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jonneeboy

Subzero Refrigerator

12 posts in this topic

Ice is building at the back of my Subzero 501R (refrigerator only, no freezer).  Temperature is coolish, but not as cold as I would expect for a setting of 8 (out of 10).   Some foods seem to spoil much sooner than I would expect.  

I opened the kick panel on the bottom and carefully vacuumed everything I could reach, but improvement was only marginal. 

Do I need to replace whatever thermostat controls the defrost cycle?

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Need appliance parts? Call 877-803-7957 now!

Follow  up after further troubleshooting.  Condenser fan is always running regardless of the temperature setting.   I suspect that the temperature setting switch is not working and the condenser is always on, always trying to make the fridge colder and causing a buildup of ice?

I found a wiring diagram behind the kickplate and while it contains light, refrigerator fan, condenser, and condenser fan, there is no mention of defrost coils or defrost timer.  Does a refrigerator-only appliance not require a defrost system?

Refrigerator fan seems to work normally (comes on when door is close).

Light works normally.

Thanks.

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The ice buildup is from a defrost system failure (yes, your model has an evaporator that requires periodic defrosting like all evpaorators).   The condenser fan running all the time may be because the compartment temperature is unable to satisfy the cold control due to the ice acccumulation on the evaporator. 

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Any recommendations on where I go from here?

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I have disassembled the innards of the refrigerator.  The top fifth of the evaporator is iced up.  There are two long skinny metal lines or tubes running from the cold control down through the evaporator fins.  One of the these lines terminates beneath the evaporator in what looks like some sort of sensor or probe, silver in color.

Where is the defroster?  I see nothing that looks like a timer or heater?  Is the timer built into the cold control?  Are the silver lines the defrosting elements?

 

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How badly iced up?  Light frost or modo fuzz?  Feel free to post a photo

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Light frost...defrosted very quickly.

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Symptomatic inconsistency:  on the one hand you say there was a buildup of ice and other hand you say there was only light frosting.  Which are assumptions and which are observations?

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Not at all.  Initially I wrote that the refrigerator was iced up, meaning the inner wall of the fridge, prior to any disassembly, had significant ice build-up.

Then I wrote that I disassembled the refrigerator to reach its innards.  By this time I observed that the evaporator had a light frost on it.

So...heavy ice on the fridge liner, light frost on the coils.    I did turn off the refrigerator before I began the disassembly, which took about 1/2 hour because I did it carefully.  Did heavy ice melt from the evaporator during disassembly?  Not sure. 

Thanks for the help.

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Johneeboy,  your sub zero does not have a defrost heater or bi-metal,  it has an off cycle defrost, which means when the thermostat is satisfied,  it shuts down.   The evap fan shuts down with the compressor and will start again when the door is shut.  I have run into your problem on several occasions and found the easy way to handle it is by using a heat gun where the ice build up has formed.  I never had one come back on me.   Other things you can look at  includes moving the sensor bulb up on the evaporator.  The top part of the evap is colder than the bottom.  This will eliminate a longer run time.   Sub Zero also came out with a different evap fan blade for this model when the condition was too cold at the bottom and too warm at the top.  Part number for this blade is 3-15-045-0.     Hope this helps you out...Ron

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Ron, thanks so much.  I think you are right on the mark; seems to be working much better once I got the ice out.  Running on a lower setting and the ice is not returning, but everything seems plenty cold.  I will try your recommendations if the ice returns.  Thanks again.

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I have a 501R Subzero...It's not staying cold.  It will fluctuate from 50 degrees to 20.  More on the 50 degree side.  We have cleaned it several times and then it will work and then it won't.

The thermostat in the top of the frig seems to click on sometimes when I move it and then it won't.  I thought it was too full and then I thought the door was not closed by visitors.  But, all in all, it's mostly warm (luckily I have other frig's in the garage).

Help!!

northstar@olympus.net

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