Electric On Demand SEISCO water heater

Was trying to figure out age of a Seisco Electric Water heater. Found another website that says the first 2 numbers are the year of manufacture but that is obviously not the case - 1954 by that method.

The seller was pretty sure the unit was installed in 2004 when they did a major remodel so I can live with that unless someone has a better guess.

The thing that gets me is that, according to Seisco website, this model - RA-28 - runs at 28kw. That’s a lot of power. I=P/E tells me this thing can suck over 110 amps. It was hooked to a 100 amp breaker (200 amp panel) and it’s been that way since 2004. They had to replace the heating element about 4 years ago. Also a household of of a dozen people, kids & adults. Wouldn’t want that electric bill.

Any comments about age or size of breaker would be appreciated.

The Seisco website says a model RA-28-240 draws 60 amps X 2. See pg 6 of the User’s Manual for some complicated instructions for providing power. Looks like that model requires two 2-pole 60 amp breakers for a total of 120 amps at 240 vac. It says: