We replaced our AMFA pump back in 2011 when we were in Vanauatu, proved to be a very expensive exercise, only to have it fail again 2013. Old technoligy I'm afraid, the the plumbing method is used on every residence who are surviving on a rain water tank. I am not sure what the small Acumilator did that was mounted on the top of the pump itself, but we retained the 10 ltr Accumilator mounted behind the Quick Marine Boiler (Hot water system) that maintains a regular water pressure. We replaced the AMFA pump with a SPX Johnson Pump WPS 3.5. I managed to wire up the green light in the galley and the system has worked perfectly since.