Loretto Cold Service — (904) 664-4866 — independent Sub-Zero refrigeration service in Mandarin, Jacksonville, FL.
Booking: (904) 664-4866 (tel:+19046644866). Source: https://duvalsubzero.com/porch-notes/storms-and-control-boards/

# After the Power Blinks, and What to Check

> Controls and displays that behave oddly after a storm week are a familiar call in Mandarin. What to check yourself first, and what actually needs a board.

Topic: controls. Published 2026-05-18.

Duval County runs on the order of sixty-eight thunderstorm days in a typical
year. On streets under a heavy oak canopy — which is most of Mandarin — that
also means branches in lines and a fair number of momentary interruptions that
never make it to an outage map.

We are careful not to overstate the effect, because it is easy to turn a real
pattern into a scare story. What we can say is what we see: complaints about
displays, settings and control behaviour arrive in clusters in the weeks after a
bad storm week. Some of those calls need a board. Many of them do not.

## The first question is not about the panel

If a display has gone dark or stopped responding, the useful question is whether
the compartment is still cold.

**Dark but still holding temperature.** The refrigeration is running and the
control that drives the display has a problem. That is a real fault, but it is a
different and usually smaller one than a machine that has stopped cooling.

**Dark and warming.** Either the unit has lost power, or the control that
commands the system has failed. Those are two different repairs at two very
different prices, which is exactly why it is worth establishing before anyone
quotes anything.

Put a thermometer in the compartment for an hour, or simply feel whether the
food is still properly cold. It takes almost no effort and it splits the
diagnosis in half.

## Things worth checking yourself

**The breaker.** Obvious, and skipped constantly. Check that it is fully off and
back on rather than merely looking on — a tripped breaker can sit in a middle
position that reads as closed at a glance.

**Whether anything else on the circuit went out.** Kitchens in the older
Mandarin housing stock were not always given dedicated appliance circuits. If a
counter outlet or a light went with the appliance, the fault is on the circuit,
not in the cabinet.

**Whether the settings changed.** Some units come back from an interruption at a
default rather than at what you had chosen. A cabinet that is running two
degrees warmer than you expect, after a power event, may simply need setting
again.

**How long it has been.** A unit that has been off for a while will take hours,
not minutes, to come back down. Judging it after twenty minutes will worry you
for no reason.

## What a board failure actually looks like

Genuine control failures tend to be either total or erratic. Total is
straightforward: nothing responds, nothing runs. Erratic is the more
interesting one — a unit that runs when it should not, ignores a setting change,
alarms with the door plainly shut, or shows a display that changes on its own.
Intermittent behaviour that started in a specific week, and that week had
weather in it, is a strong hint.

## What we do about it

We check the supply first: voltage at the outlet, the state of the circuit, and
whether the unit is seeing what it should. Then the control, then the sensors it
reads, because a control acting on a bad sensor reading behaves exactly like a
control that has lost its mind.

Where a board is genuinely the answer, it is a genuine OEM part, covered for 365
days, with 90 days on the labour. Where it is not, we will say so, and the flat
$129 diagnostic is what you will have spent finding out.

If your cabinet started behaving differently after the power blinked, tell us
when it happened. Dating the change is the single most useful piece of
information you can hand us.

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Loretto Cold 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.

Loretto Cold Service · (904) 664-4866 · Mandarin, Jacksonville, FL