Capacitor replacement

[Shane826]

Thanks to Wayne’s explanation of what a hard start capacitor does, I was able to fix the central A/C in my house this evening. New start/fan capacitor plus a hard start, a d we are nice and cool again.

[Bill]

Originally Posted by Wavery

Maybe Bill can be of some help there.

I'll try - and I have corrected a mistake I made above.

For anyone who wants to dig a little deeper into the kinds of capacitors in an air conditioner, and find out why you might have trouble replacing one, I found a good and simple explanation.

https://www.trane.com/residential/en...ch-a-big-deal/

It turns out that some of the terminology we have been using is wrong. The article explains that although simple ACs like our RV units have a "run" capacitor (as DanSTL noted), there is no such thing as a "hard start" CAPACITOR. So if you ask the parts counter jockey for a "hard start capacitor", he may not find one.

The story in the link also explains that there is an aftermarket item called a "hard start KIT", which is a capacitor plus a sensor plus a relay. Of course it is bigger than a capacitor alone. Some residential AC's have a built-in hard-start kit, but a simple RV air conditioner does not. This explains why you would have a hard time fitting a "hard start capacitor KIT" into an RV AC that doesn't already have one.

Note also that a "hard start kit" is not the same as a "soft start kit", which has some sophisticated electronics buried in it, as Wavery mentioned above. Confusin', ain't it?

I know. Nobody cares ... until they do.

Bill

[Shane826]

Interesting. Mine was literally just a hard start capacitor with jumper wires to wire it in parallel with the new start/fan capacitor.

Start capacitor was rated at 45 µF, hard start measured 413µF. That should be a serious kick in the rear end. Also had to replace some melted wires.