Simple marine accumulator tank question

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Oscarpop

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The water flow on our new boat has become stuttery and the pump is not flowing at a constant rate when the taps are open.


I think this means that the pressure in the accumulator tank needs adjusting. I am also assuming that as the water didn't originally come out stuttery, that there is a pressure loss in the bladder.

So, my assumption is that air needs to be added not removed.


Also as the pressure required is unto 45psi, this is within the realms of a good quality high pressure bicycle pump, which I have onboard?
 
Here's a practical method that works perfectly without trying to set pressures with a gauge. Open a tap and listen to the frequency with which the pump cuts in and out. Now begin to pressurise the accumulator with your bike pump. As the pressure you add goes up the water pump will cut in less and less, but then begin to cut in more and more as the accumulator pressure exceeds the pump pressure switch setting. Now let some air out of the accumulator until the pump switching is at its minimum.
 
If it's a normal accumulator, surely all you do is loosen a coupling at the base and allow the water to drain out, thus filling it with air? I haven't had one with a membrain on a boat although I've seen them in central heating applications.
 
Oscarpop - Find out which type of accumulator it is first before you try and pressurise it.

Some (as Billjrat says) are the type where you just drain, open and close the top vent and then turn the water pump back on again.

Some (as the others have said) are of the pre-charged type that are pressurised from something like a car tyre pump.

Warning - That quoted pressure is probably what the acccumulator will take from the pump. The pre-charge pressure will probably be way way below that.
 
Two examples...

The Jabsco 12573-3000 which must be mounted vertically and relies on a trapped bubble of air within it. No pre-charge required.

The replacement Jabsco 30573-000 which relies on a pre-charge of up to 10psi.

This second one has a maximum operating pressure of 125psi.

Note the big difference between operating pressure and pre-charge pressure.
 
Last edited:
Martin_J said:
Oscarpop - Find out which type of accumulator it is first before you try and pressurise it.

Some (as Billjrat says) are the type where you just drain, open and close the top vent and then turn the water pump back on again.

Some (as the others have said) are of the pre-charged type that are pressurised from something like a car tyre pump.
Click to expand...

There's a clue on top of the tank - ones with a valve on top can be pumped up.
 
One question: I have JABSCO model No: 23240-2000. It says: max working pressure 10 bar, pre-charge pressure to 0.3 bar.
So if I want to check the pressure I have to turn off water pump, let all the water out (by opening a tap in, let's say, kitchen) and then try to fill the air (if necessary) with a pump.
But how many bar? 0.3- pre-charge pressure?

Thanx.
 
Definitely check the pressure our Jabco water pump is 20 lbs. Large systems have 40lbs. Measure the pressure before pumping. Also stuttering may not be the pressure tank. Stuttering can be cased by a small blockage somewhere and a diaphragm on the way out. With that sympton I would buy a service pack and strip the pump down first.
 
KellysEye said:
Definitely check the pressure our Jabco water pump is 20 lbs. Large systems have 40lbs. Measure the pressure before pumping. Also stuttering may not be the pressure tank. Stuttering can be cased by a small blockage somewhere and a diaphragm on the way out. With that sympton I would buy a service pack and strip the pump down first.
Click to expand...

He says it is rated to 10 bar. That's somewhat in excess of 140 psi. Unlikely his boat has a system pressure as high as that. ;)
 
So it is written on the accumulator label...

I started to look at the problem because fresh water is pooring into bilge. So I checked everything and I guess the problem would be in the pressure relief valve on the water heater.
I guess the accumulator is working fine since the pump does not run so often when I wash dishes etc.
Many posts on this problem but no one says how to clean the valve (hard to reach it with tools).
The case is that even on an anchor for three days when there is no hot water, the bilge is constantly pumpimg fresh water and it is comming from the direction of the water heater...
Not nice, loosing fresh water:(

Btw, I have Jeanneau SO 43ds.
 
Sometimes the cause of the leakage can be scale accumulations, but it might be a broken spring, pitted seats or any number of other problems. Better just to replace it, they are a cheap item. Google the maker of the calorifier and you will probably find a supplier. If you cannot reach the valve you may have to partially or fully remove the calorifier.
 
vyv_cox said:
Sometimes the cause of the leakage can be scale accumulations, but it might be a broken spring, pitted seats or any number of other problems. Better just to replace it, they are a cheap item. Google the maker of the calorifier and you will probably find a supplier. If you cannot reach the valve you may have to partially or fully remove the calorifier.
Click to expand...

I'll do that. Everytime something goes wrong, I try to fix it but at the end I find myself on google:)
Or this forum... of course :p
 
>He says it is rated to 10 bar. That's somewhat in excess of 140 psi. Unlikely his boat has a system pressure as high as that

I'm guessing that's the calorifier not the water pump.

>pressure relief valve on the water heater.

If it is pouring wate don't try to fix the valve buy a new one. When you put it back use PTFE tape on the threads, four or five turns clockwise (the way the thread screw in).
 
So, I got a new pressure relief valve but I see that I have to change the hose since the old one is stucked to the valve and I have to cut it.

But as far as I know it should be a hose that can take around 95C hot water so I guess not every hose is suitable?
The hose mounted now is black (like fuel one..)?
Any idea, please since I could not get the right hose here in Preveza...
 
For he thisnokd thread that might have solved my problem.

20PSI pump never stops as the pressure release valve on the calorifier kicks in.

It should be rated at 3bar (27psi?). But I think it is opening prematurely and hence the pump never gets to cut off pressure.

This forum is a goldmine of fixes and info.
 
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