Water Pump Issues

Purchasing a boat that currently has a 3 year old Jabsco Vflo 5.0 (model: 42755-0092) that feeds a galley sink, head sink/shower and cockpit wash down - none of these demand water simultaneously. There is no accumulator tank. When water is called for, the pump pulses constantly and so does the water pressure coming out of the faucet. This just doesn't seem right and as I read more about this pump, just about every buyer seems to regret their purchase.
Is there a recommended pump that will provide a nice even flow without an accumulator tank? Any suggestions would be most welcomed.

Jmreim said:

Purchasing a boat that currently has a 3 year old Jabsco Vflo 5.0 (model: 42755-0092) that feeds a galley sink, head sink/shower and cockpit wash down - none of these demand water simultaneously. There is no accumulator tank. When water is called for, the pump pulses constantly and so does the water pressure coming out of the faucet. This just doesn't seem right and as I read more about this pump, just about every buyer seems to regret their purchase.
Is there a recommended pump that will provide a nice even flow without an accumulator tank? Any suggestions would be most welcomed.

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You could add an accumulator to even out the pressure flow, even though it's not really recommended by the manufacturer. We went thru 3 variable speed pumps, and I finally replaced the 12V pump with a 120V Headhunter Mach 5. Excellent pressure and no more variable speed.

+ 1 re what Pau Hana said. We have the 110v AC Headhunter Mach 5 with an accumulator. Works beautifully.

I highly recommend an accumulator. Evens out the flow and promotes longer pump life.

I went the other way. My headhunter started to leak, and the manufacturer advised that it was not repairable, but that they would sell me a new one for $1200. Instead I bought a Jabsco. Pumps just as well, but is noisier. I kept the accumulator tank to even out the flow.

If you like the idea of saving the space that an accumulator tank takes, consider a Shurflo Aqua King II. It is not a variable speed pump but it has an internal bypass that returns excess water to the intake side of the pump. This allows the pump to run at full speed even if you just crack the faucet a little bit. You don’t get the excessive cycling you would with a regular pump without a tank.
https://www.pentair.com/en/products...r-delivery/aqua-king-ii-fresh-water-pump.html

I'm guessing your resistance to an accumulator is the size and cost? In my old boat we added a small sureflow accumulator to even the flow, it worked great and took up very little room. There are several choices for less than $100 that are compact and as long as you're not running multiple outlets at the same time they help a lot. It might be cheaper than buying a new pump. We have a large accumulator on our current boat, really isn't that much better than the small one unless multiple people are using the system at the same time.

A variable speed pump doesn't need an accumulator and shouldn't pulse. Maybe there is something wrong with the pump.


Open all faucets at once to see if the pulsing continues. If it does, I strongly suspect it is bad. If it doesn't, then maybe there is an accumulator in the system that is causing the pump to pulse. Check and remove it if so.


David

A little history. A few years ago both a Jabsco and Shurflo came out with variable speed water pressure pumps. Both had problems.

Shurflo quickly gave up on variable speed and went to by-pass pumps to accomplish the same thing. Not quite, it is noisier than a variable speed pump. It does eliminate the need for an accumulator tank.

Jabsco stuck with the variable speed and came out with new improved models. Sounds like they may still have problems.

If there is an accumulator tank in the system with a Jabsco variable speed pump it can cause the pump to act as the OP described.

I’ve wondered if a water system made of flexible hose doesn’t fool the pump into thinking there is an accumulator in the system. A hard system, like Pex, probably wouldn’t do that.

If you have the space and access to 110VAC, consider a Grundfos MQ-3-35. Plenty of steady pressure and volume with no accumulator tank. We went through three 12 volt pumps until happening on a recommendation for the Grundfos. Cost is about $650 but it will be the last pump ever bought for this boat.

Thx - i’m a bit confused by numerous suggestions for a 110v AC pump. Since I have no genset, that would mean I have no running water when not tied up at the dock. I do have an inverter but wouldn’t that be a very significant draw?

Jmreim said:

Thx - i’m a bit confused by numerous suggestions for a 110v AC pump. Since I have no genset, that would mean I have no running water when not tied up at the dock. I do have an inverter but wouldn’t that be a very significant draw?

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I'd stick with 12 volts. Otherwise needlessly complex systems ensue.

Jmreim said:

Thx - i’m a bit confused by numerous suggestions for a 110v AC pump. Since I have no genset, that would mean I have no running water when not tied up at the dock. I do have an inverter but wouldn’t that be a very significant draw?

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Not necessarily. We anchor out often using the inverter for AC loads as most boaters do. The 120VAC pump is a significant draw but only briefly. We do have a large house bank (932 amphours, nominal) that after 18 hours is generally 50% depleted. Five hours of steaming gets the house bank back tp 100%. Extrapolate from that if you wish.

catalinajack said:

Not necessarily. We anchor out often using the inverter for AC loads as most boaters do. The 120VAC pump is a significant draw but only briefly. We do have a large house bank (932 amphours, nominal) that after 18 hours is generally 50% depleted. Five hours of steaming gets the house bank back tp 100%. Extrapolate from that if you wish.

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"Most boaters do"? Not in my personal experience. Inverters and large house banks are terms bandied about here like everybody has them, but that is far from true IMHO.

rgano said:

I'd stick with 12 volts. Otherwise needlessly complex systems ensue.

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Complex as in?

Whether 12 or 110 volts, the watts consumed should be about the same. JMR, assuming you buy the boat, take your time to assess the optimum way to suit your particular circumstances. Several good suggestions are tabled here.

“Whether 12 or 110 volts, the watts consumed should be about the same.”
The problem is that the inverter is drawing 2 amps continuously while at idle. At least in my case.

Should the house batts be low most inverters will cut off.

So you are out of water.

A DC pump may not be happy at 10v , but it will pump water.

The continuing problems I've had with jabsco products has led me do not buy any of their pumps including bilge pumps and switches. They usually work okay at first but they do not last long.. I think if it can be made cheaper jabsco to knows how to do it

Okay. How about many instead of most? Geez, do you have any more nits to pick? And, I certainly did not say or even imply that lots of folks have large banks. I just gave one example, my example, as a point of reference. I even said, extrapolate IF YOU WISH. Why are you trashing a guy who is simply trying to help with providing an example of something that works? Did I provide any bad information? I don't think so. So, tell me, of what added value was your comment?

rgano said:

"Most boaters do"? Not in my personal experience. Inverters and large house banks are terms bandied about here like everybody has them, but that is far from true IMHO.

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FWIW I've had decent luck with a Shurflo pump, four years on the last one. The only thing I didn't care for was the off on off surging as the system (with accumulator) neared the high pressure cutout. Bypassing the integral switch and replacing it with an irrigation pressure switch eliminated the surging.

Jabsco Variable Pressure FW pump

Fitted as OEM on 2004 Nordic. Replaced by PO before 2016. On fritz 2018. Replaced with brand new spare. Worked well for a week. Got refund for the spare. Research said these units are unreliable. Replaced with Johnson Uno - regular pump with accumulator tank. Problem solved.
best
NornaJ

Added and adjusted a 30-50 water pressure switch to a Jabsco pump. Pulsing fixed.

Shur Flo Pumps

Had several vari flow pumps of 5.5 gal flow rate, one lasted eight years and I sold the boat with it still running, put another one in a different boat and it is running on six years . Was nervous about the bad press these pumps gathered so I bought spares, probably why they worked so well.