subject: refrigerator repair [print this page] Refrigerators are the most used, least troublesome of all appliances. Yet they have plenty of potential trouble areas. It is a minor miracle of technology that they cause so few complaints. Appliance repair is something you should expect and be prepared for.
In most modern refrigerators, the compressor and motor are sealed with no exposed moving parts. Lubrication is provided continuously. The motors usually are of a type that has a startup winding which cuts out when running speed is attained, and the running winding takes over. An overload and a relay switch, in a separate, serviceable compartment, complete the motor's electrical equipment.
Refrigeration systems in modern refrigerators have the sealed-in compressor, which is a pump for converting low-pressure gas to high-temperature, high- pressure gas. Then, by way of the condenser, the resultant heat is removed to the air outside the refrigerator. These functions cause refrigeration to occur.
A heat exchanger, consisting of a capillary tube and suction line, is another component. The exchanger serves to regulate and assist in cooling.
The evaporator, another link in refrigeration, consists of a cooling plate in the fresh food compartment and an evaporator in the freezing compartment. It helps regulate correct, different temperatures in the various chambers of the refrigerator.
Any major breakdown of a refrigerator either compressor or motor requires service you cannot perform at home. Usually, and unless the guarantee remains in effect, you will be forced to buy anew one, unless the shop makes you an offer you can't refuse such as a guaranteed compressor-motor unit for much less than the new refrigerator, and the refrigerator is one you are reluctant to junk. We'll discuss replacing the unit below.
Refrigerator life should be between 15 and 20 years. What goes wrong before then is usually nothing more than an occasional broken parta shelf latch or compartment clip or runner or other purely mechanical disabilities. Electrical problems are often traceable to power sources that are inadequate to run the motor- compressor. If there is a voltage drop below 110 volts, this could cause the motor to fail. If the line is overloaded, the refrigerator's starting could trip the circuit breaker or blow a fuse.
Major problems sometimes can be understood by listening for certain noises. In low voltage, the starting; relay switch will click in and out, giving a "chattering" effect. The contacts open and close rapidly. If the motor begins and runs briefly, then stops, this could mean relay problems. A rapid "click, click" sequence when the motor begins probably means a short circuit in the winding. Motor hum followed by a clicking noise also involves the winding (coil) of the motor. None of these problems can be repaired at home, but you will at least know what is involved.
Replacing lights and light switches can be done by you. The door switch that controls the light is held either by a screw or a tension spring. In the latter case, it simply pulls out.
But if you open the door and no lights come on, in a refrigerator with more than one light, you know that the problem is not in the switches or anything else inside the refrigerator, but in the power supply. (If it has only one light that could be burned out.)
If you open the door and the light does come on, but the refrigerator doesn't work and the freezer compartment shows signs of melting, you know that the problem is in the motor or its switch. Look first at the control dial (thermostat). Some dials are placed in a position that exposes them to inadvertent movement merely from using the refrigerator you can brush against the dial and turn it off.
If the dial is on, however, the chances are that you have nothing more than a defective relay switch that controls the motor, or it can be the thermostat itself, or a defective overload device that protects the motor but is itself vulnerable.
The starting relay is a magnetic switch with the coil connected into the running winding of the motor. When electricity flows, the magnetic coil pulls up the relay plunger and the movement closes the starting contacts of the motor. Since the relay switch has moving parts, as well as a coil winding, it is doubly vulnerable over the long haul; relays are basically sturdy components.
Relay switches may be found close to the motor but in a separate housing for purposes of accessibility (in some models). They may also be found in the motor compartment, mounted near or at the motor housing. The switch has various configurations, but the fact that it has a circular coil around a magnet may be deceiving since the housing rarely is circular. Typically the relay and overload protector will be in the same box since both of them control motor starting and running.
The relay housing should be removable, even when it is attached to a sealed compressor and motor. It will be held by a screw or set of screws, and you may actually be able to see it at the bottom of the refrigerator, in the rear. You will, of course, have to move the refrigerator out from the wall.
A relay switch is replaced by one with the same capacity, expressed in horsepower. If you can't buy an identical make, you can use one with the same capacity. They are inexpensive and easy to replace. If the electrical posts don't have identical characteristics, ask how to resolve the differences. Often the leads are color-coded, but if you remove the relay, it is important to mark the leads so that you don't mix them up.
That illustration also shows the two-wire overload protector, which is a heat-sensitive device that turns off power to the motor-compressor when the motor runs hot. What causes that? It could be the motor, with the usual electric motor problems, or it could be the compressor dragging the motor.
It is well to have both relay and overload protector tested at the same time. One must suspect that some-thing is wrong with the motor when the overload protector is not functioning, but that is not necessarily the case. So the best course is to have both relay and overload protector tested.
If the relay and overload protector test out to be in shape, and no cooling is taking place, you are faced with a failure of the motor-compressor, assuming that the thermostat inside the fresh food compartment also tests out to be working. That means a new refrigerator is in the cards. It is rare that a replacement motor- compressor is worth buying, unless you are especially fond of the refrigerator and are satisfied that the rest of the components are in working order and you are willing to do the replacement job yourself. (More of that below.)
If the overload protector and relay test good, and there is some but not adequate cooling, or the compressor overheats and is shut off by the overload protector, it doesn't automatically mean that the motor-compressor is worn out. One further possibility involves the way you use the refrigerator: if the compressor and condenser don't get enough air circulation, overheating can result; if you put too much warm food in the refrigerator, the overload will respond and turn off the motor; and overheating can cause the overload protector to trip open repeatedly in response to temperature variations.
The cure for too much warm food is obvious enough. Also, it is well not to put too much food in the fresh food compartment, generally, in contrast with the freezer compartment which should be kept more or less full.
Insufficient air circulation around the compressor is caused mostly by dirt around it. Regular cleaning is the usual answer, unless the refrigerator is in a position where it is unable to get ventilation.
In some cases the thermostat needs adjustment to achieve proper cooling throughout.
First, use a thermometer in various parts of the refrigerator. The fresh food compartment should be around 37F (5C), give or take a few. The freezer should be about 0F (-20C), again give or take a few degrees. It should be noted that temperatures in a refrigerator are in part a reflection of temperatures outside it that is, extreme heat outside the refrigerator will inevitably add heat inside it, especially if the refrigerator is used a lot. So you should take the refrigerator's temperature in the morning before it has been used.
If the refrigerator Seems to be working but not cooling adequately, it could be that the thermostat needs adjusting. To do that, pull out the plug, remove the dial from the thermostat by pulling it off (or releasing a setscrew that holds it in some makes). Behind the dial there will be a hole with an adjustment screw. Turn the screw counterclockwise just a small amount from l/18th to l/16th of an inch. That should lower operating temperatures one or two degrees, by extending the operating time of the compressor per cycle. If this adjustment doesn't change the operating temperature satisfactorily, the problem lies elsewhere. The next place to look is at the gasketaround the rim of the door. The usual test is to pull a dollar bill out of the closed door from a half dozen places. If you can pull the bill out of a closed door easily, that means air is getting in and out at that point. Examine the spot. You can be confident that if there is one such spot there are others.
The most obvious cure is a new gasket. Sometimes the door itself has gotten off center. Doors have adjustments, but they are tricky. Door adjustment is indicated when an entire section of the door seems to be pulled away from the cabinet with the clear evidence that a new gasket won't make a correcting difference.
Mechanical adjustments on the door alignment often can be avoided simply by leveling the refrigerator properly. Leveling adjustments can be found in the legs. A good test of a smooth gasket seal is to measure the amount of gasket compression when the door is closed it should be up to 16th inch, but no more.
The first thing to do with a cabinet whose gasket isn't sealing properly is to turn out the handle side front levelers if the distortion is a toe-out direction or turning in the handle side front leveler to correct a toe-in distortion. But if that doesn't cure the problem, you have a much more elaborate set of adjustments. These require loosening all the inner panel mounting screws along the top, bottom, and handle side of the door (but not along the hinge side).
Mechanical and other nonelectrical problems of refrigerator repair are outside the scope of this book, but the door alignment problem is not much more than any trial-and-error job it isn't like wheel alignment on a car.
Refrigeration is an entirely separate technology from motors, even though the motive power is electrical and the controls often touch electricity. Any faults in a refrigerator that cannot be cured by attention to switches and the processes described above must be cured by the techniques of refrigeration or with a new refrigerator. Given the cost of replacing a motor- compressor and other expensive components in the cooling system, most people will buy a new refrigerator.
Also, because the motor is sealed into the compartment that contains the compressor, it does not lend itself easily to repair in case the compressor remains in working order. But you can replace the entire unit yourself, and if you are willing it suddenly makes sense to save the refrigerator, since much of the replacement cost when performed by professionals is installation labor (and of that labor, taking out the old motor-compressor is the hardest part, usually).
So, if you have such symptoms as a compressor that won't cool properly, with all cooling surfaces covered by a thin layer of frost, it is probable that you need a new compressor. Warning: this symptom is also the same as a refrigerant leak and that's unfortunately something very hard to track down, though it can be done. Here's how:
A refrigerant leak can occur virtually anywhere in the cooling system, including the least accessible parts of it. This means not only the tubing in the rear portion, which you can usually see (unless it is boxed in), but also the buried tubing and components. Let us agree, however, that with many modern refrigerators the task of exposing the potential leaking parts means undertaking a kind of search and destroy mission that many people simply won't consider, because it requires elaborate cutting away of housing compartments. Older refrigerators aren't so completely sealed in. In these cases you can remove the motor and compressor, as well as the condenser from the machine, in one fell swoop by pushing the refrigerator out from the wall and unscrewing the panels that contain these components. But without removing anything beyond covering panels, you can do a lot of testing for leaks with soapy water. Simply brush a solution of soap powder and water over anything that looks the least bit suspicious, and over anything you can reach without major excavation.
You are seeking Freon gas leaks; bubbles in the soapy water brushed on any part are proof of a leak. To repair a leak, use any epoxy-type preparation, or inquire about the best product your hardware store sells. You will be asked what kind of metal and it will usually be aluminum tubing; for example, the capillary tube which is a long, thin (l/8th- inch diameter) piece of tubing between the condenser and the cooling plate. There are many other possible leak spots. The accompanying illustrations show the layout of parts and tubes of a typical Montgomery Ward refrigerator (Signature). This recent model type is mostly sealed in, but it reflects components and tubing in older models, as well as new. Refrigeration technology changes slowly; change is almost entirely cosmetic.
The evaporator may well be the element most exposed to Freon leaks because it lies directly behind and/or above the freezer compartment (or between freezer and fresh food compartments) where it can receive blows from ice picks and knives during defrosting by hand or other ice removal. Or it may receive less calculated blows.
Some modern refrigerators also have components such as precooler coils, which are part of a special compressor system that also includes a condenser loop. These components aid in the cooling process by removing defrost water; they are at the bottom in Montgomery Ward models. Also, larger refrigerators may have multiple condensing units in order to transfer more heat from the high temperature Freon gas to the outside air. The more space in a refrigerator, the more heat there will be picked up in the Freon gas.
Leaks are possible not only in the aluminum tubing and the aluminum evaporator but also in copper tubing. Copper must be soldered and requires a rather skilled technique and special solder. If the leak is in the copper tubing which flows into the condenser, the problem is compounded by the different metals the steel of the condenser and the copper. Heat must be on the copper only to avoid damage to the condenser, which is of rather delicate steel. When soldering on copper tubing, heat is applied to the copper until the solder flows from contact with the heated copper you do not turn the flame on the solder itself. It's like soldering joints in copper water pipes; the solder extracts the heat from the copper surface, which it then seals by flowing into any cracks.
Any components, including the motor and compressor, can be replaced on refrigerator. The cost of replacing a component yourself can be judged in relation to your area labor charges for such work. Then you have to figure what your own time is worth or how much it means to you to salvage an appliance.
Refrigerator repair work is highly specialized and expensive, and even if you manage to find a leak in the system, and repair it, you still have the problem of removing air from the system and refilling it with Freon gas.
If you are willing, you can, but you need highly specialized equipment a valve for purging and for charging the system, a gauge, and a cylinder of Freon gas. Because these are not commonly circulating components, you may have a problem finding them. Also, the skills to use them won't translate readily into other home repair situations where the most that is usually required is how to use a wrench or screwdriver. This homiletic advice is not presented to frighten you, but merely to keep relevant data in focus. If you decide to go ahead and repair a refrigerator that isn't cooling properly, you must be forewarned that replacement of the motor and compressor is not the only issue, and in some cases even that won't be possible for you to do unless you are willing to undertake a multiphased operation involving special skills (those cases in which access requires cutting away of compartment metals and tubing lines).
