New ac unit can be shall we say tight. have higher FLA (full load amps) to
start with then after some use.
an older breaker that has tripped a few times is the same way it trips at a
lower current than it did when brand new, were talking 10ths of an amp if
that. loose wires on the breaker will also cause tripping, seen that on our
AC unit, check the wires make sure they are very good and tight. Ours would
work fine for a while then when system had to work harder due to outside
temp, and longer running cycle would trip out, was only loose wires.

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