Fan On Top Of Outdoor Central Air Unit Sometimes Stops Working

[Sichuan]

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
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.

 

[NFS4]

We have a heatpump and the unit fan doesn't always spin when the system is running. That's normal for our system.

 

[Sichuan]

We have a heatpump and the unit fan doesn't always spin when the system is running. That's normal for our system.

Thank you for your prompt reply NFS4. I would love to buy a heat pump and have both heating and AC in the same unit; however, a heat pump is not an option in northeast Ohio unless I want to install a secondary heating source.

 

[Modelworks]

Could be the fan relay. Inside the outdoor cover there will be a relay for the fan and another for the compressor. Ants and other insects love to make a home inside the relay. It is easy to check, usually when you see the fan not running, tap on the relay and see if the fan starts.

 

[Rubycon]

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
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.

You should definitely replace it with a more efficient unit!

If that outdoor (condenser) fan motor is the original and has not been periodically oiled you can count on its bearings being shot. WD40 is not a suitable lubricant! Use a light machine oil. If the motor does not have sealed (lifetime lubricated) bearings there will be two small caps on each end of the motor. Remove these and squirt some oil and replace. If you tug on the shaft and notice excessive play - say more than 1/4" up and down movement of the shaft - the bearings are excessively worn. In bad cases up and down movement of the shaft can be 1/2"!

The motor is a cheap fix to get you through the season, etc. "Rescue" kits are available with capacitors. These are universal and should fit the belly if the motor is mounted that way, for example. Many have a long shaft that will need to be cut down.

Definitely get some quotes on a new system. You have natural gas - look into a condensing type furnace. These are over 90% efficient! The AC units will also be much more efficient and quiet.

We have a heatpump and the unit fan doesn't always spin when the system is running. That's normal for our system.

Heat pumps have a defrost cycle. When this happens the fan will be off in order to raise the head pressure and make the coil get HOT to melt off frost and thin ice build up. This won't happen during the summer, however.

 

[Sichuan]

Thank you for the replies, Modelworks and Rubycon. The fan seems to be working fine since it was lubricated. I know I should have used a machine oil instead but I didn't have any at the time. I need the AC for only another two or three weeks and then the weather will cool down substantially. I'll buy a new AC unit next April or May and a new furnace before the end of next summer. I'll get them from a reputable local HVAC company/contractor, one with knowledgeable technicians. I'll spend a lot of time online researching the best models for my needs.

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?

 

[piasabird]

If the unit is 40 years old maybe a new unit will use less electricity. You should probably consider an upgrade.

I have been hearing commercials for a new type of Zone heating and cooling that Fujitsu sells. It is kind of anti-central Air. They claim it works better uses less ductwork etc. The concept is to cool off only the zones you want. For instance one zone could be lightly cooled and another zone could be more intensely cooled.

 

[T_Yamamoto]

If the unit is 40 years old maybe a new unit will use less electricity. You should probably consider an upgrade.

I have been hearing commercials for a new type of Zone heating and cooling that Fujitsu sells. It is kind of anti-central Air. They claim it works better uses less ductwork etc. The concept is to cool off only the zones you want. For instance one zone could be lightly cooled and another zone could be more intensely cooled.

They're trying to bring a Japanese concept to America.

In japan you separate coolers for each room. And so you can turn one on for a room that you want cool, while you can keep the others cool. My grandparents cooler/heater runs at ~9cents for every 2 hours you have it on, and it auto cleans as well ensuring that it lasts very long.

 

[Rastus]

If your unit isn't cooling like it should you probably should replace it at that age.

Save up, you've probably made it through this summer. Do it next spring.

 

[vshah]

wouldn't it make sense to buy towards the end of summer? or are aircon prices not seasonal?

 

[Sichuan]

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.

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.

 

[alkemyst]

don't overlook the contactor. This can corrode and cause problems. Being your unit is so old it's a hard call, but usually the motor is the last to go. It usually comes down to the relay, low freon (your's probably is too old to have a low charge shut-off), the capacitor, contactor, a fuses, or just a loose wire.

You'd have to trace the circuit to the motor and see where you are losing voltage.

 

[Rubycon]

Contactors are a sore spot but that would also affect the compressor.

Yank your shaft, if it has 1/2" of slop your ball bearings are bad.

 

[vshah]

Yank your shaft, if it has 1/2" of slop your ball bearings are bad.

quoted for awesomeness

 

[boomerang]

Thank you for your prompt reply NFS4. I would love to buy a heat pump and have both heating and AC in the same unit; however, a heat pump is not an option in northeast Ohio unless I want to install a secondary heating source.

Just wanted to point out that you already have a secondary heating source. You heat your home now with natural gas. That would be your secondary heating source with a heat pump.

 

[her209]

What/who are they a fan of? And they do need to take a rest from time to time.

 

[BUTCH1]

Contactors are a sore spot but that would also affect the compressor.

Yank your shaft, if it has 1/2" of slop your ball bearings are bad.

I had to replace my fan motor 5 years ago, it's supposed to be a sealed bearing unit but unless I oil it at the start of every season it starts squawking kinda loud..

 

[klod]

We have a heat pump, but had similar symptoms a couple of years ago. Called a service guy. He pulled the fuses first to kill the power, and then removed a small cover plate on the upper back corner of the compressor. Inside was the capacitor, about the size of a small soup can. He removed it and showed me how the bottom was bulged out. He replaced it, replaced the fuses, and now nice cold air. Good luck!