Is A/C capacitor supposed to look like this?

May 04, 2010 61 Replies

Trane central air unit quit doing its thing (recently made another post about it) and I finally cracked open the housing.



Here are some pics - front and rear of a capacitor and a pano of the electronics. Am I mistaken or is the cap leaking stuff out that it's not supposed to be leaking? If so, under what heading in the yellow pages should I be looking for replacement pieces?



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Anything else you see that stands out as being obviously bad or suspicious? I can take closeups of anything you want a better look at.



Thanks for all input.


Look under > electric motor repairs< ww

5/370 should be the cap for the fan. Looks like the terminals are pretty badly rusted. GE had a bunch of bad caps. I'd be wanting to test that one for farads, and then replace it regardless of the reading.

I notice you have a big round cap (can't tell if it's double value, but at the moment it doesn't look like it) to the left.

You likely won't find replacement AC caps sold at retail. Might try "capacitors" in the yellow pages.

Yellow pages? How quaint!

Enter "air conditioning capacitor" + {name of your town} in Google.

Take the presumed defective one with you. Say "Gimme one of these" to the guy at the counter.

How do you know it's the cap? You have to start with the basics first. When you turn down your t-stat to turn on the A/C, the contactor should click closed. If it doesn't, you have to look at that first.

Guy at counter will ask for tax license, and proof of being in the trade.

Yellow pages may be retro, but they still work. Even when the power is out.

Actually the big horizontal fan at the top runs, the basic problem is the compressor isn't engaging. First noticed due to no "quish-quish- gurgle" in the freon line inside going into the air handler as should be happening. A few months ago when it was last fired up it was doing fine.

They are.

I did find a couple of dessicated dead lizards hung up in the electronics.

Thats crap..Just send me $100 in cash and I will send you one.

>

Don't they both use one capacitor?

Those are there to increase the joule value. Don't remove them.

Yes, this is the place, assuming it it the cap.

That fan run capacitor looks like the crimp on the top is damaged and leaking. Those things cost less than $10 around here. The start capacitor terminals and top looks burned from what I can see in the picture. That capacitor is less than $20 in this area. If you found critters in the control box, the circuit board could have been damaged and that's the most expensive item $60-$100. If you can't get an HVAC supply house to sell to you, try an electric motor sales and rewind company. Either supply houses will have a capacitor tester and most will be glad to test the capacitor for you. Dress like a working man and you may get away with it. If you show up wearing an Izod knit shirt, white shorts and deck shoes, the city sales crew might get suspicious. *snicker*

TDD

Some units use a dual value cap, but this one appears to be separate caps.

  1. So, wait for the next customer. Approach him and say: "I'll give you .00 cash if you buy one of these for me."
  2. The Yellow Pages DOES work if the power is out - but only half the time. It doesn't work, for example, during the night.

But, of course, the internet doesn't work at all during a power outage.

This latter can be overcome by a portable generator and WiFi.

Looks like a heat pump to me? Isn't that a defrost board?

Most hvac supply places won't give you much grief if you just show up with a cap and ask for a new one. Don't start asking them troubleshooting questions though. See if you have a johnstons, they carry a lot of stuff.

I think that's the fan cap though so while it might be leaking a bit it's not your main problem. Use a vom to check and make sure you have

240 vac on the downside of that contactor. You could try replacing the compressor cap since it won't cost you much. You need to observe it to see if it even tries to start. You can do that either by having a helper turn it on while you are there or push the contactor in yourself with an insulated screwdriver. It's ok to run the unit for short periods without the fan on top. You can tell when a compressor is trying to start as it will make noise for a few seconds and then quit. Compressors have thermal overload switches inside them so they cutoff after a bit if they can't start. It's a lot easier to tell what it's doing or not doing with the fan removed. With out gauges and other test equipment it can be difficult to fix hvac systems. You can try simply replacing the cap on the compressor but after that then you need to check the charge and possibly the current draw if it's trying to start. A hard start kit might help too.

Don't know about trade shops in your neck of the world, but here, in this economy, they don't care about who you are as long as you have money to pay for the items. Regarding the tax, here it is a VAT tax and they collect it from everybody, in or out the trade.

Come on Chris, not every one lives in New York. ww

Guy at the counter just don't want to deal with your sorry lame mormon ass.

Here's what I've found so far. The spade connector contacts on both the capacitors were highly corroded. I used a Dremel to grind off rust to get a clean contact surface.

The electromagnetic contact switch works, definitely engages. I hooked everything back up, put the top of the unit back on secured it with a few of the screws.

The top fan works so apparently that capacitor isn't bad enough to prevent that. As I was sitting by the unit after a few minutes I heard a humming noise that sounded like the compressor had momentarily kicked in but then stopped.

Further, on that circuit board there's a red LED that flashes while the unit is running.

Maybe if you were to take a crowbar to your wallet and called a *competent*, licensed, insured, professionally trained tech??

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