Panasonic CU-4KS31NBU service manual Low Ambient Cooling Operation

Page 68

< Low Ambient Cooling Operation >

When the outdoor air temperature reaches 57.2 °F (14 °C ) or less during the cooling operation, the operation mode is switched to low ambient cooling operation.

When the mode is switched from cooling opration to low ambient cooling operation, the compressor is stopped for 150 seconds temporarily.

When the mode has been switched to low ambient cooling operation, the outdoor fan speed is lowered as the outdoor air temperature falls.

Outdoor fan speed [ rpm ]

32 °F ( °C )

Outdoor air temperature

When the outdoor air temperature reaches 62.6 °F (17 °C ) or more during the low ambient cooling operation, the operation mode is switched to cooling operation.

The following protective actions are available to prevent the compressor from operating with abnormal loads.

At that time, they initiate thermo-off ( stopping the outdoor unit ) of the air conditioner.

Outdoor air temp. °F ( °C )

14(-10)

8.6 (-13)

Compressor

ON

OFF

ON

Indoor fan

ON

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Contents DC Inverter MULTI-SYSTEM AIR Conditioner Safety Precautions Prohibit Table of Contents Appendix a Wall Mounted Type Semi-Concealed TypeOperating Range Unit Specifications Outdoor Unit CU-3KS19NBUIndoor Unit CS-MKS9NKU × Duct Less Type RatedOutdoor Unit Indoor 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 Major Component Specifications Outdoor UnitOutdoor Unit CU-4KS24NBU Outdoor Unit CU-4KS31NBU Other Component Specifications CU-3KS19NBU CU-4KS24NBU CU-4KS31NBUDimensional Data Unit inchmm 852-0-0010-20500-0 Unit inchmm 852-0-0010-20600-0 Refrigerant Flow Diagram Insulation of Refrigerant TubingIndoor unit Outdoor unitIndoor unit Outdoor unit 1/4 Strainer Header Sub Main Compressor Accumulator Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS7NKU × Temperature ChartsTemperature Charts CU-3KS19NBU Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS9NKU × Cooling Characteristics Outdoor Unit CU-3KS19NBU Indoor Unit CS-MKS12NKU ×Outdoor 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 × Temperature Charts CU-4KS24NBU Outdoor Unit CU-4KS24NBU Indoor Unit CS-MKS7NKU ×Outdoor 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 × Cooling Capacity Indoor OutdoorPower Supply 230V Single Phase 60Hz Cooling Capacity CS-MKS12NB4U ×CS-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 Electric Wiring Diagrams Outdoor Unit CU-3KS19NBU 8FA2-5251-11800-1Outdoor Unit CU-4KS24NBU 8FA2-5251-11600-1 Outdoor Unit CU-4KS31NBU 8FA2-5251-11400-1 Functions Explanation of FunctionsCool Fluctuation fan DRYLow Ambient Cooling Operation Protective Functions Current ControlDescription of function Automatic frequency controlCurrent control Compressor Temperature ControlLow Start Current Troubleshooting Before Calling for Service Precautions before Performing Inspection or RepairDisplay of the Error Monitor Lamps Trouble Diagnosis by Error Monitor LampsLocation of the Error Monitor Lamps Checking the outdoor unit Work procedure Check items unit operationChecking the Outdoor System Problems of Each Part and Inspection Points Trouble Diagnosis of Each PartInspection Points for Each Part Outdoor control circuit boardFuse CompressorElectric expansion valve CU-3KS19NBU MV0 MV1 MV2 CU-4KS24NBU MV3 CU-4KS31NBURefrigerant gas pressure Branch tubing temperature sensorBreaker Diagnostic procedure Diagnostic resultsRemedy for symptom 3 to Trouble Diagnosis of Fan MotorCharacteristics of New Refrigerant R410A What is New Refrigerant R410A?Characteristics Components mixing proportionsChecklist before Servicing Tubing Installation Procedures Tools Specifically for R410AProcedure for Replacing Compressor Case of Compressor MalfunctionAmount in the charging cylinder is less than 20% ExampleTo prevent the composition R410A from changingRecharging Case Refrigerant is LeakingWelding leaking points When Tubes are Extended Charging Additional RefrigerantRetro-Fitting Existing Systems Use of Existing Units852-6-4190-581-00-1 Contents For Outdoor UnitPlease Read Before Starting Fins of the outdoor unit. You may get injured ‡ 8VHWKHIODUHPHWKRGIRUFRQQHFWLQJWXELQJGeneral For ceiling-mounted cassette units Installation Site SelectionFor wall-mounted units H1, H2, H3, H4 Connecting indoor unit for CU-4KS24NBU Connecting Indoor UnitsConnecting indoor unit for CU-3KS19NBU 815.88mm Locally purchased Connecting indoor unit for CU-4KS31NBU CS-MKS24NKU Baffle Plate for the Outdoor Unit It is recommended to use baffle platesFront BackAir Intake Baffle Air Discharge BafflePrecautions for installation Outer Dimensions of Outdoor Unit CU-3KS19NBUCU-4KS24NBU CU-4KS31NBUDiagram of Outdoor Unit Installation Never install only a single indoor unitUse of the Flaring Method Installation ProcessFlaring Procedure with a Flare Tool To 0.5 mm Adjust so that the amount of tube Tubing ConnectionsInsulation of Refrigerant Tubing To prevent heat loss and wet floors due to dripping of con For wall-mounted units  For ceiling-mounted cassette units Air Purging with a Vacuum Pump for Test Run Finishing the InstallationAir Purging External diameter of service port R410A 5/16 Adapter manual, and use the adapter correctlyWhat is pump-down? Pump-down procedure Pump Down If pump-down is not possibleRecommended Wire Length and Diameter Wiring InstructionsGeneral Precautions on Wiring Disconnect switch may be required by national or local codes How to connect wiring to the terminal For Outdoor Unit  For solid core wiring or F-cable For stranded wiring For Indoor UnitWiring Instructions for the Outdoor Unit Indoor unit DIndoor unit B Indoor unit CPerforming a test run Checking tubing and wiringTest Run Connecting a Home Automation Device Installation Check SheetDC1111-0