HOW REFRIGERATORS WORK.docx

1、HOW REFRIGERATORS WORKHOW REFRIGERATORS WORK Refrigerators have separate systems that are responsible for different features. However, not all refrigerators have all systems. To look for information about the operation of your refrigerator, click one of these topics: Automatic defrost Years ago, all

2、 refrigerators had to be defrosted manually. You would turn the refrigerator off, open the door(s), and allow any frost build-up to melt. When the frost had completely melted away, you would turn the refrigerator back on. Today, all but the smaller, apartment-sized refrigerators are self-defrosting.

3、 Self-defrosting means what it implies-though frost continues to accumulate inside the refrigerator, it melts automatically. The self-defrosting system has three functional components: Defrost timerDefrost heaterDefrost thermostat. Defrost timerThe timer is like a clock. It continually advances, 24

4、hours a day. Every 6 to 8 hours, the timer turns off the cooling system of the refrigerator and turns on the defrost heater. Defrost heaterThe defrost heater is similar to the burners on an electric stove. Its located just beneath the cooling coils, which are concealed behind a panel in the freezer

5、compartment. The heater gets hot. And, because its close to the cooling coils, any ice or frost build-up melts. As the frost and ice melt, the resulting water drips into a trough. The trough is connected to a tube that drains the water into a shallow pan at the bottom of the refrigerator. The water

6、is then evaporated by a fan that blows warm air from the compressor motor over the pan and out the front of the refrigerator.Defrost thermostatThe process ends after either the amount of time specified on the timer or when the defrost thermostat near the cooling coils senses that the heat near the c

7、oils has reached a specific temperature.CoolingYoull more quickly understand refrigerator cooling systems if you think of their action as removing heat from the air in the refrigerator rather than cooling the air in the refrigerator. All residential refrigerators work on the same principal for cooli

8、ng. They all have:A CompressorA CondenserA Metering Device (Capillary Tube)An EvaporatorCompressorThe compressor is the motor (or engine) of the cooling system. In built-in refrigerators the compressor is located on top of the refrigerator behind a grill or grate. In all other units its normally at

9、the bottom of the refrigerator in the back. Its almost always black and about the size of a football. If the refrigerator is self-defrosting, the compressor may be behind a thin panel. The compressor runs whenever the refrigerator thermostat calls for cooling (and the defrost timer is not in a defro

10、st cycle, for self-defrosting units). It is normally very quiet. When running, it is compressing a refrigerant that is in a low-pressure gaseous state to a high-pressure gas. CondenserThe condenser is a series of tubes with fins attached to them, similar to a radiator. Its always somewhere on the ou

11、tside of the refrigerator. It may be:* A large black grid mounted to the back of the refrigerator* Folded and placed under the refrigerator* Coiled up and placed near the compressor* Integrated in the liner of the refrigeratorIf the condenser isnt a big grid on the back of the refrigerator, it will

12、always have a cooling fan nearby to draw room air over the tubes and fins-to dissipate the heat from the tubes and fins. The high-pressure refrigerant gas, coming from the compressor, flows through the condenser and becomes a liquid. As this occurs, the refrigerant gives off heat. The heat is conduc

13、ted away from the tubes by the fins. Metering Device (Capillary Tube)The metering device in most household refrigerators is a capillary tube, a tiny copper tube. The capillary tube is attached from the end of the condenser to the beginning of the evaporator. The capillary tube controls the pressure

14、and flow of the refrigerant as it enters the evaporator.Once the liquid refrigerant has traveled the length of the condenser, it is forced through the capillary tube. EvaporatorThe evaporator is always located on the inside of the refrigerator, usually inside the freezer compartment. It also resembl

15、es a radiator. When the liquid refrigerant comes out of the small capillary tube, its injected into the larger tubes of the evaporator causing a pressure drop. This pressure drop allows the refrigerant to expand back into a gaseous state. This change of state from liquid to gas absorbs heat. The gas

16、eous refrigerant travels through the evaporator tubes, back out of the refrigerator and down to the compressor to begin the circulation process again. Because the evaporator is absorbing heat, it is very cold to the touch. The coldness causes any humidity in the air to freeze on the evaporator as ic

17、e or frost. (See the Automatic defrost section). The fan inside the freezer compartment circulates the air of both the refrigerator and/or freezer to keep the temperature constant.Temperature controlAll refrigerators have a thermostat to maintain the proper temperature. These are usually very simple

18、 devices. When the refrigerator reaches the set temperature, the thermostat interrupts the electricity flow to the compressor, which stops cooling.LightingRefrigerators with internal lighting normally have only one functional component-the switch-which is usually a white push-button mounted inside t

19、he refrigerator near the door. When the refrigerator door closes, the door pushes the switch to turn the light off. When the door opens, the button automatically pops back out to turn on the light. The light bulb itself is usually a standard appliance bulb.Ice makerThe ice maker is a small appliance

20、 within a freezer. Its usually independent of the other systems of the refrigerator. Ice maker systems have two basic functional components: the icemaker itself, and the water fill valve.This is the most common ice maker operation cycle:* The ice maker sends a signal to the water fill valve (normall

21、y located on the outside back of the refrigerator, near the bottom) to open and let water into the ice maker tray. The amount of water is determined by a cam and switch within the ice maker control panel. The icemaker sends the signal to open the water valve for a certain length of time (7-10 second

22、s)then stops the signal. * The ice maker waits until the water is frozen-which it senses with a small thermostat located near the water tray. When the tray reaches approximately 10-15 degrees Fahrenheit , the ice maker begins to harvest (eject) the cubes. * To harvest the cubes, the ice maker first

23、turns on a small heater beneath the tray. The heater warms the tray slightly, which allows the ice cubes to move freely. * Then a sweep fork rotates and pushes the cubes up and out of the tray. * While the ice maker is dumping the cubes into a holding bin, a metal wire similar to a coat hanger swing

24、s up to let the cubes drop below it. When the cubes have dropped, the wire comes back down. If the holding bin is full of ice, the wire cannot come all the way back down, which stops further production of ice. * When the wire is allowed to come back down all the way, the ice maker refills with water

25、 and repeats the process.Ice and water dispenserThere are several different systems for delivering ice and water through the refrigerator door. What follows is an explanation of the common attributes of all of the systems. Ice dispenserFor a refrigerator to provide ice through the door, the ice make

26、r first dumps the ice it produces into a large bin. To request ice at the door, a person presses a lever that activates a switch. The switch turns on a motor that rotates the auger. When the auger rotates, it pushes ice out of the bin, through a chute to the user.Water dispenserThe water dispenser w

27、orks much like the ice dispenser. To request water at the door, a person presses a lever on the front of the refrigerator that activates a switch. The switch turns on an electric water valve at the back of the refrigerator. Water flows through the valve into a tube, then flows into a container in th

28、e refrigerator to be chilled. As new water enters the container, the water that is displaced flows through a separate tube to the user.Door seals and hingesAll refrigerator/freezer doors have a seal-a rubber-like gasket attached to the door. Usually white, almond, black, or brown, the seals job is t

29、o keep the cool air inside the refrigerator and the room air out. The seal is lined with a magnet that runs its length and width. The magnet helps to hold the door closed and create a tight seal. The screws that hold the seal to the door also hold the door liner in and help to square the door.The hi

30、nges allow the door to swing open. Some hinges also assist the door in closing. For the door to close properly, the hinges must be correctly adjusted. InstallationProper installation of a refrigerator is both easy and important. The primary concerns are that the unit has sufficient clearance from th

31、e walls for proper ventilation, that it is not pinching any electrical cords or water lines, and that it is level. Many refrigerators must be tilted back slightly so that the doors self-close. Consult your owners manual for further installation instructions. 到这里WHAT IS WRONG WITH YOUR REFRIGERATOR?

32、Warning! To avoid personal injury or even death, always disconnect your appliance from its power source-that is, unplug it or break the connection at the circuit breaker or fuse box-before you do any troubleshooting or repair work on your appliance. Also, because some components may have sharp edges, use caution while working on your appliance.Note: If your repair problem isnt listed, click here to email the RepairGuru. He will give you the help you need. Its stopped completelyFirst, check to see if the light comes on or if there is any fan, motor, or other sound coming from the appliance