[Fredi]

The compressor fan for my AC (Central Air) unit (that is located out side of the house) works intermittently. The fan comes on for few seconds and then turns off. Sometimes I can hear some noise from the compressor unit before the fan turning on.


Any help is highly appreciated.

Best regards,
Fredi

[TxGreaseMonkey]

Sounds like you need a new condenser fan run capacitor. You could have a separate condenser fan run capacitor or you could have a dual round run capacitor, that satisfies both your condenser fan and your compressor motor. Either way, an easy fix.

The smart thing to do, while you are checking out the condenser fan run capacitor (use a digital multi-meter that can test for capacitance, such as a Fluke 16), is to replace the contactor (relay) as well. This should be done proactively every 6 to 8 years. You would be amazed at how much better you unit runs and sounds. Having a contactor, whose points are in great shape, is one of the keys to having trouble-free air conditioning. Do it, you'll thank me later. Both of these items are inexpensive, especially if you learn to do it yourself. That's what I'm all about. Remember, when you test your capacitors, remove all wires going to them first.

[letmetellu]

Very possible that the motor is bad or the start capacitor is bad. But first I would oil the motor and give it a chance to see if it is just a case of no oil.

[Fredi]

Thanks for your quick response. But please excuse my ignorance, where is the capacitor that you're talking about and how can I replace it?

Thanks,
Fredi

[letmetellu]

The capacitor is in the outdoor unit and is not something for person to fool around with unless they know exactly what they are doing, not only is it dangerous to change them our but if a mistake is made it can cost you a complete condensing unit at a cost up in the thousands of dollars. Call a Service mean if you are sure that is what is wrong

[TxGreaseMonkey]

Turn off thermostat, 220v. Breaker (or pull AC disconnect) going to the condenser unit, and 110v. Going to the furnace. Remove outside panel to the condenser unit, usually the side panel nearest the high and low pressure lines. Nutdrivers (5/16") are comonly used to remove cap screws on ACs. Inside this panel you will see another panel, behind which lies the contactor, start capacitor and relay, and the run capacitor(s). If in doubt about whether the current is off, take a non-contact voltmeter and check for any voltage. Lastly, take a large insulated screwdriver and place across the line terminal going to the contactor and to ground. If current is still on, you will see a large blue flash, but it will save your life. On the backside of the inside panel is a plastic bag that normally contains a very detailed schematic and technical information on your unit. Take it out, copy it for your use, and replace the original. That information should help you locate everything you need. Most units are pretty similar and you could easily learn to spot the various components through self-study on the internet, if you have the aptitude.

Yes, there are risks associated with working on ACs, just like working on your own car. You need to honestly assess your abilities to accomplish the task. However, let's face it, what we are talking about here is not rocket science.

[Fredi]

Thanks to all of you for the very valuable responses. I managed to locate the Capacitors. The problem I am facing now is that I cannot find any specification/documentation on the capacitors. Is there such a thing as “General Condenser Capacitors” that I can replace the old ones with? I cannot even find a label on the outside unit. This shows how old the unit is :) . Any information is highly appreciated. I do have the pictures of the capacitors, I will post it on this forum if that helps.


Thanks in advance,
Fredi,

[TxGreaseMonkey]

There should be the manufacturer's name and part no. on each item. You might have to remove them from the unit, so take pictures of wiring, tag everything, and make a wiring diagram. Another possibility is go to the metal condenser unit tag. It will give you a lot of information that you could research on the internet or contact the manufacturer and get a Service Fact Sheet on your unit.

[Fredi]

Hello txgreasemonkey and letmetellu,

I managed to buy a new capacitor over the internet. I changed the damaged capacitor about 20 minutes ago and the whole system seems to be working fine. My thanks go to you both for responding to my questions.

I had a serviceman (from a local AC company) to check the problem, they gave me a $2200.00 estimate to replace the whole unit. They told me that the only solution. It’s amazing how some people do business.

Once again many thanks to you, I truly appreciate your help.

May you live a happy and healthy life,
Fredi

[Fredi]

Hello,

It’s me again and I have a new problem. The Condenser fan is working fine, but the air it’s blowing is not hot and the AC is not cooling the house that much. Have I lost some gas in the system due the problems I had earlier (Fan working intermittently)? Any help you can provide is highly appreciated.

Thanks,
Fredi

[srinivas_durvasula]

Hi everyone, I have a AC unit also and sounds to me like what Fredi's problem was, I don't have the aptitude to learn about the electrical stuff and also the pressure is mounting from the family yo get it fixed soon. Yesterday there were high winds and rain and the Power went off 4 times briefly. After that I have been facing the problem that the outlsde blower unit in the condenser is not working. I treid to reset the Condenser unsit by pressing the reset button for high cut off pressure or something close to that, but it starts the fan but the fan is not turning on full speed and then stops after 10 minutes. Do you all think this is capacitor problem as well? IF you could also kinldy let me know how much this might cost for getting it repaired, I would appreiciate it.