Panasonic CU-2S18NBU-1 service manual Protection Control, Freeze Prevention control Cool

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12. Protection Control

12.1Freeze Prevention control (Cool)

When received freeze prevention signal from indoor unit, the compressor frequency changes according to indoor heat exchanger temperature.

When indoor unit request capability OFF due to freeze condition , immediately the capability supply to targeted indoor unit stops.

12.2Dew Prevention control (Cool)

When received dew prevention signal from indoor unit, the compressor frequency changes according to indoor intake temperature and indoor heat exchanger temperature.

12.3Electronic Parts Temperature Rise Protection 1 (Cool)

This control prevents electronic parts temperature rise during cooling overload condition.

Start conditions:

o Outdoor ambient temperature is at protection region as shown in figure below:

oOutdoor unit total current is above 5.5A

Control content

oOutdoor fan speed is adjusted accordingly.

Control stop condition

oWhen outdoor ambient temperature is back to normal region.

During this control, outdoor fan speed does not reduce for Quiet operation.

12.4Electronic Parts Temperature Rise Protection 2 (Cool)

This control prevents electronic parts temperature rise during cooling/dry operation.

Start conditions:

o Total current is at protection region as shown in figure below:

Control content

o Outdoor fan speed is adjusted accordingly.

Control stop condition

o When total current is back to normal region.

During this control, outdoor fan speed does not reduce for Quiet operation.

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Contents Table of Contents Disassembly and Assembly Instructions Items to be followed are classified by the symbols Safety PrecautionsPage Model Outdoor Unit CU-2S18NBU-1 SpecificationMulti split combination possibility Dimensions Refrigeration Cycle Diagram Block Diagram Wiring Connection Diagram Electronic Circuit Diagram Main Printed Circuit Board Printed Circuit BoardNoise Filter Printed Circuit Board Check Points Installation InformationOutdoor Unit Installation Diagram Installation InstructionOutdoor Unit Installation Guidelines Gas Leak Checking Connecting the Piping to Outdoor UnitEvacuation of the Equipment Heat Insulation Operation Control Powerful OperationCooling Operation Outdoor fan controlElectronic Parts Temperature Rise Protection 2 Cool Electronic Parts Temperature Rise Protection 1 CoolProtection Control Freeze Prevention control CoolIPM power transistor Protection Control Time Delay Safety Control Restart ControlCooling overload control Cool 12.7 30 seconds Force OperationCompressor Protection Control Gas leak detection control Valve close detection controlCompressor discharge high pressure protection control Wiring Error Check Servicing ModePump Down Operation Test OperationMode priority function Power Save ModeSelf Diagnosis Function Troubleshooting GuideIndoor high Check indoor heat Exchanger Outdoor Unit Removal Procedure Disassembly and Assembly InstructionsRemoving the Cabinet Top Plate and Cabinet Front Plate Remove the Control Board Cover and Particular PlatesRemoving the Propeller Fan and Fan Motor Removing the Control P.C. BoardPage Technical Data Operation CharacteristicsCS-S9NKUW-1 CU-2S18NBU-1 Page CS-S9NKUW-1x2 CU-2S18NBU-1 Page CS-S12NKUW-1 CU-2S18NBU-1 Page CS-S12NKUW-1x2 CU-2S18NBU-1 Page CS-S12NKUW-1+CS-S9NKUW-1 CU-2S18NBU-1 Page Exploded View and Replacement Parts List REF. no Description & Name QTY Shock Absorber Left