What could cause the cooler to freeze other than a faulty thermostat?

If the freezer is set at the lowest temperature the compressor will run continuously causing this. Also if humidity is high where you live and the seal on the freezer isn't sealing properly the excess moisture will cause it to ice up.

It doesn't defrost

1. Defrost control board

If the defrost function is not working on your refrigerator it could be an issue with the defrost control board. This control board oversees several internal conditions and regulates the activation of the defrost cycle. A faulty board can be the primary reason your refrigeration unit is not transitioning to the defrost cycle. Over time, the buildup of ice on the evaporator coil will prevent the refrigerator and freezer from maintaining proper internal temperature. It is advisable to first check the defrost heater and the defrost thermostat for continuity prior to replacing the defrost control board.

1. Main control board

A possible cause for a refrigerator not defrosting, especially on more modern units, is the main control board. The main control board acts as a "brain" for the unit controlling the defrost cycle, compressor, and run time, and essentially acts in place of the defrost timer. The control board can be tested using an ohm meter for functionality and will need to be replaced if bad.

1. Defrost timer

If the refrigerator is not defrosting the timer could be malfunctioning. Numerous times throughout the day the defrost timer should cycle the defrost heater on as a means to melt frost buildup on the evaporator coils in the freezer. If this timer does not cycle on, then it may be faulty and require replacement.

1. Defrost heater assembly

If your refrigerator is not defrosting accurately this could be an indication that your defrost heater assembly has failed. This could cause the frost to accrue on the evaporator coils, eventually blocking the airflow resulting in the unit not cooling properly. The defrost heater assembly can be monitored for continuity using an ohm meter and will need to replaced if there is none present.

1. Defrost thermostat

Another cause of your refrigerator not defrosting is a faulty defrost thermostat. A requirement for the defrost heater to activate to melt away frost on the evaporator coils is a functional defrost thermostat. The defrost thermostat senses the temperature of the evaporator coils and initiates the thawing process by activating the defrost heater. If the thermostat is faulty, it will not sense the lowering temperature of the coils and will not turn on the heater, resulting in an advanced frost build-up. The defrost thermostat can be checked for continuity by using an ohm meter; if there is no continuity the damaged part will need to be replaced.

1. Defrost sensor with fuse

Another possible cause of a refrigerator that does not defrost properly is a defrost sensor with a fuse. If the defrost sensor fails, the fuse acts as a one-time-only fail safe for the sensor -- if the sensor does not shut off the defrost heater, the fuse will blow when the set temperature is reached. This safety precaution is to keep excessive harm from your unit by the heater and is a one-time use, resulting in the replacement of the entire defrost sensor.
Defrost drain problems

1. Clogged or freezing defrost drain

If you are experiencing defrost drain issues, it is possibly due to a clogged or freezing drain that is blocking water flow to the bottom of the freezer. This will cause the defrost water to drain and drip down to the bottom of the freezer section. To correct this issue, thaw any ice or remove debris that could be causing the clogged drain or replace the drain heater.

1. Drain heater

If you are experiencing defrost drain problems, inspect the defrost drain heater. A dislocated or burnt out drain heater will result in the drain tube freezing over. Attempt to return the part to the designated position or replace the damaged part to correct the issue. Search Over 2 1 Million Appliance Parts

Failed temp-sensor ?

Thermostat bulb likely lost charge causing it to not turn off. Replace whole thermostat. Bulbs do tn come separately.

dont worry about it, you probably didnt get the freezer drawer closed all the way. frost will form when it doesnt get closed properly. just make sure it is closed now and the unit will clear the frost in a few days thru normal defrosting cycles. be sure that the drawer is closing on all sides by looking at the gasket and all should be ok in the future.

Hello there,
The problem with the refrigerator that is causing it to freeze continuously is simply because the defrost heater is not working. Have the defrost heater tested and replaced once found faulty.
Also you need to check the defrost timer and defrost thermostat to see if they are still in good condition. Once any component is found faulty, then you have to replace it with a new one.
To test the defrost heater http://www1.fixya.com/support/r10523771-test_defrost_heater To replace the defrost heater http://www1.fixya.com/support/r10523754-replace_defrost_heater
Hope this helped. Elect_Comp

Without knowing if it a freezer or a cooler I will have to guess. Could be caused by a few things. I'll list them in order of the one I think is the most common reason.

Cooler

1. Door gaskets or someone left door open for a time.
2. Thermostat set to low.
3. Low freon
4. expantion valve out of adjustment or needs replaced

Freezer

1. Defrost not working (Will have heaters with a timer)
2. Low on freon or expantion valve

There are 3 parts to the defrost system,Which did he replace? You should ask and don't name the parts for him,Let him tell you what he replaced.Here are the 3 parts to listen for.

Improper installation,a faulty part,or a short could cause it to fail in that short time.

1. Defrost timer
2. Defrost element
3. Defrost thermostat.

Any other question, feel free to ask


Please rate this a fixya

You have an automatic defrost problem. Here are the three components that can cause this defect in order of most common to least. #1 defrost timer or equivalent adaptive defrost control board, #2 defrost termination thermostat (should be replaced regardless since it has been frozen in ice several times) #3 defrost heating element(rarely fails but is possible). If you have a meter you can check the thermostat and element for continuity they should show an infinite reading if they are operational. the termination thermostat must be below 35 deg f to show a closed circuit.