A/C Help

[MattCary]

Anyone here good with Home A/C?

 

Our outside unit's compressor fan is having "I think I can" issues when it's supposed to start.

 

The motor was replaced less than two years ago. 

 

When it "tries" to start, you can push the blades and the fan will then build up and run. Until today, now it won't.

 

We can't really afford to have someone come out and check it out. 

 

Is there a capacitor or something similar that could cause this by the motor not getting enough juice, or is the motor likely just going bad (again?) and needs to be replaced?

 

Any help is greatly appreciated as it's starting to get really warm in here.

 

[Guest 6.8 AR]

The capacitor is for the compressor. If the condensor fan motor is starting to die, replace it. Not much to do, but there

is a lot that will go wrong without it. Could also be the relay that switches power on and off to the fan motor, but I think

you would have other problems like the compressor not starting as well, also. That relay is usually the one that

handles both.

Edited June 12, 2013 by 6.8 AR

[2.ooohhh]

I generally replace my fan and compressor capacitors every other year as preventative maintenance. Some units have a single capacitor that services both.

[Dennis1209]

Could be a few things but try this first... If only two years old I doubt it's the CFM bearings but you have nothing to lose.

 

Take the top of the A/C unit off so you can get to the fan, then spin the fan and it should spin easily and freely. If it does not, it's probably the CFM (condenser fan motor) bearings or binding on the shroud. If it DOES NOT have sealed bearings, it will have 1-2 yellow oil caps that accept oil. If you have the yellow bearing oil caps, put a half dozen drops of oil in them.

 

If it's not the bearings, it's a little to complicated to describe troubleshooting in writing.

 

Could be you have head pressure control and your low on refrigerant.

Might be a bad CFM.

Might be a weak capacitor or electronic control?

 

Good luck!

[mikegideon]

Look at the wiring diagram. There could be a cap for the condensing fan motor. It may even be a dual capacitor that's shared with the compressor. The cap will be an aluminum can, and may show some swelling if bad. If the bearings are spinning free, it's either the run capacitor or the motor itself.

 

One thing I learned the hard way. Buy a fan blade with the motor. They're cheaper than the gas it takes to back and buy the replacement that you just destroyed trying to get it off the old motor.

Edited June 12, 2013 by mikegideon

[Trekbike]

I'm also guessing it's the capacitor.

[Guest 6.8 AR]

Come to think of it, mine has a smaller cap next to the large one. Guess it's for the fan motor, eh?

[mikegideon]

Come to think of it, mine has a smaller cap next to the large one. Guess it's for the fan motor, eh?

 

That's my guess. My unit is 20 years old, so it's on its 3rd set of capacitors and 3rd fan motor.

[Parrothead]

Sounds like the capacitor. You might be surprised how cheap you can get it repaired for at this time. Spring has been very mild. Lots of contractors are hungry and eager for whatever they can get at this point. Try calling the independents first if you are worried about price. I doubt the companies have dropped much.......

[MattCary]

Thanks, everyone. 

 

I know the motor is going bad, because the bearings are hanging up. But it's less than two years old, and I suspect it's a capacitor not hitting it with enough power that keeps killing the motor.

[K191145]

Anyone here good with Home A/C?

 

Our outside unit's compressor fan is having "I think I can" issues when it's supposed to start.

 

The motor was replaced less than two years ago. 

 

When it "tries" to start, you can push the blades and the fan will then build up and run. Until today, now it won't.

 

We can't really afford to have someone come out and check it out. 

 

Is there a capacitor or something similar that could cause this by the motor not getting enough juice, or is the motor likely just going bad (again?) and needs to be replaced?

 

Any help is greatly appreciated as it's starting to get really warm in here.

 

All motors except for 3-phase motors have capacitors, 3-phase systems are large industrial systems so you don't have that. It's definatly cheaper to replace the capacitor, I hope you didn't have to boost the fan to get it to run very long, that may be hard on the motor to run without a capacitor. Most motors have a start/RUN capacitor so it needs it to run also. Just use common sense if you try to replace anything, of course disconnect the power at the disconnect box outside and search for a company that sells and repairs motors, not an AC supply company because most wont sell to you unless you work for an HVAC company. Be sure to carry your old capacitor, probably a 5uf/370vac for a residential size condensor motor, you can go up to a 5uf/440vac but don't go down.

Hope that's all your problem, small capacitors should be only a few dollars unless it's a duel capacitor also supplying your compressor.

[DWARREN123]

Quite possibly the cap. Some units have one, a dual cap and some have two. Make sure to turn unit off before doing anything.

Hope it is cheap and easy to fix.

[mikegideon]

All motors except for 3-phase motors have capacitors, 3-phase systems are large industrial systems so you don't have that. It's definatly cheaper to replace the capacitor, I hope you didn't have to boost the fan to get it to run very long, that may be hard on the motor to run without a capacitor. Most motors have a start/RUN capacitor so it needs it to run also. Just use common sense if you try to replace anything, of course disconnect the power at the disconnect box outside and search for a company that sells and repairs motors, not an AC supply company because most wont sell to you unless you work for an HVAC company. Be sure to carry your old capacitor, probably a 5uf/370vac for a residential size condensor motor, you can go up to a 5uf/440vac but don't go down.

Hope that's all your problem, small capacitors should be only a few dollars unless it's a duel capacitor also supplying your compressor.

 

I buy over the counter from the biggest HVAC parts vendor in Nashville. They don't care who I work for. I normally don't pay folks to work on my unit.

[Guest 6.8 AR]

I replaced the compressor last time, instead of finding a new five ton r-22 unit. Everything else is still working,

thankfully. That's when I learned how to braze.

[Guest Riciticky]

Remove motor and run capacitor. If you don't have a hub puller, you will need a new blade or you can try working off the blade by holding the shaft with an adjustable wrench and turning blade until you can free it. There are set screws on the fan hub that you need to remove first. Take to Johnstone or CC Dickson and they will match it for you. Some motors will run for years and some go out in a year or two. If your motor will run with your assistance, then the capacitor is not bad but they can check it for you at the supply house. If you are gonna buy a motor, you might as well replace the capacitor as they are inexpensive. JMO. I have done this work for over 25 years both commercial and residential. I had an indoor blower motor that went out in a little over a year.

Edited June 13, 2013 by Riciticky