Probably neither one. A seized motor sort-of "hums." The only thing that can
"buzz" (like a bee) is the power relay.
You can try this: With all the power off, look at the contacts on the power
relay. The contacts may be pitted or burnt, thereby preventing a good
connection. If so, more life can sometimes be extracted from the relay by
filing the contacts down to a smoother surface. This may buy you some time
to get a replacement.
While you're at it, might as well replace the capacitors.
Outside unit. Remove the removable panel and there it sits. Trace the main
power wires - they go to the relay. It works like this: The wires from the
thermostat in the house (24v) activate the relay which supplies mains power
to the compressor and fan. At up to 30, 40, or more amps, you can see this
little relay is switching a LOT of power. It is this raw power that burns
the relay's contacts. The contacts, over time, become pitted or deformed
just like the contact points in the older type automotive distributor.
Before you touch anything, take several digital pictures so that, if a wire
pops off, you'll know where it went.
Someone has already mentioned blown capacitors.
Whenever severe weather comes through the area,
all the HVAC and refrigeration repair techs are
running around like ants to replace all the blown
Chinese made start and run capacitors. If repair
techs could find American made capacitors they
would be snapping them up. The problem is that
the American manufactured capacitors are usually
two to three time the price of the Chinese made
capacitors and people shop for low price.
It was just beginning to storm when the problem started last night. I
called around and found a service tech who will come out to diagonose
the problem for $50. Having no experience with capacitors (and
understanding the dangers of them discharging even when disconnected
from a power source) I'm fine with letting a pro take a look at it.
Hopefully it's just the capacitor and a relatively inexpensive
Anyone know what I should expect to pay if it's the capacitor?
They do store charge, if the power is removed at the non-zero voltage
crossing. Please know what you are talking about, as misinformation
could kill in this case if the capacitor was charged to the peak of
the 240 V supply, about 300 Volts.
I don't know why they keep using unreliable capacitors on motors when it
is totally unnecessary. Motors can be made with start and run windings
with centrifugal switches which last much longer than caps and are
simple and cheap to replace. Must be the cheapness of Americans.
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