View Full Version : Replacing dual and single capacitors with new dual

May 18, 2009, 10:27 PM
My A/C unit went out about a month ago and the technician diagnosed the problem as a bad half of the dual capacitor (the fan side I think). He didn't have the correct capacitor to do a swap, but he did have one that he could install that he said would substitute for the bad half of the original. He installed the new capacitor and things went along fine until last Wednesday when, I believe, we lost the other half of the original capacitor (similar symptoms, intermittent buzzing sound, A/C stopped working). I ordered a replacement for the original dual capacitor and am preparing to install it myself only I'm not exactly sure how to do it. I'm assuming I can just move over the wires that are still connected to the original cap to the new one, but I'm not sure where the blue and yellow wires would go. I have included some images that I hope will allow someone to help me. The pic showing the blue wire is the new capacitor that was installed that I hope to remove. The other pic with the yellow, orange and red wires is the original capacitor that I want to replace. I have also included a pic of the wiring diagram. Thanks!

May 18, 2009, 10:47 PM
I can't see what I need to see, but I can offer this:

1. To use the separate cap, a wire was added
2. These caps have no polarity
3. The dual cap has a common and then markings for each value which is aparently 80 and 5 uf. It's important which cap goes to what device (compressor or fan)

1. locate the wires that go to the extra cap and the old cap that go to the same place. These wires go to common of the new cap, but since they originate from the same point, one can be removed.

2. Look at the value on the separate cap and find the terminal corresponding to that value on the new dual cap.
Move that wire(s).

3. Move the wire(s) from the remaining terminal of the defective dual cap to the unused terminal on the new dual cap

May 19, 2009, 06:25 PM
A dual capacitor will have three terminals: one designated "C", one "FAN", and one "HERM". The "C" terminal will usually be connected to the contactor, the "FAN" terminal will usually be connected to the brown, or "CAP" fan lead, and the "HERM" terminal will usually be connected to the "S" compressor lead.

May 20, 2009, 12:44 PM
Thanks guys! With your help I was able to get the capacitor hooked up properly. I know this because the a/c tech told me so... just as he was diagnosing my seized up compressor. Aarrrrrgh! And, silly me, I thought replacing the entire unit two years ago would give us some peace.