Compressor Application Manual
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Index Page I. Introduction ........................................................... 03 II. Refrigeration circuit ............................................... 04 III. Hermetic compressor ............................................ 06 IV. Diagnosing the problem ........................................ 11 V. Procedure for changing the hermetic compressor ............................................ 34 VI. Further important recommendations ..................... 46 VII. Further information ...............
2 Compressor Application Manual
I Introduction Dear refrigeration professional! Since its incorporation in March 1971, Embraco has been doing its utmost to keep an ever closer relationship with its customers. This relationship has been translated in its commitment to continuously provide timely technical information that contributes further to the professional knowhow of our refrigeration professional partners. The purpose of this Manual is to facilitate your work. It is a valuable aid to solving problems in the refrigeration system.
II Refrigeration Circuit The following figure shows you the essential components for the operation of most refrigeration circuits.
II We will show below how a basic refrigeration system works: The compressor draws in the refrigerant fluid from the evaporator by reducing the pressure in this component. The fluid is compressed by the compressor and moves to the condenser. In the condenser the refrigerant fluid under high pressure releases heat to the environment and becomes liquid. The next component of the circuit is the control device, which may be a capillary tube or an expansion valve.
Hermetic compressor The compressor is a very important item in the refrigeration circuit. Its function is to circulate the refrigerant fluid inside the circuit. 1 - Use of compressors The choice of a compressor for certain refrigeration equipment depends on the following factors: 1.1 - Control Device As mentioned above, every refrigeration system needs a control device. This may be an expansion valve or capillary tube.
III The compressor motors appropriate for these two systems are called: LST – Low Starting Torque used in capillary systems. HST – High Starting Torque, used in expansion valve systems. Classification Control System LST Capillary Expansion valve HST (or Capillary) Compressors Indicated Example of Application All Embraco Refrigerators, freezers and compressors Only compressors with the letter X in the code of model e.g.: FFI 12BX, FFI 12HBX etc...
• Dehumidifier that works at an evaporator temperature of over 0oC (32oF). Heat absorption by the refrigerant will depend on the evaporator temperature. A certain pressure corresponds to a certain temperature in the evaporator. The gas density is higher at low temperatures and, therefore, only a small quantity of heat may be absorbed during evaporation. If there is evaporation at a higher temperature, for instance, 0oC (32oF), the pressure and density will increase and more heat will be absorbed.
III Depending on what kind of compressor model is involved, it may be used in a range from the LBP to HBP classification (see following table).
III To facilitate identification, there are special labels on the compressor informing the refrigerant fluid used. Figure 3 - Compressor label for R 600a refrigerant fluid Figure 2 - Compressor label Figure 4 - Compressor label for R 134a refrigerant fluid ! Since September 1997, Embraco has approved some refrigerant blends to be used in its compressors and only those with the respective label will be Attention suitable for the blends.
IV Diagnosing the problem Before changing any part of the refrigeration system, the good refrigeration professional undertakes a full diagnosis to identify the real cause of the problem. The following table shows the most frequent failures in a refrigeration system and their possible causes. For each problem presented, you will find its possible causes marked with a (•). The problems are listed in the upper part of the table. Follow the arrows and you will find a (•) on each possible cause.
Example: IV PROBLEM The refrigerator refrigerates too much (1st column in Table of Main Refrigerator Problems - Part 1). POSSIBLE CAUSE Wrong connection in connection box (first (•) in 1st column). STEPS Item 2.2. When looking for this item in the Manual you will find: Check the connections with the help of the refrigerator's electrical diagram. If the connections are correct, go back to the table and you will find another (•) in the 1st column.
IV Table of Main Refrigerator Problems - Part 1 EXCESSIVE REFRIGERATION INSUFFICIENT REFRIGERATION ELECTRICAL SHOCK NOISES EXTERNAL SWEATING OF THE CABINET INTERNAL SWEATING OF THE CABINET HIGH POWER CONSUMPTION DOES NOT WORK COMPRESSOR DOES NOT SWITCH ON/OVERLOAD PROTECTOR NOT WORKING DOES NOT WORK COMPRESSOR DOES NOT SWITCH ON/OVERLOAD PROTECTOR WORKING DOES NOT WORK COMPRESSOR SWITCHES ON/OVERLOAD PROTECTOR WORKING POSSIBLE CAUSES - ELECTRICAL ORIGIN MEASURES See item in Chap.
IV Table of Main Refrigerator Problems - Part 2 EXCESSIVE REFRIGERATION INSUFFICIENT REFRIGERATION ELECTRIC SHOCK NOISES EXTERNAL SWEATING OF THE CABINET INTERNAL SWEATING OF THE CABINET HIGH POWER CONSUMPTION DOES NOT WORK COMPRESSOR DOES NOT SWITCH ON/OVERLOAD PROTECTOR NOT WORKING DOES NOT WORK COMPRESSOR DOES NOT SWITCH ON/OVERLOAD PROTECTOR WORKING DOES NOT WORK COMPRESSOR SWITCHES ON/OVERLOAD PROTECTOR WORKING POSSIBLE CAUSES - MECHANICAL ORIGIN Condenser improperly fixed - metal tubes touching 8.
IV 1 - Problems and Solutions 1.1 - Voltage 1.1.1 - No voltage at power supply Check using a voltmeter or test lamp. 1.1.2 - Very low voltage at power supply To eliminate problems of voltages below 103 V (115 V nominal) and 198 V (220 V nominal), at the end of the Manual we recommend the use of a voltage stabilizer. When the compressor does not start, the problem can be solved most often by using the right starting capacitor. 1.1.
2.2 - Wrong connection at the terminal board Check the connections using the refrigerator's electrical diagram. 2.3 - Wiring or electrical components touching metal parts Check if there is a fault in the insulation of an electrical component that is touching metal parts. Correct the defect. 2.4 - Electrical components interrupting the current flow to the compressor Defect in such components as thermostat, auxiliary transformer, timer, etc. Check. 2.
IV 4 - Thermostat 4.1 - Thermostat switched off Turn the thermostat button to maximum (coldest) and see if the compressor starts. 4.2 - Thermostat with no current passing through contacts Install a bridge wire between the thermostat terminals. If the compressor starts, substitute the thermostat. 4.3 - Thermostat does not switch off Check if the thermostat bulb is correctly installed. Turn the thermostat button to the minimum (least cold) and check if the compressor disconnects.
4.6 - Thermostat making noise Inform the user that a clicking noise is normal when the thermostat switches on and off. In any case, please check whether the thermostat is correctly installed. 4.7 - Thermostat with loose bulb Correctly install the thermostat bulb. 4.8 - Thermostat with incorrect bulb position Install the bulb according to manufacturer's specifications. 4.9 - Thermostat with failure or irregular operation Substitute the thermostat. 4.
5.2 - Faulty overload protector IV Ther mal pr otector 3/4" Thermal protector Check if there is oxidation at the terminals and if the bimetal thermal protector disk is not twisted. Also check if there is continuity between 3 in 1 terminals (fig. 6). In the case of damage or no current, substitute the protector and starting relay.
6 - Start Relay IV Remove the compressor relay, check to see if the start relay is to specification. The relays for high starting torque compressors, models "X" (e.g., FF 8.5BX / FF 10BX and FFI 12HBX), must not have a bridge (copper wire) between terminals 11 and 13. This connection must be made through the start capacitor. For the other models, however, where the use of the capacitor is 11 not obligatory, the relays must 10 13 have a bridge connecting 12 terminals 11 and 13.
6.2 - EM electromechanical relay IV 4 3 2 1 6.2.1 - With the relay in any position, check if there is continuity between relay terminals 1 and 2. If not, change the relay. Figure 15 - EM relay 1 2 3 4 6.2.2 - With the relay in the vertical position, relay coil upwards, check if there is continuity between relay terminals 1 and 3. If not, change the relay and repeat item 6.2.1. Figure 16 - EM relay 6.2.
6.3 - PTC Relay IV With the help of an ohmmeter, measure the ohmic resistance between terminals 2 and 3. At room temperature, the figures must be near those in the above table: Relay – PTC* Ohm Resistance (! = OHMS) 1 4 8EA1BX 2,8 a 5,2 ! 2 3 7M4R7XXX / 8M4R7XXX / 8EA14CX 3,8 a 5,6 ! 8EA4BX / 8EA3BX / 8EA21CX 3,5 a 6,5 ! 8EA5BX 14 a 26 ! 7M220XXX / 8M220XXX / 8EA17CX 17,6 a 26,4 ! Figure 17 – PTC * The (X) can be a number or a character.
IV 7 - Starting Capacitor 7.1 - Incorrect starting capacitor Check if the capacitance and voltage values are suitable for the compressor. Consult the Embraco Compressor Application Table or the manufacturer of the refrigeration system. If the capacitance value is wrong, change the capacitor for the one recommended. 7.2 - Faulty starting capacitor ! Check that the voltage in the output is the same as that showing on the capacitor. Caution Do not touch the terminals of a charged capacitor.
8 - Pipes and Components 8.1 - Condenser improperly fixed metal tubes touching With the compressor in operation, check the metal parts in contact. For example, the capillary touching the filter dryer, condenser incorrectly installed in the cabinet etc. (fig. 21). 8.2 - Partial blockage in tubes Blocked tubes generally occur as a result of incorrect brazing (excessive additional material), solid particles from deterioration of the filter drier desiccant or excessive bending in the tube.
8.3 - Capillary blockage due to water / wax / paraffin IV Check if ice has formed at the entrance to the evaporator. Warm this point and check if the refrigerant fluid starts circulating. If so, it is a sign that there is water in the system. In this case, you must remove the water from the circuit replace the filter drier and put in a new refrigerant fluid charge. (See the necessary procedures for changing the hermetic compressor from page 34 onwards in this Manual).
8.4 - Dirty / covered condenser or no air circulation Clean the condenser and unblock the air passages. 9 - Noise caused by other Components or Problems 9.1 - Incorrect leveling of refrigerator or compressor base If there is a noise, check if it disappears when the refrigerator is leveled. 9.2 - Noise caused by other components Check if the noise starts in components such as: fan, thermostat, transformer, voltage stabilizer, etc. 9.
IV 11 - Wrong Location for the Refrigerator 11.1 - Ventilation and other causes The refrigeration system must not be placed next to stoves, sun-exposed walls and places without ventilation. The refrigeration system loses its performance when in the aforementioned situations. Figure 22 – Kitchen 12 - Very High Relative Humidity (over 85%) 12.1 - Climatic conditions Explain to the customer that this is not a defect in the refrigerator but a characteristic of the regional climate.
13 - Refrigerator without Freezer Tray 13.1 - Missing or wrong use of the tray Check if the dividing tray is being used and if it is installed correctly (in single-door refrigerators). 14 - Refrigerator Used in Excess 14.1 - Frequent door opening Instruct the user not to open the door so frequently. 15 - Refrigerator Used Incorrectly 15.1 - Lack of internal air circulation Instruct the user not to use plastic towels on the shelves, nor use the tray deflector in the defrosting position, etc.
IV 17 - Refrigerant Fluid 17.1 - Expansion of refrigerant in evaporator Explain to the customer that it is normal that there is a certain noise when expansion occurs. The noise level varies according to the type of evaporator and refrigerator. 17.2 - Excess refrigerant fluid charge in the refrigerator Check if there is condensation on the suction line, outside the cabinet. If so, install the correct refrigerant fluid charge. 17.
compressors with the letter "X" (FF BX and FF HBX) in their name or FG compressors with the specific relay to change it to HST (see item 3.2 in Chapter VI) must be used. IV 19 - Compressor 19.1 - Compressor connected to a voltage different from the one specified Use a transformer or change the compressor. 19.2 - Compressor winding interrupted or burned out With the help of an ohmmeter, measure the main and auxiliary coil resistances.
IV 19.3 - Compressor with current leakage to the housing Connect the megohmeter terminals to the common pin of the hermetic terminal and grounding terminal of the compressor. With 500V/DC voltage, the reading should show a resistance of over 2MΩ. If there is no megohmeter, use a test lamp as follows: connect one of the test points to the common pin of the hermetic terminal and another to the grounding terminal of the compressor. If the bulb lights up, change the compressor.
19.4 - Incorrect compressor installation / fixation Check if the rubber grommets are too tight. If so, loosen them, otherwise this detracts from the vibration damping. Bolt Nut Rubber dampers Washer Sleeve Compressor base Cabinet base INCORRECT CORRECT Figure 25 - Rubber Dampers 19.5 - Compressor inadequate for the system Consult the Embraco Compressor Application Table. Change the compressor for the right model. 19.6 - Compressor with low capacity This defect is not common.
IV ! 19.7 - Compressor with internal noise If the noise continues after analyzing all the aspects described above, it might come from the compressor. In this case, change it. Important Do not mistake noises inside the compressor with noises from the refrigeration system (see items 8.1, 9.1, 9.2 and 9.3) 19.8 - Compressor locked (stalled) Check all possible causes described above. If necessary, change the compressor. ! 19.
Procedure V for changing the hermetic compressor After completing all the analyses on possible faults in the refrigeration system, you will be able to decide whether the compressor really needs to be changed or not. Before starting the change process, you must be sure that a compressor model is available with identical characteristics to the original system, refrigerant and compatible filter drier, in addition to the proper tools and equipment.
V The compr essor must not be switched on compressor without its being pr operly installed in the properly refrigeration system! When buying a new Embraco compressor, do not do unnecessary tests. The factory has already tested it, as you can seen in the guarantee seal accompanying it. Only remove the plugs from the compressor tubes at the time when it is installed in the refrigeration system. In this way you will prevent moisture and dirt from entering the compressor.
14 15 16 17 18 19 20 21 22 - Soldering rods; Brazing flux; Vacuum gauge; Oxy-acetylene or axi-gas welding equipment; Device for checking electricity range (multimeter, test lamp and others); Pressure/hose analyzer with retention valve; Connectors/fast couplings/hoses with manifold; Universal pliers; Small clamp 2 - How to remove a used compressor • We recommend that the used refrigerant fluid is collected for later recycling or incineration, according to the following procedure: First, install a perforati
V • Undo the connections from the electrical starting and protection devices; • Remove all oxidation and paint using sandpaper (fig. 26.a) in the brazing region, to facilitate brazing later; • Warm the brazing region (fig. 26.b) in order to separate the compressor from the system's piping; • After cooling, close off the compressor tubes and system's tubes with rubber plugs (fig. 26.c); • Loosen the locks that fix the compressor base to the system. Figure 26.a - Sand papering the tube Figure 26.
3 - How to Remove the Filter Drier Remember that changing the compressor also requires a change of the filter drier, in the order as follows: Slowly warm the soldering region of the capillary with the filter dryer and, at the same time, pull the capillary with pliers, using moderate force not to break it inside the filter drier. Preferably, during the removal of the capillary, make nitrogen circulate to prevent the capillary end from blocking up.
V available for refrigeration professionals to recycle used refrigerants. More information may be obtained from the refrigerant wholesalers. • Never use alcohol or other byproducts as a solvent. They cause corrosion on the compressor tubes and metallic parts and the electric insulation becomes brittle. • Only use filters with desiccants suitable for the type of refrigerant (see table 2, Chapter VI).
To complete the cleaning operation, proceed as follows: • Place a fast coupling on the return line and connect it on the cleaning machine's outlet side; • Connect the capillary to the cleaning machine’s suction side, leaving it operating for around 15 minutes; • Blast some nitrogen into this circuit to remove any cleaning fluid residue.
V • Braze the filter into the condenser and capillary. Do not unnecessarily heat the body of the filter dryer, and take great care not to block the tubes. • Install the fast coupling to make a vacuum on the high pressure side; • The filter dryer must be installed in the vertical position with the capillary at the bottom (see figure 29). This position prevents the desiccant grains from rubbing and releasing residues. It also helps equalize a pressure faster (capillary systems).
At the other end of this tube, install a fast coupling or similar register to make the vacuum and gas charge. 6 - Caution with Vacuum and Refrigerant Fluid Charge Never use the new compressor as a vacuum pump. It may absorb dirt and water from the tubes, which will be detrimental to its operation and working life.
V With R 600a, the systems in this range of inside volume may only have 36-48 grams (1.3-1.7 ounces), that is, approximately 40% of the R 12 charge. In relation to the original charge with R 12, the R 134a refrigerant fluid charge is approximately 90% and blends 80%. This fact confirms the need for correct procedures and proper equipment for successfully charging a refrigerant fluid.
10.2 - If you are using scales and chargereceiver cylinder: a) Weigh the empty cylinder. The correct charge will be the quantity supplied by the manufacturer plus the weight of the empty cylinder; b) With the compressor switched off, connect the receiving cylinder to the process tube. 1) Open the valve of the receiving cylinder and wait until the pressure has equalized (cylinder/sealed unit). 2) Close the receiving cylinder valve and switch on the compressor. 3) Gradually open the receiving cylinder valve.
V totally empty, switch on the resistance of the charge cylinder to increase the pressure and release the refrigerant to the refrigeration system. If it is not possible to increase the pressure in the charge cylinder through the resistance, you may lock the register of the charge cylinder, switch the compressor on and then slowly open it until the correct refrigerant charge is transferred.
Further VI important recommendations ! 1 - Embraco Compressor Tubes The drawings and tables in the sequence show the position, diameters and tube material of the compressors. Remember Oil Cooler Tube (TRO) Inside Diameter mm inch 4.77 ± 0.17 0.188 ± 0.007 4.90 + 0.02 - 0.05 + 0.10 -0 ± 0.09 0.193 0.201 + 0.001 - 0.002 + 0.004 -0 0.256 ± 0.004 5.10 6.50 In the EM, EG and FFI series, the suction tube cannot be inverted with the process tube.
VI VI Suction Tube Grounding Terminal Process Tube Discharge Tube Figure 30 - EM Compressor with copper tubes Suction Tube Grounding Terminal Process Tube Discharge Tube Figure 31 - EM compressor with copper-plated steel tubes Compressor Application Manual 47
Process Tube Suction Tube Discharge Tube Grounding Terminal Figure 32 - F/EG compressor with copper tubes Process Tube Suction Tube Discharge Tube Grounding Terminal Oil Cooler Tube Figure 33 - F/EG compressor with copper-plated steel tubes 48 Compressor Application Manual VI
VI VI Process Tube Discharge Tube Suction Tube Grounding Terminal Figure 34 - PW compressor with copper tubes Process Tube Discharge Tube Suction Tube Grounding Terminal Figure 35 - PW compressor with copper-plated tubes Compressor Application Manual 49
2 - Filter Driers There are filter driers suitable for each refrigerant fluid. See the following table: Refrigerant Recommended Filter Drier R 12 XH5, XH6, Universal (MS594) R 134a XH7, XH9, Universal (MS594) R 600a XH5, XH6, Universal (MS594) Blends XH9, Universal (MS594) 3 - Start Capacitor EMBRACO compressors with an LST motor were designed to work without a start capacitor, under normal conditions of use.
VI VI Compressor Capacitor to be used in capillary systems Capacitor to be used in expansion valve systems FFI12BX 115V60Hz 378 to 454 "F (115VAC) or 233 to 280 "F (150VAC) 378 to 454 "F (115VAC) FFI12BX 220V60Hz 124 to 149 "F (180VAC) or 64 to 77 "F (250VAC) 124 to 149 "F (180VAC) FFI12HBX 115V60Hz 378 to 454 "F (115VAC) or 233 to 280 "F (150VAC) 378 to 454 "F (115VAC) FFI12HBX 220V60Hz 124 to 149 "F (180VAC) or 64 to 77 "F (250VAC) 124 to 149 "F (180VAC) FF8.
VI One of the power leads must be connected to the thermal protector and the other to the terminal 2 of the PTC (see fig. 36). 1 4 2 3 Figure 36 - PTC relay In addition to being more efficient, the FG compressors can also be used in applications requiring a high starting torque (HST), that is, in expansion valve systems.
VI VI Comments: a) FG compressors for HST applications make it obligatory to use the starting capacitor and must be installed according to figure 38; b) The FG compressor relay for HST applications is different from that used in FF compressors with regard to the following aspects: Terminal 11 Terminal 11 Terminal 10 Terminal 13 Terminal 13 Figure 37 - Short relay without capacitor Figure 38 - Short relay with capacitor • terminals 11 and 13 are longer than normal to permit capacitor's connection; • i
3.3 - EM compressors EM compressors have been designed to operate without a starting capacitor. However, if the use of a capacitor is necessary, you only need to remove the copper wire (electric bridge) between terminal 3 and 4 and connect by soldering the starting capacitor's terminals, as shown in the figures below.
VI VI 5 - Water A little water in the sealed unit can cause freezing and block the capillary outlet. The blockage, although partial, will hamper the operation of the refrigeration system. Moreover, water reacts chemically with the refrigerant to form acids. These acids attack the metal parts of the compressor and destroy the motor insulation, causing a short circuit and burnout. 6 - Antifreeze Methyl alcohol or any other antifreeze is extremely harmful to the refrigeration system.
7 - Models of Compressors VI PW Basic type Compressor rated displacement Refrigerant Motor Type Maximum rated motor torque Compressor cooling (TRO) PW 5.
VI VI EM Basic type Valve system Compressor capacity Refrigerant Efficiency level / application Electric equipment R EM I 60 115V 60Hz P - PTC + run capacitor (optional) R - Relay C - PTC + run capacitor (mandatory) S - PTC + run Cap. + starting capacitor V - PTC + run Cap.
EG VI Basic type Efficiency level Capacity in Btu/h - 60 Hz - Check point divided by 10 Refrigerant Application Electric equipment Oil cooler tube EG S 70 H L P 220V 50Hz NIHIL - Without oil cooler tube W - With oil cooler tube R P C X - Relay PTC + run capacitor (optional) PTC + run capacitor (mandatory) Relay + starting capacitor L - LBP M - L/M/HBP H - HBP NIHIL H C B S T U Y Z 58 - - R 12 R 134a R 600a R 22/R 152a Standard 1st generation 2nd generation 3rd generation 4th generation Co
F VI VI Basic type Electrical system Efficiency level Approximate compressor displacement (for FG compressors, approximate capacity in Btu/h - 60 Hz - Check point divided by 10) Refrigerant Application Starting characteristic Oil cooler tube (TRO) F G S 60 H A 220-240V 50-60Hz W NIHIL W NIHIL K X - Without oil cooler - With oil cooler - LST improved efficiency compressor - LST - HST A - LBP B - HBP, LBP/HD H - HBP H C NIHIL NIHIL E I V S T U - - R 134a - R 600a - R 12 Standard efficiency Im
8 - Compressor Label C G J VI D E SERRATED LINE 10 mm I B F A H A - Traceable serial number E- Logos indicate institute approval of compressor B - Compressor code / Part number F - Bar code 39 (ratio 3:1 and 6.5 mils) C - Compressor designation D - Locked rotor amperage G - Paper: White - LRA Frequency - Hz Refrigerant - R 12 Number of phases - 1 PH Nominal voltage of compressor - VAC Voltage indication: (115V white background Graphics: Black Size: 70 x 38 mm (2.76” x 1.
VI VI • The compressors cannot undergo starting or high voltage tests under vacuum conditions. All Embraco compressors have already undergone a one-second 1650 V high voltage test. • The compressors cannot be charged with antifreeze agents because they are harmful to insulation materials (see item 5). • The use of antifreeze agents, traces of grease, mineral oil, impurities in R 134a or the presence of chlorinated substances causes the compressor warranty to be null and void (see item 6).
• Due to the sensitivity of the ester oils used in R 134a compressors, the following recommendations are necessary (which also apply to any other refrigerant): • It is recommended that one system only be connected to each vacuum pump; • It is recommended that a vacuum be made on both sides of the system, with the vacuum level below 0.
VI VI • To prevent excessive water in the compressor, the tubes must be kept sealed at all times. The rubber plugs must only be removed immediately before brazing the tubes to the system's tubes (as short a time as possible, never more than 15 minutes). • Refrigeration system manufacturers, who use inflammable refrigerants, such as R 600a, are recommended to develop a correct charging method, leakage test, etc., to guarantee that all necessary safety procedures are adopted.
Further information 1 - Impacts 1.1 - Water In a refrigeration system using a compressor that operates with R 12 (compatible with mineral and synthetic lube oils), a little water means an enormous hazard to the whole system. In a refrigeration system using a compressor that operates with R 134a, the negative impacts caused by water are even greater. The lube oils for R 134a compressors are highly hygroscopic (water-absorbing) and unstable esters.
VII In the event of partial blockage, the system's performance drops in proportion to the size of the blockage. If completely blocked, this prevents the circulation of the refrigerant and consequently it stops working. 1.2 - Antifreeze Antifreeze is extremely harmful to the refrigeration system, especially for the compressor. Firstly, because of its corrosive characteristics and high water content.
1.3 - Hygroscopicity A property characterizing the affinity of a product with water. Ester oils (used in compressors that use R 134a refrigerant) are hygroscopic and consequently have a high water-absorbing capacity when compared to the naphthene mineral oil and synthetic oil (alkylbenzene) used with R 12 or R 600a. Figure 43 - Graphs comparing hygroscopicity between ester oil and mineral oil 1.4 - Miscibility in Lube Oil R 12 blends in mineral or synthetic oil (perfect miscibility).
VII The R 134a does not blend with mineral or synthetic oils (non-miscible). Ester oils have been specially developed to work with R 134a (acceptable miscibility). 1.
1.6 - Chemical Compatibility 1.6.1 - Non-miscible Residue Non-miscible residues are those that remain dissolved in the ester oil blend and R 134a at temperatures above -35oC (-31oF). The main potentially non-miscible products belong to the families of: Wax, Grease and Oils Silicone and paraffin are the most undesirable components in the composition of the aforementioned products.
VII The main incompatible products are: Water, Alkaline and Chlorinated Products. The presence of these products can cause an increase in the acidity of the oil that, in its turn, will react with metal or plastic components.
Approximately 90% of the Earth's ozone is located in a natural layer immediately above the Earth's surface, known as the stratosphere. Figure 45 – Schematic of the atmospheric layers that envelope the earth. This natural layer formed by the ozone acts as a protective shield against the ultraviolet rays.
VII Some CFCs can live in the atmosphere for more than 120 years, that is, they do not dissociate in the lower atmosphere (troposphere). As a result, the CFCs slowly migrate to the stratosphere where they are affected by higher levels of radiation, releasing the chlorine, which once free, repeatedly bonds with ozone molecules to cause the separation of the oxygen atoms from the molecule in question. With the destruction of the ozone, higher levels of radiation tend to penetrate the Earth's surface.
2.1 - How is the ozone destroyed? VII CFC molecule. At the 1st stage, ultraviolet rays breaks the link of a chlorine atom in the CFC molecule. Ultraviolet light Chlorine atom Ozone molecule Figure 46 - CFC molecule Figure 47 - CFC molecule with separation of chlorine CFC molecule with chlorine separation. Next, the chlorine atom attacks the ozone molecule (O3), breaking the link between the atoms. A common oxygen (O2) and chlorine monoxide molecule are formed.
VII 3 - Maintenance of domestic refrigeration system 3.1 - Blends Normally consisting of two or three refrigerant fluids of the HCFC type (hydrochlorofluorocarbons), or HCs (hydrocarbons) have the following main characteristics: • Ozone Depletion Potential (ODP) less than R 12. • Its components do not completely blend and this is why they are called non-azeotrope refrigerants. • Developed to be used in compressors currently manufactured for R 12.
• Due to problems of chemical compatibility, the filter drier normally used for a system that operates with R 12, shall be substituted by one compatible with the blend (see Chapter VI, item 2). • Refrigerant fluids (blend) in the system shall only be charged at the liquid stage, due to the aforementioned differences in density. 4 - Alternative refrigerant R 134a Chosen to replace the R 12 because it has properties similar to it and does not have the power to destroy the ozone layer (ODP = 0).
VII – It requires all components of the system to be free from contamination (alkaline substances, grease, wax, water, paraffin, silicone, chlorinated residues, etc.), due to the characteristics of the compressor to be used. To date, there is no definition of a sufficiently effective cleaning method that is reliable and reasonably uncomplicated and which guarantees the simple substitution of the R 12 of a domestic refrigeration system with R 134a.
If after these instructions you still have doubts, please do not hesitate to call us.
Note: After replacement, the compressor and it's accessories must have proper processing, and the components must be recycled according to the material group (ferrous, non-ferrous, polymers, oils, ...) directives. These recomendations are intended to minimize the adverse impacts that may be caused to the environment. Disclaimer of Liability The compressors here into introduced were designed for strictly use and application according to their respective specifications.
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