Why is my Sub-Zero refrigerator not cooling?

The reasoning behind that

On a Sub-Zero built-in the two compartments run on separate sealed systems, so a freezer still hard-frozen proves the refrigeration itself is working and puts the fault on the refrigerator side: its evaporator fan, a defrost failure icing that coil, or a thermistor reading out of range.

How the diagnosis goes

What we check, in order: which compartment is warm and by how much, read at the shelf rather than off the display; the evaporator fan, by ear and then by hand with the rear panel off; the defrost heater and its thermistor; and finally the condenser and its fan. The order is deliberate. The cheap causes are also the likely ones, and nobody should be paying for a sealed-system diagnosis before a fan has been ruled out.

If both compartments have gone warm together, look lower. On coastal Carlsbad units that is most often a condenser loaded with salt-laden dust, which is a cleaning rather than a repair if it is caught before the compressor has spent a summer at high head pressure. What changes with your address in Carlsbad is where that list is likely to stop. West of the freeway, in Olde Carlsbad and the streets above the lagoons, the condenser is the first suspect any time both compartments drift together and the unit sounds like it is running constantly. Inland, in La Costa and Bressi Ranch, single-compartment faults dominate and the evaporator fan is the part that comes off the van most often.

If that matches what yours is doing, say so when you call — it decides which parts come on the van.

Questions

Frequently asked questions