Accumulator tank positioning

[krissteyn]

I'm hoping I can learn what I'm doing wrong. The accumulator tank used to be mounted horizontally and would lose the air bubble till the supply pump worked every time. So I moved it to vertical , and the same thing is happening... Is the fresh (rainwater) liquid absorbing the gas ?
Do I have to add air regularly ??

[pcmm]

Originally Posted by krissteyn

I'm hoping I can learn what I'm doing wrong. The accumulator tank used to be mounted horizontally and would lose the air bubble till the supply pump worked every time. So I moved it to vertical , and the same thing is happening... Is the fresh (rainwater) liquid absorbing the gas ?
Do I have to add air regularly ??

Most accumilator tanks in marine installs actually have a membrane in the middle and a schrader valve on top to be able to adjust the pressure. I prefer to install them Upright with the valve at the top. Try adding a few pumps of air to the tank (just 1 or 2) and see what happens

[krissteyn]

I wasn't aware of the membrane.
This doesn't appear to have any way of repairing that membrane ?
Is it possible their is no membrane and it's just a tank ?
The unit is black with no name...
I'm used to seeing these tanks on pumps taking municipal water and pressurising it for the home. Certainly never seen a membrane version ��

[pcmm]

Originally Posted by krissteyn

I wasn't aware of the membrane.
This doesn't appear to have any way of repairing that membrane ?
Is it possible their is no membrane and it's just a tank ?
The unit is black with no name...
I'm used to seeing these tanks on pumps taking municipal water and pressurising it for the home. Certainly never seen a membrane version ��

The tanks normally look like this. you can see the bolted join in the middle where the membrane is. and the valve on top to adjust pressure with.

[Bowdrie]

The typical tanks used in systems do have membranes.
Without them the air charge will gradually be absorbed by the water.
The little one by Jabsco pictured above is quite small, it's more of a device akin to a "water hammer" tube as used in home plumbing that's rigid pipe/copper. but they're widely used in RVs and little boats.
Yes, having the water connection in the down position is better, it allows full drainage when working on the system.
https://www.groco.net/products/water...e-storage-tank

[Sailor 99]

The accumulator tank is not required with most modern water pumps. BUT when you go into the hot water tank you are supposed to have a check valve to stop water from going back to the main when it heats up.

All of these hot water tanks have a little bit of air in them and the water air expands. Even if the outlet is on the top the water expands. This will start to force your hot sides hoses off the barb. You can not contain expanding water.

You really need a bladder expansion tank on the hot side as others have shown. If it has no bladder the water will absorb the air.

[Bowdrie]

In days gone by the use of a hot water expansion tank was of little concern, because smaller boats tended to have only a 4 gal or so heater and be plumbed with a mile or so of vinyl hose, and the hose would generally expand enough to accommodate what expansion there was.
Today, with larger heaters and tubing that's more rigid we'd like a better method.
The problem with only having a hot water expansion tank is that when only cold water is used you have no accumulator effect, so you either need a pump designed for use without an accumulator tank, or install both an accumulator tank and an expansion tank., (so many tanks, so much space, so much tubing and fittings,) it's no wonder so many boats are plumbing nightmares.
The recommended water heater inlet check valves are another unnecessary appurtenance.
With the low flow/low pressure/low demand boat systems, (as compared to your home/city water,) the typical brass/bronze "flap valves" installed are quite prone to sediment build-up on the flap, one little bit of debris and they don't seal anyway, now their worthless. Answer?
1, Install an accumulator tank downstream of the pump.
2, Remove the heater inlet check valve.
Now you've got a system that gives you the benefit of an accumulator on both hot and cold sides, (pumps models be da**ed, your whole system works better with an accumulator tank, and I might add, a remote adjustable pressure switch like a Square D, the 20>40psi model).
And the expansion of the hot water simply backs-up into the inlet tubing, the accumulator tank handles it all in stride.
Loss of hot water is almost immeasurable, 2>3 ft back from the water heater you'll never see the difference.
Now you have a simple system, no hassle, no extra tank, no additional tubing/fittings, and can set the cut-in/cut-out the way you want it.

[Putt-Putt]

Bowdrie

I whole heartedly agree with what you have said, especially the "pump models be......." part.
One other comment is that accumulator/pressure tanks to be long lived and useful, need to be big. Annoyingly big sometimes!

My system has no check valves downstream of the pump, (given time they leak anyway) an old Square D $15 pressure regulator and a couple of fibreglass 15 gallon pressure tanks which have replaceable bladders that are formed like a balloon. They are 28 years old, look & function as new and I replaced the bladders once, 17 years ago. They are offered by Headhunter (my brand of heads) for $340 more, but they are actually made by WellMate, now part of Pentair it seems.

Pentair's info, as offered by WSP is attached.

https://watersoftener-parts.com/inde...oducts_id=7173

They have been flawless.

I should order new bladders before they are discontinued. Pentair is like that.

[krissteyn]

Thanks for the detailed reply...
Here in the Caribbean, my hot water system is unnecessary, so it's just a cold water supply...
I see ill need to get a new bladder / tank to make it work nicely...
The pressured pump is activated more often now- it's 7 years old , dunno how much longer it will last without the bladder addition... ��

[noelex 77]

While the pump is operating and pressurized, open the air valve. If water emerges, the bladder is compromised. If not, inflate the air chamber using a bicycle pump.

[mako]

OP, you mentioned an accumulator, as opposed to an expansion tank. If you wish to install a/o replace your accum tank then you can use any from Home Depot, Lowes, etc., just make sure it has an internal bladder and the air valve like is mentioned above. I installed a large (20 gal-ish) tank on one of my previous boats and it drastically cut down on the cycle time of my horribly old water pump.

[Bowdrie]

Originally Posted by noelex 77

While the pump is operating and pressurized, open the air valve. If water emerges, the bladder is compromised. If not, inflate the air chamber using a bicycle pump.

The trick ticket with an accumulator tank is to plumb the Shrader valve to an easy to see/operate location.
You get one of those fittings that screws on to the Shrader and has a hose barb, (Parker Hose or air-hydraulic shop,) add a few parts and gage and you're styling.
I put mine all together for ~$25 and a 1/2 days' work.
Mounted in the head, can visually see the pressures when the pump cycles, and can bleed/charge the tank without crawling around in some inaccessible cavern.
It's a no brainer for keeping tabs on the system and setting your cut-out/cut-in points on a remote pressure switch.

[krissteyn]

Thanks... I'm a long way from a reasonably priced Lowes , but yes I'll be making a move to replace it .

[reflectionsv37]

If your accumulator tank is one of the black ones, typically sold by Jabsco and other pump manufacturers, take it out and throw it away! They are all junk and won't last, leak, and you'll be adding air to them constantly because the membrane fails.

About 10 years ago I purchased a real accumulator tank used on water well systems for about $80. It has a hose fitting on one end and schrader valve on the other. It's a 2 gallon tank so it's much larger than those worthless little black junk units. I had some unused space on a shelf underneath the v-berth where the anchor chain lives. I tapped into the water supply system and ran a hose to it. They can be placed anywhere in the system. They do not need to be near the pump.

Since then my pump runs for a long time to fill it but the benefit is that the pump doesn't cycle often. The biggest culprits for failure of the pumps is the little micro switch that activate the pump based on the pressure. Less cycles equals longer life. I also have a very even level of water pressure. It does not fluctuate much at all. It's barely noticeable now. I need to pump it up and air to it about every 18 months but the tank is positioned so it's very easy to access the schrader valve.

If you do this, you'll be glad you did!