AC Capacitor

Just a curiosity question. Seems like every year and a half to two years I have to have the capacitor replaced on the outside part of my central AC. Is this normal? I mean, do capacitors normally wear out this often?
I'm in central Texas, so the AC gets a lot of use in the summer. I think the outside unit is about six or seven years old.
Thanks,
8^)~~~~~~ Sue (remove x to email) ~~~~~~~~~
http://suzie-q-wacvet.com / http://intergnat.com/malebashing /
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wrote:

pulled and replaced it this spring. With as hot as it has been this summer, I'm glad I replaced it BEFORE it quit.
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Where are you located? I ask as it could be a problem with the line conditioning (or lack of) in the mains. We had a place out away from town that had a major plant on the same line. Their load reflected a major phase shift to our AC and until an active phase balance was set up on our leg we were blowing stuff (not just caps) all the time.
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wrote:

I live in a small subdivision inside the city limits. As far as I know, my neighbors haven't had this problem, but I haven't asked. I will!
8^)~~~~~~ Sue (remove x to email) ~~~~~~~~~
http://suzie-q-wacvet.com / http://intergnat.com/malebashing /
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On 7/17/2012 7:35 PM, Suzie-Q wrote:

A lot of the new capacitors are coming from China and I don't believe the voltage rating on the labels but I always replace 370vac rated caps with 470vac rated units as a matter of routine. When a rural customer has problems with capacitors failing, I often instal surge arresters on the AC equipment and it seems to mitigate the problem of damage to capacitors due to voltage spikes. Newer equipment often has some very expensive circuit boards in it that surge protection will help preserve. Always ask your service tech to install 470 volt rated capacitors when replacing a blown cap. You might also ask about surge arresters that can be installed on the AC equipment. There are some very good and inexpensive arresters that can be wired in to were the power connects to your outside AC unit and also the cabinet of the indoor air handler or furnace. ^_^
TDD
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On 7/17/2012 10:09 PM, The Daring Dufas wrote:

OOPS! I just realized, it's 440 volt capacitor not 470 volt. Silly me. ^_^
TDD
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What's a few volts, among friends? As hot as it's been, I'm amazed any of us are on the usenet lists.
Christopher A. Young Learn more about Jesus www.lds.org .

OOPS! I just realized, it's 440 volt capacitor not 470 volt. Silly me. ^_^
TDD
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On Wed, 18 Jul 2012 08:32:03 -0400, "Stormin Mormon"

The AC works (after $1500 for an evaporator and a day off work waiting around for the HVAC guy to get it right).
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On 7/18/2012 7:32 AM, Stormin Mormon wrote:

We were back in Tupelo yesterday, 300 mile round trip to get on the roof of the drug store to install an interface board in a Trane AC unit so it could hook to a standard thermostat thus communicate with the remote control energy management system. At least it wasn't so hot that any metal we touched gave us second burns. The last time we were there it was 105-107F in town. We're not working today [yet] because we're worn out and haven't received a call that the point of sale system equipment has arrived which we installed the network for earlier in the week. My hair hurts, my toenails itch and my eyeballs are squeaking. A sure sign I'm very tired. ^_^
TDD
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responding to http://www.homeownershub.com/maintenance/ac-capacitor-705073-.htm DA wrote: Suzie-Q wrote:

Which of the two capacitors or which side of the dual capacitor is failing - run or start? Were you testing them yourself or did the tech just tell you "the capacitor is bad"? What exactly was wrong, what type of a failure: loss of capacitance, a short or an open, did it just blow apart? They all have their own different reasons and knowing what exactly is wrong can help you find the issue with the motor(s).
For example, an open capacitor can be indicative of overvoltage or voltage spikes. If your replacement capacitors are 440V (or 370V), it may be helpful to install a 600V next time. A capacitor lifetime increases greatly if the operating voltage is further down from the maximum rated. You will more than make up the $30 difference in prices between 600V and 440V capacitors of the same value if you skip just one service call.
A short, a significant loss of capacitance or the mini explosion of a capacitor may be results of high peak currents suggesting either compressor hard start condition or capacitor value not matching the motors (fan and compressor). Perhaps you just need a different replacement capacitor next time. Or address the compressor pressure issues or install a hard start kit.

Temperature is also very important - lifetime of the capacitor halves for every 10C (18F) degrees increase in temperature. Not sure what you can do about it except of course verify that there's proper air flow through the unit, the coils and the cage are clean, no leaves or bushes, that sort of thing. A bad connector at the capacitor terminals can heat the terminal and subsequently the rest of the capacitor. Would not hurt to verify if all wires are secured. Would not hurt if the power is off and the capacitor is discharged, I hope you understand that.
Anyhow, just wanted to say that next time don't let the tech just throw the faulty capacitor out, find out what is wrong with it and fix the reason. 2 years is a very short lifetime for a capacitor, definitely not normal.
------------------------------------- /\_/\ ((@v@)) NIGHT ():::() OWL VV-VV
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Suzie-Q wrote:

Hi, Regarding caps. It better have same or higher W.V. rating and if value is not matched, bigger cap is better than smaller cap. ie, if cap is 5 mF,if same 5mF one is not available to replace 6mF is better than 4mF.
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There is no reason why a capacitor should not last forever. It must be inferior. Try another make or one of the same value in microFarads (?F) but a higher voltage.
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