How your refrigerator works
The refrigerator is a standard item in today's household. Many homes in fact have not only a refrigerator with its built-in freezer compartment but also a separate stand-alone freezer. Some also have smaller refrigerators for the wet bar or out in the motor home. Basic operation, maintenance, troubleshooting, servicing, and repair is the same for all of them
A refrigerator or freezer works on the principle that a gas cools as it expands and gives off heat when it is compressed. A refrigerator or freezer has four basic parts: the compressor, the tubes carrying refrigerant, a fan, and a thermostat. A compressor is used to compress or "squeeze" the refrigerant and usually also to pump it. A length of tubing is connected to the compressor and provides a completely sealed path. The tubes are filled with the refrigerant, which is usually Freon, either type R-12 or type R-22. This tubing is divided into two basic sections: the evaporator and the condenser. The names tell you just what is going on in that section. In the evaporator, the liquid Freon vaporizes into gas. It evaporates. In doing so it becomes cold and is capable of absorbing heat from the inside of the refrigerator. Evaporation occurs because the liquefied Freon flowing into the evaporator is flowing into an area of low pressure. It then passes through the compressor and into the condenser.
The compressor squeezes the vaporized Freon and puts it under high pressure. As the pressure increases, the Freon loses the heat it has picked up in the evaporator side. This is helped along by cooling fins or wires attached to the tubing and often by a fan that blows air across the coils. The increasing pressure and the lowering temperature turns the vapor back into a liquid. It condenses. To further increase this action, a capillary tube is used to connect —or rather to separate — the high pressure condenser from the low pressure evaporator. As the refrigerator shuts off from its cooling cycle, you will hear a soft whooshing sound. This is the rebalancing of pressure between the two components. A thermostat is used to measure the temperature inside the refrigerator and to trigger the compressor and fan. If the temperature inside exceeds the setting, the compressor comes on and the cooling cycle begins all over again.
Caution must be exercised when working with any refrigeration appliance. The Freon inside the tubes is under pressure. It can be dangerous under certain conditions and can turn into a poisonous gas. Many of the problems involved require special equipment and background and are best left to a professional.
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