Friedrich WS10B10 service manual Refrigeration System Sequence of Operation

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REFRIGERATION SYSTEM SEQUENCE OF OPERATION

A good understanding of the basic operation of the refrigeration system is essential for the service technician. Without this understanding, accurate troubleshooting of refrigeration system problems will be more difficult and time consuming, if not (in some cases) entirely impossible. The refrigeration system uses four basic principles (laws) in its operation they are as follows:

1.“Heat always flows from a warmer body to a cooler body.”

2.“Heat must be added to or removed from a substance before a change in state can occur”

3.“Flow is always from a higher pressure area to a lower pressure area.”

4.“The temperature at which a liquid or gas changes state is dependent upon the pressure.”

The refrigeration cycle begins at the compressor. Starting the compressor creates a low pressure in the suction line which draws refrigerant gas (vapor) into the compressor. The compressor then “compresses” this refrigerant, raising its pressure and its (heat intensity) temperature.

The refrigerant leaves the compressor through the discharge Line as a hot High pressure gas (vapor). The refrigerant enters the condenser coil where it gives up some of its heat. The condenser fan moving air across the coil’s finned surface facilitates the transfer of heat from the refrigerant to the relatively cooler outdoor air.

When a sufficient quantity of heat has been removed from the refrigerant gas (vapor), the refrigerant will “condense” (i.e. change to a liquid). Once the refrigerant has been condensed (changed) to a liquid it is cooled even further by the air that continues to flow across the condenser coil.

The WallMaster design determines at exactly what point (in the condenser) the change of state (i.e. gas to a liquid) takes place. In all cases, however, the refrigerant must be totally condensed (changed) to a Liquid before leaving the condenser coil.

The refrigerant leaves the condenser Coil through the liquid line as a warm high pressure liquid. It next will pass through the refrigerant drier (if so equipped). It is the function of the drier to trap any moisture present in the system, contaminants, and large particulate matter.

The liquid refrigerant next enters the metering device. The metering device is a capillary tube. The purpose of the metering device is to “meter” (i.e. control or measure) the quantity of refrigerant entering the evaporator coil.

In the case of the capillary tube this is accomplished (by design) through size (and length) of device, and the pressure difference present across the device.

Since the evaporator coil is under a lower pressure (due to the suction created by the compressor) than the liquid line, the liquid refrigerant leaves the metering device entering the evaporator coil. As it enters the evaporator coil, the larger area and lower pressure allows the refrigerant to expand and lower its temperature (heat intensity). This expansion is often referred to as “boiling”. Since the unit’s blower is moving indoor air across the finned surface of the evaporator coil, the expanding refrigerant absorbs some of that heat. This results in a lowering of the indoor air temperature, hence the “cooling” effect.

The expansion and absorbing of heat cause the liquid refrigerant to evaporate (i.e. change to a gas). Once the refrigerant has been evaporated (changed to a gas), it is heated even further by the air that continues to flow across the evaporator coil.

The particular system design determines at exactly what point (in the evaporator) the change of state (i.e. liquid to a gas) takes place. In all cases, however, the refrigerant must be totally evaporated (changed) to a gas before leaving the evaporator coil.

The low pressure (suction) created by the compressor causes the refrigerant to leave the evaporator through the suction line as a cool low pressure vapor. The refrigerant then returns to the compressor, where the cycle is repeated.

Suction

Discharge

Line

Line

Condenser

EvaporatorCoil

Coil

Metering

Compressor

Device

Refrigerant Drier Liquid

RefrigerantLine

Strainer

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Contents Thru-the-wall Table Of Contents Important Safety Information Your safety and the safety of others are very importantRefrigeration System Hazards Introduction Property Damage HazardsFriedrich wallmaster Model Number Code Sleeve / Chassis Dimensions Performance DataElectrical Data Plug/Outlet/Circuit RatingElectric Shock Hazard Fire HazardTo adjust fan speed Electronic Control OperationTo activate Smart FanWS cool-only models To activate Smart FanWY/WE heat-cool modelsChecking Room Temperature To set the timerTo Activate Money Saver WY/WE models To adjust temperature To set mode of operationTo start unit Error Code Mode Testing the Electronic ControlElectronic Control Panel Automatic component protectionError Codes Listing for WS Models Error Codes Listing for WE/WY ModelsReboot the Control Panel E7 Motor Operation E9 Heat Pump FailureComponents Testing Coil SensorsFAN Motor FAN Motor TestCapacitors Heating ElementDrain PAN Valve Capacitor Check with Capacitor AnalyzerRefrigeration System Sequence of Operation 410A Sealed System Repair Considerations Refrigeration system under high pressure410A Sealed Refrigeration System Repairs Equipment RequiredEquipment Must be Capable Risk of Electric ShockBurn Hazard Method Of Charging / RepairsFreeze Hazard Undercharged Refrigerant Systems Overcharged Refrigerant SystemsRestricted Refrigerant System Hermetic Components Check Metering DeviceCheck Valve Capillary Tube SystemsReversing Valve DESCRIPTION/OPERATION POSITION, 4 Port Reversing ValveTesting the Coil Checking the Reversing ValveTouch Test in Heating/Cooling Cycle Procedure For Changing Reversing ValveExplosion Hazard Compressor Checks Single Phase Resistance Test Ground TestRecommended procedure for compressor replacement Compressor ReplacementHigh Temperatures Rotary Compressor Special Troubleshooting and Service Routine Maintenance Front Cover Sleeve / DrainClearances Room AIR Conditioner Unit Performance Test Data Sheet Date Model SerialGeneral Troubleshooting Tips General Troubleshooting Tips Cooling only Room AIR Conditioners Troubleshooting Tips Possible Cause Possible Solution Problem Possible Cause Possible Action HEAT/COOL only Room AIR Conditioners Troubleshooting Tips Heat Pump Troubleshooting Troubleshooting Chart Heating Heat Pump Troubleshooting Chart CoolingProblem System Cools When Heating is Desired Electrical Troubleshooting Chart Heat PumpYES Normal Function of Valve Malfunction of ValvePage Page Page Installation Accessories Wall Preparation Mounting Hardware ProvidedDescription QTY Installation Requirements MECHANICALCUT/SEVER HazardhazardInstallation Instructions for Baffle Adapter KIT BAK MECHANICALCUT/SEVER HazardWallMaster Thru-the-Wall CUT/SEVERInstallation Instructions Mechanical Hazard MECHANICALCUT/SEVER HazardAssembly & Installation Instructions Installation Instructions Subbase for WS, WE & WY Models Installation Instructions Architectural Grille Model AG MECHANICALCUT/SEVER Hazard WALLMASTER≤ THRU-THE-WALL AIR Conditioners Limited Warranty Technical Support Contact Information Page Page Friedrich AIR Conditioning CO