Sub-Zero refrigeration
Sub-Zero control faults after a Clay County outage and the surge on restore
The strike is not the problem. The surge when power comes back is, and a board that half-survives it behaves worse than one that dies outright.

Northeast Florida gets around 68 thunderstorm days in a typical year, and Clay County takes its share of them. Most people assume the damage happens when lightning hits something. In practice, the calls we take are about what happens when the power comes back on.
The restore is worse than the outage
An outage on its own is harmless to a refrigerator. It sits without power, warms slowly, and picks up where it left off. What causes trouble is the moment of restoration: a surge as the grid re-energises, or a sequence of brownouts and short cycles as the utility works through a fault. Electronics do not enjoy being brought up on unstable voltage, and a compressor asked to start against a still-pressurised system on marginal voltage draws far more current than it was designed to.
A board that dies cleanly in that moment is, oddly, the easy case. The unit is dead, the fault is obvious, the repair is bounded. The awkward case is the board that half-survives — it powers up, lights the display, and then behaves in ways that make no sense.
What half-survival looks like
The panel reads 38 degrees while our probe reads 47. An alarm announces a condition that is not occurring. One sealed system restarts and the other does not, so a household with two independent systems suddenly has a working freezer and a warm refrigerator, and concludes the refrigerator side is broken. Fans run when they should not. The ice maker works for a day and then does not. The whole unit resets itself at three in the morning.
The reason these faults are confusing is that they are intermittent by nature. A damaged trace or a marginal component behaves differently warm than cold, and under load than at rest. That is also why “we unplugged it for ten minutes and it seemed fine” is not the reassurance it appears to be. It usually means the fault is thermal, and it will be back.
We do not lead with a board replacement
Control boards are among the more expensive parts in a built-in, and they are also the easiest thing to blame. Before we quote one, several cheaper possibilities have to be eliminated.
A failed thermistor produces a wrong reading on the display, which looks exactly like a control fault and costs a fraction as much. A corroded low-voltage connector produces intermittent behaviour that comes and goes with vibration. A built-in sharing a circuit with a microwave or a garbage disposal can brown out briefly every time the other appliance starts — that is a house wiring issue, and replacing the board will not touch it. In older Orange Park kitchens where a built-in was retrofitted into a space that was never wired for it, we find shared and undersized supplies more often than we would like.
So the sequence is: confirm what the machine is actually doing, verify the supply at the outlet, test the sensors, inspect the harness and connectors, and only then condemn the control. If the fault is intermittent and has not shown itself while we are there, we will say so rather than sell you a part on a hunch.
Afterwards
If a surge has already cost you a board once, it is worth talking about how the unit is supplied — dedicated circuit, surge protection at the panel, and whether the outlet behind the cabinet is in good condition. That is a conversation, not an upsell; some of it is electrician work rather than ours.
Flat diagnostic fee, credited toward the repair. Written estimate before any part is ordered. Genuine OEM parts, 90 days on labour and 365 days on parts.
Where we take this call
What it costs
What does a boards and power repair cost?
The bands this fault lands in: $240 to $810, depending on which component it turns out to be.
$80 Flat $80 diagnostic covering the visit and the full diagnostic sequence, credited toward the repair once you approve the work.
| Repair | Typical range |
|---|---|
| Diagnostic visit | $80 flat, credited |
| Electronic control board | $430–$810 |
| Evaporator or condenser fan motor | $260–$570 |
| Ice maker, water valve or supply line | $240–$620 |
90 days on labour, 365 days on parts, genuine oem parts. The whole table is on what it costs.
Asked on the phone
What else comes up on a boards and power call?
- The panel is blank since the storm. Does that mean the board is dead?
- Not necessarily, and the supply to it gets tested before it is condemned. A board can be perfectly healthy and starved of its low-voltage feed by a failed transformer. Replacing the board in that case fixes nothing and costs $430–$810, which is why the measurement comes first.
- What does control work cost?
- Electronic control board work runs $430–$810, parts and labour together. Boards are ordered against the serial number on the plate inside your cabinet rather than the model, because components are revised within a model designation and two units that look identical can take different parts.
- Will a surge protector stop this happening again?
- It helps, and it is not a guarantee. It is the surge when power is restored, and the brownout cycling on the way there, that reaches the electronics rather than the strike itself. What is worth avoiding is the board that half-survives and behaves erratically for months.
Customer reviews
Owners who called about this
Chosen for this page because they describe the same fault, and printed in full.
4.44.4 out of 5 across all 63 reviews published on this site
5 out of 5
We lost power for most of a day and the unit came back beeping and not cooling. He checked the supply first, then the board, and found a relay welded shut. He replaced it and explained why an outage does that.
Linnea D.May 2026
4 out of 5
The unit kept alarming for a condition that was not happening. He described it as a board that half survived the surge rather than one that died, which matched the odd behaviour exactly. The part had to be ordered.
Aurelia P.December 2025
5 out of 5
He read the outlet before quoting anything, which turned out to matter here: our kitchen circuit is marginal and the cabinet had been browning out for months. Honest advice rather than a quick part sale.
Ottilie N.December 2025
All 63 of them, three-star entries included, are on what owners said after the visit.
Book a diagnostic visit
One flat fee to find out what is actually wrong, credited toward the repair. We cover Orange Park and the rest of Clay County within about 40 miles.
- Diagnostic
- $80
- Labour warranty
- 90 days
- Parts warranty
- 365 days
- Monday – Friday
- 08:00 – 18:00
- Saturday
- 09:00 – 16:00
Written estimate before any work starts. No parts ordered until you approve the figure. Closed Sunday. Calls placed after hours are returned the next working morning.