Heating Help

Air Handler Howling

I had my air handler serviced last year towards the end of the year. I used the air conditioner about twice after he had worked on it. It howled during this time but I didn't think anything of it since it didn't do it right after I turned the furnace on. This summer though I noticed it howls again so I did a little deducing. I found that it doesn't howl when just the fan is on. It doesn't howl when the furnace is on. It only howls when the A/C is running. I change the filter very regularly so I don't believe it is that. It drains properly since I clearly see it eject the water outside using a condensation pump.. The howling seems to be coming from a lower section of the air handler. Right above the fan where the furnace is. I'm fairly certain the sound is below the A coil. What I don't understand is if its coming from the furnace part of it why does it not make any such howling when the furnace runs. I'm including a wma file of the sound if that will give you a better hint. Any help would very much appreciated.

How-ler

Is your fan "on " motor speed the same speed as your ac fan on speed ?

How-ler

Is your fan "on " motor speed the same speed as your ac fan on speed ?

How-ler

Is your fan "on " motor speed the same speed as your ac fan on speed ?

Triple play!!

Must  have been my twitchy finger!!!!!!!

Yes

As far as I can tell yes it is.

How -ler

Turn the condensing unit disconnect off ,and give another listen.

Huh..

So I turned the therm to off went outside and disconnected the condenser and turned it to cool.. And it makes the howl. Turned the ac off and ran just the fan and no sound.

O.K.

Is the indoor blower motor a variable speed motor ? 16 SEER  system ?

System

I don't know the SEER rating but I'm fairly certain its not variable.. Can't be positive about it but fairly certain its not. I moved into this house last year so thats why I don't know much about it.. Its an american standard model #CUB060A936C1 if that helps at all.. I can also say this.. generally around here they don't put very expensive A/C units in..

Something I can do

Is there anything I can do to find out what type it has? Though I'm fairly certain now its not variable cause I'm pretty sure that would be a two stage type system and this is a one that I know of.

Speed Adjustment

I have a lot more information now.. its a 4 speed 115v GE motor with an rpm rating of 1075. Since its a four speed motor do you think i could change the a/c part down to the next lowest speed and have it not make the noise anymore?

air handler howling

it can't bark lol

air handler howling

it can't bark lol

Distribution system to small

What you have and i think this is the case is that when you swith the fan from auto to on without a call for ac the board in the furnace picks a lower speed.
Now with a call for cool the board will choose  a higher speed for ac and there a reason for that.not going go into why bc whenever you make a change with fan speed one need to test static pressure and freon charge again to make sure the system is dail in correctly.
In short making a fan speed adjusment could be a bad move without testing you made the right choice.
Also it could be something as simple as a loose piece of tape or the doors on the coil casing is loose and air is trying to get out the crack and give you a noise.