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Accumulator Tank

Captron

Member III
This past winter season while cruising the Bahamas, our pressure water system developed a leak. I found that the Jabsco Accumulator Tank was leaking; not the fittings, the side wall of the tank! I replaced the fool thing a year ago for the exact same reason. The plastic tank just decided to start leaking.

When I complained to Jabsco, they said I had to take it up with my vendor (Defender) because that model of plastic tank had been recalled and taken off the market prior to 2006. Great, I bought mine in 2007??? Anyway, Defender made good on it, crediting my account for the purchase price.

Ok so far so good. I was able to plug off the plumbing to the accumulator tank and so completed the cruise without an accumulator tank. The pressure pump cycled every time a valve was opened but it worked fine otherwise except the shower now alternated between blasts of hot water and blasts of cold; Fun fun fun.

I decided to explore the leaking accumulator tank so I cut it open to see what was inside and to my small surprise, there was nothing inside?? It was just an empty cylinder of air on the output side of the pressure pump.

Anyway, this got me to thinkin' (always dangerous) why couldn't I just install say an 18" hunk of 3 or 4 inch PVC pipe capped off and installed vertically. It would have more volume than the old 1 liter plastic tank and probably last longer. It would certainly be cheaper. They get $50 and up for the new and (I'm sure) improved models. OR for that matter why not plumb in a used 2 liter Pepsi bottle (sans Pepsi) upside down? If I need a new one every year or so I could just get another one off the beach somewhere.

Any thoughts??? Anyone out there tried it?
:confused:
 
Last edited:

Guy Stevens

Moderator
Moderator
Yes you can do this

Yes, this would work..... If you have no leaks. The advantage of the pepsi bottle would also be that you can see when the water has disolved all the air in your pressure dampener device, and then turn off the water and unscrew the cap flooding it with more air.

The better models have a diaphragm internally that separates the air and the water so that the air is not dissolved into the water as it passes.

Guy
:)
 

rwthomas1

Sustaining Partner
The PO of my boat was a plumber. There is a full-sized residential accumulator on my boat..... :rolleyes: I don't see why the PVC wouldn't work just fine, provided you can drain it every once in a while as Guy suggested. BTW, the residential sized accumulator allows you to get halfway through a shower before the pump kicks in! RT
 

P Abele

Member II
In a previous life I did plumbing work and everything stated here is correct. I worked on well water systems which all included pressure tanks (accumulators) and the old ones were very big, maybe 100 gallon, galvanized tanks which you would pump air into until it came out in the water. The air would then dissolve into the water over time and then maybe a couple of years later, the homeowner would call to complain that the water was surging so we would come out and do it again. Modern pressure tanks have solved the problem of air dissolving into the water with a rubber bladder, but in time that rubber bladder will wear out and break, causing the same problem which is more complicated to fix. As of about 15 years ago, the best tank in my opinion was made by "well-X-trol" which was a fiberglass tank which was fitted with a removable (replaceable) bladder. I don't know if these are still available today, or if there might be something better available, but would suggest looking at their smallest tank for use on a boat if you can find room - for most likely more function and less cost than a "marine" version of the same thing. Another benefit of a bladder filled pressure tank is you can mount it on it's side and it will still work as compared with a simple air accumulator - never mind what happens when the boat heels.
Another trade secret worth mentioning, is how much to inflate the bladder. The goal is to have as much air in the tank, to allow for as much expansion, as possible. Your pump turns on at one pressure, and off at some higher pressure so ideally you would bleed the system of water pressure and then inflate the bladder (shraeder valve fitting) to the same as the pump turn on pressure. In reality the pressure switch isn't very accurate so we would inflate the bladder to always be 2 PSI lower than that.
I probably just gave you all enough info to get in trouble, but good luck!!
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
I installed my own accumulator tank a few years ago, and I have checked the bike pump fitting on top occasionally for pressure and it continues to hold at the prescribed 20 #.
Mine is supposed to have a butyl diaphram.

Given the hassle to install it, if doing it again, I would spend the extra $ for one of the new variable speed pressure pumps. A friend put one in and reports that it really is as quiet as advertised.

Loren
 

gulfcoaster

Member III
Hi guys! Will someone please explain to me what exactly is an accumulator tank. I understand the fresh water pump. Is this the same thing?
 

rwthomas1

Sustaining Partner
An accumulator is merely an air tank, anywhere from a liter to a gallon or so in capacity. It is installed with a T after the potable water pump. The pump pressurizes the water system and some of this water enters the accumulator as it compresses the air inside the accumulator. What this does is create a small reserve pressurized reservoir. When a faucet is opened the pressurized water from the accumulator is used first. As the pressure decreases enough the water pump pressure switch turns the pump on and it runs until the faucet is turned off and/or the accumulator is recharged. The effect is that the pump cycles less frequently and runs longer when it does run. This makes the pump happier. There are new water pumps that are variable speed and have sensors that match demand so no accumulator is necessary. RT
 
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