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Old 06-10-2014, 13:53   #16
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Re: Freshwater pumps in parallel?

Sailorchic Clyde and a64pilot give best solutions.Clyde good one !

Repair centrifugle-observe the"how to"-Buy spare parts(in case )-reinstall centrifugle-Add T with pressure shutoff switch(no more washing machine residual filling)-For-ged - about -it !


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Old 06-10-2014, 13:55   #17
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Re: Freshwater pumps in parallel?

Sure you can run two pumps in parallel but it drastically increases the potential for failures and unless you install a manifold so you can shut one off while running the other, it makes the system more likely to fail.

A simpler solution is to install an acumulator tank downstream from the pump.

It's unusual to need 4gpm for more than a few seconds at a time. An acumulator tank can keep the system pressure up if 2-3 people wash thier hands simultaneously. Now if you need to run 3-4 showers simultaneously, it won't work.
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Old 06-10-2014, 14:03   #18
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Re: Freshwater pumps in parallel?

A single flojet par-max can provide 7.0 GPM. How much more water than that do you need?
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Old 06-10-2014, 14:28   #19
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Re: Freshwater pumps in parallel?

Most of the small pumps give gpm at 0 psig. for example for a par max plus pump has a 6 gpm rated capacity at 0 psig., At 30 psig it flows 5 gpm and at 50 psig it flows 4 gpm. Flow and pressure vary along the flow curve, more flow less head and visa-verse.

I expect with a 70 foot boat that the pressure drops in the pipe/hose will add up.

With two pumps in parallel, the OP will want to install valves up and down stream of each pump for servicing. A large accumulator would help the OP, but if two people shower at the same time, water will run out quickly.

The other thing the OP could do is rebuild/replace the original pump and install a pressure switch on the discharge of the pump to kick off the pump when pressures drop below 5 psig. That would prevent the pump from burning out. Of course you would need to install a bypass switch for the initial prime and pressurization, but that would save a pricey pump rebuild.
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Old 06-10-2014, 14:33   #20
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Re: Freshwater pumps in parallel?

Quote:
Originally Posted by sailorchic34 View Post
Most of the small pumps give gpm at 0 psig. for example for a par max plus pump has a 6 gpm rated capacity at 0 psig., At 30 psig it flows 5 gpm and at 50 psig it flows 4 gpm. Flow and pressure vary along the flow curve, more flow less head and visa-verse.

I expect with a 70 foot boat that the pressure drops in the pipe/hose will add up.
Good point...
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