freshwater pumps that don't work

[TooCoys]

I skimmed the thread so I'm not sure if this was addressed, but our problem with our fresh water pump is that it "pulses". When our last pump crapped out, we told our guy "not to skimp on the pump." What I mean was that I wanted a good quality, heavy duty pump from a reputable company. I believe he took that to mean "put the biggest pump he could find" in.

Now, while showering for instance, the pump will pressure up and shut off for a few seconds, and then start over. This leads to a hot/cold/hot/cold/hot/cold shower. We've learned to deal with it for now, but I have aspirations of changing the pump out soon, for something more suitably sized.

However, I don't know what size that should be. Thoughts?

We're a 40ft boat with the galley, two heads, an ice maker, and a wet bar on the top deck - so 9 outlets all together.

[rslifkin]

Originally Posted by TooCoys

I skimmed the thread so I'm not sure if this was addressed, but our problem with our fresh water pump is that it "pulses". When our last pump crapped out, we told our guy "not to skimp on the pump." What I mean was that I wanted a good quality, heavy duty pump from a reputable company. I believe he took that to mean "put the biggest pump he could find" in.

Now, while showering for instance, the pump will pressure up and shut off for a few seconds, and then start over. This leads to a hot/cold/hot/cold/hot/cold shower. We've learned to deal with it for now, but I have aspirations of changing the pump out soon, for something more suitably sized.

However, I don't know what size that should be. Thoughts?

We're a 40ft boat with the galley, two heads, an ice maker, and a wet bar on the top deck - so 9 outlets all together.

If you don't use more than 1 - 2 faucets at a time, something in the 3 - 4 gallons per minute range should be plenty. I'm happy with a 3 gpm pump on my 38 footer, but it's rare that we use more than 1 faucet or shower at a time (and I rarely even turn the shower all the way up).

[TooCoys]

Thanks! We don't ever use more than one faucet at a time. There's only two of us on board.

[belizesailor]

Originally Posted by TooCoys

I skimmed the thread so I'm not sure if this was addressed, but our problem with our fresh water pump is that it "pulses". When our last pump crapped out, we told our guy "not to skimp on the pump." What I mean was that I wanted a good quality, heavy duty pump from a reputable company. I believe he took that to mean "put the biggest pump he could find" in.



Now, while showering for instance, the pump will pressure up and shut off for a few seconds, and then start over. This leads to a hot/cold/hot/cold/hot/cold shower. We've learned to deal with it for now, but I have aspirations of changing the pump out soon, for something more suitably sized.



However, I don't know what size that should be. Thoughts?



We're a 40ft boat with the galley, two heads, an ice maker, and a wet bar on the top deck - so 9 outlets all together.

Sounds like an accumulator tank issue. Whats your configuration?

[TooCoys]

Originally Posted by belizesailor

Sounds like an accumulator tank issue. Whats your configuration?

I don't think we have an accumulator tank. Although I must admit, I have no idea what an accumulator tank is. As far as I'm aware, our pump is connected directly to our holding tanks.

I have no documentation from either the mfg, or previous owners surveys that mention an accumulator tank.

[belizesailor]

May be a good time to get familiar with your system. Short cycling, like you describe, puts more wear on the pump. An accumulator tank holds a quantity of pressurized water to reduce short cycling of the pump (also solves some other problems too).

[Simi 60]

We have gone through several accumulator tanks over the years.
Full time cruiser not being near shops and had hack of buying crap that fails I had to mcgyver a replacement
1.5 litre soft drink bottle, a t piece to suit water hose and a hose and clamps to suit neck of bottle and t piece
Stand bottle in upright position and we were good to go.
Been working well for a couple of months now and no bladder to burst.
Made from rubbish and bits in the spares bin.

[torrmundi]

Anyone notice that the Jabsco/Xylem Vflo 5.0 is a discontinued item now? Most online sites, including West Marine, no longer have stock. The closest replacement is the Floject R4426-143A, which looks almost identical.

[wingssail]

Originally Posted by Simi 60

We have gone through several accumulator tanks over the years.
Full time cruiser not being near shops and had hack of buying crap that fails I had to mcgyver a replacement
1.5 litre soft drink bottle, a t piece to suit water hose and a hose and clamps to suit neck of bottle and t piece
Stand bottle in upright position and we were good to go.
Been working well for a couple of months now and no bladder to burst.
Made from rubbish and bits in the spares bin.

Simi, could you explain how this works? Seems like when the pump comes on the water flows into the bottle (along with the existing air in the bottle) until the shut off pressure is reached. With the neck of the bottle up doesn't that let pressurized air to come out first when you next open the tap? And surely there must be some air present because water is not compressible so how do you keep some air after a few cycles?

[Simi 60]

Originally Posted by wingssail

Simi, could you explain how this works? Seems like when the pump comes on the water flows into the bottle (along with the existing air in the bottle) until the shut off pressure is reached. With the neck of the bottle up doesn't that let pressurized air to come out first when you next open the tap? And surely there must be some air present because water is not compressible so how do you keep some air after a few cycles?

Bottle in upright position but facing neck down
Water pushes 3/4 of the way up bottle

[Simi 60]

Originally Posted by Lepke

An accumulator will greatly extend the life of pumps, contacts, and check valves. Wiring that is too small will shorten the life of motors. A supply line that is too small will shorten the life of pumps. Line to the pump inlet should be 1.5x the outlet.

And how do you do that when most well type pumps have a 1 inch inlet and outlet yet the PEX plumbing or hose on the boat is 1/2 inch

I have a shallow well pump that is decades old and I can still buy a pump rebuild kit or replacement motor. I live aboard, have laundry, dishwasher, so it get plenty of use.

Care to link to it please?

After having 2 vetus 24v pumps crap out in the last few months I installed a 1/2hp 350w @ 240v model made of cast iron but the first few litres of water is rust coloured every time it sits for more than an hour or two.

I can install a 10inch carbon filter when I get back to civilization, gave one sitting here ready to go just need to get connections.

Overall not impressed, uses a lot more power than the 24v pump and I guess as 1 inch outlet goes to 1/2 inch PEX and inlet the same it puts out less flow than the 24v ones.

[Hoodsail]

I removed my accumulator tank when redoing my fresh water system. I just have fresh water for two sinks drawn from two tanks. Replaced all w/ 1/2 inch PEX, installed new water pump (55 aquajet ARV) from RV water filter store (i have no connection with) and new canister filter. When speaking with the owner (Dave Brannam) at RV he noted that variable speed pumps (the aquajet) work best w/o an accumulator. The aquajet is able to move water thru the canister filter as the pump produces about 65 psi (per my memory). thnks

[Bowdrie]

Most of the smaller pumps we use are really not much more than some plastic/rubber parts coupled to what's basically an automotive windshield wiper motor.
A few things I've learned about having a fairly reliable system:
1, Big hoses/lines, no 1/2 in., 5/8ths to 3/4 works SO much better.
2, Don't use the built-in pressure switch. Get a "Square D" commercial pressure switch that allows you to adjust both the cut-in and cut-out pressures.
3, Use a large accumulator tank;
Without any water pressure in the system, pressurize the air charge in the accumulator to 1/2 the desired pressure that you want the water pump to shut off at.
4, Don't set the cut-in/cut-out too close together, let the energy stored in the accumulator be used to reduce the start/stop cycles.
5, Reduce system pressure, a big benefit that comes with big lines is that you can get the same flow rate with much less pressure.
6, If possible, mount the pump at or below the bottom of the tank.
I know, it's all so basic and simple, but all of the above pay dividends in pump life.