Blocked Drain
If your refrigerator has ice forming on the inner walls of the fresh food compartment or on the floor of the top or bottom compartment with pooling water in the vegetable drawers, then there is likely a clog in the freezer drain. If ice or a food particle gets hung in the drain in the floor of the freezer compartment, the water from the coil defrost is unable to drain into the pan at the bottom of the unit as designed. Instead, the water pools and runs down into the lower compartment and potentially freezes because of the ice buildup above. Clearing this clog by hand is the simplest way to make the flow of condensation run in the right direction and stop the overflow.
Gasket Seal
When the gasket on the refrigerator or freezer door is damaged or worn out, moist warm air from outside the unit can creep in and cause frost or ice to form on the inside of the refrigerator. The freezer gaskets can cause heavy icing in the upper freezer compartment walls and any items inside. Check the gaskets around the doors for rips or flattening. Clean the gaskets thoroughly if they are dirty. Damage to the gaskets will require replacement.
Defrost System
Frost is a natural occurrence on the evaporator coils in the freezer compartment of your refrigerator. To prevent frost buildup, a self-defrosting refrigerator warms the coils using a defrost heater several times each day to melt away the frost. This frost melts into water and flows out of the compartment through the drain. If any part of the defrost system is not working properly, the result can be heavy frost buildup that may affect the cooling capacity of the refrigerator.
The defrost timer is a mechanism that tells the defroster how long to run to melt the frost. The limit switch measures the temperature in the freezer and helps to maintain it, while the heater is the key element that melts the frost. Any one of these components could need replacement at a given time, which will result in this over-frosting.
Temperature Settings
Some refrigerators do the job too well. The thermostat settings inside your refrigerator allow you to choose how cold your foods remain while inside. Most refrigerators have a recommended setting that works well, but sometimes you may want to keep items a little colder to better preserve freshness, or a little warmer to save on energy consumption. Some refrigerators may get cold enough to form ice on your food or on the walls of the fresh food compartment. This may simply be a result of turning the temperature down too low. Try adjusting the knob to the recommended setting or higher to see if the problem goes away.