Hi,
If you HAD a bad converter, why are you so ready to get another one of the same brand? Like saying "I bought a saw at Harbor Freight and it only lasted 6 months, I want to get the same model and replace it as soon as possible"
Why not talk to the experts at a place like
http://www.bestconverter.com/WFCO-9865-65-Amp-Deckmount-Converter-MuCharger_p_44.html#.U2MMYFe9aws and see what brand they would recommend.
As far as installing it, most plug into a 120 volt receptacle, and then there are two large wires. Normally white will be connected to the - terminal and another color to the +12 volt side.
The problem is you don't know the amperage rating. If you look at your brochure for your RV, you might see a converter size. It probably is rated at 45 amps. You should be able to replace with a 55 amp if you like, the wiring should handle the potential extra 10 amps, but the converter will only put out what is being used and what the battery will accept.
I would also recommend that you have a battery charger - say one rated at 10 amps. This can be used when the converter is not working right. It will not keep the battery "Full" - however it can replace 240 amp hours daily and that likely is much more power than you would use in a campground, even with a lot of lights on and running the furnace.
Fred.