I don't believe an accumulator was a stock item on Ericson's. I installed one on mine and it works but I don't know if is worth the expense and effort.
I was reading something in Nigel Calder's book on marine diesel engines and there was something in there about making sure the pressure cap on the tank and the pressure cap on the engine are the same rating. (Or one of them could be lower, but I don't remember which one; the book is on the boat right now...)
The one on my boat is definitely connected to the engine.