Accumulator tank question?

[Moonstruck]

When a boat is connected directly to the city water system at the dock, the water system could very well have a back flow preventer (in fact that is starting to be required), In that case the boat water system will act exactly like the one in your home.

 

[CPseudonym]

Ron is correct. There is no optimal location for the accumulator tank, plumb it anywhere it fits best in your boats cold water line.

Psneeld was likely fighting undersized pipe on his install cited.

Don Moon is correct that thermal expansion tanks are required by code on most new land based hot water systems. Funny thing is they seldom do any good in residential installs unless there is a check valve (rare) on the cold water make up line to the water heater. The tanks are identical in design and will do their assigned job fine anywhere in the hot water system.

Typically they are located close to the source (well or water heater) for convenience of the installer. Boat lazarette's get crowded in a big hurry so put it where it makes sense and is out of your way.

 

[caltexflanc]

Actually there is an optimal spot and that is as close to the pressure switch as possible, which by definition is very early in the system and close to the pump. Just take a look at what the various tank makers (Shur Flo, Jabsco, Well X Trol) recommend. In my case, I had some hammering and "chattering" issues with the diaphragm DC pump when the boat came to me. A wise man figured out that moving the pressure switch for that pump close to the tank, as shown in my picture, was the solution, which it was.

 

[FlyWright]

Maybe we're all talking about different types of accumulators. Here are circuit drawings to illustrate function:

I could see where a bladder accumulator type could be installed anywhere to keep the pressure uniform, but this type of installation would provide little or no suppression to hydraulic shock or hammer.

My vessel has a flow-through suppressor type accumulator which does not allow reverse flow. The only components protected by this one-way flow circuit would be those items downstream from the accumulator. Components in the system PRIOR to the accumulator would experience the full effects of hammer and shock since the accumulator's check valve prevents back flow.

 

[Peter B]

I think some of the confusion is some folk missing the point that the op was planning on putting his accumulator tank downstream from the hot water heater, because of proximity of the heater to the pump. I tend to agree with all those who said this is probably not a good idea. There seems to be unanimity that it can go anywhere in the cold side of the circuit, but best near the pump, even if a T junction and a length of flexible pipe is needed to place it somewhere convenient. I find it hard to believe the OP's water heater is so close to the pump he cannot do that.

PS. Sorry, just re-read his post - he is referring to the T, and not the tank, so yes, if in the cold circuit, even tho the hot comes off close to & before it, the hot water would not flow through it, so it would be ok done that way, as it would still work to prevent hunting of the pump, even when drawing just hot water.

 

[Shay]

I don't see any reason to think hot water will flow out of the water heater backwards and down stream to the accumulator it the accumulator is mounted in a cold line down stream of the water heater.

I think the accumulator will work just fine mounted anywhere in the cold circuit.

Shay

 

[Ski in NC]

I don't see any reason to think hot water will flow out of the water heater backwards and down stream to the accumulator it the accumulator is mounted in a cold line down stream of the water heater.

I think the accumulator will work just fine mounted anywhere in the cold circuit.

Shay

When you posted "after the water heater", that to me meant downstream of the water heater, on the hot line. Nowhere did you say on the cold line, til this post.

So yes, on the cold line it can be tee'd after the water heater, no issue there.

 

[Shoalwaters]

I recently found a stainless accumulator tank that someone had replaced rather than fix it. I can't resist shiny stuff, especially when it's free, so I took it home to play with. The membrane had a pin hole and the stainless canister was in good shape. I now have a good-sized stainless accumulator and will install as time permits. I understood the principle, but had not seen inside one before - pretty straight forward really.

FWIW: the Schrader valve doesn't inflate the bladder, it pushes air into the space between the bladder and the canister. The closed end of the bladder is hooked onto the valve to stop it (the bladder) from flopping around.

 

[Larry M]

Mike how are you going to repair or are you going to replace the membrane? It needs to hold as much as your water system pumps up to.

 

[Shoalwaters]

Larry, I got lucky. I found a replacement membrane locally - about $30.00.

 

[HopCar]

Many years ago there was a marine pump company named Crowell (I think).
They made a strange accumulator tank that used the rubber bladder from a football as the air reservoir. If the bladder went flat you'd take the tank apart, inflate it with a needle, and reassemble the tank. It was a miserable thing.

 

[Patemey]

What are people's thoughts about the use of an accumulator tank and a variable speed water pump? Manufacturers like Jabsco say that "no accumulator tank is needed". But does it hurt to have one?

 

[HopCar]

"But does it hurt to have one?"
We had a lot of returns on the early variable speed pumps until we figured out that accumulator tanks, left in the system, seem to confuse them. I can't remember exactly what it caused the pumps to do but people were unhappy until they removed the tank.

You really don't need one so take out the tank and enjoy the extra space for beer storage. If you're happy with the tank, don't spend the extra money for a variable speed or by-pass pump.

 

[Larry M]

Larry, I got lucky. I found a replacement membrane locally - about $30.00.

You sure did! What a score.

 

[Pau Hana]

Reviving a semi-dead thread...


Parks, what is your take on the Mate-USA/Marco pumps?
10.6 GPM Water Pressure System - Water Pressure Systems - Products - Mate USA

 

[HopCar]

Hi Peter, I've never seen those pumps. I like gear pumps.

Those look a lot like the ones that Reverso imports from Italy to sell as oil change pumps. The Reverso pumps are very reliable.

I'd bet the basic pump is good but I don't know how reliable the electronics are.

I had a Fiat one time. The Italians know less about electricity than the British! It sure is a pretty pump.

 

[Pau Hana]

I may bite the bullet and give it a try. The pump is much quieter than the Flo-jet currently onboard (well, the display was...)

Report later when I have more info....

 

[FlyWright]

I'll be interested in how that works for you, Peter. I noticed the gears are PTFE...interesting.

I have a diaphram pump that's been very reliable, but noisy. Now that I installed the new accumulator from HopCar, it runs less often. It's amazing what a properly operating accumulator can do.

 

[N4712]

We looked at them when we were replacing our current, but ended up with the Mach 5.

Let me know how it goes, might get one to replace the now back up jabsco.

 

[FF]

I would care 10X as much about installing the largest tank anywhere in the system , rather than the tanks location.

While you are trashing about in the bilge , lead a wire up to the galley from the FW pump , so you can see it operate with a small light..

Easier than listening when the engine is on,to be sure you are not pumping your drinking water into the bilge.