Hi,

The blower for my HVAC started producing a noise a couple of weeks back. The noise is continuous once the blower motor is energized(and starts the moment the motor fires up). It goes away immediately once I turn the blower off(even though the blower wheel is still turning).

The noise is a continuous low pitched ticking noise. Its almost like the noise you would hear from a diesel noise. I have uploaded the video clip here:

http://www.youtube.com/watch?v=UBUt4pebf4Q

I checked the capacitor and it was reading 9.18 UF. The capacitor is rated at 10UF with +/- 6%. Could the capacitor be the problem?

Sorry, I couldn't hear anything unusual in the clip.

Hi Grady,

I uploaded another clip where it's a closeup. Can you give a listen to this. If this still isn't helpful to you, I will go into my attic to make a clip of my other unit. Unfortunately, because my attic is unfinished, it's a bit of a project climbing in it.

By the way I swapped out the capacitor with a new capacitor and the unusal noise is still there.

You can find the new clip here: September 7, 2013 6:49 PM - YouTube

I don't know if I'm hearing the same thing as you but it sounds like metal vibrating. Make sure the mounting screws for the blower & motor are tight. You can also try holding your hand against various places on the furnace cabinet to see if the noise stops.

Il troubleshoot it some more tomorrow. I tried pressing different spots on the housing but the noise was consistent. The one contraindication is that the noise goes away immediately on motor shutoff(even thought the blower cage is spinning at a good clip). Won't that suggest its not a mechanical/vibration noise?

I would first check to see if the air filter is clean. Then check (after shutting the power off) to make sure that there is nothing that got sucked into the blower wheel itself.

Is it possible that the heat and air are running at the same time? Sounds like it is firing.

Can you stop the unit and start it in another video so we can hear the difference... hard to hear what you are - sounds like a blower running.