ECN Forum Forums General Topics of the Trade General Discussion Area A/C buzzing on start up

What brand/size/voltage are we talking about here?.
Is it a Hi-Wall or a Cassette or a Ducted system?
I'm very familiar with the Carrier and Mitsubishi and Toshiba units.
Chi Spark,
Good point, does it use the old R-22 or the newer R-134a or R-404 High Pressure Refrigerant.
It can make the difference.
Has the unit been serviced lately?
Is the Indoor unit Heating and Cooling as it should?
Is the Indoor unit coming out with a fault code?.