Droning Blower

[jed1154]

I had my blower removed and cleaned a couple of months ago. Everything seems to work fine except for a drone.

I have a variable speed blower and when the unit kicks into LOW speed on one zone, it runs for 20-30 minutes on the heat pump. This is a very low speed and it has a very audible drone that resonates through the house, especially in the kids rooms.....its one of those drones that in a room, you can step three feet over and never hear it, but in certain parts its just annoying. When the unit ramps up the RPM or adjusts its speed for other zones, the sound disappears.

The unit is 10 years old and I was told it would be hundreds and hundreds to replace. So....is there anything that can be done for the motor to help isolate it or get rid of that drone? I know my tech can come out and adjust the low speed RPM, which would probably be a better idea anyway, but is there anything else?

[Kevin Weaver]

This may sound un-real but it could be a return air grille. Put your hand on it and see if the noise quits. Sometimes when there is too much air going thru a grille it will make a low sounding drone noise. Or maybe the blower door is not positioned exactly right on the furnace.

[keeplearnin]

Or the motor is failing

[jed1154]

It could be the motor failing. I will check the air grate, but keep in mind this only happens on the lowest setting...on that setting, you can hardly feel air passing through the return.

the door to the unit int he attic is secure. I even unbolted, slid and reseated the blower.....so, its possible its just on its way out.

I have not confirmed if it does it when cooling, but I suspect not since the RPM for the cooling is a little higher.

Ill check these things and if nothing else, ill ask the tech when they come out again for inspection. The house and attic is really funny about amplifying and transferring sounds from that motor and system....its strange.