One of the above posts suggest that accumulators are hard on pumps. I guess I would be a bit surprised that that is the case. I am not sure how an accumulator would affect the pump. It still sees pressure all of the time whether there is an accumulator or not. Indeed, I would think the accumulator might keep the pump from seeing any significant spikes in pressure when a faucet is closed.
AquaHot is very clear that you must put an accumulator in the water system. I suspect the issue is increased pressure as the water temperature in increased. I would think a normal water heater might have the same affect.
About accumulator to reduce pressure spikes is what it design for. Shurflo has a optional 2 gallon chrome tank available. My suggestion for larger tank such as 2 gallon tank or larger being not only act as a accumulator but a storage tank like we have in home with pump. It will allow longer time delay between cut-in to cut-out pump cycling. In other word, just when you turn water faucet while in high pressure mode...it will not pump until about 10% water is removed to lower psi.
My point is if these DC pump for RV are less reliable then home type system, then install small storage/surge tank to lower pump problem as well less power waste via fewer pump cycling.
Sojourn for Christ, Gerald