Refrigerator Repair – Saving on Repair Bills By Understanding Normal Operations
Much of refrigerator repair is based on understanding the normal sequence of operations. Simple watch what the unit is doing, step by step. The step that is missing will lead you to the problem. This is the sequence of operations for a typical self contained fridge such as a reach in, make up table or beer bottle cooler.
The evaporator fan is the one that blows the cold air in the box. On many units this fan runs all the time. On some units the fan shuts off when the door is opened. This is to reduce the amount of cool air lost when the door is opened.
The air circulates and is warmed with heat from the food and from outside the box. The temperature increases until the ON set point of the thermostat is reached. Then the switch in the thermostat closes.
The compressor in the condenser starts to run along with the condenser fan. The condenser is the part that is usually an top or bottom of a reach in cooler. It blows warm air through the condenser coils. The big compressor pipe is cool and the small one hot.
The evaporator coils are in the box and start to get cold. The evaporator fan blows air through them. This air circulates through the box and enters the evaporator coil again.
This continues as the air in the box is cooled. Eventually the temperature reaches the thermostat OFF set point. Then the compressor and condenser fan shuts off. When the box has warmed the process repeats.
It is important to note that the air warms and then is cooled. So the actual temperature of he air varies. Perhaps from 36 Degrees Fahrenheit to 40 Degrees Fahrenheit. At 40 degrees the compressor turns on. At 37 degrees the compressor turns off.
It isn't possible to maintain an exact air temperature but the product can be maintained at an average temperature. The coldest air temperature is in the air being blown out of the evaporator. The warmest air as the air being pulled into the evaporator. This is where the thermometer should be.
1) The evap fan is running as the box warms
2) The thermostat closes calling for cooling
3) The compressor and condenser fan come on
4) The thermostat opens, it is satisfied
5) Go to #1
A household refrigerator is actually a freezer that uses some of the freezer air to cool the refrigerator section. They follow the some basic sequence but also have a defrost cycle.
Some equipment may vary slightly. Temperature could be controlled with pressure. The condenser could be in a remote location. If it is outside the fan may cycle on and off in cold weather. But understanding the basic sequence of operations will help you decide if you really need a refrigerator repair. This link, refrigerator repair, will give you a different an needed perspective on understanding how your equipment operates.