Tank Piping Questions

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Eric Johnson

Mod Emeritus
Nov 18, 2005
5,871
Central NYS
Hey gang, it's been awhile.

I finally decided to go with a pressurized tank storage system for my EKO 60 and managed to find this 500 gallon tank pretty cheap. It has the added advantage of being narrow enough to fit through my basement door, which should come in handy. I know--it's ugly, but in its own way, beautiful.

tank.jpg


So, my questions are as follows:

1.) I assume that I need to run four lines into this tank--a supply and a return from the boiler and a supply and a return to the system (i.e., my gas boiler vessel). Is that the best way to do it, basically, two separate supplies and returns?

2.) I'm not sure how much expansion capacity I'll need. I've thought about buying a water heater and using it for expansion. If I do that, do I need to position it at the highest point in the system (i.e., in the attic above the boiler), or can it be down in the basement with the tank? I currently have an Extrol Model 60 hanging on my system, which handles a lot of water (two boilers, lots of ci rads), so I'm wondering if I can just stick another one on the system to accommodate the extra 500 gallons. I also want to be flexible enough so that whatever I do, expansion wise, can either accommodate an additional 500 gal. down the line, or be expanded to handle 1,000 gal.

3.) Finally, getting back to the piping--I assume that the supply line from my EKO should be piped into the bottom of the tank, presumably through a diptube of some kind. You can see that the tank has a few fittings, plus that plate. I'm thinking perhaps the best approach would be to have a new plate with four 1" fittings welded onto it, which would make it easy create a dip tube. Does that sound reasonable?

I realize this has all been covered numerous times here in the Boiler Room but, you know, it's a lot easier just to ask.

Thanks!

--Eric
 
Eric welcome back!!!

That looks like a 1000 gal to me??? Anyways you want to run your supply from eko to top of tank. Return to eko from the bottom of the tank. Then pull off the top of tank to heat loads and return to tank with dip tube so it returns water to middle of the tank.


Rob
 
Thanks, Rob! It's good to be back.

It's a weird looking tank, but I think it's 500. I have to talk to the guy (friend took the pics and put me on to it), but I did some rough volume calcs and came up with 685 gal, so it's probably 500 gallons of actual capacity. At this price ($150 delivered), I'll take another one just like it and stack them. Good thing thing this thing is 3' because that's the width of my basement door.

What do you recommend for expansion?
 
3ft. diameter x 10ft. long is about 425 gallons (CDN). I thought 1000 when I first saw it too (looks huge), but that's what my calculator tells me.
 
Great to hear from you Eric. That may be an odd size but if it fits through the door what the heck. If the 12' doesn't count the bell ends, then is looks like it should be at least 600 gals.
 
Regarding the exp. tank,
Given the tank volume 685gallons
An additional 115gallons in existing system volume(I do not know your specifics so I am aiming high).
Total 800gallons, at a12psi feed, 30psi relief, and a rise of 135f(60f-195f), requires 26gallons acceptance and 66-67 gallons total volume.
If you have an Extrol 60(Amtrol) you are getting about 2.5gallons acceptance & 7 gallons total volume.
So you need an additional 2.5 gallons acceptance / 66gallons total.
A standing vertical Amtrol Extrol SX-110V(62gallons total) should be getting you there, if your system does not exceed 800gallons total and better if it is closer to 750gallons.

SK
 
So, my questions are as follows:

1.) I assume that I need to run four lines into this tank--a supply and a return from the boiler and a supply and a return to the system (i.e., my gas boiler vessel). Is that the best way to do it, basically, two separate supplies and returns?
Two lines can work, with the boiler lines and the load lines teed together at points away from the tank, but there needs to be some sort of flo-chek on the boiler circuit to insure that the load circ doesn't draw parallel flow through the boiler when the boiler is off line. With four lines you don't have to worry about the parallel flow problem.

[Edit:]
As gasifier points out, if you have a Danfoss or equivalent on the boiler circuit that should guarantee that the load circ can draw only from the tank when the boiler is off line, so no need for four ports.
3.) Finally, getting back to the piping--I assume that the supply line from my EKO should be piped into the bottom of the tank, presumably through a diptube of some kind. You can see that the tank has a few fittings, plus that plate. I'm thinking perhaps the best approach would be to have a new plate with four 1" fittings welded onto it, which would make it easy create a dip tube. Does that sound reasonable?
If you're saying the hot water from the boiler goes into the top of the tank and the cold water to the boiler pulls from the the bottom of the tank, then yes, that's how it's done.

If you're going to have work done to the tank, it would be great to have horizontal ports going into an end (or ends) of the tank. This would really help prevent vertical jetting from disturbing your stratification, which would be nice for tanks as long and skinny as that. Maybe raise one end as high as you can and put the hot pipe on the top of the high end and the cold pipe on the bottom of the low end.

Also if you're having work done to the tank you should check out Dean Zook's tankless coil fixture fitted into a storage tank to supply DHW. Since your tank is going into the basement it might work quite well for you.

--ewd
 
Is it necessary for Eric to have four entrances into the tank for the piping? Does he have to have 2 inputs and to outputs? Or could he have one feed to the top of the tank from the boiler. Then one from the bottom of the tank to the return of the boiler. With a "T" Just before the input to the top of the tank from the boiler and circulation pump above that "T", couldn't he feed(small circulation pump between boiler and tank), and draw from the top of the tank all with one outlet at the top? And the same with his outlet on the bottom for return. A "T" after he comes out of the tank for his return from his zones or demands and then another "T" which, would be his danfoss or equivilant, a little further out that line to have his hot water boiler feed mixing with his return water weather it be from his storage or his zones returns?

Ah. When I was writing this EW beat me too it. I guess he answered my question. Mine is done with just two. My tank is vertical.

Eric, my tank is close to 400 gallons and it is 108" from end to end. 36" diameter.
 
As dudley said above you can make this work with 2 lines per tank. I have (2) 500 gallon tanks and I tee'd my boiler supply/system supply and return before I go into and out of the tanks. Saves on plumbing and makes for a more simple system in my opinon vs separate connections at the tanks themselves.

I have 120 gallons of acceptance for my system with 1,000 gallons of storage. I planned ahead for future radiant loops and any other extra system capacity I don't currently have. More is always better, right? ha.

And last...my 500 gallon tanks are roughly 37" diameter and 120" long. I know this because my basement slider door is 34" wide. They weigh about 1,000lbs each.
 
Eric Johnson said:
It's a weird looking tank, but I think it's 500. I have to talk to the guy (friend took the pics and put me on to it), but I did some rough volume calcs and came up with 685 gal, so it's probably 500 gallons of actual capacity. At this price ($150 delivered), I'll take another one just like it and stack them.

You dog! That's scrap price.
 
I tee'd my boiler supply/system supply and return before I go into and out of the tanks. Saves on plumbing and makes for a more simple system in my opinon vs separate connections at the tanks themselves.

I tee'd my return before the tank too and now i am changing it. What happens is I charge my tanks to 180 and my pump in the house ran 24-7 it was returning water out to the boiler that was 180* even when the boiler burned out of wood. My boiler pump will not shut off until the water gets to 170* So i circulated water 300' until it reached 169*

My system will be a on demand system now. Pumps will turn on when they have a call for DHW or the forced air furnace blower turns on. I should get less mixing and a better control of my boiler pump set points.


Rob
 
Everyone seemed to get side tracked about the size of your tanks (its a male thing) No one answered your question about the expansion tank. I am wondering the same thing as I have a 86 gallon bladder tank and I have it standing on the floor next to my EKO 40. Its not feasable to place it higher than my system. I suppose I could put it upstairs in the kitchen but the little lady won't be happy.
 
Glad to see you back on this forum Eric!

I use a used (free) 50 gallon electric water heater for expansion. There are plenty of good ones tossed away at our local dump.
Mine sits on the floor beside my EKO 40. Three years of operation and no problems. I just remove any absorbed water each fall (about 3 gallons) and pre=presureize to 12 lbs.
Works great!
 
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