Refrigerator Repair

1 December 2009

Repairing Refrigerators
Refrigerator is one of the most common household equipment. This article will give some tips on how to locate and repair some common faults in refrigerators

What are the common faults
Modern refrigerators need little or no maintenance except for the regular cleaning of blocked ventilation holes if it is located in a dirty environment. Poor cooling is often caused by faulty or aged components. One of the common fault is frozen cooling coils. Other faults can be motor related; for example, motor starter problem. Because the refrigerant system is a total sealed system, leakage of refrigerant is not usually the problem.

How to Check if the Fridge is Working Properly
A working fridge should:

1) Feel warm on some part of the panel. This is because fridge uses these panel to dissipate heat;

2) Have noise coming out of the electric motor;

If the fridge panel is always cold or there is no running motor noise for a long period, most likely the fridge is dead; otherwise, it could be due to the following problems:

a) Frozen cooling coils
b) Faulty components

This article will concentrate on how to clear frozen cooling coils

Frozen Cooling Coils

Frozen cooling coils could happen under 2 conditions:-

a) Refrigerator is short of freon gas;
b) Faulty defrosting circuits

Like any refrigeration equipment, coils are easily frozen when there is a shortage of freon gas in the system. However, this is quite unlikely in the case of refrigerators because most refrigeration system is sealed and there is little chance for freon leakage. When the coil is frozen, it will not allow air to pass through the colling coil and hence, cooling is affected.

Checks for Frozen Cooling Coils
Modern refrigerators are frost free. Cooling is achieved by a circulating fan and defrosting is done by a defrosting heater.

Because the cooling coil and the fan are hidden from view, visual inspection is often not possible. However, one could deduce if the coil is frozen by checking if the compressor is working and also by observing if defroster is functioning.

How to Check
Step a) Check if the defroster is working

If the refrigerator has a defrosting tray underneath, check the tray for some water. The defrosting heaters will be turned on automatically once a day by a self running time, during which, ice if any on the cooling coil will be drained to the defrosting tray.

For refrigerator that has concealed defrosting tray, then the only way to check if the defroster is working is to turn off the refrigerator for more than 1 hour, allowing ice to be defrosted. If by turning on the refrigerator resume the cooling function, one can confirm that the defroster circuit is faulty; then, proceed to step c);

Important Note: The compressor panel consist of electrical components. Proceed to step b) & c) when you know what you are doing.

Step b): Check if the compressor is working properly
1) Open up the compressor chamber by removing the back panel of the refrigerator;

2) Check for oil leakages in the refrigerator pipe and tube; if there are traces of oil anywhere, most likely the system have a freon leak;

3) Check if the compressor motor is running. If it is running, check for its proper working by hand feeling the temperature of the compressor's discharged and the suction tubes. One should notice the discharged tube is always warm and suction tube is always cool. If there is not much temperature difference, most likely the compressor is not working properly and it is time to change the refrigerator.

Step c)
The defrosting components normally consist of a timer and a few heaters. Check the heater circuit for fault using an ohm meter. If the heaters are ok, most likely the timer is fault. Repair or replace the timer.

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