Home AC quit - capacitor???

2busy

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If the inside blower doesn't come on in the FAN only setting on the thermostat, The problem is inside the air handler unit and not the outside unit. The circuit board in the air handler is what controls the outside unit via the thermostat and transformer. Could be bad transformer, thermostat, thermostat wire, circuit board, no power to circuit board. Process of elimination starting with power to circuit board .

And to clarify, The fan only setting on the thermostat is for the blower in the inside unit. It has nothing to do with the outside condenser fan. My assumption when you said nothing happens when on Fan only was that there was no air coming from the vents.
 
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sh00ter

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Have you checked your contactor?
Not sure what that is or where.
The disconnect you have is also a fuse holder. The absolute very first thing I would check is the two slow-blow fuses to the unit.
Pull out the fuses using this handle here.

Us an Ohm Meter to check the continuity of the two fuses.

You also mentioned a clacking noise on a previous unit. That was probably the contactor which can go bad too.
Thx for the recommendation, the fact the inside fan will not come on from the t-stat makes me think the issue is bigger than just at the outside condesneor unless those fuses also control the inside fan?
I'm thinking a qualified service technician is going to be your best (and safest) bet.
Probably good advice
If the inside blower doesn't come on in the FAN only setting on the thermostat, The problem is inside the air handler unit and not the outside unit. The circuit board in the air handler is what controls the outside unit via the thermostat and transformer. Could be bad transformer, thermostat, thermostat wire, circuit board, no power to circuit board. Process of elimination starting with power to circuit board .

And to clarify, The fan only setting on the thermostat is for the blower in the inside unit. It has nothing to do with the outside condenser fan. My assumption when you said nothing happens when on Fan only was that there was no air coming from the vents.
Yes, it is the inside fan and outside fans that will not work at all, no air moving in house. I've had issue with the heater before and had to get a code off the circuit board in the attic, so I'll check that and see if it was any warning lights or anything (its a newer unit so it has this). Thanks!
 

John6185

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I had a lightning strike nearby and it blew a fuse out. It was obvious and I went to Ace Hardware and bought a new one...worked fine after that. The fuse wasn't in the condensing unit or circuit breaker, it was in the box near the outside unit. You can push the contactor with a non metallic tool, piece of wood etc. I wouldn't mess with the capacitors due to the electrical charge retained. There are two, one is round which is the start capacitor and the oval which is the run.
 
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Shadowrider

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I had a small tube type fuze on my control circuit board that would blow on occasion. Changing that always fixed it. Hopefully it not something on the board itself. Hope you get it up and running, today it's pretty hot.
 

sh00ter

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Thanks to another member who PM'd me, I think I have it figured out. The drain pan was full. I sucked out the water and the AC now works! I am going to under his advice, cut open the drain line in a specific spot and try and blow it out for hopefully a permanent fix. I will report back when it is all said and done or if not fixed.
 

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Thanks to another member who PM'd me, I think I have it figured out. The drain pan was full. I sucked out the water and the AC now works! I am going to under his advice, cut open the drain line in a specific spot and try and blow it out for hopefully a permanent fix. I will report back when it is all said and done or if not fixed.
I had completely forgot about the drain pan sensor. Used too they would have an aux drain that drain in a area that you would see it and alert you to the need to correct and it would keep running
 

Perplexed

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Thanks to another member who PM'd me, I think I have it figured out. The drain pan was full. I sucked out the water and the AC now works! I am going to under his advice, cut open the drain line in a specific spot and try and blow it out for hopefully a permanent fix. I will report back when it is all said and done or if not fixed.

What a heck of a fix… I’d never have thought of that!
 

Rooster1971

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I have changed hundreds of capacitors on AC units for the last 30 years. Never discharged one nor been shocked unless I didn’t cut the power off to the unit. Maybe I’m doing something wrong.
Glad you found the problem. It’s a pain to get the water out of the pan but beats the heck out of a ceiling falling in. Sometimes it still amazes me how much moisture the air can hold.
 
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dennishoddy

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I have changed hundreds of capacitors on AC units for the last 30 years. Never discharged one nor been shocked unless I didn’t cut the power off to the unit. Maybe I’m doing something wrong.
Glad you found the problem. It’s a pain to get the water out of the pan but beats the heck out of a ceiling falling in. Sometimes it still amazes me how much moisture the air can hold.
Agree 100% with your post. AC capacitors discharge themselves because they are AC.
DC capacitors on the other hand are an entire different animal.
They actually store current and need to be discharged manually by shorting between the poles with a shorting rod like a screwdriver for low voltage caps. (480v and below)
High voltage DC caps may require grounding rods that can be 8’ in length and flash suits to discharge.
Sounds like a high power rifle shot going off when the grounding rod gets close to the pole which generates an arc that is brilliant enough to cause vision damage if not wearing the protective gear.
Quite the experience to do that.
 
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