The high limit switch is designed to protect the compressor from burning
out, when the amperage or discharge pressure is too high. When it trips,
you're supposed to to call a HVAC service company to come out and repair
the unit. If you press the reset and do it all over again (the next day),
eventually you will have a compressor burn out. And the resulting repair
will be several times more expensive than having the unit serviced. Talk to
the people in the stores near you, see who they use, and who does a good
job. Your cheap approach is going to cost you mega bucks before too long.

Christopher A. Young
Learn more about Jesus
www.lds.org
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wrote in message
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Our office has a rooftop Lennox THA090 AC unit. It comes with 2
compressors. Almost everyday we have to go to the roof to restart the
compressors because they often will trigger an internal circuit
breaker that protects the compressors. According to the PCB board that
is next to the compressors, when it trips the breaker, it says it is
because of a High Pressure fault (LED1 will flash, and LED2 will be ON
solid). What would cause this fault on a daily basis?
Thanks for any tips!

Here are some pictures of the AC unit:
http://www.flickr.com/photos/54230006@N07/8391891825/
http://www.flickr.com/photos/54230006@N07/8392974016/
http://www.flickr.com/photos/54230006@N07/8392973520/