Service Manual Beer Dispenser Model: SCK02SMWBS
Contents
1. Service Manual Beer Dispenser Model SCKO2SMWBS PTT04252007 VN O A A N Specifications Circuit Diagram Exploded View Part List TABLE OF CONTENTS Safety Instructions ceisiccicciccseticedesctiacecandies daccciesdantecdedaniseanecapseabeasacssenetans System Flow Chart 5 rarsesorrtssarsanrsrdnseesbenenenekmetndenabstanmmnktnonkenabsakensdhesekonsed Maintenance Service and Trouble Shooting Specifications Specifications Models SCKO2SMWBS Net capacity 140 L Color White Power Supply V Hz 115 60 Rated Input Power 140 W Net Weight 36 kg Gross Weight 40 kg Unit Dimension D W H 510 628 855 mm Packing Dimension D W H 567 700 885 mm IMPORTANT SAFETY INSTRUCTIONS READ ALL SAFETY INSTRUCTIONS BEFORE USING THIS APPLIANCE When using electrical appliances basic safety precautions should be followed including the following Read all instructions before using the beer dispenser 2 Plug into a grounded 3 prong outlet do not remove grounding plug do not use an adapter do not use an extension cord 3 Replace all panels before operating 4 Itis recommended a separate circuit be used for this unit Use outlets that cannot be turned on and off with a switch or pull chain 5 Never clean unit parts with flammable fluids Do not store or use gasoline or other flammable vapors and liguids in t2. Do not use this unit for anything other than its intended purpose 20 Before throwing away an old unit remove the doors but leave the shelves in place so that children cannot easily climb inside 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 2 Brief Description of System Flow Chart Model MTR17W is a direct cooling single system refrigerator When the refrigerator is powered on the refrigerant flows in the sequence 1 gt 2 gt 3 gt 4 gt 5 gt 6 Circuit Diagram Circuit Diagram 1 Schematic Circuit Diagram THERMOSTAT COMPRESSOR Brief Description of Control Principle Model is a direct cooling single system refrigerator A mechanical type of all the controls is generally adopted The thermostat controls the start and stop compressor and the refrigerator temperature Maintenance Service and Trouble Shooting Maintenance Service and Trouble Shooting 1 No cooling No cooling T If compressor NO Check and repair according to can run after it stops to the section of The compessor run five minutes then doesn t work give power YES T If compressor Refrigerant can run naturally and NO leak check and temperature raising l a repair charge of condenser is refrigerant again very low YES T When charging refrigerant check Blocked by ice or dirt to make sure refrigerant is true Ch
3. 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 problems may share a common abnormal phenomenon and two or more of these may occur simultaneously due to a certain problem With this method you can reject some suspicious problems 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 refrigerate normally but the temperature in the refrigerator cannot drop to the prescribed value under the stipulated working conditions There are many causes for this phenomenon that we are going to discuss and analyze 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 exhau
4. 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 reducing 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 are higher gas discharge pressure higher discharged gas temperature the gas discharge tubing is considerably hot when you feel it with your hand and poor 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 b
5. 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 Dismanile 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 rare to occur This problem 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 may 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 Troubles 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 guite difficult to differentiate this trouble from others be
6. ange filter and change refrigerant again Maintenance Service and Trouble Shooting 2 The Compressor Doesn t Stop Compressor doesn t stop NO Check and repair according to Does the refrigerator the section of No Cooling refrigerate YES T Is cooling capacity NO 0 Check and repair according to insufficient the section Cooling capacity is insuffcient V YES 1 The thermostat was set at the coldest position 2 The ambient temperature is very high or NO Adjust and instruct the refrigerator is near a heat source consumer how to use 3 The door was opened too many times or there is more fresh food inside NO V Check and repair the main control panel Maintenance Service and Trouble Shooting 3 Cooling Capacity Is Insufficient Cooling capacity is insufficient T Is the ambient YES f Check is the thermostat temperature lower than i correct 16 C YES NO la l j Does the refrigerant Adjust and instruct leak siowly consumer how to use V Repair Maintenance Service and Trouble Shooting 4 The compressor doesn t work The compressor doesn t work l Does the l lamp illuminate NO GECE ine DOMET NO whenthe door is gt source and power Repair opened soro YES YES Is the ambient YES l Check if the thermostat temperature lower than is correct 16 C pe Adjust and instruct consumer how to use T Does the control NO pan
7. as flowing sound resulting from an abrupt gush is heard and the gas suction pressure rises as well it can be confirmed that the problem 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 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 17 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
8. ate and the fuse blown 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 problem care should be taken to differentiate it from other real problems 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 probably there are many causes including 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 find out the real cause and take correct measures to remove this problem Remed
9. ay 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 determined that thetemperature sensing agent has leaked out and it must be replaced with a new thermostat 4 Motor Problems 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 particularly 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 21 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
10. be used in this inspection too f the insulation resistance is lower than 2 MO 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 the 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 actua
11. cause they often have similar symptoms In repairing first listen 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 for 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 both cases stop the compressor at once and if technigue 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 Running 18 Maintenance Service and Trouble Shooting The cause of sudden stop of a compressor during its running is mostly that the gas suction pressure and or discharge pressure exceed their respective prescribed ranges 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
12. ed 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 the gas flowing sound will be 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 14 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 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 can be be blocked with your finger if you just apply a litt
13. een 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 to go 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 Electrical Problems a Thermostat Is Out of Control Analysis of Trouble In case the thermostat does not work in good order or its 19 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 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 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 actu
14. el have 230V power Check and repair the output control panel YES T NO Does the compressor Check all cords and have 120V power power cords output YES V Check and repair compressor and accessory Maintenance Service and Trouble Shooting 5 Normal Phenomena Not Problems 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 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 and operation properties will become unstable Refrigerators are generally a large appliance which makes it difficult to send to a service department Therefore before we deal with the topics of common problems we should first give a description of normal refrigerator phenomena In case any one of such phenomena occurs there is no need for concern 1 When the compressor of a refrigerator has just stopped running a rumbling sound can be heard from inside its evaporator This sound is 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 a certain time therefore this sound is normal 2 A click sound can often be heard from the refrigerator This is a normal sound produced by
15. el 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 lefi part depending on the type of condenser coil this indicates that the refrigerant is circulating If the condenser is not hot this means leakage of the 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 a 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 12 Maintenance Service and Trouble Shooting ambient temperature this means that most meshes of its screen have been clogged resulting in an obstructed flow of refrigerant thus causing a drop in temperature due to throttling d Feel the temperature of exhaust gas from the refrigerating system The exhaust gas should be very hot which is the normal working state For those refrigerator s with an enclosed compressor refrigerating system no frost or dew drop will form on the gas suction tube otherwise there is something wrong in the system
16. enerally 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 generally no trouble indicating instrument mounted on the domestic refrigerator locations and natures of troubles should be determined according to their respective features therefore experience in servicing is very important in troubleshooting Service technicians with rich experience can correctly locate them and take reasonable remedy measures based on their comprehensive 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 the refrigerating system for cracks and various welding points for leaks if leakage occurs an oil
17. ght up intensively measure the resistance between the power cord plug and the case body with an avometer the reading will be zero 00 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 the refrigerator 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 2 Abnormal noise from compressor Three suspended spring inside the compressor case are out of balance and strike against the case 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 24 Maintenance Service and Trouble Shooting 4 Inspection method To find the sources of noise press the vibration spot with your hand whi
18. he 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 problem and it is relatively complicated In servicing special attention to finding direct causes for this phenomenon are important 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 for 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 Symptoms of total leakage of refrigerant are mainly as follows 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 16 Maintenance Service and Trouble Shooting heard and
19. he vicinity of this or any other appliance Fumes can create a fire hazard or explosion 6 Before cleaning or doing any maintenance to the unit ensure the power is turned off and the power cord is disconnected from the power outlet 7 Do not attempt to service the unit unless it is specifically recommended in this manual All other servicing should be referred to a gualified technician 8 Use two or more people to move and install the unit Failure to do so may result in back or other injury 9 To ensure proper ventilation the front of the unit must be completely unobstructed Choose a well ventilated area with temperatures between 60 F and 90 F 10 Do not place this unit near heat sources 11 This unit must be installed with all electrical water and drain connections in accordance with state and local codes A standard electrical supply properly grounded in accordance with the National Electrical Code and local codes and ordinances is required 12 Do not kink or pinch the power supply cord 13 The fuse or circuit breaker should be 15 amperes 14 It is important the unit be level in order for it to work properly You may need to make several adjustments 15 All installation must be in accordance with local plumbing code requirements 16 Make certain the pipes are not pinched kinked or damages during installation 17 Check for leaks after connection 18 Never allow children to operate play with or crawl inside the unit 19
20. ing 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 In case excessive refrigerant has been charged the liquid refrigerant that cannot evaporate 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 the compressor Remedy According to the operating procedures it is mandatory to turn the machine off and several minutes later open the refrigerant charging tube and let the refrigerant escape from it replace the dry filter recharge refrigerant after evacuating and then seal the charging port 3 There ls 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 rat
21. le 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 block the temperature in the refrigerator from dropping 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 flow 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 the evaporator the heat conduction effect will be severely affected thus causing a poor refrigerating effect Remedy It is quite difficult to determine whether this problem is caused by the refrigerating oil left in the evaporator tubing because this kind of phenomenon and other problems tend to be confusing Generally speaking you can make a judgment based on the frost formed on the evapo
22. le the refrigerator is in operation and listen attentively whether the vibration becomes weaker 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 25 55 56 57 43 58 59 60 61 62 32 31 26 19 20 22 23 24 25 SCKO25MWBS Part List Part number Desriptton djustment Leg helf Hanger mmovable Leg Wheel and Mount CO2 Cylinder CO2 Regulator Cleaning Kit 27
23. ne 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 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 d
24. none 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 have 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 of these will cause the expansion valve to be clogged with ice The symptom for this problem 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 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 In order to determine whether it is clogged with ice heat the suspicious points with hot water to make ice melt After a while if a g
25. oor 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 23 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 test 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 li
26. rator If the frost does not cover the evaporator and moreover it is loosely formed you can make a judgment that the deterioration of 15 Maintenance Service and Trouble Shooting refrigerating effect is due to the accumulation of refrigerating oil left in the evaporator tubing in case no other problems 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 charge refrigerant from the evaporator inlet to wash it several times then purge and dry 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 period of time thus resulting in a decrease in flow rate and a poorer refrigerating effect The abnormal phenomena caused by this kind of slight clogging in the system are as follows the gas discharge pressure 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 Refrigeration The phenomenon that t
27. st 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 No frost or a smaller guantity 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 13 Maintenance Service and Trouble Shooting There are so many joints and sealed surfaces in a refrigerator that many potential leak points 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 severe leak point charge the system with nitrogen and detect leak points with the commonly adopted method repair evacuate charge the system with refrigerant and then turn on the refrigerator to make a test run 2 Too Much Refrigerant Charged Into the System Analysis of Trouble a In case the amount of refrigerant charged into the system exceeds its nominal capacity the superfluous refrigerant will take some space of the evaporator thus reducing its heat dissipation area and the refrigerat
28. stain can be seen 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 t able 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 11 Maintenance Service and Trouble Shooting A hum 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 sound 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 und
29. te 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 22 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 Thermostat 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 o
30. 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 it can be heard distinctly at night 3 The compressor consists of an electric motor and a compressing apparatus During its normal operation the motor s stator core and windings will rise to a temperature between 100 C 110 C and the temperature of the piston and cylinder of the compressing mechanism can also reach above 100 C due to the heat produced when compressing the 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 All of this is normal 4 For the direct cooling refrigerator a kind of irregular crack sound can often be 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 of expansion and contraction when the temperature changes and will not affect the normal application of the refrigerator 10 Maintenance Service and Trouble Shooting 6 Common Troubles in Refrigerators and Their Solutions Causes for problems 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 g
31. ulation of electric current can generally be heard 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 vapor 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 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 after running for a long period of time b After the compressor has operated normally for 5 10 minutes touch and fe
32. y 20 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 a 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 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 m
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