Air Conditioning - compressor Fan Stops 15 mins after AC starts

Greetings,

My Central Air conditioner get the following problem lately.

The compressor fan stops 15 mins after I start the AC. I had the compressor checked and it is fine. The capacitor doesn't cause the problem either(I replaced with a new capacitor,but still same problem).

Is the fan motor bad? If so, why it starts and works for 15 mins? Is there anything else cause the fan stops?

Do I have to replace the capacitor if I replace fan motor?

BTW, the CA produce cold air before the fan stops.

Thanks in advance!


Mark

The compressor fan stops 15 mins after I start the AC. I had the compressor checked and it is fine. Why didnt he check the fan then. Sounds bad . Put a amprobe on it and see what it does. Dont run the AC with out this fan.

Is the fan motor bad? If so, why it starts and works for 15 mins? Is there anything else cause the fan stops?

Yes , Ill bet it over heats

ED ;)

Why didnt he check the fan then. Sounds bad . Put a amprobe on it and see what it does. Dont run the AC with out this fan.



Yes , Ill bet it over heats

ED ;)



Hi Mark:

Assuming that the replacement capacitor was the same, [ie: same mfd and vac rating as the old one] most likely the bearings/thrust washers inside the motor are worn. Why does it run for a while and then quit? The failure is related to heat. The motor has to run for a while before it gets good and hot and then the heat is kicking in the failure mode. When the motor is replaced, should the capacitor also be replaced? Yes!! We use a rule, new motor, new capacitor. I realize you have new cap now, but it's luck of the draw whether it will be the correct one for the new motor. Relative to the cost of a motor, capacitors are cheap. I agree with Ed, don't continue to run your a/c this way or you'll be looking at a compressor replacement- mucho bling bling. Let us know how you make out.

Ed & John,

Thank you for your suggestions and I will replace the Fan Motor and The Cap. Where can I get them?

Mark

Any elec or hvac shop. Make sure you get same cw or ccw same Hr and RPM. Get a new capacitor with it.

ED ;)

Any elec or hvac shop. Make sure you get same cw or ccw same Hr and RPM. Get a new capacitor with it.

ED ;)


Hi ED,

What is cw/ccw, Hr?

Thanks.


Mark

CW = Clock Wise
CCW= Counter Clock Wise
HP= Horse Power
RPM=Rotation Per Minute

Any elec or hvac shop. Make sure you get same cw or ccw same Hr and RPM. Get a new capacitor with it.

ED ;)

Do I have to get the same brand & model? Is it ok as long as same cw or ccw same Hr and RPM?

Thanks.

First, go to www.fasco.com On the home page, highlight the distributor services link and click on fasco facts. Work your way thru a couple web pages and then download the brochure. It will guide you to selecting a replacement motor. While matching horsepower is a good idea, you also have to compare the amp draw of your motor and the one you're considering using. There are "energy efficient" motors out there that will not have enough oomph to do the job. You don't need the same make and model, you will find that the parts jobbers sell universal type condensor fan motors that will cover many applications. They are multi horsepower motors with reversible rotation [accomplished by switching around some of the wires] and feature all angle mounting [iow- shaft up, shaft down, shaft horizontal.

If you've got the motor out just take it with you for them to match it up.

I bought the motor and capacitor from Johnston supply and replaced them already. My AC is working now.

The new capacitor is much smaller than the one I had before. The holder is too big for my new capacitor. I still can put the capacitor in the holder, but it can be moved. How to make it exactly fit in the metal holder? Does it matter?

I'd like to thank all of you who tried to help me out here. It is really nice to have a place like here for people who needs help.

Thank you!!!


Mark

Hi Mark:

Glad to hear your unit is running again. You want to secure the cap coz you don't want it vibrate around and have the terminals touch metal which could smoke the new motor. To secure it you could:

1. Uscrew the strap, pull it tightly to the cap and drill a new hole in the strap and secure it to the bulkhead.

2. Lash down the cap to the metal strap with some long cable ties.

3. Get a roll of plumber's strap [it's about 1/2" to 3/4" wide, it has holes along it's length about every 1/2" or so on center] and fabricate a new mounting strap out of that.

4. Go back to Johnstone Supply and ask then to sell you a capacitor mounting kit that fits your cap and install that [they're cheap]. They also sell a rubber boot that slips on over the terminals to keep water off of them.

Can I just use some tapes to tie it?

Thanks.

Up to you. What you don't want is the cap coming loose, falling over, touching it's terminals to metal, and smoking your nice new motor.

It works fine now!

Thank you everyone!