My outside AC unit was not working the fan wasn't turning. So I changed the dual run capacitor and everything worked fine for about a month and now today it stopped again. Is something causing my cap to die or did I just get a bad cap. I have a Lennox unit model number 10acb30-9p. The voltage across the contractor seems to be good and my unit is and furnace filter is clean.

Please help I have a small baby and the heat has been unbareable at night for her to sleep

If you had a bad capacitor then it wouldn't have worked correctly in the first place. You say the fan isn't turning after you replaced the cap? Then I would look into the fan motor itself. You may be seeing voltage but if the motor is bad it just won't turn

The was not working I replaced the cap and it worked great for about a month now it is not working again.

If the last one you bought was a bad capacitor then it wouldn't have worked correctly after you installed it. (hence, answering your question of "...or did i just get a bad cap". If the fan isn't turning after you replaced the cap then I would look into the fan motor itself. You may be seeing voltage but if the motor is bad it just won't turn

There must be a misunderstanding of what I am asking. The AC was not working I replaced the cap and it worked for about a month. Now it is dead again the question about a bad cap was more along the lines of; did it just die as in I got a bad one that should have lasted a lot longer than a month, or is there some under lying problem causing my cap to die such as a bad fan or compressor motor over drawing current or something.

If anyone has had a similar issue I would love to hear about it.

Thanks for your help JWASKE but I found the problem today. I had two wires with corroded female spades connectors. A simple cut and crimp and it all back up and running.