The inverter board drives the variable-speed compressor in newer Sub-Zero models, converting line power into a variable-frequency output. A failed inverter board makes the compressor stop running, which looks just like a dead compressor. Testing the inverter first can save the cost of an unnecessary compressor replacement.
What It Does
Variable-speed compressors ramp up and down instead of cycling on and off at full power. The inverter board, usually mounted near the compressor in the mechanical compartment, receives a speed command from the main control and powers the compressor accordingly.
Symptoms of Failure
- Compressor doesn't run while fans do
- No cooling in any compartment
- Service indicator with a compressor or inverter fault
- Clicking or no sound from the compressor
Why It Fails
- Heat from a dirty condenser or failed condenser fan
- Power surges
- Age
Diagnosis & Replacement
We check power into the inverter, the speed signal from the main board, and the output to the compressor, and we test the compressor windings separately. Only then do we decide between an inverter board and a compressor.
In stock: we carry common Sub-Zero parts on our service vehicles, so most sub-zero inverter board repair repairs are completed on the first visit.
Typical Cost
| Repair | Typical range |
|---|---|
| Inverter board replacement | $695 – $1,350 |
| Compressor replacement (incl. filter-drier, vacuum & charge) | $1,895 – $3,450 |
Typical totals for parts and labor in the Las Vegas area. The $75 service call is credited toward your repair, and every repair is backed by a 1-year parts and 180-day labor warranty. Your exact price depends on the model, the part and access, and you approve a firm quote before any work begins. Full price list →
Need a Sub-Zero Specialist?
$75 service call, credited toward your repair · 1-year parts · 180-day labor warranty · EPA 608 certified · Mon–Fri 8am–7pm · Sat–Sun 8am–4pm