Crosswater Appliance Service — independent Sub-Zero refrigeration repair in Nocatee, FL 32081 (St. Johns County). Call +1 (904) 395-4339.

# The 6-stage diagnostic sequence

The fixed order every visit runs in, one page per stage, and what finishing each stage takes off the table.

Source: https://subzerorepairnocatee.com/diagnostics/

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## The sequence

- [Stage 1 — Stage 1 · Power](https://subzerorepairnocatee.com/diagnostics/power-and-controls/): Before anything is opened, we establish whether the cabinet is being told to run — and what has happened to its power since it last worked properly.
- [Stage 2 — Stage 2 · Air](https://subzerorepairnocatee.com/diagnostics/air-and-clearance/): The cheapest fault on the list and the most commonly missed — a cabinet that cannot reject its heat produces the entire symptom list of a failing compressor.
- [Stage 3 — Stage 3 · Door](https://subzerorepairnocatee.com/diagnostics/door-and-seal/): A door that has stopped pulling flush over its last inch produces frost, condensation and an endless duty cycle — and it is an adjustment, not a repair.
- [Stage 4 — Stage 4 · Temps](https://subzerorepairnocatee.com/diagnostics/temperature-and-defrost/): What the cabinet is actually holding, measured over the visit rather than read once — and what the frost pattern on an evaporator is telling you.
- [Stage 5 — Stage 5 · Water side](https://subzerorepairnocatee.com/diagnostics/fill-and-dispense/): Measured with a graduated vessel and a stopwatch, because cube size is an opinion and fill volume is a number — and because the split tells you where to look.
- [Stage 6 — Stage 6 · Sealed](https://subzerorepairnocatee.com/diagnostics/sealed-system/): Last, because everything cheaper has already been eliminated — and because it is the only stage that legally requires EPA Section 608 certification.

## Why the order matters

1. **Power and controls** — Is the cabinet being told to run at all? A dark or unresponsive cabinet is a power or control investigation, not a refrigeration one. Quoting it as refrigeration is the most expensive mistake available on a first visit. (A meter and a question. No panel comes off.)
2. **Air and clearance** — Can it reject its heat? A restricted condenser produces the entire complaint list of a failing compressor — long runs, poor recovery, a warm cabinet, more noise. It is the cheapest fault on the list and the most commonly missed. (A grille off and a light. Ten minutes.)
3. **Door and seal** — Is the cold staying inside the box? Frost on the back wall, condensation at a panel edge and a duty cycle that never ends are all produced by a door that has stopped pulling flush. That is an adjustment, not a repair, and it should never reach a refrigeration estimate. (A straightedge, a torch and a sheet of paper.)
4. **Temperature and defrost** — What is it actually holding, and does it recover? Frost on one section of an evaporator with clear metal on the rest is a charge or restriction pattern. Uniform heavy frost that clears when the cabinet is emptied and left open is usually defrost. They need different parts and different money, and only a measurement separates them. (Logged temperatures, and the patience to wait out a cycle.)
5. **Fill and dispense** — Is the water side passing what it should? If ice and dispensed water weaken together, the restriction sits upstream of the point where the line splits. If only one side weakens, it sits downstream. That single comparison halves the investigation before a part is touched. (A graduated vessel and a stopwatch.)
6. **Sealed system** — Is the refrigeration circuit itself at fault? Nothing. This stage is last because everything cheaper has already been eliminated, and because it is the only stage that legally requires EPA Section 608 certification to carry out. (Gauges, a recovery machine and EPA Section 608 certification.)

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**Contact.** Crosswater Appliance Service, Nocatee, FL 32081. Phone +1 (904) 395-4339. Mon–Fri 8am–6pm · Sat 9am–4pm · Sun closed. The phone is the only channel — this site publishes no contact form and no email intake.

**Affiliation.** Crosswater Appliance Service is an independent appliance repair company. We are not affiliated with, authorized by, or endorsed by Sub-Zero or its parent company. All brand names and model numbers are the property of their respective owners and are used only to identify the appliances we service.