# Matanzas Kitchen Service — Thermador appliance repair, St. Augustine FL — (904) 442-8210

> Independent Thermador Service. Booking by telephone on (904) 442-8210. Independent: not affiliated with, authorized by, or endorsed by Thermador.

## Storm Season and Control Boards

Page: https://thermadorrepairstaugustine.com/notes/storm-season-and-control-boards/

Control boards in this county usually die of cumulative surge damage, not of one strike. That changes both the diagnosis and what is worth doing about it.

Topic: power
Published: 2026-07-08


The area averages roughly 68 thunderstorm days a year. People reasonably assume
that means appliances die in dramatic strikes, and occasionally one does. Far
more often, what we find is a board that has been degraded gradually by hundreds
of small events, none of which was noticeable at the time.

## What a surge actually does

A transient over-voltage lasting microseconds does not usually punch a hole in
anything. It stresses the components that sit closest to the incoming supply:
the surge suppression device on the board, the rectifier, and the electrolytic
capacitors in the low-voltage supply. Each event takes a little capacity out of
the suppressor and a little life out of the capacitors' electrolyte.

The result is an appliance that works fine for years and then develops symptoms
that make no sense: a display that flickers, a relay that clicks but does not
close, a cycle that aborts at a different point each time, a machine that comes
back to life after being unplugged for an hour. Those are the signatures of a
low-voltage supply that has lost its margin, not of a component that failed
cleanly.

## Why it shows up in late summer

Two things stack in August and September. The storm frequency peaks, and so does
the load — compressors run longer, cooling fans run constantly, and the ambient
temperature inside a cabinet or a control compartment is at its annual maximum.
Capacitors lose capacity faster when they are hot, and a board that had just
enough margin in March does not have it in September.

That is why a board failure in early autumn usually has no single event behind
it, and why asking a homeowner "was there a storm?" rarely produces a useful
answer. There was. There were sixty of them.

## Diagnosing it honestly

A board is the most expensive part in most appliances and the easiest to blame,
so we make it prove itself. Before we condemn one we check the supply voltage
under load at the appliance, not at the panel — a shared circuit sagging under a
compressor start looks exactly like a failing board. We check the ground. We
check connector pins for corrosion, which in coastal houses causes the same
intermittent behaviour for a fraction of the cost. And we check that the control
compartment's cooling fan is actually running, because a board cooked by its own
enclosure is a fan repair wearing a board's symptoms.

Only when those come back clean is the board the answer.

## What is worth doing

**Whole-house surge protection at the panel.** This is the one intervention that
changes the odds, because it clamps the transients before they reach any
appliance. It is electrician work, not appliance work, and it protects the
kitchen far better than individual outlet strips — most built-in appliances are
hard-wired or plugged into an outlet nobody can reach anyway.

**A point-of-use protector where the appliance is plugged in and reachable.**
Second best, and still worthwhile for a coffee system or a countertop unit.

**Do not leave a built-in unplugged through a storm and forget it.** We have been
called out to refrigerators that were fine and had been switched off at the
breaker three days earlier.

## The part we cannot promise

Surge protection reduces risk; it does not eliminate it, and anyone who tells
you otherwise is selling something. What it does reliably is convert a
population of boards that fail in year eight into a population that fails in
year fifteen, which in a built-in kitchen is the difference between one
replacement and none.

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Source page: https://thermadorrepairstaugustine.com/notes/storm-season-and-control-boards/
Phone: (904) 442-8210 · Hours: Monday to Friday 8:00am – 6:00pm; Saturday 9:00am – 4:00pm. Closed Sunday. Scheduled appointments only — we do not run an after-hours line.
Area: St. Augustine, FL and St. Johns County, about 40 miles out.

Matanzas Kitchen Service is an independent appliance repair company. We are not affiliated with, authorized by, or endorsed by Thermador 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.