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  • HVAC Question

    I have a general question.....last night got home and outside A/C unit not working.....open the panel and the contactor was not engaged....slightly pushed it and the fan tried to come on...looked at the capacitor and the top was pushed out.....called a friend who works at a local HVAC supplier and he got me a new one, put it on and everything's good.....So here the question: the unit is only 5-7 years old....what makes a capacitor fail and can anything be done to prevent or slow it down? Thanks!!!
    Poor Planning On Your Part Does Not Constitute An Emergency On My Part!!
    You can fire me...but you can't tell me what to do!

    Derek

  • #2
    Re: HVAC Question

    Originally posted by dcman View Post
    I have a general question.....last night got home and outside A/C unit not working.....open the panel and the contactor was not engaged....slightly pushed it and the fan tried to come on...looked at the capacitor and the top was pushed out.....called a friend who works at a local HVAC supplier and he got me a new one, put it on and everything's good.....So here the question: the unit is only 5-7 years old....what makes a capacitor fail and can anything be done to prevent or slow it down? Thanks!!!
    Buy a good US made capacitor. Aerovox is still in business. There capacitors used to be built like tanks. Don't know these days, no supplier around these parts carry them. Chances are the replacement cap your buddy installed was made in China and will last about 2 years on average. I've replaced two of the "bubble top" GE capacitors in the last two days. Both were between 7 &12 years old.

    Keep a spare on hand.

    James

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    • #3
      Re: HVAC Question

      dc, I replaced the cap in my two year old AC a little over a week ago. The suggestion I was given when I asked on here was to use a 440v capacitor rather than a 370v. Also, American Radionics makes one with a 5 year warranty.
      No, it's not rocket science, it's plumbing and unlike rocket science it requires a license.

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      • #4
        Re: HVAC Question

        That what I did today was put in a 440V....unfortunately there is only one HVAC parts store here....so I will have to go online to order something better.....

        And James P......I bought two for now.....

        thanks guys....
        Poor Planning On Your Part Does Not Constitute An Emergency On My Part!!
        You can fire me...but you can't tell me what to do!

        Derek

        Comment


        • #5
          Re: HVAC Question

          Always put in a 440v cap over any other voltage, according to my good friend and supply house owner. The voltage can always go up and give better insulation qualities but the mfd must stay within tollerance of course. I wish American made was still available here but Walmart mentality has well ended that.

          Comment


          • #6
            Re: HVAC Question

            Originally posted by dcman View Post
            I have a general question.....last night got home and outside A/C unit not working.....open the panel and the contactor was not engaged....slightly pushed it and the fan tried to come on...looked at the capacitor and the top was pushed out.....called a friend who works at a local HVAC supplier and he got me a new one, put it on and everything's good.....So here the question: the unit is only 5-7 years old....what makes a capacitor fail and can anything be done to prevent or slow it down? Thanks!!!
            sorry but I am a slow typer so this is what I posted at an other question:


            As far as the cause of a "blowed up" cap it is dirty power and or power surge... ever notice that you get several of these calls after a thunder storm?

            Also when you check the cap and it is say reading a little lower than the rated mfd it is ok if it is within the + - % (tolerance) rating of the cap (example: 50mfd @ + - 6% reads 48mfd its good because 6% of 50 is 3, get it?) better caps have a lower % rating.

            Also there are some really cheap made ones out there today that have water in them instead of oil. get the oil, "Mars" are good.

            Also you can use 440v on a 370v motor but not a 370v on a 440v motor (or compressor)

            Also use the "Turbo 200+" as a tool rather than a replacement i.e. if you don't have the right one on the truck put it on to get them running and next time you pass that job replace it with the regular size.
            ROMANS 10:9 confess with your mouth that JESUS is LORD and believe in your heart that GOD raised him from the dead and you will be Saved.

            Comment


            • #7
              Re: HVAC Question

              reasons for blown caps... compressor has a bad megohm reading stressing the cap but not blowing a breaker or fuse.. another reason tight cond fan bearings drawing high amps.. most likely cause low refer or poor heat load on a-coil causing liquid flood back... I would bet your 440v cap will also go bad then you will call in a pro to determine the secondary problem, hopefuly erreversable damage doesnt happen like acid contamination. You realy should call in a pro.

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              • #8
                Re: HVAC Question

                Years ago, capacitors and transformers, etc. were made with Polychlorinated Biphenyls (PCB's). In 1978, when it was determined that PCB's are carcinogens, they immediately removed them from all electrical components. Ever since then, Manufacturers have been faced with the dilemma of finding a suitable replacement. Since the PCB oils were used as dielectric and coolant fluids, the capacitors lasted for 30 years average. Now, you are lucky if a capacitor lasts 6-7 years, even on a new factory installed capacitor. When the viscosity of this replacement coolant begins to break down, and along comes a 95 degree day, good by capacitor. I guess it is just like anything else these days, nothing is as good as it used to be. But, at least it is job security for the Service Tech, right?

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