The original water heater on my 1988 Pearson 27 (#150) died at the end of last season. It was a Raritan 6 gallon. After a call to them I learn that the replacement model 1700 series is not the exact same, so a "switch out" is not going to be the case. Is this something an amatuer can do? Has anyone replaced this with another make? Mine has the heat exchanger function and I wonder of that poses additional difficulties? Thanks for any help!