Compressor Application - Embraco

1 CompressorManualApplicationThis manual may not be reproduced in whole or partwithout prior permission from Application Manual1 PageI. Introduction .. 03II. Refrigeration circuit .. 04 III. Hermetic 06IV. Diagnosing the problem .. 11V. Procedure for changing thehermetic 34VI. Further important 46 VII. Further information .. 64 IndexCompressor Application Manual2 Compressor Application Manual3 IntroductionIDear refrigeration professional!Since its incorporation in March 1971, Embracohas been doing its utmost to keep an ever closerrelationship with its customers. This relationshiphas been translated in its commitment tocontinuously provide timely technical informationthat contributes further to the professional know-how of our refrigeration professional purpose of this Manual is to facilitate yourwork.

2 It is a valuable aid to solving problems in therefrigeration system. You will find that you rarelyneed to change a hermetic Compressor . Generallythe faults are in other parts of the , however, you do need to substitute thecompressor, this Manual will help you do so step bystep, even if you do not have all the Manual also gives some tips on how to prolongthe working life of the hermetic information is easy to understand and keep this Manual in your you success in your and manysatisfied further information, consult our site on theInternet, at the following Application Manual4 The following figure shows you the essentialcomponents for the operation of mostrefrigeration drierSuperheatedrefrigerant fluidin gaseous form(high pressure)

3 Refrigerant fluid inliquidand/or blendedformMainevaporatorCold plate orSecondaryevaporatorCondenserSuction lineRefrigerant fluid ingaseous form (lowpressure)Capillary tubeFigure 1 - Operation of a basic refrigeration systemDischarge lineCompressor Application Manual5We will show below how a basic refrigerationsystem works:The Compressor draws in the refrigerant fluid fromthe evaporator by reducing the pressure in thiscomponent. The fluid is compressed by thecompressor and moves to the condenser. In thecondenser the refrigerant fluid under high pressurereleases heat to the environment and becomesliquid. The next component of the circuit is thecontrol device, which may be a capillary tube or anexpansion valve. The control element reduces thepressure of the liquid refrigerant which was formedin the condenser.

4 This drop in pressure permits therefrigerant to evaporate at low temperatures andreturn to the gaseous state when passing throughthe change from a liquid to gaseous state requiresheat. So the refrigerant fluid removes the heat frominside the refrigeration system through theevaporator. The condenser releases this heat intothe environment. The control element offers a certainresistance against the refrigerant's circulation,separating the high pressure (condenser) from thelow pressure (evaporator) refrigeration system also uses a filter drierwith desiccant to retain any water that may be leftin the oil cooling tube that exists in some compressorsis used to help reduce the Compressor , there are systems that use a suctionaccumulator to evaporate any residual liquidrefrigerant, stopping it from returning through thesuction Application Manual6 The Compressor is a very important item in therefrigeration circuit.

5 Its function is to circulate therefrigerant fluid inside the - Use of compressorsThe choice of a Compressor for certain refrigerationequipment depends on the following - Control DeviceAs mentioned above, every refrigerationsystem needs a control device. This maybe an expansion valve or capillary capillary-equipped circuits, thepressures on the suction and dischargesides are equal when the Compressor isstopped. In this kind of circuit, thecompressor is equipped with a lowstarting torque an expansion valve circuit, however,refrigerant only flows through the valvewhen the Compressor is switched on. So,the pressure between the suction anddischarge are not equal when thecompressor is stopped. In this case, thecompressor is equipped with a highstarting torque Application Manual7 The Compressor motors appropriate forthese two systems are called:LST Low Starting Torqueused in capillary High Starting Torque, used inexpansion valve ofApplicationLSTC apillaryRefrigerators,freezers anddrinking fountainsHST compressors may be used insystems using LST (capillary tube)compressors when the off cycles are shorter,not permitting equal equalized , LST compressors cannot be usedin expansion valve - Evaporation temperatureAnother factor influencing the choice ofthe Compressor is the evaporatortemperature range required by thesystem.

6 We now point out two extremesituations: Freezers that work at low temperatures,varying between -25oC (-13oF) and-35oC (-31oF).CompressorsIndicatedAll EmbracocompressorsHSTE xpansion valve(or Capillary)Only compressorswith the letter X inthe code of : FFI 12BX,FFI 12 HBX foodcounters, softdrink machines,Refrigeratedfood counters anddisplays andwalk-in refrigeratorsIIIC ompressor Application Manual8 Dehumidifier that works at an evaporatortemperature of over 0oC (32oF).Heat absorption by the refrigerant willdepend on the evaporator certain pressure corresponds to acertain temperature in the gas density is higher at lowtemperatures and, therefore, only a smallquantity of heat may be absorbed duringevaporation. If there is evaporation at ahigher temperature, for instance, 0oC(32oF), the pressure and density willincrease and more heat will be this reason, we can conclude thatthe work required by the motor in acompressor for a high evaporationtemperature will be more than thatrequired by the same Compressor at alow evaporation , motors to be used in highevaporation pressure systems must havea higher operating compressors can be classifiedaccording to their use as follows.

7 HBP High Back PressureHigh evaporation temperatureMBP Medium Back PressureMedium evaporation temperatureLBP Low Back PressureLow evaporation temperatureIIIC ompressor Application Manual9 When choosing the replacement model,it is very important to check the class ofthe original Compressor . As you know,the Compressor 's operating conditionscan vary according to each this way, some drinking fountains mayneed an HBP while others use an LBP orMBP - Type of refrigerant fluidEmbraco markets compressors for usewith R 12 and/or blends, R 134a andR 600a refrigerant compressors differ from eachother inside (motor, pump, oil type,displacement, etc.) in order to providethe best performance and guarantee ahighly reliable ofApplicationLBPL/MBPHBP-35oC to -10oC(-31oF to +14oF)-35oC to -5oC(-31oF to +23oF)-5oC to +15oC(+27oF to +59oF)Freezers& RefrigeratorsRefrigerated foodcounters and drinkingfountainsDehumidifiers, soft drinkmachines and drinkingfountainsIIID epending on what kind of compressormodel is involved, it may be used in arange from the LBP to HBP classification(see following table).

8 Compressor Application Manual10 IIIF igure 2 - Compressor labelFigure 3 - Compressor label forR 600a refrigerant fluidFigure 4 - Compressor label for R 134arefrigerant fluidFigure 5 - Label for Compressors that can use blendsTo facilitate identification, there arespecial labels on the compressorinforming the refrigerant fluid September 1997, Embraco hasapproved some refrigerant blends to beused in its compressors and only thosewith the respective label will besuitable for the blends approved to beused in the Embracocompressors are FX 56,MP 39, MP 66 and ISCEON 49. Blends approvedonly for use with theR 12 compressorsAttention! Compressor Application Manual11 Before changing any part of the refrigerationsystem, the good refrigeration professionalundertakes a full diagnosis to identify the realcause of the following table shows the most frequent failuresin a refrigeration system and their possible each problem presented, you will find itspossible causes marked with a ( ).

9 The problemsare listed in the upper part of the table. Followthe arrows and you will find a ( ) on eachpossible cause. In the same line as each causeyou will find the number of the item related to thenecessary actions to correct the problem. Look inthe Manual for the item corresponding to thataction and proceed with Application Manual12 Example:PROBLEMThe refrigerator refrigerates too much(1st column in Table of Main RefrigeratorProblems - Part 1).POSSIBLE CAUSEW rong connection in connection box(first ( ) in 1st column).STEPSItem When looking for this item in theManual you will find:Check the connections with the help ofthe refrigerator's electrical diagram. If theconnections are correct, go back to thetable and you will find another ( ) in the1st will be another possible cause of theproblem:Thermostat does not switch off.

10 You willfind the step to take in the same line ( ). Look in the Manual under this itemand the step will be there: Check if thethermostat bulb is correctly installed. Turnthe thermostat button to the lowest point(least cold) and check if the compressordisconnects. If the problem continues,substitute the thermostat. If necessary,you will also find other possible causesfor the problem, always accompanied bythe necessary steps. Try for yourself. Youwill see that it is much easier than it Application Manual13 Table of Main RefrigeratorProblems - Part 1 IVNo voltage at power supplyVery low voltage at power supplyVery high voltageInterrupted electric cable or wiringWrong connection at the terminal boardWiring or electrical components touchingmetal partsElectrical components interrupting the current flow tothe compressorInternal light does not switch offInadequate transformerInadequate groundingThermostat switched offThermostat with no current passing through contactsThermostat does not switch offThermostat adjusted to the maximum (coldest)Thermostat adjusted to the minimum (least cold)