"Ron" wrote in message
news
On Thu, 23 Sep 2010 08:09:56 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Steve" fired this volley in
:

I do approximately 5 semester hours a year in
continuing education just to keep up with the new technologies. The
newest super high efficiency systems are serial controlled, with
variable frequency inverter drives and can vary their output capacity
from 40 - 115%. Even the compressors are driven by electronically
commutated, variable speed motors. This technology has only been on
the streets for a year or so in residential split systems. If you
don't have the proper training, you can cause some very expen$ive
problems by something as simple as getting 2 control wires crossed.

??? Wiring things incorrectly has always been a problem since there
were wires.

That doesn't require any new knowledge.

And PLL is not new technology.

It is new for residential heating and cooling systems, and it does require
the knowledge to be able to troubleshoot and repair.