Best fresh water pump

[Docsparks]

Very happy with our Seaflo, 3 years on, used almost everyday for liveaboard, 2 head with, showers, deck shower...I completely gutted the old system on our 49 foot, 1985 sailboat. No accumulator tank, no regrets. Under $70, Seaflo 42 Series Diaphragm Pump with Bypass for Reduced Cycling 12V/24V 3.0GPM 55PSI. Plenty of room under the galley sink where there was a snake nest before. I have a spare mounted on the wall to the left.

[Waylee]

Here is my situation. T5 with internal diaphragm serves as expansion tank and accumulator. Jabsco HD4 with 40 psi shut off and 20 psi turn on. Pressure in tank set just below 20psi. Pump goes on at 20 and off at 40. Open fawcett and get smooth flow until pressure drops to 20 and then pump turns on. Runs pretty long during that time and flow at fawcett very low...almost nothing until pumps shuts off. How to get continuous flow??

[Bowdrie]

Originally Posted by Waylee

Here is my situation. T5 with internal diaphragm serves as expansion tank and accumulator. Jabsco HD4 with 40 psi shut off and 20 psi turn on. Pressure in tank set just below 20psi. Pump goes on at 20 and off at 40. Open fawcett and get smooth flow until pressure drops to 20 and then pump turns on. Runs pretty long during that time and flow at fawcett very low...almost nothing until pumps shuts off. How to get continuous flow??

"Continuous flow" at the same pressure is a tall order on most boats.
Where in the system is the accumulator tank located?
Is it an "expansion tank" on the OUTLET of the hot water, or is it an "accumulator" tank first thing downstream of the pump?
Do you have a check valve on the input of the water heater?
As previously mentioned, use an adjustable pressure switch and tighten-up the differential, i.e. make the cut-out/cut-in a little closer together.

[Waylee]

Originally Posted by Bowdrie

"Continuous flow" at the same pressure is a tall order on most boats.
Where in the system is the accumulator tank located?
Is it an "expansion tank" on the OUTLET of the hot water, or is it an "accumulator" tank first thing downstream of the pump?
Do you have a check valve on the input of the water heater?
As previously mentioned, use an adjustable pressure switch and tighten-up the differential, i.e. make the cut-out/cut-in a little closer together.

It is an expansion tank on the outlet of the hot water tank. There is no check valve on the input of the water heater. The pump sensor has an on of 20 and off
of 40. However, I set the pressure of the tank at 20 and am now thinking I should have set it at 40. If necessary I can alao adjust the diff at the sensor. Thanks for your help.

[Bowdrie]

Originally Posted by Waylee

It is an expansion tank on the outlet of the hot water tank. There is no check valve on the input of the water heater. The pump sensor has an on of 20 and off
of 40. However, I set the pressure of the tank at 20 and am now thinking I should have set it at 40. If necessary I can alao adjust the diff at the sensor. Thanks for your help.

No check valve on water heater inlet? Good.
You will get better performance if the tank is plumbed after the pump and ahead of anything else (This is important).
And without the water heater inlet check valve the expansion of the hot water is simply relieved at the cold-water inlet, (there isn't really any "back flow" per se, it's quite minimal.
The way it's plumbed now is that when you open a cold-water faucet the tank is trying to force hot water backwards into the system where the cold water is.
1, Re-plumb the connections on the tank.
2, Reset the differential of the cut-in/cut-out to ~15lbs.
3, The air charge in the tank wants to be one half of the cut-out pressure.

[rslifkin]

For my setup I have 2 expansion tanks and a check valve on the water heater. Big expansion tank is after the pump, small one is on the water heater input after the check valve to function as an expansion tank for pressure on the hot side. It all works nicely with that setup.

[Bowdrie]

Originally Posted by rslifkin

For my setup I have 2 expansion tanks and a check valve on the water heater. Big expansion tank is after the pump, small one is on the water heater input after the check valve to function as an expansion tank for pressure on the hot side. It all works nicely with that setup.

Yes, your system works well because of having 2 tanks.
In the old says when boats were commonly plumbed with vinyl hose the hose would expand on the hot water side to "take-up" the increase in volume of the water as it was heated.
With a check valve on the heater inlet and a system that was all rigid pipe the increase in pressure from heating the water might well open the relief valve or cause a hot-water faucet to leak.

[rslifkin]

Originally Posted by Bowdrie

Yes, your system works well because of having 2 tanks.
In the old says when boats were commonly plumbed with vinyl hose the hose would expand on the hot water side to "take-up" the increase in volume of the water as it was heated.
With a check valve on the heater inlet and a system that was all rigid pipe the increase in pressure from heating the water might well open the relief valve or cause a hot-water faucet to leak.

I specifically added the second tank because of that. When I changed to a new water heater that runs at a higher temp and has a lower pressure relief threshold, the math said I'd need the tank to avoid the system venting if heated up from cold. I didn't want to delete the check valve and potentially get warm backflow into the cold side of the system.

[Bruce K]

Originally Posted by Matt Johnson

Marco gear pumps get my vote. But as Bowdrie says, the accumulator is still a good idea.

Marco gets my vote also. Quite, reliable, no pulsation.

[Waylee]

Originally Posted by Bowdrie

No check valve on water heater inlet? Good.
You will get better performance if the tank is plumbed after the pump and ahead of anything else (This is important).
And without the water heater inlet check valve the expansion of the hot water is simply relieved at the cold-water inlet, (there isn't really any "back flow" per se, it's quite minimal.
The way it's plumbed now is that when you open a cold-water faucet the tank is trying to force hot water backwards into the system where the cold water is.
1, Re-plumb the connections on the tank.
2, Reset the differential of the cut-in/cut-out to ~15lbs.
3, The air charge in the tank wants to be one half of the cut-out pressure.

Bowdrie...first, let me thank you again for all your help. Much appreciated. Bear with me. Until recently, when I opened my faucet, the water ran strong and then got a bit weaker...the pump kicked in and the water continued to flow a bit on the weak side (assuming expansion tank was being filled). THEN, I left the Watermaker flush on and the tanks were drained..once I filled them, water pumped freely, but pump would not turn off even when faucet closed. I'm trying to get back to that point...same plumbing I've had for 5 years. So two ago, I check the pressure on the expansion tank and it was very low...after emptying the tank, I set to 18 psi...a few points below the 20psi on the pump "on" switch....then (as I watched the pressure) the pump would kick on as it got down to 20psi and run for until it reached 40 and then kicked off (sensor was working)....the problem was/is that once it gets down to 20 there is almost no flow until the tank fills up and gets to 40....same pumping as always...so having trouble getting back to where I was. No problem if I'm wearing your out...I understand. I do understand your suggest would lead toward optimization, but at the same time, I didn't have much of a problem before I drained the water tank accidentally.

[rslifkin]

It sounds like you might have air trapped in the system somewhere. Have you run a bunch of water through the water heater to purge any air from there?

[Waylee]

Originally Posted by rslifkin

It sounds like you might have air trapped in the system somewhere. Have you run a bunch of water through the water heater to purge any air from there?

Thank you...no I have not. That is a good idea. Will try that next. Appreciated. The other thing I'm wondering is whether or not I may have overestimated the status of the pump. It ran dry for 5-7 days....I took it apart, but looked good to me. It takes a LONG time to bring the system back up to pressure and once it does it runs strong, but primarily from the pressure in the system. So, maybe the pump is not pumping as strongly as it should. 4gpm. It seems like to me when it goes down to low pressure, that with only one faucet open it should still produce a steady stream of water...which it use to. Thanks for the help.

[COOGOR]

I think it was mentioned already: Marco UP6. SELF-PRIMING ELECTRIC PUMP FOR TRANSFERRING VARIOUS LIQUIDS

[X Fernandez]

I had a Shurflo that eventually died. I didn’t have time to order a new one and all West Marine had in stock was a Jabsco. I took the opportunity to soundproof the compartment as best I could while I was swapping out the pump.

Even with the soundproofing the Jabsco was much louder than the Shurflo. So that is one data point for you.

I’ll be swapping back to Shurflo when the Jabsco quits.

X

[Bellinghamster]

Originally Posted by Docsparks

Very happy with our Seaflo, 3 years on, used almost everyday for liveaboard, 2 head with, showers, deck shower...I completely gutted the old system on our 49 foot, 1985 sailboat. No accumulator tank, no regrets. Under $70, Seaflo 42 Series Diaphragm Pump with Bypass for Reduced Cycling 12V/24V 3.0GPM 55PSI. Plenty of room under the galley sink where there was a snake nest before. I have a spare mounted on the wall to the left.

That's a tidy installation! Is that a hot water mixing valve behind the pump? If so, could you share what model and where you got it? Also, is that smaller than 1/2" PEX? if so, where'd you get the PEX and fittings?