[RE-wrenches] Sunny Boy constant off line problem

[Jeff Yago]

We have installed many Sunny Boy grid tie inverters in all size ranges with
no problems until this head scratcher.  For this client we installed a 4 kW
grid tie system 2 years ago that included a 4 kW Sunny Boy inverter.  At the
time we anticipated this client would want to upsize the ground mounted
array located about 180 feet from his home that was all landscaped, so we
installed an empty conduit with the required conduit when we dug the trench.
A few dollars of PVC might come in handy later.  

This system has worked perfectly for 2 years. Almost a year ago we were
called back to install the second system, which was an exact duplicate of
the first.  Same modules, just lengthened the racking so same orientation,
same model inverter, same wire size using the empty conduit we left the
first time, and supplying the same breaker panel.  Starting several months
ago the second Sunny Boy inverter has started to go off line for no known
reason.  The first inverter right beside it is "seeing" the same grid, yet
it is not having this problem.  

We suspected the added circuit breaker was flaky and replaced it but this
did not resolve.  The error message always indicates no grid AC.  This last
time the inverter was off line for 2 days then came on by itself again and
is now working just fine.  During all this the first inverter worked
perfectly.   After 3 trips to check out and finding nothing out of place, is
it time to send this one back to the factory?

Jeff Yago