What is going on
When a Sub-Zero stops cooling, it feels like a crisis, and that is exactly how we treat it. It is also among the most common calls we take, and it is fixable. In nearly every case the machine is protecting itself from a fault in one of its refrigeration systems rather than failing outright. Our technicians restore Sub-Zero cooling across San Francisco and the Peninsula every day, and with the right parts on hand, most repairs are completed in a single visit.
Sub-Zero builds refrigeration differently. Most units run dual refrigeration, two sealed systems, dedicated compressors, and electronically controlled defrost, so the refrigerator and freezer cool independently. That sophistication is why this symptom has a short list of likely causes, and why guesswork is expensive. A factory trained diagnosis reads the control board's fault history, measures temperatures and pressures across both circuits, and isolates the failing component before anything is replaced.
The usual suspects
What causes it in a Sub-Zero.
The sealed system
The compressor, condenser, and refrigerant lines that generate cold. A weak compressor or a slow refrigerant leak lets temperatures drift upward over days. Our technicians test pressures, locate the fault, and repair it with genuine Sub-Zero components.
Condenser cleaning
The condenser sheds heat through a coil that quietly collects dust and pet hair. A blocked coil forces the compressor to overwork, and cooling fades until the unit protects itself. We deep clean the coil and verify airflow and fan performance.
The evaporator
The evaporator absorbs heat from inside the cabinet. When it ices over from a failed fan or airflow fault, cold air stops circulating even though the compressor runs. We trace the cause, restore circulation, and confirm even temperatures throughout.
The defrost cycle
Sub-Zero schedules brief defrost cycles to keep the evaporator clear. A failed heater, sensor, or control leaves frost building until cooling collapses. Our technicians test each defrost component electronically and replace only the part that has actually failed.
A Sub-Zero is engineered around sealed refrigeration systems that reward precision. Generic parts and improvised fixes are the most common reason a cooling failure returns within months. Factory trained diagnosis, genuine components, and correct procedure protect the machine, its efficiency, and the decades of service it was built to deliver.
Food and wine, protected
We treat a warm Sub-Zero as today's priority
Time stays on your side while the doors stay closed. Fully loaded, a Sub-Zero holds safe temperatures for hours, and wine storage protects its bottles even longer. Keep everything shut and call us. We answer daily from 7am to 7pm, and a cooling failure moves to the front of the schedule, with same day service at your door in Portola Valley, San Mateo, and San Carlos, and across the Peninsula.
Why Onyx
The care your kitchen deserves.
Factory trained specialists
Vetted, uniformed technicians who work on Sub-Zero and Wolf and nothing else.
Genuine factory parts
Only Sub-Zero and Wolf OEM components, sourced direct. No aftermarket substitutes.
White glove home protection
Floors, stone, and cabinetry are draped and protected before a single panel comes off.
$95 diagnostic, waived with your repair
One flat diagnostic visit. Go ahead with the repair and the diagnostic costs you nothing.
Concierge scheduling
One point of contact, arrival windows kept, and updates by text or call, whichever you prefer.
Licensed and insured
Bonded and fully insured on every visit. Documentation ready on request.
Questions, answered
Before you call.
How fast can you get here?
Same day in most cases. We answer daily from 7am to 7pm, and a Sub-Zero that is not cooling goes to the top of the route, from Los Altos Hills to Emerald Hills and across the Peninsula. Call and we schedule the earliest available window, confirm your model and symptoms, and arrive prepared to diagnose on the first visit.
What should I have ready when I call?
Nothing is required. If it is handy, the model number from the rating plate just inside the cabinet helps, along with a note of anything the display shows. Describe what you see and our coordinator walks through the rest with you on the call.
How much does the diagnostic visit cost?
$95 diagnostic, waived with your repair. Your technician inspects the full refrigeration system, reads the control board's fault history, and presents a written finding with a firm quote before any work begins. Every completed repair carries the 3 Year Onyx Warranty on parts and labor, in writing.
Will you tell me if it is not worth repairing?
We are a repair company, and we do not push replacements. Sub-Zero builds these machines to be serviced for decades, and a cooling failure is almost always repairable. Your technician gives you an honest assessment and a firm quote, and the decision stays entirely yours.
My freezer is cold but the refrigerator is warm. Why?
That pattern is useful information. Most Sub-Zero units run dual refrigeration, so each compartment cools on its own sealed system. When one side stays cold while the other warms, the fault is isolated to the warm side, usually its evaporator, defrost system, or airflow. Our technicians confirm the exact cause with instrument testing.
Should I empty the refrigerator before you arrive?
No. Keep the doors closed and let the insulation work. The cabinet holds temperature far longer than a standard refrigerator. If the display shows a service icon or temperature alarm, note it but leave the unit powered on. The stored fault history helps your technician confirm the diagnosis quickly.
The Onyx guarantee
The 3 Year Onyx Warranty, parts and labor, in writing.
A $95 diagnostic, waived with your repair, and 24 years on luxury appliances behind every visit.
Other faults we cover
Something else acting up?
See every fault we fix on Sub-Zero and Wolf.
Same day service · San Francisco & the Peninsula
Your peace of mind is one call away.
One number, and it is handled, from diagnosis to a kitchen that simply works again.
$95 diagnostic, waived with your repair.