiring or F-cable How to connect wiring to the terminal For stranded wiring For Indoor UnitIndoor unit D Wiring Instructions for the Outdoor UnitIndoor unit B Indoor unit CChecking tubing and wiring Test RunPerforming a test run Installation Check Sheet Connecting a Home Automation DeviceDC1111-0