Service Manual
Contents
1. 12 50250020000A screw 2 13 501119850012 temperature control box 2 14 502407050008 thermostat 1 15 501119850011 control panel 1 16 502410000075 running LED 1 17 502410000051 running LED 1 18 502410000003 power LED 1 19 501119850001 thermostat knob 1 20 502500200016 screw 10 21 500719850009 compressor mounting panel 1 22 502501200010 screw assembly 3 23 501602000031 dry filter 1 24 501601050002 compressor process tube 1 25 50160405000D suction transition tube 1 26 27 28 50140065001C Compressor assembly 1 29 30 50121985000W shutter 1 31 502500200028 screw 5 32 50240105002T power cable 1 33 50240305001 Y indicator light harness 12. Symptoms of total leakage of refrigerant are mainly asfollows the compressor can be started easily if there is no damage to the compressor parts and its operating current becomes low its gas suction pressure is high and discharge pressure is lower the gas discharge tube feels rather cold no sound of gas eruption from the liquid in the evaporator can be 20 Maintenance Service and Trouble Shooting heard and no will gush out of the process tube if you cut it open after shutdown Remedy Check the whole machine particularly those locations which are liable to leak After leak points have been found repair them or replace them with new parts according to specific circumstances then evacuate the system and finally charge refrigerant 2 Refrigerating system has been clogged a Clogged with Ice Analysis of Trouble The dryness treatment for the major parts in the refrigerating system has been performed improperly the effect of air purging for the whole system is not good or the water content in the refrigerant is out of standard all these will cause the expansion valve to be clogged with ice The symptom for this trouble are as follows the refrigerator sometimes can refrigerate and sometimes cannot the refrigerator compartment works normally at the beginning but after working for a certain period of time frosting begins at the clogged position evaporation temperature reaches below 0 C water will accumulate at the narrow
3. recharge refrigerant after evacuating and then seal the charging port 3 There is air left in the refrigerating system Analysis of Trouble Residual air in the refrigerating system will reduce its refrigerating efficiency The prominent phenomena are the increase in its gas suction and exhaust pressures however the gas exhaust pressure will not exceed its rated value obvious increase in temperature in the segment from the compressor outlet to the condenser inlet Because there is air in the system both the gas exhaust pressure and temperature will rise and moreover the gas flowing sound is intermittent and obviously louder Remedy After shut down for several minutes open the tubing evacuate it and then recharge the system with refrigerant 4 Low efficiency of compressor Maintenance Service and Trouble Shooting Analysis of Trouble Low efficiency of a refrigerating compressor refers to the actual reduction of gas discharge capacity and hence the corresponding reduction of refrigerating capacity under the condition that the refrigerant in the system is unchanged This phenomenon occurs mostly when the compressor has been used for quite a long time its moving parts have worn to a considerable degree fit clearance between various parts have increased and sealing property of its gas valve has deteriorated resulting in an decrease in its actual gas discharge capacity Methods of Judgment Measure the high and low pressures
4. 2 Abnormal noise from compressor Three suspended spring inside the compressor case are out of balance and strike against the case moreover the wear of compressor parts may cause noise sometimes 3 Resonance of tubing and loosening of parts Improper and compact laying of tubes or the loosening of parts may cause vibration and noise 28 Maintenance Service and Trouble Shooting 4 Inspection method To find the sources of noise press the vibration spot with your hand while the refrigerator is in operation and listen attentively whether the vibration becomes weake or vanishes If the refrigerator has not been levelly placed put a level meter on its top table and adjust the leveling screws on its legs In case noise occurs from the compressor strike different locations on the side surface of its case using a rubber hammer or hand hammer with a wood block in between so as to determine whether the suspended springs are out of balance or being seized 29 CODE DESCRIPTION QTY 1 501114250001 door seal 1 2 5037001500AM freezer door assembly 1 3 50290505000Q hinge 1 4 50111425000F upper hinge cover 2 5 50111425000G bottom hinge cover 2 6 50290505000Q hinge 1 7 501115050066 inner tube cover 1 8 502903050005 freezer hanging basket 2 9 5037050506NR cabinet assembly foamed 1 10 500719850005 fixed plate 2 11 501115050006 drain tube cover 1
5. a certain time therefore this sound is a normal phenomenon 2 A click sound can often be heard from the refrigerator This is a normal sound produced by the pull in or release of the armature of a current deadweight start relay when starting the compressor The compressor motor will produce a slight and uniform sound while it is running This sound is not easy to be heard in the daytime but of course it can be heard distinctly at night 3 The compressor consists of an electric motor and a compressing apparatus During its normal operatio the motor s stator core and windings will rise to a temperature in the range of 100 C 110 C and the temperature of the piston and cylinder of the compressing mechanism can also reach as above 100 C due to the heat produced when compressing refrigerant Most of the heat radiates to the air through the compressor casing therefore its casing is generally at a temperature between 85 C 90 C it is very hot particularly in summer when the ambient temperature is higher All these are normal phenomena 4 For the direct cooling refrigerator a kind of irregular crack sound can be often heard when the compressor is running for a certain period of time or has just stopped its running This sound is caused by the stress relief due to expansion and contraction when temperature changes and will not affect the normal application of refrigerator 14 Maintenance Service and Trouble Shooting 6 C
6. it with your hand and poorer refrigerating effect Furthermore the gas discharge pressure will exceed its normal value when the compressor has run for a period not too long thus making the protective relay actuate and bring to a stoppage Remedy Check up how the air has been left in the refrigerating system Generally there are two possibilities one is that the air has been sucked into the system when repairing due to carelessness or it has not been purged out totally when evacuating the system the other is that there are leak points at the low pressure end of the refrigerating system Leak points appear mostly in those low temperature parts or assemblies because the evaporation temperature is lower for such low temperature devices especially at the low pressure end it is easier for the air goes into the system Once it has been ascertained that air does exist in the system you have to open the tubing re evacuate it and then charge it with refrigerant 2 Stoppage due to electric troubles a Thermostat is out of control Analysis of Trouble In case the thermostat does not work in its good order or its 23 Maintenance Service and Trouble Shooting temperature sensor has not been installed properly frequent stoppage is also likely to occur Remedy Try to adjust the temperature sensor s position until the compressor can be started and stopped normally If this cannot be achieved and the stoppage still occurs repeatedly it is
7. part of the capillary and clog it gradually then frost begins to melt at the evaporator no gas flowing sound can be heard and the gas suction pressure assumes a state of vacuum Note that these phenomena will appear intermittently sometimes the refrigerator works well and sometimes not well In order to determine whether it is clogged with ice heat the suspicious points with hot water to make ice melt and after a while if a gas flowing sound resulting from an abrupt gush is heard and the gas suction pressure rises as well it can be confirmed that the trouble is caused by ice clogging Remedy If there is too much moisture in the refrigerating system it is advisable to release the refrigerant purge the tubing with nitrogen and then charge the system with the filtered refrigerant However the commonly adopted method is to connect a filter with moisture absorbers such as silica gel anhydrous calcium chloride to the refrigerating system so as to filter out the moisture from the system then replace the filter evacuate it again and finally charge the system with refrigerant b Clogged with dirt in capillary Analysis of Trouble The capillary inlet is a place where coarse grained dirt or refrigerant oil in the system will tend to settle down and clog it In case considerable dirt accumulates there the whole filter screen may be blocked totally making the refrigerant unable to go through Clogging with dirt exhibits the same symptoms
8. this phenomenon we are going to discuss and analyze it in the following 7 aspects 1 Leakage of refrigerant Analysis of Trouble The leakage of refrigerant in the system will result in an insufficient refrigerating capacity the resulting phenomena are its lower gas suction pressure and exhaust pressure as well as higher exhaust gas temperature The exhaust tube feels rather hot and a continuous gas flowing sound louder than usual can be heard at the outlet of the capillary and no frost or a smaller quantity of loose frost appears on the evaporator After shut down the balance pressure in the system is usually lower than the saturation pressure corresponding to the same ambient temperature Remedy In case there is leakage of refrigerant from the system do not hurry to recharge it with refrigerant manage to find out leak points immediately and make a note of from where it leaks welding points and parts After having them repaired recharge refrigerant Maintenance Service and Trouble Shooting There are so Many joints and sealed surfaces ina refrigerator accordingly quite a lot potential leak points do exist in the system In troubleshooting pay attention to those parts that are liable to leak check main connection points for oil seepage and tubing for cracks If there is no severer leak point charge the system with nitrogen and detect leak points with the commonly adopted method repair them evacuate charge the system wi
9. Refrigerator Service Manual Models L150CFW13 Features Energy efficiency Micro foam technology Low noise operation Thick insulation for energy efficiency Latest No 2 micro biological technology CONTENT CONTENT 1 Content 1 2 Product code illumination and Series Introduction 2 3 Specifications 3 4 Safety precautions 4 5 Function Schedule scape deea is o oaia pa tie ac ea 7 6 System Flow Chart 8 7 Circuit Diagqgram 9 8 Maintenance Service and Trouble Shooting 10 9 Exploded View ta ui ala 30 10 Eist of Paris 31 Specifications Specifications L150CFW13 capacity L Power Supply V Hz 220V 240V 50 Hz Rated Input Power W Power Consumption Net Weight kg Gross Weight kg Unit Dimension D W H 551 730 850 mm Packing Dimension D W H 575 770 885 mm Container Quantity 40 HQ PCS Safety precautions This appliance uses220 240V 50Hz AC forpower supply Failure in Operation and damage 10 fie control panal ferrme 141 0r Me campa ssor vill OC Cur l voltage is Outside ihe range 15 7 242V unless a regulator wih a Capaci
10. as that with ice namely higher gas suction pressure lower temperature of discharged gas and no gas flowing sound from the evaporator The difference between the both is as follows if the clogging is 21 Maintenance Service and Trouble Shooting caused by dirt tapping the suspicious clogged point generally in the capillary or the connection joint of the filter may cause the refrigerant to flow through partially resulting in some corresponding change whereas in that case if you heat it with a hot towel no reaction will happen no flowing sound can be heard moreover there is no periodic change After rejecting the possibility of ice clogging it can be generally considered as the clogging due to dirt Remedy Dismantle the system remove the dry filter from it purge the tubing with nitrogen install a new filter then evacuate it and finally charge it with refrigerant C Clogging in filter Analysis of Trouble Total clogging of a filter is rarely to occur This trouble is mostly caused by the paste like matter formed from the substances filled into the system or other dust after the refrigerator has been used for a longer time or by the dirt accumulated gradually inside the filter Sometimes tapping the filter nay cause a passage for flowing Touching it with your hand you will feel that it is cooler compared with its temperature in the normal state Remedy The same as described in the capillary clogging with dirt 3 Troub
11. dden stop of a compressor during its running is mostly that the gas suction pressure and or discharge pressure exceed their respective prescribed ranges thus making a pressure operated protective relay shut off the power to the compressor and stop it In the following we discuss mainly the reasons for causing excessively high gas discharge pressure and low suction pressure 1 Stoppage due to excessively high gas discharge pressure A Too much refrigerant charged into the system Analysis of Trouble The phenomenon such as loose frosting and poor refrigerating effect may occur if excessive refrigerant has been charged into the system Superfluous refrigerant will occupy a certain space of the evaporator thus reduce its heat dissipating area and the phenomenon of liquid striking may occur too Meanwhile dew or frost condensation may occur on the gas return tube and the gas discharge pressure will obviously rise when it reaches the threshold value the protective relay will actuate and shut off the power supply to the compressor Remedy Open the tubing re evacuate and then charge the system with a proper quantity of refrigerant b Air left in the system Analysis of Trouble The residual air in the system will circulate together with the refrigerant in the system The major symptoms caused by this residual air is higher gas discharge pressure higher discharged gas temperature the gas discharge tubing is considerably hot when you feel
12. er dismantle its door as wellas its doorgasket plug and to waitat least 5 minutes for to avoid accident occurred when a child switching on itagain topreventdamaging goes inside for playing its compressor by continuous starting Function Schedule Function Schedule Energy efficiency Micro foam technology Low noise operation Thick insulation for energy efficiency System Flow Chart System Flow Chart 1 Schematic diagram of System Flow Chart 1 Compressor 2 Condenser 3 Dry Filter 4 Capillary Tube 5 Evaporator flows in the sequence 1 gt 2 gt 3 gt 4 gt 5 gt 1 Circuit Diagram Circuit Diagram 1 Schematic Circuit Diagram Thermostat pilot lamp Compressor Power pilot lamp High temperature alarm Compressor Maintenance Service and Trouble Shooting Maintenance Service and Trouble Shooting 1 No cooling No cooling If compressor Check and repair according to can run after it stop to the section of the compessor run five minutes and doesn t work give power If compressor Refrigerant can run naturally and leak check and temperature raising repair charge of condenser is refrigerant again very low Block by ice or dirty things change filter and change refrigerant again When charging refrigerant we must A notice to make refrigerant true 10 Maintenance Service and Trouble Shooting 2 The compressor doesn t stop Compressor doesn t
13. essure is lower the temperature of discharged gas drops down the position clogged has a temperature lower than that in normal conditions and for a severe clogging even dew condensation as frosting may appear Remedy Purge the tubing and after replacing the dry filter with a new one or clearing it thoroughly recharge the system with refrigerant and seal the charging port B No Refrigerating The phenomenon that the compressor runs normally but no frost or only a little frost appears on the evaporator and the refrigerator temperature does not drop down is called no refrigerating There are many causes for this trouble and it is relatively complicated too In servicing special attention to finding direct causes for this phenomenon Three main potential causes for this trouble are analyzed below 1 All refrigerant in the system has leaked out Analysis of Trouble Leak points in the refrigerating system have not been found and repaired timely thus resulting in the total escape of refrigerant There are two kinds of leakage slow leakage for instance when we want to use a refrigerator that has been put out of quite a long time we find the leakage of refrigerant or in the course of its operation we have found that the refrigerator is gradually becoming not so cold and finally no refrigerating cab be achieved ii fast leakage in that case all the refrigerant will escape swiftly due to abrupt rupture of system tubing
14. has been clogged 3 Touch and Feel a Feel the compressor when running its temperature should be generally less than 90 C in the normal state it may exceed 90 C in case of running for a longer period of time b After the compressor has operated normally for 5 10 minutes ouch and feel the condenser the temperature of its upper part should be higher than that of its lower part or its right part is hotter than its left part depending on the type of condenser coil this indicates that the refrigerant is circulating If the condenser is not hot this means the leakage of refrigerant In case the condenser radiates heat for only several minutes and then cools down this means that the filter and capillary have been clogged As for the forced air cooling condenser hot air will be blown out of it this means that the system is out of order c Feel the filter s temperature During the normal operation of refrigerating system the temperature on the filter s surface should be a little higher than the ambient temperature if you touch it with your hand you will have a sense of slight heat In case dew condensation appears due to the fact that its temperature is obviously lower than the 16 Maintenance Service and Trouble Shooting ambient temperature this means that most meshes of Its screen has been clogged resulting in an obstructed flowing of refrigerant thus causing a drop in temperature due to throttling d Feel the tempe
15. he appliance This refrigerator explosive articles strong corrosive acid is for household use which cannot store alkali etc item with strict requirement fortempeature Do not store or use gasoline or other Do notplace any electrical plugs regulators flammable article in the vicinity of the or microwaves on top of the refrigerator Do refrigerator to avoid fire not use electric app liances Expect thoes p allowed by manufacturer inside the refrigerator Do notplayby hanging on its door to Do notplace heavy or unstable articles or prevent tilting the door or toppling the watercontainers on top of the refrigerator refrigerator to hurtperson 8 Safety precautions When the refrigerator has staned running Do not spray water onto the refrigerator or take care notto touch the cold surface of place it in wet area susceptible to be the freezer compartment with hand splashed with water so as to avoid especially with wet hand Otherwise your influencing the electric insulation skin is lable tobe stuck onthe cold surface performance ofthe appliance ee Tio it is strictly prohibited to privately dismantle Do not p ut the bottled beer or beverage in or change the appliance For the repair of the freezer compartment to prevent frost refrigerator it can be carried outby crack professional only At no power supply or when carrying out When the appliance is to be discarded cleaning it is required to pull out the pow
16. he evaporator the heat conduction effect will be severely affected thus causing a poor refrigerating effect Remedy It is quite difficult to determine whether this trouble is caused by the refrigerating oil left in the evaporator tubing oecause this kind of phenomenon and other several trouble are tends to be confused Generally speaking you can make a judgment based on the frost formed on the evaporator If the frost does not cover the evaporator and moreover it is loosely formed you can make a judgment that the deterioration of 19 Maintenance Service and Trouble Shooting refrigerating effect is due to the accumulation of refrigerating oil left in the evaporator tubing in case no other troubles have been found To clear off refrigerating oil left in the evaporator dismantle the evaporator purge it thoroughly and then dry it In case it is difficult to dismantle it charge refrigerant from the evaporator inlet to wash it several times then purge and dry it with nitrogen 7 Flowing obstructed in refrigerating system Analysis of Trouble Because the refrigerating system was originally not purged thoroughly some of the filter screen meshes have been clogged by dirt accumulated in the filter after using it for a certain time of period thus resulting in a decrease in flow rate and hence a poorer refrigerating effect The abnormal phenomena caused by this kind of slight clogging in the system are as follows the gas discharge pr
17. he lubricant oil will increase its viscosity and cause the shaft to be seized Copper plating may also result in seizing of shaft b Seizing of piston This is caused by too small fit clearance between the piston and cylinder or expansion due to heat Judgement of seizing shaft and piston After the refrigerator has been powered on the compressor will not start and run but a slight hum sound can be heard and several seconds later thermal protective relay will actuate and make the contacts open this process will occur repeatedly but the compressor cannot be started E Compressor won t stop Sometimes the compressor will run continuously for several hours or run without end If the food placed in the refrigerator is not too much there may be the following two situations i the refrigerator very low this means that the control system is probably out of order ii the control system works normally and there are troubles in the refrigerating system or other parts 1 Temperature is set improperly a The temperature control knob is set to the coldest position This 26 Maintenance Service and Trouble Shooting position is to be used for fast freezing or continuous running Its temperature for power off is too low therefore the compressor won t stop and the temperature in the refrigerator becomes lower and lower b Inspection method check the temperature control knob to see whether it is set in the position coldest 2 Ther
18. les of Compressor a Breakage of gas suction and discharge valve blocks Analysis of Trouble The compressor works by means of the opening and closing of gas suction valve and discharge valve to suck and discharge the refrigerant If the valve block is broken the refrigerant can not be discharged and hence no refrigerating can be achieved Method for making judgement It is quite difficult to differentiate this trouble from others because they often have similar symptoms In repairing firstly hear attentively if there is some abnormal sound coming from the compressor sometimes the broken pieces of valve block may strike against the cylinder and feel the compressor casing with your hand to ascertain whether it is too hot this is also helpful to the troubleshooting secondly measure the pressures at the high and low pressure ports of the compressor with pressure gauges if the gas suction valve block is broken the suction pressure gauge pointer will swing violently and the suction pressure is very high whereas when the gas discharge valve block is broken the discharge pressure gauge pointer will swing drastically and the discharge pressure is very high In the both cases stop the compressor at once and if technique is available open the cylinder cover and check up the valve block repair it or replace it with a new one C Sudden stop of Compressor during Its Running 22 Maintenance Service and Trouble Shooting The cause of su
19. most likely that the mechanical parts or contacts are out of order disassemble the thermostat make a thorough checkup and repair it b Overload of electric motor Analysis of Trouble Probably too many things have been put into the refrigerator and hence the thermal load exceeds its refrigerating capacity or in case the power supply voltage drops considerably the current flowing through the motor will increase drastically making the thermal protector actuate and the fuse blown and hence the motor stops running If the motor is still running continuously in such a case its windings will be burned out Remedy Reduce the thermal load pay attention to the variation in voltage of the power supply c Abnormal thermal protection Analysis of Trouble The compressor current is within its normal range but the thermal protector actuates repeatedly Remedy Replace the thermal protector with a new one 3 Sudden stoppage due to other causes Normal Stoppage Start and stop of the compressor is generally controlled by a thermostat When the temperature in the refrigerator reaches its desired value the thermostat will shut down the compressor automatically Never take this normal operation as a trouble care should be taken to differentiate it from other real troubles in servicing D Compressor won t start In case the compressor cannot be started you must find out the origins of this trouble through checkup step by step because pr
20. mostat is malfunctioning and makes the compressor running continuously Analysis of Trouble When the thermostat doesn t work normally it will make the compressor run continuously and hence very low temperature will be achieved in the refrigerator The fault is generally due to the fact that the contacts of the thermostat cannot be released Remedy Dismantle the thermostat and make a through checkup if it is totally out of functioning replace it with a new one 3 evaporation temperature is too high in refrigerating system resulting in lower refrigerating capacity and hence continuous running of compressor Analysis of Trouble Leakage of refrigerant and clogging in a refrigerating system will directly affect its refrigerating capacity Due to the reduction in its refrigerating capacity the refrigerator temperature cannot reach its rated value the thermostat won t work thus the compressor runs continuously When the evaporation temperature in the system is too high the temperature sensing agent in the temperature sensor is also hotter therefore the thermostat is unable to cut off the power supply to the compressor and stop it Remedy If it has been found that the refrigerant in the system is insufficient in quantity recharge it with refrigerant In case clogging occurs disassemble the part where it is blocked If the evaporation temperature is too high settle this problem with an appropriate quantity of refrigerant 4 No stoppage
21. obably there are many causes including those electrical and mechanical 1 Inspect the power supply to see whether it is connected to the compressor circuit Analysis of Trouble In case the compressor cannot be started this will generally exhibit in the power supply circuit for instance power failure poor contact of switch and blown fuse Make a comprehensive analysis of these phenomena fine out its real cause and take correct measures to remove this trouble Remedy 24 Maintenance Service and Trouble Shooting a Check the input power circuit to see whether where is voltage of the power supply namely the circuit which is connected to the knife switch This can be determined with an avometer or a test pencil If a blown fuse is found ascertain and remove its cause then replace it with a new one of the same specifications b Check the compressor accessories including its thermal protector and relay In case the thermal protector is damaged the compressor cannot be powered on If the relay is out of order the motor will not run and hum sound can be heard from it after the compressor is turned on in that case shut it down immediately otherwise the motor windings will be burned out in case this condition lasts longer c Check the relay contacts and plugs to see if they are perfect and work reliably Poor contact may cause the motor not running or humming 2 Check the circuit voltage to see whether it is normal Analysis
22. of compressor due to damaged heat insulation layer inside case body and or door seal Analysis of Trouble When the heat insulation layer inside the case body deteriorates or the door seal is not closely touches the door frame the temperature in the refrigerator will rise and makes the compressor running continuously Remedy Check the heat insulation layer for its damaged parts repair it to improve its heat insulation property If the door has deformed or the door seal is not tightly sealed against the case body repair them respectively 5 Too much food is placed in the refrigerator or is placed too densely resulting in poor ventilation or poor conditions for temperature sensing and hence no stoppage of the compressor 6 Too high ambient temperature poorer ventilation and heat 27 Maintenance Service and Trouble Shooting dissipation make the compressor running without stop F Electric leakage of refrigerator 1 Slight electric leakage Electric insulation has deteriorated due to being affected with damp thus resulting in slight electric leakage 2 Serious electric leakage Refrigerator case has become live due to faults occurred in some electric devices or the erroneous wiring in installing power cord plug or outlet by the user This is very dangerous 3 Electric leakage test a Slight electric leakage A tingle sense will be experienced as soon as you touch the metal parts of the refrigerator with your hand When you tes
23. of trouble If the circuit voltage is obviously lower than its rated value it will be difficult to start the motor and a hum sound can be heard from it Remedy Measure the voltage with a voltmeter if it is really too low give directions to the user for buying a stabilizer so as to step up the voltage thus normal operation can be achieved 3 Check the thermal relay to see whether its contacts are closed Analysis of Trouble The contacts of thermal relay sometimes may be open due to the leakage of temperature sensing agent from the temperature sensor Remedy Remove the relay cover to check up its contacts if they are open this means that the original setting is not properly set or temperature sensing agent has leaked out of the temperature sensor Try to turn the adjusting stem of this value in the direction of the lower temperature graduation then check the contacts to see whether they are closed If they are still not closed dismantle the temperature sensing disc and then immerse it into warm water to see whether the contacts actuate if not it can be preliminarily determine that temperature sensing agent has leaked out and it must be replaced with a new thermostat 4 Motor troubles and other electric faults a Motor windings have been burned or short circuited between turns Analysis of Trouble When motor windings have been burned or short circuited between turns the fuse will be blown repeatedly and the blowout occurs partic
24. ommon Troubles in Refrigerators and Their Remedies Causes for troubles occurring in refrigerators are closely related to the quality of components and workmanship in assembling by manufacturers as whether refrigerators are properly used and maintained The parameters generally used to express the working conditions of a refrigerator include the temperature inside the refrigerator operation rate electric power consumption noise level and other functional indexes If any one of these parameters is beyond its permissible range this indicates that there is a fault or trouble in the refrigerator During the whole service life of a refrigerator the probability of troubles occurring within a union time is called its failure rate Making a comparison between the control circuit system of a refrigerator and its refrigerating system we can find that the failure rate of the former is higher and that of the thermostat is the highest In troubleshooting the first thing you must do is to determine where the trouble comes from the control system or the refrigerating system There is general no trouble indicating instrument mounted on the dome stic refrigerator locations and natures of troubles should be determined according to their respective features therefore experience in servicing is very important to troubleshooting Service technicians with rich experience can correctly locate them and take reasonable remedy measures based on their comprehen
25. rature of exhaust gas from the refrigerating system the exhaust gas should be very hot and this is the normal working state For those refrigerator with enclosed type of compressor refrigerating system no frost or dew drop will from on the gas suction tube otherwise there is something wrong in the system Frosting and dew condensation may appear for a very short time period when just starting the machine this is a normal phenomenon Because a refrigerator is a combination of several components they are related and have influence on each other In case an abnormal phenomenon has been found through the above mentioned checkups you need not to make a hasty conclusion based on only one abnormal phenomenon It is advisable to find out two or more abnormal phenomenon or conduct troubleshooting comprehensively with the aid of instruments or other ways because several kinds of troubles may share a common abnormal phenomenon and two or more abnormal phenomena may occur simultaneously due to a certain trouble With this method you can reject some suspicious troubles and finally make a correct judgment 7 Analysis of Troubles and Troubleshooting A Poor Refrigerating Effect The so called poor refrigerating effect refers to the fact that the refrigerator can operate and refrigerator normally but the temperature in the refrigerator cannot drop to the prescribed value under the stipulated working conditions In view of there are many causes for
26. sive analysis of trouble characteristics as well as operating conditions for various kinds of refrigerators Three Essentials for Checkup 1 Look a Check the tubing of refrigerating system for cracks and various welding points for leaks if leakage occurs an oil stain can be seen definitely b Check the suction and exhaust pressure values high pressure and low pressure of compressor to see whether they are normal c Check the conditions of frost attached to its evaporator and gas return tube It is abnormal if frost has formed on part of the evaporator or there is no frost attached to it d Pay attention to the speed of temperature drop inside freezer compartment It is abnormal if the speed of temperature drop is obviously slower than the corresponding normal speed e Check the environment to see whether it is suitable for placing a refrigerator f Check refrigerator door seal case table surface and heat insulation layer g Look at the main control board to ascertain if various indication states are normal 2 Listen a Listen to the noises produced when the compressor is running 15 Maintenance Service and Trouble Shooting Hums from a fully enclosed aggregate unit is the sound caused by overload indicating that the motor cannot be started normally meanwhile a clattering sound can be heard from inside the start relay which is produced because the start contacts cannot be released normally A whistling so
27. stop Check and repair according to the section of No cooling Does the refrigerator refrgerate NO Check and repair according to iho section of Cooling capacity is insuffcient Is cooling capacity insufficient 1 The thermostat was set at the coldest position 2 The ambient temperature is very high or Adjust and instruct the refrigerator is near by heat resource consumer how to use 3 The door was opened too many times or there are more fresh food inside Check and repair the main control panel Maintenance Service and Trouble Shooting 3 Cooling capacity is insufficient Cooling capacity is insufficient s the ambient YES temperature low than Check the therostat is correct Does the refrigerant leak siowly Adjust and instruct consumer how to use 12 Maintenance Service and Trouble Shooting 4 The compressor doesn t work The compressor doesn t work Does the refrigerated room lamp illuminate when the door is opened YES Is the ambient temperature low than Does the control output Does the compressor has 220V power output panel has 220V power NO Check the power NO source and power cord YES YES Check the therostat is correct Check and repair the control panel Check all cords and power cords Check and repair compressor and accessory 13 Adjust and ins
28. t them with a test pencil its neon lamp will come on In that case the first thing you need to do is to determine whether the grounding is perfect If the grounding is no problem turn off the refrigerator immediately then check the insulation of electric circuits with an avometer b Serious electric leakage Never touch the case body of the refrigerator its door handle or other metal parts with your hand Test the refrigerator with a test pencil it will light up intensively measure the resistance between the power cord plug and the case body with an avometer the reading will be zero 0Q in the worst case the fuse will be blown Check the 3 prong outlet to see whether the live wire and the null line are inversely connected this makes the ground protection lead out from the power cord plug being connected to the live wire Another possibility is that the live wire and null line of the outdoor power supply circuit have been inversely connected accordingly this makes the null line become a live wire G Stronger vibration and loader noise 1 Refrigerator placed improperly a Uneven ground Uneven ground will cause there frigerator to be placed unsteadily causing stronger vibration and noise during its operation b Leveling screws not properly adjusted If the leveling screws on refrigerator legs have not been adjusted properly vibration and noise will still occur even if the refrigerator has been placed on a level ground
29. th refrigerant and then turn on the refrigerator to make a test run 2 Too much refrigerant charged into the system Analysis of Trouble a Incase the amount of refrigerant charged into the system exceeds its nominal capacity the superfluous refrigerant will of course take some space of the evaporator thus reducing its heat dissipation area and hence the refrigerating efficiency of the system The abnormal phenomena caused by this reason are as follows the gas suction and exhaust pressures are generally higher than their respective normal values the temperature of its condenser is higher and the electric current of the compressor rises loose frost forms on the evaporator the refrigerator temperature drops slowly and frost appears on the gas return tube b Incase excessive refrigerant has been charged the liquid refrigerant that cannot evaporates in the evaporator will return to the compressor and thus a phenomenon of liquid striking will occur The liquid refrigerant evaporates and effervesces as soon as it flows into the refrigerating oil at the bottom of compressor If the condition is severe foams will fill all over inside the compressor housing and be sucked by the piston causing damage to the components of compressor Remedy According to the operating procedures it is mandatory to turn the achine off and several minutes later open the refrigerant charging tube and et the refrigerant escape from it replace the dry filter
30. truct consumer how to use Maintenance Service and Trouble Shooting 5 Normal Phenomena Not Troubles for Refrigerators In a domestic refrigerator there is not only a complicated electric control system but also a refrigerating system that is difficult to discern whether it is in a good working condition Both the systems are related and affect each other If a certain part of a refrigerator works abnormally Its refrigerating efficiency will decrease operation properties will become unstable or even it cannot be used normally for those serious cases Refrigerators are generally of larger volume once troubles appear to send them to a service department is really a tough thing if such is the case the user will always be in suspense sometimes normal phenomena will be erroneously regarded as troubles Therefore before we deal with the topics of frequently occurring troubles of refrigerators and their remedies we should firstly give a brief account of some normal phenomena which are not troubles In case any one of such phenomena occurs there is no need to worry about it and the user can use it at total ease 1 When the compressor of a refrigerator has just stopped running a rumbling sound can be heard from inside its evaporator This is a sound caused by the flowing of refrigerant in the evaporator tubing Because the pressure difference is still greater after the compressor has just stopped running the refrigerant will flow for
31. ty Of over 750W cr higher is installed Do not damage power cable Ge sure not 10 pull cui ihe plug of ihe appliance by Gravario ihe power Cable Ba sure 10dirac1ly pull Out i1 GF 1ha guile by ferity Grasping Me plug DONOt Cause the aD plano boy press Me pomar cable Nor Should any pacole tread on it When moving fie appliance rom wall be Careful aca 10 Cll Gr Garage power Cable When there is leakage of inflammable gas iese ihe valve of leaking gas Open doers and windows Neither wy 10 drag nor inseri any power plug for arly elec incal urii Such as retriper aioe Safety precautions It is required to use separate dedicated outlet with securely grounding The power Cable of ihis aop ancais fitted with three core oroun Giro plug ComplyinG with Piree core orcun ing cuile Inno case should Wie ihid plug pin Lorcunding Of he p Oaer Cable be Cut ce removed In case of damaged power cable When ihe power cable or plug has been worn it is PrOhibiNd 10 continue ouso it If his case itis raQuired 1Grapla ca ii by iaciory duiicnzed Sarwce shop FA Please pull out power plug under the following situations Pull Out power Mud prier 30 Cleaning amp repaking When replacing darnaged lamp it iS rewired topul Cut power plug 10 preveni electrica shock Safety precautions itis absolutely prohibited to put inside the Do notkeep medicine vaccine or chemical appliance hazardous inflammable or reagent in t
32. ularly at the instant when you close the knife switch Remedy Check the terminals and the outer casing to see whether they are short circuited and measure the resistance of each phase with an 25 Maintenance Service and Trouble Shooting avometer If short circuit occurs or the resistance of a certain phase is low this means that short circuit does exist in the windings and or between turns and insulation layers have been burned or deteriorated A megameter can be used in this inspection too f the insulation resistance is lower than 2 MQ this means that the insulation layer is already breakdown If the motor has been burned repair it or replaced it with a new one b Fault of control relay Analysis of Trouble Overheat burnout or wear of control relay contacts may occur generally All these will cause poor contact in electricity Remedy Dismantle it to repair or replace it with a new one c Poor electric contactor in thermostat Analysis of Trouble Burnout of contactor and leakage of temperature sensing agent may occur generally Remedy Replace the old with a new one d Check the terminals for loose connection and electric circuits for other abnormal phenomena 5 Mechanical faults of compressor a Seizing of shaft This phenomenon is caused mostly by poor lubrication such ad insufficient quantity of lubricant clogging in the lubricant oil line or intermittent lubricant oil supply Dirt and other impurities in t
33. und is caused by the high pressure gas flowing out of the crack of the pressure tube inside the compressor and clucks are the sound of striking after the suspended spring inside the compressor has broken During the normal operation of compressor a slight and uniform hum sound due to undulation of electric current can be heard generally this is a normal phenomenon However if it sounds like tong tong i e an impact sound inside the compressor this means that a large quantity of wet vapour of refrigerant or refrigerating oil has come into the compressor cylinder if it sounds like dang dang a striking sound of metal parts inside the compressor this means that some moving parts have loosened note to differentiate this sound from those formed during starting or stopping the compressor b Listen to the sound caused by the flowing of gas in the evaporator Open the refrigerator door while the compressor is in operation incline your ear and listen attentively the gas flow sound inside the evaporator If it sounds like gentle whistling accompanied by a sound similar to water flowing this is the sound produced by the normal circulation of refrigerant within the evaporator In case only the gas flowing sound can be heard and there is no water flowing sound this indicates that the refrigerant has already percolated If neither the flowing sound nor the gas sounds from the evaporator can be heard this means that the filter or capillary
34. with pressure gauges to see whether they are normal If an abnormal sound comes from the compressor or the temperature of its causing is too high Cut the discharge port open and operate the compressor feel it if there is pressure at the discharge port with your finger For a normal compressor its discharge port is difficult to be blocked with your finger if you just apply a little effort 5 Too thick frost layer formed on evaporator Analysis of Trouble If a direct cooling refrigerator is to be used for a prolonged period of time be sure to defrost its evaporator regularly if you fail to do so the frost layer on the evaporator tubing will become thicker and thicker Heat conduction will be severely affected when the whole tubing is wrapped with a transparent ice layer and finally the temperature in the refrigerator cannot drop down to the prescribed range Remedy Turn the refrigerator off and make preparations for defrosting open the refrigerator door to let the air come in or use a fan to speed up air flowing so as to shorten the time needed for defrosting Never strike the frost layer with any iron tools or wood stick in order to avoid damage to the evaporator tubing 6 Refrigerating oil left in evaporator tubing Analysis of Trouble During the process of refrigerating cycles a little refrigerating oil may remain in the evaporator tubing and after a longer time of operation if there is considerable refrigerating oil left in t
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