I am not a water heater specialist; however, we have Helia #4 and I, as in
DIY, had to replace the hot water heater 30 months after
delivery. When our Helia was delivered, the hot water heater did obtain power through the inverter. Yes, I am sure about it; no, you definitely don't want your WH powered through the inverter.
We replaced the water heater because there was a very small leak in the engine/WH
heat exchanger that allowed pressurized fresh water from the tank to come into the
coolant side of the
engine. The symptom was a very slow leak from the
engine coolant reservoir. We thought at first it was an engine
heat exchanger problem, wrong. The water heater was still under warranty; however, Indel will not honor the warranty until you ship in your old heater. Not worth it from most places we go cruising.
We find the hot water to be quite sufficient for all our hot water needs. I have never contemplated adding a second. Between engine time and
generator time for
charging or Aircon, we very seldom start the engine for hot water. There is an adjustable valve on the WH that mixes cold water with the hot water in the tank when dispensed. I would suggest adjusting this otherwise the water coming out of the tank could easily burn someone if you accidently bump the
shower faucet to full hot. This happens in small showers.
The last thing I'll discuss is we have had 3
leaks in the red flex fresh water water pipe all within 1 foot of the hot water heater. The problem is that every time this has happened; the engine has been running, we are motoring and the
bilge pump alarm is the alert method. The
leaks are all tiny pin holes. The first time 1 inch away from the WH; fixed with just cutting off an inch. The second time again 1 inch from the WH; I added a 4 inch
repair piece. The third was 1 inch onto the original red flex pipe; this time I cut out a 6 foot piece. The original red flex has a larger ID than the flex pipe I have found in any
chandlery. This means that a
repair piece will not
work with the fitting from FP that comes on the tank. I would suggest everyone buy the Whale type fitting that will allow you to use any 15 mm OD pipe coming out of the WH.
Sorry about the long post. Thought I would share some of my WH stories.