RBM wrote:
"AngryOldWhiteGuy" wrote
in message ...

Hi - we have a typical home AC system - ours is a Ruud - the model number
on the outside unit is UAKA- 037JAZ. It's been very hot here in Texas -
over 100 all day long, but the system is working OK and cooling the
house - plenty of cool air coming out of all the vents - the AC runs a lot
these days, but it always has when it's very hot outside since we've lived
here - I guess that's because it's an older unit (1996) and not as
efficient as some of the newer units. The filter has always been changed
regularly.

For several months now, I'm hearing a loud buzzing noise from the outside
unit when it's running - the fan spins OK and there's hot air coming off
of the unit - the noise is nothing that keeps us awake at night, but
certainly noiser than my neighbor's units - they were replaced within the
past few years and they're newer.

Is this kind of noise typical of the older units?? If not, what am I
likely to hear is the main problem from the AC repair guy if the unit goes
out and I need to make a repair call?

I had something on the outside unity replaced a few years ago - I think it
was the start capacitor.

Thanks!


What you are hearing is the relay , or contactor,inside the condenser. It
receives 24 volts from the blower unit, which energizes it's coil, pulling
in the relay,sending 240 volts to the condenser motor . When these relays
get old or worn, then start making humming or buzzing noises. It's not an
expensive part and with limited electrical experience, can be changed by a
homeowner.





In my experience, when the relay is located outdoors and not well sealed
from the environment, what happens is that the D shaped copper "shading
coil" at the armkature end of the relay coil corrodes into nothingness
and can no longer serve its function of creating an out of phase AC
magnetic field to prevent the buzzing of the relay armature.

(More than you needed to know, huh?)

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.