The copper pipes at the hotel in which I work have been springing leaking fairly frequently and the owner has decided if possible to convert the copper pipes to pvc pipes. But not throughout the entire hotel, only the main piping coming out of the boiler. First of all, is this even possible and second, how would I do it?

WHat size pipes are we talking?

2 inch and bigger, probably up to around 3 inches.

This is a bad idea... on so many levels. PVC isn't rated for the temperature of the application. Check the grade of the copper present. Look into conditioning the water in the system. There is a reason it hasn't been done already... at least I hope it hasn't.