Air Conditioning - Condensing Unit Fan making noise

Hi,
I have a Bryant unit with a GE motor in the outdoor condensing unit. The condensing unit has recently started to make an odd "grinding" type noise. It only makes the noise sometimes. It seems to be coming from the fan. Sometimes it makes the noise on startup, other times it makes it after running for a while. I have manually moved the fan as well and it seems to be moving freely.
The unit is running fine, it does throw out cold air.
Its roughly 8 years old.
I have not opened the fan yet to see if it indeed is the fan and the motor just needs to be replaced. But the unit and the fan seems to well fastened. There is no debris in the unit and I don't see any scratch marks where the fan blades might be touching the inside of the unit.

Any thoughts?.

thanks :)
alam

The bearings in the fan motor may be worn. That can come from normal wear or a fan blade that is not balanced well enough. When you open up the unit, try to move the motor shaft side to side and up and down. You will feel it if there is movement. A slight bit of up and down movement is OK but not 1/4". If you decide to replace the motor, get a new capacitor too.

Ken

Hi, thanks for the reply. However, I think the situation has gone from bad to worse. After my initial post, I decided to replace the motor, however had to leave town for the weekend. I left the thermostat on hold at 80. However, when I got back the house was like burning hot. The condensor motor was not running. The internal ac unit was running. So now I thought it has finally burnt out and I will just have to get it replaced.
However, the next day I decided to try to turn it on again and it came on. Some cold air started to flow. But it ran for about 15 min and then shut off again. The internal ac unit kept running, so I immediately turned it off because it was starting to throw mildly warm air.

I have now taken the motor out. Its a GE motor 1/4 HP HC39GE237a. It doesn't seem to have a lot of play in it. The fan does move. There is a little bit of up and down movement. I am thinking of replacing both the motor and capacitor.

But my question is, has this killed my compressor because it probably ran for over 24 hours without the condensor fan motor running. The only good thing is that when it worked last, I did feel cold air coming.

What should I do. I am planning on replacing the motor and capacitor.

thanks
alam :(

If it blew cold air then it is probably ok but you won't know for sure until you install the new motor and get it running again. I would go ahead and replace the motor and capacitor. Let us know how you make out.

:confused: Hi, I got the new motor and capacitor today. I installed it. However. the capacitor that i got in mail ony has two points. The original has 3. One for yellow, one for brown, and another for a blue wire coming from inside the unit.

So I didn't replace the capacitor and used the old one. I wasn't sure of the where the wires go, so tried to read the schematic diagram and connected the wires mostly from memory. The fan ran for one second, then my wife turned it off. When I tried to turn it on again, it didn't. So I waited about 15 min, then plugged in the wires again, the fan did run, but I think the wrong way, because it wasn't blowing any air outside and seemed like it was getting very hot so I turned it off again. Is the polarity messed up? Is the brown wire for ground?
Is the capacitor shot? How do I replace a three point capacitor with two?

Where do the wires go. and what is the purpose of the capacitor anyways?
help

thanks
alam

The capacitor with 3 terminals is actually 2 capacitors in one can. One terminal is common to both. All you need to do is put a jumper on the common terminal of the existing capacitor and connect it to one terminal of the new capacitor. The two capacitor wires from the new fan motor go to the terminals of the new capacitor. The other wires from the motor go to the load side of the contactor. Hopefully you can understand the explanation but if not, post back with more questions.

Ken

well after all that, all I had to do was switch the wires on the old capacitor. apparently i had connected the wires from the motor backwards and thus had messed up the polarity. The was fan was running the wrong way, was heating up and so on.
so after I fixed the wires, it runs fine, no need to replace the old capacitor. I still don't understand the jumper from the old to the new capacitor. does that mean, I would have had to keep both capacitors in there?
I guess really doesn't matter now, but I am thinking I should keep a capacitor handy, incase the old one goes bad on me
thanks for all your help. and if you can pls do elaborate on how to replace the old three terminal capacitor with the new two terminal capacitor.
thanks
alam :)

My friend you are very lucky. Normally, having the motor miswired like you did smokes it as soon as you apply the power. Now on the capacitor issue. Look closely at the three terminal capacitor [after you turn the power off and discharge the capacitor]. You should see three markings at the terminals. The middle one will be C or COM for common, one of the others will be H or HERM for the compressor motor and the third will be F or FAN for the fan motor. Even if there are no markings, you should see that the middle terminal has at least 3 wires on it, one of the other terminals has a single wire that goes to the compressor and the third has a single wire that goes to the fan motor. The capacitor is called a dual rated capacitor and it serves both the compressor motor and the fan motor. The larger rating is for the compressor motor and the smaller rating is for the fan motor. In order to use the new capacitor you bought for the fan motor, you will not remove the dual rated capacitor, you will simply discontinue using the C to F side. Here's what to do- remove both of the fan motor wires from the dual capacitor [write down which color went to the middle terminal and which one went to the F terminal by itself- should have been brown] Do not disturb any of the other wires. Securely mount the new capacitor near the dual capacitor. Attach both wires from the fan motor to new capacitor; one on each side. Make up a short piece of wire with a slip on connector crimped on each end [I don't have to tell you to strip off a little of the insulation first before inserting the wire into the connector, right?]. The jumper wire goes from the MIDDLE terminal on the dual capacitor to the terminal on the new capacitor which has the wire you REMOVED FROM THE MIDDLE TERMINAL on the dual capacitor. Check your wiring 3 times to make sure it's right [look around to ensure that no other wires popped off from somehwere] and turn the unit back on.