This, is a common issue with Air Conditioners.
Three common causes and usually the same repair fixes them both but one for the wrong reason.. That repair is described already and I'll not improve on his description (nor can I)
Why does it sometimes work for the wrong reason? Well I had that problem several times and finally figured it out.
1: Sometimes it is a simply matter of levelilng, The Carrier Air V "Drips" water off the rear of the water tray onto the roof. If the RV is nose down. Well the FRONT of the tray may be lower than the drip lip and it drips inside.
2: (Which is the one that drove me nuts) The intake filters inside the RV get dirty, as they get dirty air flow through them is reduced, the blower sucks mightly to pull air in for cooling and as the vacuum builds it starts sucking water out of the drip tray.. now you will hear a "Gurgling sound" with the blower running and if you do have towels and buckets ready when you turn it off because NIAGARA FALLS.
Why does tightening the bolts fix this: Well... When you remove the cover to access the bolts for tightening.. YOU CLEAN THE FILTERS.
Oh, WARNING:... I had two Carrier air V's.. Still have one.
Next time you are "up on the roof" Remove the cover.. Look at the plumbing near the compressor.. You will see where two pipes come out of the compressor and drop down into what looks like a plumbing trap (Actually it is a vibration trap and as such it is a very good idea)
Well at the bottom of the drop. on both mine. these pipes were touching, and vibrated themselves into a relighous state.. Yup, they got Holy (or is that holey) and let all the coolant out.. And that is why I now only have one of them left.
The solution is to spread 'em about 1/2 inch.