Not cooling - hot compressor - bad defrost thermosat

Hello,

My stand up, stand alone, freezer is not cooling. The compressor is running and gets very hot. The fan is running. The defrost timer appears to be operating. The temp control knob seems to operate.

I tested the defrost thermostat and it does not appear to be good.

QUESTION: will the defrost thermostat cause the freezer to not blow cold air?

ps: coils are clean (internal coils)

Thanks,

Greg

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Hi,

Does the evaporator feel icy cold? (be careful of ice burns when you touch it - use a cloth to feel through so that you won't get stuck to it if it is).

If not then perhaps there is a loss of refrigerant in the system or a faulty compressor

If the evaporator is covered in ice because it is not defrosting properly due to a faulty defrost thermostat then the evaporator fan may also be prevented from rotating due to ice build up therefore no air is being drawn across the evaporator fins to be cooled down and then passed throughout the freezer. The set temperature thermostat keeps the compressor going trying to cool the freezer to the desired temperature but it never reaches the set temperature because the air is not cold enough.

You may also wish to check that the evaporator defrost heater is working properly

Here is a link to all the relevant parts in your freezer. The evaporator fan etc is shown in the cabinet diagram and the defrost heater is shown in the System diagram

http://www.searspartsdirect.com/model-nu...

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Comments:

Thanks for the answer. But... I guess I forgot to mention that the freezer is not blowing cold air at all - even after the coils are defrosted. I've left the unit completely warm up by unplugging it for a day. When I plug it back in, it will simply not start cooling again even though the compressor is running.

The reason I think the main temperature thermostat is still good is because when I turn it all the way down, the unit shuts off. But I am reconsidering this... the dial, when turned all the way to the left ends up putting the unit in a OFF position. Could it be the thermostat?

The reason I think that the defrost timer is fine is because when I twist the knob it clicks and shuts off the compressor. So this one is probably fine.

The reason I think the defrost thermostat is bed is because after letting it sit in a glass of ice water, it still shows no continuity. Will a 42-17F thermostat even kick on in a glass of ice water?

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Hi, is the evaporator starting to get cold once the compressor starts up. It may take a little while if it is warm say 30 minutes from ambient to start to notice a change. This is where the cooling starts from. If the evaporator isn't getting cold because the compressor should be pushing refrigerant gas through you have a problem in either the compressor or the amount of refrigerant

The evaporator fins should never be totally iced as the defrost cycle should prevent a major build up of ice . Is the evaporator fan running when the compressor is running?

I'm not sure re the defrost thermostat but I think that it should operate around the 33F mark as then the freezer is above freezing point and with the help of the defrost heater the ice on the evaporator fins (coils) should have melted and drain d away and now the compressor needs to be restarted to get the freezer back to below freezing point i.e. 0 degreez F

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