Question please. I just had my very old central A/C system replaced with a Carrier Infinity system: a 38TDB condensing unit coupled with a FE4 variable-speed fan coil and an Infinity Control programmable thermostat. This is supposed to be very nice stuff. Great installer - seemed to be attentive to every detail. System has been operational for one day now. Generally, I'm very impressed - cools beautifully, almost always runs at low speed even here in south Florida, very quiet blower, etc.
HOWEVER, one very annoying issue: when the house has reached target temp and the blower completely stops running, the air handler still makes an audible humming noise (reminds me of the deep hum a transformer makes). When the house is quiet, the noise can be heard for a good 30 feet away, so it is very noticeable. Is this normal? If so, what is causing this and what is it doing? Thanks.