If it's getting hot enough to shut it down more than likely there is a restriction in the fresh water system. Maybe a pugged heat exchanger from debris or pieces from an old failed water pump impeller. If the water pump housing is worn (very common) badly, it won't supply water properly even with a new impeller. Did you physically take the impeller out and inspect it?
How new is it? If it is under warranty and you know for sure the water system is good, it could be covered under warranty.