Fan On Top Of Outdoor Central Air Unit Sometimes Stops Working

cbmullenAugust 26, 2012

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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The problem could be a failing fan, capacitor, or both. The parts are not hard to replace if you know what your are doing. If not, you could electrocute yourself, or at the very least get a very bad shock.

In my opinion you should not spend money repairing 41 year old equipment. It is well past it's useful life. Many homeowners make the mistake of waiting until their HVAC system dies and then are forced to something immediately. Be thankful the AC is giving you a warning sign. Start doing your research for a new furnace and AC.

The brands which you should consider are Carrier/Bryant, Trane/American Standard, and Rheem/Rudd. Even those brands will be unreliable if they are installed poorly. It is important to find a reputable HVAC contractor who knows what he is doing.

    Bookmark   August 26, 2012 at 7:54PM
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Thank you for your prompt reply, mike_home. I appreciate the information. First, I realize how lucky I am that the AC and heating units have lasted for so long. I've lived in this house for only three years but before moving here the house was used as a model home and sales office so I assume the units were used much less than if a family had been living here for 41 years.

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. 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 imply the integrity of the unit and the knowledge 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.

Thank you again for your time and your assistance.

    Bookmark   August 26, 2012 at 9:04PM
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" I live in northeast Ohio so a heat pump is not an option."

Don't be too quick to dismiss a Heat Pump combined with a gas furnace.... I don't care how cold you think your neighborhood is, there are times when temps are in the 30s and 40s and 50s.

It MIGHT be economical to heat with electricity rather than gas in these circumstances.

follow this forum and you'll get an education in "doing the math" - but don't dismiss the notion of a heat Pump because of your Zip Code!

    Bookmark   August 26, 2012 at 9:21PM
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Thanks for the reply, saltidawg. I understand what you are saying and I do agree with you on the temperatues but I want a single unit. I don't want to use a heat pump for the higher winter temperatures and then have to depend on a gas furnace for the colder temperatures. Is it actually possible to use both a heat pump and a gas furnace and have the total combined cost of heat be lower than using a gas furnace only, considering the cost of natural gas as compared to the cost of electricity? I'm not doubting you; it simply never crossed my mind that electricity could be cheaper than natural gas.

    Bookmark   August 26, 2012 at 10:56PM
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I do have another question. The furnace ductwork in the basement is rectangular, including the cold air return, measuring 15"X08" with circular 06" duct going to each room. The rectangular ductwork is appx. fifty feet in length coming out of one side of the furnace and appx. fifteen feet in length coming out the other side. The circular ductwork coming out of it is appx. fifteen feet in length on each side. None of it is insulated. Is this size ductwork old technology? Should I replace it also? I know that insulated ductwork, both rectangular and circular is out there because I worked in the construction trades for almost forty years, mostly in the commerical and industrial sectors, and I've seen it everywhere. Should I go with firm or flexible on the circular duct? I think the firm would offer less resistance to the flow of air and be easier to clean if necessary. I can remove the existing ductwork and install the new ductwork myself since I'm retired and have all the time in the world. There's no question that I'll install the ductwork properly. Will different makes and models of furnaces require different shapes and sizes of ductwork?

    Bookmark   August 26, 2012 at 10:59PM
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You said, " I don't want to use a heat pump for the higher winter temperatures and then have to depend on a gas furnace for the colder temperatures."

I certainly can't argue that point as I do not know your reasoning. That said, I trust you do realize that the setup is seamless. You simply "tell" your thermostat once at what temps you want gas heat and what temps you want heat pump.

Set and forget.

    Bookmark   August 27, 2012 at 8:17PM
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With thermostat technology available now it is very easy to have full control of what type of heat you are using and when. The stats use an outdoor temp sensor and can be set to run the heat pump in one set of temperatures and the alternate source at other temps and also run one or the other or both depending on the temperature so you can get the best bang for your heating buck.

If its above 35 degrees my heat strips are totally locked out unless there is an unlikely defrost needed. If it is below 35 the stat will run the heat pump and stage in strips as needed down to I believe 10 degrees the heat pump is deactivated and it only operates on the heat strips until the temperature comes back up outside. This allows seamless control with no need to get up and make any adjustments other than picking the temperature you want inside the home.

The stat can still be manually set to emergency heat or auto mode just like the old systems.

If gas prices shoot up you can set the pump to run on down to whatever temp you want say 10 degrees or not even shut off at all. If gas prices drop you can have the heat pump locked out totally or at say 40 degrees.

It sounds like it might be worthwhile to check into or start considering upgrading the whole system but until then a fan motor and or capacitor isn't a massive undertaking or expense.

BTW at temps above 30 degrees a heat pumps efficiency really ramps up.

    Bookmark   August 27, 2012 at 11:41PM
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Hello saltidawg,

You'll have to excuse my ignorance. I wasn't aware that a single unit heat pump/gas furnace was available but as a result of your post I went online and discovered that they were. I haven't researched the issue as of yet but I will do so. I'm going to start another thread that deals with the issue to see if there are any people out there watching this forum who have had experience with one. I think I'll start a second new thread dealing with "instant on" water heaters as I'm going to replace my hot water heater also, which is currently a natural gas model. I'll be researching a whole house natural gas instant on water heater as I don't want to have to install one for each bathroom and one for the kitchen.Thank you again for your assistance.

    Bookmark   August 27, 2012 at 11:43PM
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As I read these posts i am thinking," I should have chosen the heat pump". I didn't because I'm getting a 96afue furnace. I put my $toward tankless water instead based on the prices I got for various configurations.

I just want to add that I have read here, and have researched it, that after May 1 of 2013 only 90afue and higher will be allowed to be sold in the north including NJ. This poster might want to consider that if he thinks he might want an 80afue furnace (if he goes heat pump he might want less eff furnace)

Do you experts think this change will raise or lower the price charged for high eff units? I was thinking raise, because people will be stuck with them and no option to choose a lower priced unit. If they need the heat they will have to pay for the higher eff and the contractors will just cite the changed law as an excuse for higher price.

Also, don't wait until it gets hot again to replace that a/c just because it seems to work in the spring....

    Bookmark   August 28, 2012 at 10:44AM
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"Is it actually possible to use both a heat pump and a gas furnace and have the total combined cost of heat be lower than using a gas furnace only, considering the cost of natural gas as compared to the cost of electricity?"


Heat pumps can give gas a run for its money at higher outdoor temperatures.

It depends on the cost of gas vs. electricity where the trade spot is.

    Bookmark   August 28, 2012 at 4:03PM
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Before you jump to tankless on the water heater Rheem/Ruud makes an electric heater with a poly (plastic) tank that has a lifetime warranty on the tank. I have one on order and other than replacing an element possibly in the future I look forward to not having to lug another leaky rusty heater up the basement steps.

As far as the combination gas furnace and heat pump with a smart stat its so seamless its hard to believe. When your laying there fast asleep and the temp drops below your set heat pump cut off it does just that and shuts off and the furnace fires up and it operates in whatever mode you have set.

Careful investigation of your electric rates and gas rates combined with rebates that might be available from both utilities is in order also. Some utilities sell the marathon water heaters at a discount which is something else to check on. I think I am saving close to 150.00 buying it from my utility as to home depot, lowes or somewhere else.

Here is a link that might be useful: lifetime water heater

    Bookmark   August 29, 2012 at 12:26AM
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Based on my two years of experience with a GE Heat Pump hot water heater I would not even consider an electric hot water heater with only resistive elements.

I have saved over $1000 in electric usage charges in twenty-four months. Additionally, the State and County gave me rebates as did the Power Co. Also, MD does not collect Sales Tax on heaters with COP of 2.3.

    Bookmark   August 29, 2012 at 9:59AM
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@saltidawg....I don't think OP is getting a water heater. I was saying I had to choose heat pump or tankless.....I have ng so an electric wh wasn't on the table.

Every time I read about a heat pump I wonder if I sould have gotten one. OP has a lot to consider.

    Bookmark   August 29, 2012 at 10:45AM
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I apologize I got mixed up on my water heater advice. I am considering adding a heat pump heating unit to the marathon so I need to pick salti's brain on his knowledge sometime in my own post or email.

    Bookmark   August 29, 2012 at 7:22PM
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If there was any way that I could reap the savings for myself, I'd buy all of my neighbors a heat pump hot water heater myself.

There is no way I could get that return in the stock market.

(No gas available here...)

    Bookmark   August 29, 2012 at 8:21PM
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