Accumulator tank size?

[GrandWood]

Replaced my fresh water pump, I purchased a direct replacement from West Marine. The old pump was a 50psi, the new is now a 60psi. Which seems to be quite high, and the pump cycles on and off rapidly at the kitchen faucet( replaced the aerator with the highest flow I could find, 30%) which didn’t make much of a difference.

Will a accumulator tank help to regulate the pump from cycling less?

Ive searched tanks and found small units(24oz capacity) a larger that will fit (2 to 4 gal).

The faucets and shower in the heads have no aerator and the pump runs continuous when turned on, plenty of water flow. Need help on how to set the system up as to what is right and wrong.

Do I need an accumulator tank? Should there be a pressure regulator right after the pump?

Thanks

 

[Nick F]

My opinion:

You do not NEED an accumulator. Many people like having an accumulator because it reduces pump cycling. It also allows minor water use during the night without the noise of the pump kicking in. It also potentially increases the life of the pressure switch (due to reduced cycling).

I have never used a combination of accumulator plus regulator, but I like the idea. With just an accumulator there is a noticeable flow difference between when the pump kicks in and when it shuts off. If you put in a regulator, it should be between the accumulator and the faucets. Putting a regulator right after the pump makes no sense at all.

 

[tiltrider1]

You didn’t give us much info on the pump you purchased. Is it a variable speed pump or just an on off pump?

Both styles benefit from accumulators. The larger the accumulator the fewer cycles.

 

[GrandWood]

Here is the pump I put in, same part# that was in it.

You didn’t give us much info on the pump you purchased. Is it a variable speed pump or just an on off pump?

Both styles benefit from accumulators. The larger the accumulator the fewer cycles.

 

[GrandWood]

My opinion:

You do not NEED an accumulator. Many people like having an accumulator because it reduces pump cycling. It also allows minor water use during the night without the noise of the pump kicking in. It also potentially increases the life of the pressure switch (due to reduced cycling).

I have never used a combination of accumulator plus regulator, but I like the idea. With just an accumulator there is a noticeable flow difference between when the pump kicks in and when it shuts off. If you put in a regulator, it should be between the accumulator and the faucets. Putting a regulator right after the pump makes no sense at all.

The cycling of the pump just seems wrong, the old pump did the same. If that’s what they do, then it is what it is. Just want to ensure I have the right set up.

I’d rather the pump ran continuous the the on and off

 

[Marco Flamingo]

You don't need anything very large. And you don't need the overpriced little plastic ones often sold along side the marine water pumps. Get one of these for $15. It is only two liters and that is usually misleading. The entire container is likely 2 liters but only holds a little over a liter under pressure. Still, a glass of water or washing one's hands doesn't mean that the pump needs to cycle. I think I put in a 4 liter. You might need to double check the thread size to make sure you don't need some kind of conversion from metric.

 

[tiltrider1]

With out an accumulator that pump will drive you crazy. It probably cycles harder than the pump you replaced because its new and works correctly. In my opinion those are pretty low quality units and the pressure switch weakens with time causing less pressure and less cycling.

You can get away with an accumulator as small as a liter but 2 gallon would be more appropriate. While 5 gallons would be nicer its probably not worth the cost and space required. If space is a consideration then even the smallest accumulator will make a huge difference.

 

[DavidM]

You don’t really need an accumulator tank. That pump will work fine without one as it cycles rapidly.

But if it bothers you, the $15 one on Amazon should work fine.

Another way is to remove the new strainer or if you still have the old one, drill a half dozen 1/8” holes in it to let enough water through to keep the pump running continuously.

David

 

[luna]

Yeah, those shiny little accumulator tanks look cute but one has to wonder why the vendors don't ever say that it can be used safely in a potable water system.
I note that the vendors do say to avoid unnecessary loss due to leakage, install it outdoors. Really?

I looked but could not find any reference to any certification whatsoever.

Would you drink from that cup?

 

[heysteve]

They did things differently in 1984. Alas, all that remains is the cutout for the accumulator tank.

 

[Nick F]

As shown in post #10, a household unit works fine and they are enormous for boat use (1 - 2 gal).

Amazon.com

 

[rslifkin]

I use a similar household well pump accumulator. Mine is 5.5 gallons, which with the pump turning on at 40 psi and off at 60 gives somewhere around 1.3 gallons of water between pump cycles.

 

[Larry M]

You can use a 2 gallon water heater expansion tank available at box stores for about $30. They come pre-charged, add a T fitting and you can splice into you water line where it is convenient. You can adjust the air pressure to go with your pump.

 

[Mac2]

Caution: When I turned up my pressure from 50 to 60 psi, a lot of my hose to barb connections started to drip even though the hose clamps were tight.
After using continuous pressure pumps on my previous boat, I would never go without a accumulator tank for the same reasons you mentioned. The cycling and initial delay of pressure drove me nuts. What sealed it for me was members on this forum mentioning extending the life of the motor. Even though a pump is designed for continuous pressure, it doesn’t mean it’s good for the motor to be continuously cycling.

 

[Iggy]

I would defiantly use a accumulator tank! Even a small one. Other wise the water flows unevenly.

 

[Bacchus]

You can use a 2 gallon water heater expansion tank available at box stores for about $30. They come pre-charged, add a T fitting and you can splice into you water line where it is convenient. You can adjust the air pressure to go with your pump.

I have used this approach on a previous boat and motorhome and it worked very well. In some cases it takes a little adjustment of surge tank pressure to work optimally but they usually come with instructions.

Both of those were constant speed pumps. I have read that with variable speed pumps there can be issues with a surge tank but can't verify that from experience.

 

[Mako]

On my big boat I used an accumulator tank from Home Depot, a domestic unit. Just make sure it has a bladder in it. I installed a 15 gallon-ish sized unit, but my water pump was a piece of garbage and I hated running it more than it had to. And yes, install your regulator downstream of the accum tank, perhaps set for 40 psi with your pump/tank at 60 psi.

 

[rslifkin]

On my big boat I used an accumulator tank from Home Depot, a domestic unit. Just make sure it has a bladder in it. I installed a 15 gallon-ish sized unit, but my water pump was a piece of garbage and I hated running it more than it had to. And yes, install your regulator downstream of the accum tank, perhaps set for 40 psi with your pump/tank at 60 psi.

I've had a similar thought with adding a pressure regulator to get constant pressure from the system as the pump and accumulator tank cycle. I haven't done it yet, but it's good to see I'm not crazy.

 

[Mako]

On both my ranches outside LA, living on a well and water tank, I installed a 100 psi high pressure, multistage, pump feeding double ~125 gallon accum tanks. The pressure regulator downstream was 60 psi running a couple hundred yards to the house. That very expensive pressure pump barely cycled. So the same philosophy for your boat.

 

[luna]

You would not want 100 psi water pressure at you sink, so a regulator on your high pressure system makes sense. For a house on the hill with the distances involved, I would do the same thing.

On the average boat things are more compact, lower pressures work just fine.
I don't think the difference in water pressure out of an accumulator tank at typical settings of 35/55 psi is that noticeable to the guy doing the dishes or important, even when the wife is showering.
If you want to reduce pump cycling, get an accumulator a bit larger than that shiny, 2 litre SS joke. My 14.5 Gal. model has a rated draw down of 4.5 Gal. although I have never measured it.

It does make a difference during anchor wash down where I use a small stream under as much pressure as I can get. Without a regulator you can try to use the water in a manner that keeps the pump working and as a result close to or working towards the high pressure cut off of 55 psi.

With a regulator you are limited to whatever it is set at, say 35 psi. Not ideal.

 

[O C Diver]

Yes you want an accumulator tank. Bigger is better. Less cycles of a longer run time is better for the pressure switch, pump, and motor.

As per post #13, yes you can use a hot water expansion tank. When I did my water system refit, I mounted the new expansion tank in the lazarette. It has about a 3 to 4 gallon usable capacity.

I used a well pump switch to fine tune the on off settings. Also used a mega carbon block filter to remove everything including the chlorine from the house water.

One final note, if you install an accumulator tank, make sure you read the directions for pressurizing the air side of the tank. Doing it wrong can negate much of its potential capacity. From memory, I believe the pressure needs to be about 2 PSI below the pump start pressure.

Ted

 

[Takoradi]

Replaced my fresh water pump, I purchased a direct replacement from West Marine. The old pump was a 50psi, the new is now a 60psi. Which seems to be quite high, and the pump cycles on and off rapidly at the kitchen faucet( replaced the aerator with the highest flow I could find, 30%) which didn’t make much of a difference.

Will a accumulator tank help to regulate the pump from cycling less?

Ive searched tanks and found small units(24oz capacity) a larger that will fit (2 to 4 gal).

The faucets and shower in the heads have no aerator and the pump runs continuous when turned on, plenty of water flow. Need help on how to set the system up as to what is right and wrong.

Do I need an accumulator tank? Should there be a pressure regulator right after the pump?

Thanks

I concur with another reply here that you don’t “need” an accumulator. But you want one. It reduces the cycling and makes it much easier on the pump itself. Jabsco makes the WM pumps and their little accumulator works well. Pay attention to your tubing going to the pump. If it’s not the reinforced tubing, it may bulge, quietly leak and eventually break under the unaccustomed pressure.

Tak

 

[Capt Ray]

Replaced my fresh water pump, I purchased a direct replacement from West Marine. The old pump was a 50psi, the new is now a 60psi. Which seems to be quite high, and the pump cycles on and off rapidly at the kitchen faucet( replaced the aerator with the highest flow I could find, 30%) which didn’t make much of a difference.

Will a accumulator tank help to regulate the pump from cycling less?

Ive searched tanks and found small units(24oz capacity) a larger that will fit (2 to 4 gal).

The faucets and shower in the heads have no aerator and the pump runs continuous when turned on, plenty of water flow. Need help on how to set the system up as to what is right and wrong.

Do I need an accumulator tank? Should there be a pressure regulator right after the pump?

Thanks

+1 For Accumulator Tanks, IMO.

The fresh water PUMPS don't fail. It is usually the teeny-tiny pressure switch attached to the top of the pump that fails. I've tested over a half dozen failed fresh water pumps.

This blog post shows what I went with quite a while ago.
Today’s project: install a larger Accumulator Tank!

I now carry a $30 household well pump "pressure switch" for my next fresh water pump failure, where I know it was not the pump, but the G.D. cheap arse switch atop the pump.

I cannot understand why some small cruisers / and express cruisers come out NEW without accumulator tanks. I can agree with the comments, they are "... not necessary". But they provide a much smoother operation of this important system, and arguably reduces the strain on the inadequate pressures switches mounted to the top of perfectly good pumps that will outlast their switch every time.