Bryant Heat Pump

[mustard_man]

I have a mid-1990's Bryant Heat Pump. Although the fan blower is "off", the outside compressor unit continually makes a loud "humming" noise. Any suggestions on troubleshooting?

[HayZee518]

compressor and the condensing fan motor runs off a magnetic contactor. if the mating surfaces of the contactor don't quite meet intimately the unit will vibrate. also one or two of the poles have a "shading coil" this is a heavy wrap of copper wire that is supposed to reduce or eliminate "eddy currents." eddy currents are currents induced into the iron punchings of the contactor. each lamination of the "iron" is supposed to be insulated from one another.

[dosser]

The "fan blower is off", is this the condenser fan or the furnace fan? Is the humming intermittent or always there?