Pull the breaker from the panel and check it. Sometimes the breakers will
"burn" at the buss and not be noticable right away. While the air condenser
/ air conditioner is running, it will overheat the breaker [bad connection
on the buss] and trip while there might be nothing wrong with the air
conditioner itself.

--
Zyp
wrote in message
ups.com...
It is a replacement and they did use the same breaker. If it were a
marginally rated breaker wouldn't it have started giving trouble before
this? Thanks for your input.

At any rate, I have called the A/C company instead of an electrician
to come look at it.

Joseph Meehan wrote:
wrote:
I have a 4 year old Lennox central air conditioner. It has run fine
until this summer.
Now after it has been running for about 15 minutes the circuit breaker
trips and the outside condensor fan stops. When running it does blow
cool air.

I have heard that it could be the compressor or something else with
the A/C unit or it could be a bad breaker. Since the unit is only 4
years old I am thinking that it is unlikely that the compressor has
gone bad. If it were a bad breaker wouldn't it trip as soon as the
unit turned on?
Any thoughts?

Was this a new or replacement A/C system?

If it was a replacement, I would tend to go with the idea that they
may
have used the existing breaker and it may be rated marginally for that
unit.
You need to check the recommended protection for that specific unit or
it
may just be tired and need replacement. That one you can do yourself
IF
you are reasonable competent and careful. But you will need to know
what
the new system calls for and if it is larger, you might also need to
replace
some wiring.

On the other hand if it was not a replacement, I would tend to
suspect
the compressor.

The electrician is not going to be qualified to check the A/C, but
the
HVAC contractor should be able to determine that the A/C is OK and that
the
correctly rated breaker is in use.

--
Joseph Meehan

Dia duit