Sub-Zero 680/S Refrigerator Not Cooling: Sealed System Rebuilt in Foster City
A Sub-Zero 680/S built in 2000 lost cooling in the refrigerator section because of a refrigerant leak. We replaced almost the whole sealed system except the condenser coil, pulled a long vacuum and recharged it.
Repair at a glance
| City | Foster City, CA |
|---|---|
| Appliance | Refrigerator |
| Category | High-End Brands |
| Brand & model | Sub-Zero 680/S built-in side-by-side, serial P1652807 (made August 2000, R134a) |
| Repair date | |
| Customer complaint | The refrigerator section was slowly getting warmer and food had started to spoil. Another company had worked on it about a year earlier, but the problem came back. |
| Diagnosis | Very low suction pressure on the refrigerator sealed system, which points to a refrigerant leak. The display showed 45°F in the fresh-food section. |
| Repair cost | $3,485 (parts and labor) |
| Warranty | 1 year on all work |
| Outcome | Repaired |
What the customer told us
The customer said the refrigerator section of her Sub-Zero was not cooling well. Someone had worked on it about a year before, but over time the temperature crept up again, and recently food began to spoil.
Diagnosis: a refrigerant leak
The rating label shows a Sub-Zero 680/S, serial P1652807, made in August 2000 and running on R134a. During the diagnostic visit the control showed 45°F in the refrigerator section.
We connected gauges and found very low suction pressure. That means refrigerant is escaping somewhere in the sealed system.
What we replaced
Since the leak could be in several old components, the customer approved replacing almost the entire refrigerator sealed system except the condenser coil: the compressor, the evaporator, the capillary tube line set, the drain loop and the filter drier.
All parts were genuine Sub-Zero parts bought from the Sub-Zero distributor in San Leandro. After the quote was approved we ordered the parts, and the whole job took about three days.
How the repair is done
The refrigerator has to be pulled completely out of its opening. We removed the top cover and vacuumed the dust out of the machine compartment.
Inside, we took apart the refrigerator section to reach the evaporator: the ice maker parts, shelf rails, covers, protective panels and the drain heater all come out. Sub-Zero now sells the evaporator with the drain pan and heater already assembled, which made this step easier.
The new capillary tube line set is fed up to the top of the unit, connected to the new compressor and brazed in, together with the new filter drier.
Vacuum and refrigerant charge
Before charging, we ran a long evacuation to remove air and moisture from the system. The vacuum gauge reached about 735 microns, as shown in the photos.
Then we charged the system with R134a and checked operation on the gauges.
Result
After the repair the refrigerator section cools again and the unit has kept running since. The total for this job, including all parts and labor, was $3,485. Sealed-system repairs like this come with a 1-year warranty on all work.
Photos from this repair
The Sub-Zero 680/S before the repair. 
The refrigerator section reading 45°F at diagnosis. 
Unit pulled out, machine compartment open. 
Taking apart the old sealed-system parts. 
The old compressor after removal. 
New evaporator with drain pan and heater pre-assembled. 
Refrigerator section stripped to reach the evaporator. 
New evaporator installed; rating label shows 680/S, serial P1652807. 
Feeding the new line set to the top of the unit. 
New line set routed up to the compressor. 
Evaporator and line set on the counter. 
The drain loop. 
Vacuum pump, refrigerant and tools set up. 
Evacuation in progress on the digital manifold. 
Vacuum down to about 735 microns. 
System charged and checked on the gauges.
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