Pianotuna; This one is absolutly false.
"Voids warranty on the furnace."
The 1974 Magnusson-Moss Act-Public Law 93-637 Section (C).
It is illegal for any primary product manufacturer to void the warranty when a 3rd party product is attached to a primary product.
I would be willing to bet Canada has a similar law of which you are obviously not aware.
If one wishes to upgrade from 30 amp to 50 amp for operating the larger BTU unit, where possible, it can be done for about $200. RV Comfort Systems will supply complete instructions to do so.