Hi all,
I have a top freezer MTB1553AR but it was not defrosting so we changed the thermosstat. Since then the fridge is not freezing properly (ice is wet).

I am wondering if the thermostat is causing this. Does the thermostat tell the fridge when to defrost?

Thanks for any feedback

Sounds like you have a problem with the self defrost system. It consists of a timer,heater,and defrost termination thermostat. Any of those three parts being defective can cause that problem so they will have to be tested or as I always did when I repaired the defrost systems was to replace all three parts. It prevented call backs since if one of those parts failed the others were not far behind.

Thanks hvac1000 for your reply. I am trying to understand how the thermostat works in the system because I believe the compressor now is not running long enough to cool the fridge properly and just before the thermostat was changed it would freeze up the condenser. I would have to use a hair dryer to clear the ice.

So I am lost.

Now we have more info

just before the thermostat was changed it would freeze up the condenser

I hope it was the same part number thermostat and the capilary had to be installed in the same place where the old one was. Was the work done exactly as described?

hvac1000, this is one of my concerns as it was a third party thermostat that was put in. I had asked that question because I am a true believer in using original parts and I was told not to worry. I am not sure where it was placed on the condenser. I will have to open the freezer to check.

Should I replace this thermostat with the original one?

Should I replace this thermostat with the original one?

That depends upon if the original one was bad. I never use replacement thermostats since the cut in cut out range is always different and that does have an effect on the control of the coldness of the refrigerator.

What was the refrigerator doing before the thermostat was replaced?

I will have to answer you tomorrow since I have something to do tonight.

hvac1000, off topic but is there a good training school that I attend for refrigeration training? I guess from a Fridge and A/C perspective.

There are many schools and for the most part they are area dependant. At the university my classes do not cover small appliance work and are specialized for service people who need there class room credit hours for there license renewal. I also have specialty classes for controls and other testing procedures. I teach a gratis (for free) so I come and go as I wish. Retirement has been good to me after so many years in the biz. When you look for a class look for one with a lot of hands on training instead of just book learning. The books are necessary for theory but not practical for service work.

Thanks hvac1000,

If I am going to look for a school in the Florida area should there be a specific accreditation that the school should have?


Back to the topic: Do you think I should get an original thermostat for the fridge?

You need to check the defrost system.

If you are going to school for HVAC make sure that you can take your NATE test there upon completion. It is easier to test right away since all the info is fresh in your head.