Refrigerator Troubleshooting Diagram

Archive for the ‘Refrigerator Compressor’ Category

Refrigerator Open Drive Compressor

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There are many of these old-timers chugging around the world and still doing the job. Some of you perhaps never saw one of these and never will, but you should know about it in the event you need one for a specific application. These compressors come in a variety of sizes from one (1) hp up. They can be used for air conditioning or refrigeration application. The biggest advantage of this type compressor is the choice of driving power you want. The compressor has a drive shaft protruding from it. The shaft can take either a pulley or a coupler. For instance, I’ve serviced a unit such as this that was driven by a six-cylinder internal combustion engine fueled by propane. The greatest advantage of this application is the capacity control. With the engine throttle linked to the thermostat, the engine idles when there isn’t a load demand. This type compressor can be driv­en by electric motor, internal combustion engine, or turbine. An­other great advantage to this compressor is that it can be installed in an area that doesn’t have ample electrical power to drive large compressors.

For all the good, there has to be a little bad. The two biggest drawbacks about the open-drive compressor is its physical size and the critical alignment. As you can see in Fig. 3-10 there has to be a close alignment between the compressor and the driving force. If the alignment goes out, beyond specifications, the front shaft oil seal will begin to leak. Both refrigerant and oil will exit here. Alignment with a dial gauge at regular intervals is prudent.


Written by sam

December 23rd, 2010 at 1:08 pm

Refrigerator Semi Hermetic Compressor

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The semi-hermetic compressor is totally different in its construction than the hennetic; this can be seen in Fig. 3-9. The compressor is constructed of a heavy casting. It is bulky and heavy to handle due to the iron content in its body. You will notice that this compressor has nuts and bolts holding it together. This advantage allows the unit to be re-built on a job site. It too has a drive motor (electric) that turns the parts of the reciprocal compressor. Not many of these compressors will be found in residential applications, yet there can be some larger homes or estates that use this kind. Many light commercial applications also use this type of compressor.


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December 23rd, 2010 at 1:05 pm

Refrigerator Hermetic Compressors

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The most expensive part in the condensing unit is the compressor. It is the heart, the pump that circulates the refrigerant as the heart does with the blood. A hermetic compressor is the most common one found in residential and light commercial air conditioning

and refrigeration systems. In Fig. 3-8 a typical hermetic compressor is illustrated. They are sealed units and cannot be serviced internally in the field. There are re-building shops that have the equipment to cut them open, replace defective parts an weld the shell together again. These compressors are suction cooled. This means that enough cool gas must return to the compressor from the evaporator coil to maintain a desired compressor operating temperature. An electric motor sealed in the shell drives a crankshaft and one or more pistons to operate a reciprocal compressor. In the case of a hermetic rotary type of compressor, vanes similar to those on a water pump impeller or vanes on an oil pump do the pumping instead of the pistons.

Located on the shell are pieces of pipe that have been welded to the body to give access to the high side and low side of the compressor. There might also be small tubes that can be used to charge the system or install pressure operated controls. The larger of the pipes is the low side, or suction side of the system. The smaller pipe is the discharge side, or hot gas line. These short stubs of pipe may be either steel or copper. The refrigeration piping is soldered to them.


Hermetic compressors can be used in small reach in refrigerators and are rated at fractional hp (horsepower). They range from 1/14 to 60 ton cooling capacity.  The larger tonnages are used in commercial units. When deciding whether you should have a compressor re-built, first check the price of a new one. Make sure the condition of the rest of the condensing unit warrants an investment as large as a new compressor. If the condenser coil is rotten and the whole cabinet is held together by rust, the customer might want to replace the whole thing. Good customer relations builds confidence in a technician.

Written by sam

December 23rd, 2010 at 1:04 pm

Refrigerator Compressors

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Air conditioning systems that are designed for residential and light commercial use are divided into three sections. Within each section there are many components. The main components are the condensing unit, the evaporator unit, and the thermostat. In some geographic areas, some of the names might be slightly different. For instance, some might call the evaporator unit the air handler. Both are correct.

Condensing units are installed wherever the builder thinks it will be cost effective. Because some of you might live in a house, some a condominium, some a duplex, we have written this book for all installation areas. Those of you that can point to your condensing units are lucky. Many owners don’t even know where their condensing unit is located. On a service call, you might spend some time trying to locate the customer’s unit. It might be under the parking area. Sometimes it is placed on the roof in clusters with other units. This gives you an idea that in certain areas, there might be a little time consumed in finding the condensing unit. When you find it and it is located in a unique place, make a notation on the evaporator unit or entrance panel where the unit is located.

Condensers can transfer heat using air or water as a transfer medium. Air-cooled condensing units are usually located in the outdoor air to be efficient. Water-cooled units are different. The heat transfer medium can be piped to the unit regardless where it is. A package unit is a unit that has only one section. The condensing unit, evaporator and sometimes the thermostat are located within a single cabinet. I tell you this to save you the embarrassment of looking for an air-cooled condenser on a water-cooled unit.

Before you open the cabinet of the condensing unit, turn off the electrical power supply to it. Always remove the panel slowly for many reasons. You might come face to face with an animal or a pressure refrigerant line about to burst. With the panel removed, you can look inside and begin to identify some of the component parts that make the condensing unit operate.

Written by sam

December 23rd, 2010 at 12:59 pm

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