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jcharlie

sub-zero vacuum condenser light, compressor always on

20 posts in this topic

I have a ~15 year old Sub-Zero 642 that has the "vacuum condenser light" on and the refrigerator compressor runs continuously:

  • The condenser is very clean--blown out with compressed air, and vacuumed. The condenser fan is running normally.
  • The freezer side seems to be running fine, and maintains a 0 degree temperature.
  • The refrigerator side maintains a 38 degree temperature, although the compressor runs continuously (for months now)
  • The refrigerator has been unplugged and replugged. This has the effect of resetting the "vacuum condenser light", but 12 hours later the light will come on again. The compressor of course will start up at some point then stay on.
  • There does not seem to be any frost/ice build-up on the rear wall of the refrigerator
  • I raised the thermostat on the refrigerator to 44 degrees for 24 hours. During this period the compressor actually did cycle on/off (at least once). After this I returned the thermostat to 38 degrees, and the refrigerator once again maintains that temperature (with the compressor running continuously).
  • The refrigerator door seals appear to be in good condition without rips or tears. "Suction" is not nearly as strong as the freezer side (after closing the door and immediately trying to open it), and probably isn't as strong as it once was.

Any ideas on what to check or where to continue my troubleshooting?

 

Thanks,

 

J.

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

may need to post pictures of the Fridge Evaporator frost pattern

May be a sealed system leak on the Fridge (common problem)

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My assumption is that the evaporator is behind the back wall of the refrigerator on the 642 (although I've never opened it up). Do you know if it is easy to open this up, and obvious how to do it, once the shelves are out? If so, I will attach pics tomorrow.

 

If it is a sealed system leak, how easy is this to positively diagnose, i.e. what is involved? Is it possible for a sealed system leak to run this way for a year without further degradation? It's been running this way for at least 12 months.

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... If it is a sealed system leak, how easy is this to positively diagnose

... Is it possible for a sealed system leak to run this way for a year without further degradation? It's been running this way for at least 12 months.

1) frost pattern usually tells

2) may have been slowly leaking for a year

 

Refrigerator Evaporator is behind Evaporator Cover # 34

 

4z6n.jpg

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If it is a sealed system leak, how easy is this to positively diagnose, i.e. what is involved? Is it possible for a sealed system leak to run this way for a year without further degradation? It's been running this way for at least 12 months.

In the attached photo I have a picture of a leaky evaporator, not the frost pattern, but the little dimples in the coil that are usually obvious. A 15 year old SubZero is definitely worth paying a professional to replace the evaporator, it's not something a homeowner can do on his/her own.

post-83029-0-94984400-1376421515_thumb.j

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Concur with Brother Spanner.  If there's a large accumulation of frost at the upper/left corner of the evaporator, there is a system leak in the coil.  The pitting has been an issue.

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First thank you RegUS_PatOff, Spannerwrench, and PDuff for your replies. Attached is my thousand words. As you predicted the frost pattern points to something ominous and expensive, right?

 

post-85559-0-23848000-1376442713_thumb.j

 

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yes,

usually a leaky Evaporator on Sub Zero's

They have a 12 parts warranty, but seems you're out of luck.

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Okay, then what should I expect as a cost for a skilled tech to make this repair?

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Some of the postings I've read say that the frosting near the inlet can be a sign of low charge. Does this beg the question: "the charge is low, because there is a leak"?

 

  1. Is it ever normal for the sealed system to lose charge over time w/o there being a leak?
  2. Does the frosting pattern conclusively indicate a leak near the frost area? It was not readily apparent that the evaporator was pitted, leaking, or damaged. The frosted area, defrosted in about 10 minutes.
  3. Upon seeing the frost pattern would you immediately go to replace the evaporator (and dryer?) as a first step?

 

Thanks for any responses.

Edited by jcharlie

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1)  No.  However, a restriction can occur that would inhibit the proper flow of refrigerant.  Restrictions sometimes are found at the drier or in the heat exchanger.

 

2)  Not always.  But history dictates that the Sub Zero refrigerator compartment evaporator (regardless of model) has had problems with refrigerant leaks.

 

3)  Yes.

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Have you had any prior service on refrigerator? Sub Zero covers 15yo system parts for my customers often. Call or Google SZ for certified service in your area.

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Have you had any prior service on refrigerator? Sub Zero covers 15yo system parts for my customers often. Call or Google SZ for certified service in your area.

I'm the second owner. I've owned it about 10 years w/o problem. It appears that the previous owner may have had it serviced--there is a Jasco appliance sticker, and the s/n seems to have been removed from the Sub-Zero sticker.

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Without the serial number the retrieval of service history under the prior owner is not possible.  Also the serial number is used when researching the proper part number for the evaporator but I'll take shot anyway.  P/N 7009366.  Retail price a little over $70.  Labor estimates vary depending on diagnosis.

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That is a 4204430 evaporator. Vacuum condensor light is before s/n 1810000. After 1810000 has service light. If prior owner had warranty work done SZ should be able to find record from address.

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That is a 4204430 evaporator. Vacuum condensor light is before s/n 1810000. After 1810000 has service light. If prior owner had warranty work done SZ should be able to find record from address.

Thanks again to all for the responses.

 

The 642 was manufactured from 1996-2008. It appears that one break in the 642 is Sept 26, 2003; units manufactured prior to this date used evaporator p/n 4204430. So, yes Woftam is correct.

 

Are all refrigerator driers the same, or do they have different part numbers depending on the model of the SZ? Is it okay to use a whirlpool dye drier that has the same capacity for contaminants? How are they rated?

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S/Z part is 7006964. I don't like dye dries on ref side. Found they can clog cap tube. Know others use them though. Do use other after market driers without problems.

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S/Z part is 7006964. I don't like dye dries on ref side. Found they can clog cap tube. Know others use them though. Do use other after market driers without problems.

Thanks for the p/n, and the advice.

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I replace the old filter-dryer with a 'Packard' brand filter dryer.........PD115.........has a access port for faster evacuation of the system,   adding a charge,   or  to get a high side reading of you so choose...........

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Just thought I'd close out this thread with the results.  I got a new (aluminum) evaporator (the original was copper), had it installed, and the system swept, vacuumed, and recharged. Everything is working great. The compressor is finally cycling on/off after a fairly long initial cooling cycle. No more vacuum condenser light.

 

I have a couple more questions if anyone is inclined to reply--just for my own edification.

 

On this 642 the tech used between 8 to 8.5 oz of R134a. The history of the unit is unknown due to a lack of s/n, so the tech had to estimate the proper charge amount based off a standard table. How sensitive is the refrigerator to getting the optimal amount of  refrigerant? Is it really to the ounce? Does an overcharge cause the compressor to work harder, the current draw on the compressor was ~1.3A, and the tech thought he'd bleed out a little refrigerant because he wanted to see it closer to 1A.

 

Last question, is there a typical cooling/defrost cycle on the S/Z 642, or is it all based on sensors? How long should I expect each cycle to be, or can that question even be answered?

 

Thank you all for your input. It was extremelly helpful. Now how do I get a beer to you?

 

J

Edited by jcharlie

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