Start capacitor or fan motor.

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  #1  
Old 06-08-19, 05:31 AM
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Start capacitor or fan motor.

Woke up this morning to a cool house, BUT I noticed I could hear the system running (or at least blowing air around). Checked outside unit which was not running however a fair amount of heat emanating from it. Pulled breakers and set a box fan on it to cool down. When I switched back on compressor kicked in but no condenser fan rotation. Pulled the lid & fan off and flipped upside down and re-energized system after giving the balds a spin. Compressor and fan kicked on, although I am going to have to check again to see if the motor was in fact up to a full speed (I only let it run a few seconds before).

So, $64,000 question (or maybe $64 question): Any opinions on whether it's more likely to be the fan itself or the start capacitor)?

Does the fact the compressor kicks on okay indicate the capacitor is okay and fan more likely?

Any help appreciated as it'll be getting warm today as usual. Also, any "best bets" on where to get parts on a Saturday other than calling out a service guy?

Thanks. And I'll post system #s here in a minute.
 
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Old 06-08-19, 05:41 AM
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Okay, looks like I solved it. Flipped the lid/fan back into position and powered up. Fan did a start/stop/start and then ran okay (although sounding a bit labored) for a minute or two and then stopped. I'm diagnosing fan motor unless I'm wrong (been known to happen).

Now just have to find a motor on a Saturday: Emerson K55HXGCE-8094
 
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Old 06-08-19, 05:54 AM
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Test the capacitor with your meter. Could be the cap is weak and causing the motor to overheat and cycle on thermal.
 
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Old 06-09-19, 03:51 AM
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Yeah already done. Turned into a comedy of errors as they say. Short version, went to electric motor shop in town thinking they had Saturday hours. Nope, closed. The appliance parts place I know also would have had it I already knew was closed. Went to another appliance store just up the road and had the motor/capacitor discussion, unfortunately did not have the cap with me, only the motor. He said he has a motor, but why not try a cap first, they're cheap. So $15 and the 15 minute drive back home and I hook everything up. Starts right up but the first thing I notice is unit has some shaking going on, uh-oh. Fan runs maybe 30 seconds and quits, thermal overload from whatever ails in the fan internally I assume. Back to the appliance store, guy is out on a junk run but office lady says she'll get the motor from in back. Brings it out and I open the box - wrong motor. Only 1 other like item on shelf and it's a 1/4 vice my 1/3 hp. Now I'm mulling whether that will get me through and decide to wait on the boss to get back. He comes back we discuss the HP difference & had have just about decided it will get me through until Monday when i mention the cap and he says, oh yeah, wait. Yep, it will take a different capacitor. Looks in his supply and guess which one he DOESN'T have. Yep. No problem, he can have me piggyback a single cap, that he does have, in place of the fan circuit of the dual cap. THEN he says, but I have a better idea. His nephew is an ac worker, but is in a contractor class until about 4 pm. He will have all this stuff right on his truck. I'll leave a message to have him call you after 4 and he should be able to supply you with the parts. So I go away with the prospect of ac by evening. Never got a call and of course by then I am totally screwed as NOBODY is open ANYWHERE.

Lesson learned, should have been more proactive as soon as I found out there wasn't the proper parts at hand. Should have hit the computer and found one elsewhere even if it was in Tampa an hour and a half drive away. So now we are having a retro Florida summer weekend with the windows open and no ac until Monday. It's that or a weekend service call to have a tech come out and do a job I can easily do myself.

 
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Old 06-12-19, 05:15 AM
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Postscript

Okay, thought I would add a postscript to my adventure, might help someone in the future:

Got up bright and early Monday and went and picked up a replacement motor from the local (really good) appliance parts store. New motor is four-wire vs three wire, but hooked it up according to diagram on motor. Installed it and switched on power. Uh-oh, fan starts fine but seems to be running at about half speed. Head scratch time, was the replacement capacitor I installed bad??? Couldn't think of anything else and since they are reasonably cheap, ran out and got a different one and installed it. Fired it up, no change! Only thing I could think of was I was somehow losing 1/2 of the 220 power. Metered both sides and got 120. Dang! I am now on the verge of throwing up my hands and calling a pro, but as a last resort called my best tow buddy who is a treasure trove of minutiae for things like this. After a few questions he hit on the wiring differences and said, "take the brown wires OFF the capacitor". I argued back how will the motor start up without the cap boost? "Trust me". So I said, okay, last ditch, what I'll do is remove them alternately one at time and/or with neither connected and see what happens. [I know you HVAC pros are way ahead of me here]. Killed the power and popped the first wire off. Hit the power and VROOM, it is blowing air to beat the band and house cooled down FAST [perhaps more efficient ac with new/better motor; the old motor was NOT ball-bearing and new one is?]

If someone can give me the technical reason, in layman's terms, for the two cap wires and only one needed and/or what connecting both does or what the second wire IS used for, I'm all ears.
 
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Old 06-12-19, 05:32 AM
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First, your using the meter wrong. You don’t measure both conductors to ground. Measure across the circuit. You could have dropped a leg and the motor isn’t getting power.
Many motors can do a 3 or 4 wire connection. It sounds like it’s wired wrong. Did you put a leg of power to the capacitor? It should be stand alone for 4 wire connection. The ONLY wires on the capacitor should be the 2 brown capacitor wires.
 
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Old 06-12-19, 01:34 PM
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It's a dual capacitor, three terminals: common, fan, herm (compressor). Working fine in that hookup as long as I only have one brown wire connected to the fan terminal.
 
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Old 06-12-19, 01:43 PM
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And you should only have one.
Hooking both brown wires up to a duel capacitor is incorrect.
You didn’t reuse the capacitor did you? The cap should specifically match the motor.
 
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Old 06-13-19, 04:25 AM
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New cap. So is there a layman's explanation on what happens with both browns hooked up or what the second brown is for?
 
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Old 06-13-19, 05:00 AM
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The other brown is for the capacitor. But your unable to do that because your using a duel cap, which has a leg of power going to C.
You’d use both if you converted to a single capacitor.
 
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Old 06-14-19, 04:20 AM
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Aaaah, got it. Thanks.
 
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