Learn me: central A/C repair

Turned on the home A/C for the first time this year and while the compressor comes on, the big fan in the top of the unit barely turns. It spins freely by hand. Google tells me the most common cause is the start/run capacitor, so I ordered one ($18) and installed it, but it made no difference.

Google tells me the second most common cause is the fan motor itself, which is $90.

Is there anything this could be other than the fan motor?

Thanks, learned friends.

Not knowing anything about fixing a central A/C unit, and presuming it runs off 110vac; I think I'd pull the fan/motor, wire up a pigtail to plug it into an outlet & see what happens before dropping $90 on a new motor.

I have over the years had to replace those fans in old York units.

What does it smell like? If the bearings are free the cap is good, and it isn't burnt I'm struggling for reasons a presumably brushless AC motor wouldn't run unless it's not getting power.

Have you checked for voltage with it running?

Check the fan relay, push it in, to see if the fan runs. If it does its the relay, assuming there is one just follow the wires from the fan.

Finally got some free time last night. The only relay I found was under the side cover where the cap was. I pushed it and the compressor came on, but the fan barely turned - just like when I start it from the thermostat inside.

Can't smell anything odd, but with my spring allergies I literally can't smell E36 M3.

The sticker on the motor says "208/230V," so I can't plug it into a regular wall outlet.

I will follow Kenny's advice and check for voltage. There's a wire from the cap to the fan, and another from the fan to the relay. There should be 230V there, right? I'll admit I'm a little concerned about playing with 230V, even with gloves on. If I electrocute myself, my wife will kill me.

Thanks, guys. The saga continues...

Do you have a meter? Play around and figure it out. If power is getting to the fan and it's not spinning, it's probably the fan.

Buy that stuff online, the markups for local distributors, if they'll even sell to DIY, is nuts.

You should have ~230V between those two wires, you will only find 115 measuring from each wire to ground, as household 230 is two 115 wires 180* out of phase, giving 230 between them. If you're worried, and if you're careful you shouldn't be, do this work with the wife behind you, holding a 2x4 or baseball bat to remove you from any potential problem.

Short version: it was the fan motor! Everything's fixed. Thanks, everybody!

Long version: 245V at the fan, so I ordered a fan motor, but the old blade assembly was rusted to the shaft on the old fan motor. Tried penetrating oil...tried heat...tried a three-jaw puller (courtesy of my friend at the FLAPS down the street)...tried pounding it out, but just mushroomed the end of the shaft and flattened my left thumb with a 4-lb sledge. So I ordered a new blade assembly. $18 for the capacitor, $95 for the motor, $60 for the fan assembly, but it works, and now I can get back to cars. Thanks, everybody!

Way to stay cool! A lesser man might have gotten a little hot under the collar.

My Mom "wrote the check" to a A/C place for what ended up being the same thing wrong with yours. Her bill was like two grand because she's foolish and listens to the "experts" who threw parts at it like it was fun.

Good job!

Kenny_McCormic wrote: do this work with the wife behind you, holding a 2x4 or baseball bat to remove you from any potential problem.

The mental image of this arrangement is not going away anytime soon

ps. give her an aluminum bat just to be funny.

bluebarchetta wrote: Short version: it was the fan motor! Everything's fixed. Thanks, everybody! Long version: 245V at the fan, so I ordered a fan motor, but the old blade assembly was rusted to the shaft on the old fan motor. Tried penetrating oil...tried heat...tried a three-jaw puller (courtesy of my friend at the FLAPS down the street)...tried pounding it out, but just mushroomed the end of the shaft and flattened my left thumb with a 4-lb sledge. So I ordered a new blade assembly. $18 for the capacitor, $95 for the motor, $60 for the fan assembly, but it works, and now I can get back to cars. Thanks, everybody!

I replaced the fan and motor in an AC unit 2 years ago, it was a DIY project I still get mad props for doing. Had the same deal trying to get the old fan off, just replaced it. Matching fan blade pitch and air volume to the AC unit is a bit of a science.

Pro tip: When the fan motor doesn't start on the condenser unit and it's the start or run cap, replace both, buy 'em from Amazon w/ overnight shipping and get an extra of each. Put the spares inside the condensing unit under the cover.

also, get one of these: http://www.amazon.com/Kool-Kap-Condensing-Protective-Across/dp/B00M4I1A1O/ref=sr_1_fkmr0_1?ie=UTF8&qid=1432885029&sr=8-1-fkmr0&keywords=a%2Fc+condenser+lid

this isnt the cheapest one, but you get the idea. it literally saves your crap from the rain, cuts the cleaning requirements down by half, and is worth every penny. you can even build one from a trashcan lid, a small hinge, and a cheap tiny bungee strap. just make sure it opens all the way when the fan comes on.

-J0N