Freezer repair

A freezer is simply a refrigerator with a fixed temperature and without the complications required for two separate refrigeration tasks. The basic components are the same. Access differs, depending on make and model. Upright freezers (front door access) are sufficiently different from refrigerators and top-loading freezers to merit some discussion.
One difference between most upright freezers and the typical refrigerator is that the evaporator, consisting of tubing of aluminum on aluminum fins of some sort, is attached to the individual shelves. Each shelf has its own evaporator, in other words. The evaporator, which absorbs heat and passes on the liquid refrigerant from the capillary tube, sends signals back to the thermostat when the temperature rises. That starts the compressor. Variations in design are many in upright freezers, even within a single family of units, but all have the same basic components, hence the same basic problems.
If warmer than normal temperatures occur in a freezer, the first thing to suspect is the capillary tube, a tiny passageway that becomes clogged with alarming ease. A tiny kink in the tube can clog it. Moisture freeze-up can clog the tube, and so can foreign particles. A check of the freezer shelf evaporator fin and tube sections will yield clues — a capillary tube restriction is signalled by noticeable lack of frost and the compressor will operate only for a short time. You can see a kink, which requires a new tube.
Moisture will freeze mostly at the outlet end of the capillary tube and a sign of it is a frost buildup in the area. When this happens, the compressor will trip the overload protector, and the frozen moisture will melt, allowing the Freon to circulate. Once the overload resets the compressor, the cycle will start anew and probably the same moisture freeze will recur. Usually this will require the installation of a new drier, a device between the condenser and the capillary tube.
If the compressor runs while the evaporator shelves are not being refrigerated, stop the freezer (pull the plug) and listen. If you hear a gurgling noise, that means the capillary tube is not restricted. Suspect aleak under operating pressures in this situation or a kink in the capillary tube.
It should be stressed that any replacement of parts in a freezer (or refrigerator) requires the cutting of tubing in most cases, and the purging and refilling of Freon gas, as well as the soldering of the new components. Replacement of relay switches, capacitors (if any) or other basic, small electrical components such as door switches, light bulbs, and light sockets is another matter. It's basically easy to do, as we note elsewhere. But replacement of refrigeration components involves another technology which you may or may not wish to undertake. Incidentally, the tools and supplies you need aren't all that expensive and can be rented in some cases (the gauges and test meters, for instance). But you do have to learn to solder nicely.
Freezers have signal lights which operate at all times unless a fuse is blown or a circuit breaker is tripped, or the light itself becomes defective. To replace a defective light, turn off the freezer by disconnecting the power cord and prying out the light assembly. Replace the light with one of identical capacity.
If the freezer fails to run despite the fact that the line is working properly, you have to make the same tests as on a refrigerator. You first check out the relay and overload protector. Then you must test the compressor and motor and the refrigeration components (evaporator, condenser, tubing, etc.) for leaks.
In frostless freezers, you have the added complications of the defrost heater. It's a radiant heater at the bottom of the freezer coil just above the drain. It is clamped at both ends and attached to a mounting panel or bracket. A defrost thermostat, at the upper end of the freezer coil, reports temperatures and automatically turns off the defrost heater. If the system fails, it can cause frost buildup and blockage between coil fins. You can see that happening, especially if the loss of freezing is occurring and you can't find other symptoms.
To replace a radiant heater is possible but first you have to know whether the heater or its thermostat is defective. Otherwise you will replace the wrong part. (However, it may be observed generally that the cost of a wrong part is far less than the cost of paying someone to come out and test for the right part. Hie ideal procedure always is to test and discover the failed member, then replace that one.)
You can test a thermostat with an ohmmeter, which is well to have in any case, and in cases like these particularly. Look for the thermostat at the top of the freezer coil — the coil that supplies the evaporator coils at the shelves (below them in those freezers with individual evaporator coils).
With an ohmmeter available, unplug the freezer and attach the ohmmeter clips to the prongs of the wall plug. Turn the timer shaft to the right (clockwise) until it clicks once. Then turn the shaft slowly to avoid passing the defrost position — the first click. If you turn into the second click, continue turning until you hear the first click once again. Close the freezer door — or push in the light switch. If the defrost heater and its thermostat are okay, the ohmmeter should read 25 or 30. If either one is defective, the reading will be about 300. Next check them individually by removing the freezer coil cover and touch the leads into both the heater and the thermostat.
Replacement of either of these parts — or both of them — begins by removing the radiant heater cover. Then remove the heater leads and detach them from their terminals on the freezer coil. Take off the clips at each end of the heater, push down on the heater shield, grab the heater at both ends and lift outward. To replace the heater, reverse these steps, but avoid touching the heater glass — you could damage it simply from the grease or anything else on your hands. To remove and replace the heater thermostat, spread the front tangs of the retainer clips.