# what is the differnce between a 35/5mfd 440 vac dual run capacitor and a 40/5 440 and does anyone have the wiring diagram.



## Marty S. (Oct 31, 2009)

Capacitor don't have wiring diagrams but AC's do. Any chance we can get a hint on which one of the thousands of AC brands/models built that you have:whistling2:. Sorry just being a joker. Brand and model number will be needed though to get an answer. BTW I wouldn't put the wrong size capacitor in. What it came with is what you want to buy.


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## Neece (Oct 27, 2010)

the one that was on there was a gemtech 35/5 x 440vac and the new one is a smart electric but is a 40/5 x 440 vac.


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## SD515 (Aug 17, 2008)

The difference between a 35/5mfd capacitor and a 40/5mfd is 5 microfarads on the compressor side of a dual capacitor. The larger number is the rating for the compressor to use and the smaller is for the cooling fan. The difference of 5mfd for the compressor (between your old cap and the new one) is small. Personally, I wouldn't worry about it, but I'm not telling you what you should do. If you want to put in a 35/5 like your original, that's fine...but the 40/5 should work until you do replace it.

Did you look inside the access cover for a wiring diagram? Usually there is one, which should show you where that yellow wire you mentioned goes.


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## hvaclover (Oct 2, 2008)

There is a rule for sizing capacitors and it is called the Rule Of Twenty.

You don't exceed 20% of the original cap micro farad rating.


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## Neece (Oct 27, 2010)

SD515 said:


> The difference between a 35/5mfd capacitor and a 40/5mfd is 5 microfarads on the compressor side of a dual capacitor. The larger number is the rating for the compressor to use and the smaller is for the cooling fan. The difference of 5mfd for the compressor (between your old cap and the new one) is small. Personally, I wouldn't worry about it, but I'm not telling you what you should do. If you want to put in a 35/5 like your original, that's fine...but the 40/5 should work until you do replace it.
> 
> Did you look inside the access cover for a wiring diagram? Usually there is one, which should show you where that yellow wire you mentioned goes.


 I didn't look inside the access cover but I will. Thanks, I sure do appreciate it.:thumbup:


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## Neece (Oct 27, 2010)

Neece said:


> I didn't look inside the access cover but I will. Thanks, I sure do appreciate it.:thumbup:


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