I am looking for an air conditioner that runs two ducts to a window. Who makes such a unit?

Hello, I am a typical lurker/reader but I am now writing because I have a question I hope someone can give me advice on. I was planning to fix my AC, but I have a fairly old AC home system so I decided to call a company this time. The outside unit was not working properly but it was not the fan so I figured it could be the capacitor or compressor - so, anyway I had the AC company coming and look at it. Long story short, the guy comes in, changes the capacitor, but as soon as he relatch the service disconnect outside the house, the unit goes for like 5 seconds, and then I have sparks in my electrical panel, and the breaker is gone. Now I connected to a different circuit breaker and it seems it's ok. My only question is: could a wrong capacitor do something like that? My capacitor had three push-up terminals on top, what the guy put in (and then removed) was a 5 one. I am happy to pay them for the diagnose, but they have been oddly defensive and I would like to get an understanding of what happened before I do. Sorry if my terms are not accurate- I do a lot of DIY stuff, just not so much in electrical. Thanks, Gabe