How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Edward Your Own Question
Edward, Home Appliance Technician
Category: Appliance
Satisfied Customers: 7966
Experience:  Small and large Appliance Technician, Electronic Tech., Handyman, 40+ years ex
Type Your Appliance Question Here...
Edward is online now
A new question is answered every 9 seconds

The refrigerator unit of my Sub Zero 550 has stopped cooling.

Customer Question

The refrigerator unit of my Sub Zero 550 has stopped cooling. I have checked the fan (it's working), and vacuumed the condenser. Still no cooling. Is there anything else I could do before calling the repairman?
Submitted: 8 years ago.
Category: Appliance
Expert:  Edward replied 8 years ago.



Thank you for asking your question on JustAnswer. The other Experts and I are working on your answer. By the way, it would help us to know:

-Could you explain your situation a little more?


What is the model number of the refrigerator?


Do you feel comfortable removing panels on the refrigerator to check parts?

Thank you again for trusting us with your problem.


Please reply as soon as possible so that we can finish answering your question.

Customer: replied 8 years ago.
Thanks for your reply. My refrigerator is an older Sub Zero, model 550, with refrigerator above and freezer below. I have visually checked the fan and condenser, located above the refrigerator portion, with the results I described previously.

I can remove some panels (I think) if needed. Thanks for your help.
Expert:  Edward replied 8 years ago.

With the information you have provided the most common reason for the failure is a problem with the self defrost feature of the refrigerator. This will cause ice to form on the evaporator coils that are located in the back of the freezer compartment. Defrost failure is often caused by a failed defrost timer. Click here for information on testing the defrost timer. If the defrost timer is not the problem the defrost heater or the defrost heater thermostat can also be the problem. These are located in the freezer compartment and can be accessed by removing the back panel inside the freezer compartment. These can be checked for opens with a volt/ohm meter.


Should you require further information or clarification, never hesitate to ask. It would be my pleasure to clarify my answer to your question. If after reviewing the above information, you have additional questions, I will be glad to answer them. My goal is your 100% satisfaction with all questions I answer.

Please click the green ACCEPT icon if you feel I have given a complete answer, and you can leave positive feedback. Positive feedback and bonuses are always greatly appreciated!



As always when using Just Answer your accept is required for me to be paid. By accepting you are agreeing that I have satisfactorily answered your questions. If you do not accept, your deposit if applicable, will remain in your account until you request otherwise.

Please do not accept unless you are 100% satisfied with the answer and feel you can leave positive feedback.

Note: If the icons or other text makes the page unreadable please refresh the page. Sorry for this inconvenience.

Expert:  Edward replied 8 years ago.

The following information was porovded by another expert


Most Sub-Zero's do not utilize a defrost timer on the ref side. Since the ref should not stay below 34° f, whatever frost accumulates during the "On" cycle of the compressor will melt during the "Off" cycle. (This is referrred to as "Off-cycle defrost"). The freezer side (if so equipped) will utilize either a mechanical timer or have a heated defrost controlled by the main bd and a defrost limit switch.


Thank you AccApp for the information. Smile

Customer: replied 8 years ago.
I'm sorry, but these answers do not seem to take into account that Sub Zero refrigerators have two (2) separate compressors--one for the freezer and another for the refrigerator. It seems unlikely to me that the freezer's system would impact the refrigerator's performance. In any event, the freeser, as I said, is performing fine with no frost build up and no problems.

It looks like I need to contact my local Sub Zero repairman. Sorry that I cannot accept this answer. Thanks for your effort.
Expert:  Edward replied 8 years ago.
Thanks for your reply. There is no need to accept any answer that you are not 100% satisfied with. I have opted out of this question since I have no information on this model in my database. By opting out this prompts other experts to reply if they have the answer for you. Hopefully another expert will respond soon.