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How I repaired my home air conditioning myself for less than $20

Updated on June 13, 2009

A dual run capacitor

Home AC Repair - Did it Myself

Ah, summer. Kids out of school, grilling in backyard, sweating to death because my AC died.

Yes, after a long winter, spring and summer have finally rolled around, and its time to crank up the AC. Time check out those air filters and flip that magical switch from 'heat' to 'cool'.

At least, that was the plan.

I came home on the first day of warm weather, and went about my usual routine in the house, let the dogs ot, steal something out of the fridge before the wife and kids got home, plop myself down on the couch and veg out for a few. However, I noticed something... It was hotter in my house than it was outside. I checked the thermostat -- it was set for 74 but the inside temp was reading 80. The blower fan was running, I could hear it. I checked a nearby vent -- yep, blowing warm air. No glorious frigid winds of respite, no relief from the sun's fury. Just moving air.

I flipped the unit off, waited a few minutes and turned it back on... Success! Cool air!

I went to bed happy that night, secure in the idead that my problem was a fluke, a gremlin in my hom air conditioning.

But I was wrong. The next day when I got home I had the same issue, everything blowing but no cold air from the vents.

I went outside and checked the compressor; the fa out there was running too, but the compressor itself was not. I could tell because the air above the unit was cool; when the compressor is running the air is warm. Also, there is quite a noticeable difference in sound.

I had a friend who had some experience in home air condition repair. I called him and described my problem, and he mentioned the possibility that my capacitor on the compressor had gone bad. Apparently these things can do that.  They used to last forever, but changes by the EPA in the materials they can use (they used to contain PCB, known to cause cancer) have resulted in capacitors that die out over time.

So, I went down and shut my compressor of at the breaker outside next to the unit.  This is very important, as I did not want to die. It was hot enough without going to hell.

I removed the service panel and saw my capacitor.  It was a 5-6" tall flask looking metal thingamabob.  It had 3 leads connected to the bottom.  My unit is about 15 years old, and probably should be replaced, but I had no intention of shelling out $5000 for a new system unless I absolutely had to.

I disconnected the capacitor(careful not to short the contacts, didn't want a shock)  and then with an INSULATED screwdriver proceeded to short the contacts on the capacitor safely to discharge an charge that was in there.  I saw stamped on the capacitor that it was a 45/5MFD 370 V.  Now, you don't necessarily need to know what these mean.  The MFD is the strength of the capacitor ( the more important number), the 370 being the voltage it operates at.  When you get a replacement make sure you get one that has the same mfd and at least the same voltage.  You can go higher on the voltage but not lower.  I would just be safe and get the same.

Now, in order to check and see if this was the actual problem, I took a multimeter with MFD settings and checked the capacitor.  Mine was a dual run capacitor and had 3 connectors.  It ran both the fan and the compressor.  The capacitor provides the "kick" that the compressor and fan need to start up.  If it gets too weak the "kick" isn't strong enough and the compressor or fan or both wont start.  I checked the fan side and the compressor side.  The fan side was okay ( the 5 in the 45/5, it needs less of a kick), but the compressor side was less than half what it should be (the 45, see).  So I knew then it was failing.  I hopped online and dug around for somewhere local I could get a replacement, but there were no AC Supply places in my area.  However, there is a Grainger store nearby.  I checked their catalog online and found a suitable replacement, called it in and went and picked it up.  All told less than a hour or so.  Headed out and plugged the new capacitor into the unit, careful to hook it up the same way the old capacitor was.

For reference, there are markings on the capacitor.  The center post is marked C, for common - that's the power- And the 2 on either side are marked F for fan and HERM for hermetic compressor.  There should be a wiring diagram on the service door or nearby that lists the color wire for either.  Dont get it wrong.  Take note which is which when you first remove the old capacitor.

I hooked everything up, closed the panel, crossed my fingers and turned everything back on.  Viola!  Success!  And cold air condition! And the part from Grainger cost me under $20!  Thats less than getting someone to come out and look at the unit, let alone fix it!  My ego was swollen for days after all that.

I'm not saying that your problem with AC will be the same as mine, but its something that is relativly easy and cheap to try on your own.  Of course, if you arent comfortable with any of this, then get a professional.  Capacitors can carry a charge and be dangerous if not handled properly.

But if you are careful, and go slowly, it sure feels good to fix your home AC yourself.

Not my video, but useful! Check your own Capacitor to fix your Home Air Conditioning!


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    • profile image

      greg 20 months ago

      Yup, this worked great. My AC was blowing, but the air wasn't cold. I took the capacitor out and ask the owner of my local U-Fix-It to test it. It was bad. New one cost $38 there (vs $12 on Amazon), but everywhere else was closed and I wanted a quick fix, so it was worth it! Whole job was really easy. Thanks for the tips.

    • profile image

      gene 2 years ago

      6 buck and fixed the issue, thanks for posting!

    • profile image

      Johne215 3 years ago

      I think this is one of the most important info for me. And i am glad reading your article. But wanna remark on few general things, The web site style is ideal, the articles is really excellent D. Good job, cheers dkfdgcggeecb

    • profile image

      Lil-J 3 years ago

      Hey just found your channel, I am going to do the things you have been suggesting I will let you know in a future post what happens. thanks for providing this info.

    • profile image

      thanks! 3 years ago

      Thanks so much! We knew nothing about a/c units, and were still able to follow the info you shared and fix ours! The capacitor was actually burned on one of the prongs, the wire had melted and burned, or something. We created a new end for the wire, ordered the capacitor for overnight delivery, and now it's all fixed!!!! Thank you again and again!!! XOXOXO

    • profile image

      jovusun 3 years ago

      Yeah, but just wait until the same over amping situation that burned up the capacitor burns up the compressor? Then who is the moose then? It gives the service guy a good chuckle when he sees that some newbie THINKS they know how to fix an A/C unit. The fix becomes real easy at that point...All you have to do is move the existing A/C unit over far enough to put the new one in it's place.....Some people never learn.....LOL

    • profile image

      thankful 3 years ago

      This article saved me AT LEAST a hundred dollars just for the house call! Thank you so much.

    • profile image

      Brian 3 years ago

      Thanks for this. My fan was kicking on when the temperature went above the thermostat temp. But I could tell the compressor wasn't humming. When I discharged the capacitor there weren't any sparks... and there was a fluid sloshing around on the inside of the capacitor itself. I don't have the expensive MFD multi-meter so I just had to hope this was the problem. Since the fan was getting power and working, I hoped the relay was fine... ;)

      I found the part at Grainger, but unfortunately they were closed on the weekend. Since this happened sometime Friday night we had to suffer a little until I could pick up the part today (Monday).

      However, once I got the part and shook it and heard no fluid sloshing around, I felt very good that I had the problem solved. After a 5 minute install process it turned right on and is working again. Only $30, which is probably 1/3 the cost of a HVAC guy making the house call, let alone finding the problem and fixing it.


    • onlygrace profile image

      onlygrace 3 years ago

      Wow.. nice share man. However, not many people have the same skill in electricity like you are. I do like to experiment things by myself, sometimes they work, sometimes they don't hahaha

      Yet I believe it's still worth to try fix AC by yourself, make me learn a lot. But if I have tried and I fail, that's the time I called professional technician

    • profile image

      Kendra 3 years ago

      Just wanted to thank you SO MUCH for this article. It was 85 in here today and climbing. We are scraping by with little to nothing and the ac unit quit working and we rent. Landord said when its out he wont replace it. We didn't have the money for sure. Bought the part on a whim and BAM cool air again. Thank you so much for this well written article!!

    • profile image

      Vincent 3 years ago

      What does it mean when the coils freezes up, and turning off the unit melts onto the basement floor?

    • profile image

      SteveD 3 years ago

      Thanks for saving me money, I appreciate it!! Nice and cool now. I respect trained workers, but if I can research and complete a simple task on my own, I will. What's next, Jovusu and Scott will want me to pay a "qualified" lawn service to cut my lawn too? Give me a break...

      Thanks again for the great post!

    • profile image

      RJK3 3 years ago

      Jovusun.....get over your self.

    • profile image

      Jovusun 4 years ago

      I had to laugh at the understanding of the technology. First of all, NEVER short out the terminals (not contacts) on a run capacitor. If the capacitor says "protected" on the side, it means it has a fuse built on it internally, and if it wasn't bad before it was shorted, it is now! Secondly, the capacitors don't short out due to the NON-PCB Dielectric Oil in them. Capacitors short out due to higher than normal amperage (meaning your compressor is working too hard) most likely due to dirt, as many homeowners only maintain their unit when it breaks. 8-o Keep replacing those run capacitors. They are only a symptom of the problem. It'll get you up and running for a while....until the compressor burns out! When an HVAC company charges $200.00 for a run capacitor, that pays for the Dispatcher, Accountants, CPA's, Attorneys, License Fees, Insurance, Advertising, Warehouse ,Vehicle costs, Technicians and many years of training and experience. Buying a capacitor over the counter also has NO WARRANTY, so for a cheap $20, you could possibly burn out the compressor and cost yourself thousands. Incidentally 370 volts is NOT the operating voltage. How many homes are wired for 370 volts? LOL Shorted Capacitors are not the problem, but rather caused by an underlying problem. How many people have had to replace A/C units because of half information?

    • jsadams64 profile image

      jsadams64 4 years ago

      Thank you so much for this!!! We followed your directions and bam cool air again.

    • profile image

      HockeyCoach 4 years ago

      You rock! Best internet explanation for a failing capacitor. They can work one day and not the next -- as in failing. Seems others explain it as either your system works or it doesn't -- not always the case. Now my AC system is given it all she's got -- cold as ice! Just 30 bucks!!!

    • profile image

      Julia 4 years ago

      Hi, nice tips. Well, I was just searching this exact post. I had the same problem with my A.C.. Now I could save my money and can do shopping for the season.


    • profile image

      Luke Taylor 5 years ago

      You're great dude. Thanks for explaining nicely the completely procedure you've been through to repair home air conditioner. $20 is a great rate indeed to repair such type problem of AC. Goo job! Keep up...

    • profile image

      slimgym 5 years ago

      maybe, this is why mine never seems to run right. You just saved me a couple bucks from hiring someone. Thanks!!

    • profile image

      scott 5 years ago

      Find a NATE certified contractor and you won't be wasting your money. There is a reason we are in business and that's because we know what we're doing. You don't see me doing your job so let us do ours, some times it is the simple problems like that but others you have a bad compressor, motor or a leak.

    • profile image

      deborah 5 years ago

      My ac is blowiwng cold air and we're in november, i need heat any ideas, just put in a new thermostat

    • profile image

      Luis 5 years ago

      Thank you so much for this article. I did exactly as you did and got my AC up and running in no time!

    • profile image

      brenda 5 years ago

      im dieing of heat in my home...i noticed my air was on but not as cold as normall,,went to basement seen the water puddle to floor drain .fan runs but real low,,but its cooled air,went out side and cleaned my airbox out side very well! put back to gether and still cold air is blowing but barly, is it the fan and what do i do to make sure it is

    • profile image

      Darlene 5 years ago

      My capacitor goes out once a year :( i just stockpile them from grainger. thankyou for the article!

    • profile image

      hot 5 years ago

      I love the way you write. The voice of your explanation comes to life...thanks for the information.

    • profile image

      vince 5 years ago

      Thank u so much. Even though i had to pay a bit more(30) to a service guy because it was after hours. It saved me quite a bit. Now i have a cool house again. Thanx again!

    • profile image

      jim t 5 years ago

      just replaced it myself. AC is ice cold!!! THANK YOU!!!!

    • Lisa Combest profile image

      Lisa Combest 5 years ago

      This article totally rocks. We got home yesterday to a hot house. I Googled the issue and your article was at the top of the list. I read it, discussed with the hub and we decided to give it a go. Come to find out, our capacitor was completely fried. It barely registered on the meter. We changed it out, after buying the part off of an A/C guy we stopped at a red light and Voila! COLD AIR. Thank you for putting this out there. You saved us an other folks a lot of money. Rockin'

    • profile image

      New_to_ac 5 years ago

      Did exactly as you specified and saved me $250. $19.55 for new capacitor (with tax).

    • profile image

      greenmatt 5 years ago

      Just replaced my capacitor as suggested and saved myslef lots of money. Thanks for the article. You can also tell a capacitor is bad by the bulging top and bottom . The top and bottom should be completely flat and will bulge when bad.

    • profile image

      Mark 5 years ago

      An a.c. guy told me that my blower motors pcm board was shorted out and that i need a new motor. i see online in the parts list that there is an ecm board for much cheaper than a motor.are they the same and can i just change that?

    • profile image

      Bount 5 years ago

      My fan and compressor works good for few hours then it blows out hot air when its overheated.

    • profile image

      floyd matthews 5 years ago

      fan not working and compressor is not working is capacitor out.

    • profile image

      Philip 5 years ago

      That is what happened to me about 9 years ago.

      Today my capacitator died! I cant believe its the same thing.

      The technical put the multimeter between the two leads and it read ZERO. That mean open circuit and that is bad!

      I have to shell out $280 for everything. It includes the $50 fee for them just ocming.

      I am mad! I will put this in my google calendar to remind me once a year!

    • profile image

      noriah 5 years ago

      how to repair my air-condition leaking

    • profile image

      One needs help 5 years ago

      Great article. It is simple and sompletely straight to the point to help a novice like me. It saves me $$$ too. Thanks a bund. Dbn in Houston, Texas.

    • profile image

      edib redzic 6 years ago

      please let me know what i need to do my compresor in back of my house non-stop running never stop and in -inside hose is evrything ok thank you for your support in this mater.

    • profile image

      june lee 8 years ago

      if you ever need capacitors,let me

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      Miguel 8 years ago

      I'm 100% agree. I had the same problem but I read this article just after getting a professional.Any way the problem was exactly same if I read this before I'm sure I can do it.Thanks