If anyone has knowledge in this matter, please help with suggestions. I had a JABSCO 3.0GPH fresh water pump with a small SHURflo 30psi accumulator. Now my understanding of how it's supposed to work is once the accumulator if full the pump shuts off. Pump turns on at system demand, correct? Well, it got to where the pump would not shutoff. I was told at West Marine the accumulator probably failed and to just remove it, don't need it. I bought a new JABSCO 4.0GPH water pump, removed the accumulator from the equation and the pump still runs continuously. The guy told me the pump shouldn't keep running. I have two wires, ground and power. Pump runs fine, but doesn't stop running. Do you all feel/think/know if I SHOULD have an accumulator back in the system? Thanks in advance.
The pumps were GPM, not GPH?
It depends on the design of the pump. On an accumulator, you have to have a check valve on most centrifugal pumps. If it is a low output, piston or diaphragm pump, you won't need a check valve. A check valve keeps the pressure in the accumulator when the pump shuts off. Piston and diaphragm pumps already have check valves as part of the pump design.
You have to have something telling the pump to shut off when it gets the accumulator tank charged to 50psi or something near that.
If your "guy" told you to buy a variable flow pump, they don't need an accumulator but run when you need water, pumping more water when you need more water or less to suit demand. They also extract a larger chunk of boat bucks from your wallet, and from what I hear, cause more problems.
Do you have a pump pressure switch? If not, find out where the old one went, or get a new one. Wire up the power into the pressure switch, and then wire the pressure switch to the pump. The pump will turn on when the pressure switch says there is less than 50 PSI (or whatever the low limit - cut-on limit is set) and when the pressure builds up to 50 PSI the high limit switch is closed which turns off the pump.
Some pressure switches are external, wired up outside the pump, and piped into the output of the accumulator so you get the tank pressure. If your pump has a pressure switch, (some do, some don't) then it senses pressure off the output side of the pump. This type won't work if you have the check valve between the pump and the accumulator.
Which Jabsco pump did you buy? Model # please...