Dave,

Since the generator starts as expected when the breaker is manually
switched, but fails to start when a power outage occurs, I would suspect the
transfer switch controller board is behaving intermittently. This board
controls the automatic transfer using a very simple method based on the
amount and duration of power outage to turn on / switch the generator, and
does the same in the reverse sequence as well when utility power returns.

Two suggestions:

1. Download the extensive (several hundred page) repair guide available at
the Generac / Guardian web site which has complete diagnostics, flow charts,
schematics, parts listings, drawings, and narrative. It is truly excellent,
and is offered in a pdf file at no charge. It explains all of the Generac in
great detail.

2. If the unit is still under the 2 year manufacturer's warranty, contact
your local dealer and document the problem, and have them look at it. Even
if it is an intermittent problem, you definitely WANT GENERAC to replace the
defective part if and when it fails completely. The board itself is probably
a few hundred bucks if you had to buy one yourself, and a new transfer
switch is well over $1000.

You might also note that there are two cartridge fuses protecting the 24
volt relay on the transfer switch, and one or both of these can, if not
snugly installed, cause switching problems. I suggest buying a couple spares
just in case one or both blow in a true emergency.

Hope this helps,

Smarty


"Dave" wrote in message
...
Utility power outage and the Generac 04390-2 (13kW NG) did not start
in 50F weather. Assuming for now the problem is not with the
generator because when the 200-amp breaker installed between the
utility meter and the automatic transfer switch was moved to the off
position, the Generac started as expected. Does this description
sound like a relay or other automatic transfer switch component
waiting to fail more permanently? Replies appreciated.