The slight buzzing was probably the relay in the operated state due the
the thermostat calling for cool. However, as there was no power to the
outside unit (compressor/condenser), it couldn't run. As for why the
breaker tripped, there might have been a brown out condition or a bunch
of on-off-on-off power failures. Many newer units protect against both
of there, however, there are probably some cheap, builder's special
units that don't have the protection.

B wrote:
The outside compresser should keep the indoor coil cold, and if it wasn't
doing that, there's no damage done by blowing air across warm coil and
circulating it through your house. It could be bad to refrigerate the coil
and not blow air across it -- it might "freeze" and break. Just ask your
installer why the outdoor unit would be buzzing while the indoor unit
worked -- why they are not wired to know that the other is down (like I
think mine is).

"Kerry" wrote in message
om...

I am hoping you can all help me. Here is the story....

We live in a 1.5 year old house. Our AC coils our in our atic, then
we have the blower unit thing outdoors (sorry I don't know the real
names of these things).

We were away for the weekend and left the AC set at 85 degrees. It
was a hot weekend and the outside temp got up over 100 (probably
around 104). Anyway, when we returned home last night, our house was
a very warm 87 degrees. The fan was blowing but no cold air was
coming out. So I went outside and the outdoor portion of the AC unit
was not on. I put my ear up to it and could hear a faint electical
buzz. So it was getting power. Then I passed the condensation drain.
The ground was wet, so the AC had worked properly at least sometime
in the weekend. My next step was to go to the main breaker panel.
Sure enough, the AC was tripped. I reset and it is working fine so
far today.

A few questions....
1) What does the breaker control? The fan in the house was still
running and the unit outside still seemed to have power (since I could
hear the slight buzz). Does the breaker just control the coils?

2) What can cause the breaker to trip? And is that mean something
really bad is wrong?

3) The fact that it tripped concerns me. Is this something that
happens sometimes in really hot weather or is it more likely a problem
with my AC?

4) I have no idea how long the fan in my house had been running
before I came home. My guess is that it had been running for a long
time (many hours if not a whole day) trying to cool the house without
luck. Was that really bad for it? We let it rest overnight before we
tried it this morning.

Thanks all for the help. Out house is still under warranty, but since
it hasn't tripped again, I am not sure what to do. Please advise.

Kerry