Fan On Top Of Outdoor Central Air Unit Sometimes Stops Working


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Old 08-26-12, 03:36 PM
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Fan On Top Of Outdoor Central Air Unit Sometimes Stops Working

I have an older GE outdoor central air compressor unit. I assume that it was installed when the home was built, around 1971. The fan on top of the unit sometimes stops working. I think it is the fan motor or a capacitor. Are these parts still available for sale and if so, are they hard to replace? The unit works perfectly at times but at other times the fan stops turning. The compressor seems to be OK since when the fan is turning I get cool air; however, when the fan stops turning I get air that is almost warm. I turn off the unit at the thermostat as soon as I notice that it's not cooling properly. The circuit breaker in the breaker box has never been tripped and I've never noticed an electrical burning odor. The outside temperature and the time of day don't seem to determine when the fan stops turning. It's more of a random occurrence. It can happen within minutes after the unit starts to operate or it can happen hours later after many on/off cycles. I don't see any dirt or obstructions on the cooling fins or any other areas of the unit. I sprayed WD-40 lubricant on the fan blade shaft today, where it enters the motor, and so far the fan continues to work. Could the solution be that simple?

Model # BTN936A100A0
Serial # 224362 709
Refrigerant 22, 09 LBS
Comp Mot 14.8 230V
Min Circuit Amp 20
Max Fuse 30 Amp

I suppose that it would be prudent to replace this AC unit, although the natural gas furnace in the basement (Whirlpool) that was also installed in 1971 continues to work flawlessly, although I'm sure it's not very energy efficient. What seems to be the most reliable outdoor central air unit for a single story home with appx. 1800-1900 square feet of living area? I live in northeast Ohio so a heat pump is not an option. I'm not looking for cheap but then again, I'm not looking for the most expensive model, because as we all know you get what you pay for.

Thank you for your time and any assistance provided.
 
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Old 08-26-12, 06:44 PM
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Several possible things could be wrong. If the motor often starts normally then it is doubtful that it is a capacitor problem. If it stops during the middle of a cooling cycle then won't restart until the fan motor cools down a bit it might be tight bearings causing an overload on the fan motor and causing the fan motor to trip on its internal overload device. If the fan sometimes fails to start along with the compressor then it is likely a failing centrifugal starting switch in the fan motor.

I sprayed WD-40 lubricant on the fan blade shaft today, where it enters the motor, and so far the fan continues to work. Could the solution be that simple?
Most of these fan motors have sealed bearings that are "lubricated for life" but I have never determined just whose life they are referring to. You might have oil holes on the ends of the motor housing and if you do then the fan should be oiled every season. However, if you have sealed bearings they would need to be replaced. Often it is less expensive to replace the entire motor than to just replace the bearings unless you have a fairly well-equipped shop and experience in these things.

Yes, the motor should be available and if not a factory replacement then an aftermarket substitution. Fan blades should also be fairly easy to find and because of its age it is likely that you would destroy the original trying to remove it from the motor shaft. Replacement is mostly removing the mounting nuts and bolts and disconnecting the wiring. Be sure to make a drawing as to where the wires go and if the mounting bolts/nuts are different sizes or lengths make not of which goes where.
 
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Old 08-26-12, 07:00 PM
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FAN01268
MOT03347

These are the replacement part numbers. You would also need a 5mfd capacitor.
 
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Old 08-27-12, 07:48 AM
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I would like to thank all of you for your time and assistance. I appreciate it very much. It's nice to know that so many people are willing to assist me with the problem I experienced. hvactechfw, thank you for the part numbers. Although I've decided to replace the units I could never have found the proper part numbers had I decided to replace the fan motor and capacitor.

I realize that I'm wasting a ton of money for such inefficient units, which is why I've decided to replace both the central air unit and furnace next year. I'll spend a lot of time online researching the various offerings by the different companies before I decide which models to purchase. I'm leaning toward Carrier, Rheem or Trane. I'll probably go with the same brand for both units if a discount is involved but the offer of a discount will not factor into my decision if the prodicts are not reliable. I'm not going to consider a heat pump because I just can't see how an electric heat pump with a standby natural gas furnace can save me money as opposed to a natural gas furnace only. It's hard to believe that heating a home with electricity can be cheaper than natural gas and it would involve the cost of two units as opposed to one unit. I would be dead and gone and converted to compost long before I could recoup the initial cost. I'm also investigating the zone units offered by Fujitsu and Mitsubishi but I seriously doubt that I will go that route because everything is already in place for a central unit. It's hard to make a decision because while reading consumer reviews of various products it seems that half the people say they're great and half the people say they're junk. I think many of those who call certain products junk have often selected a product that was inadequate for their needs, or have abused the product by ignoring the proper maintenance or have had the product installed by less than knowledgeable technicians who cared more about the money they made than the needs of the customer.

Having worked in the construction trades for almost forty years I am aware that support and service are very important and that you get what you pay for. I have a neighbor, an electrician, who gives all his business to a local HVAC company because of their service, reliability and quality of products. He recently purchased a Rheem outdoor central air unit from them and couldn't be happier. A big part of his decision was the company's service and the knowledge of the company's installers.

I don't want the most expensive model with the biggest energy savings because at the age of 62 I don't think I would ever recoup the additional cost; however, I won't search for the lowest cost either because as you know the quality of the unit and the knowledge/workmanship of the installer goes hand in hand with how much you pay. I'm going to shoot for something in the middle or 2/3 of the way up the ladder. The heat exhaust fan on the top of my current unit has been working fine since I lubricated the fan shaft so I'm going to let things stand as they are for the moment since I'll only need the AC unit for two or three more weeks before colder weather starts arriving. If it fails before then I'll simply handle it the old fashioned way and open some windows. I'll have a new central air unit installed sometime in April or May of next year and a new furnace installed sometime in late summer of next year.
 
 

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