I have pressurized storage. I'd like to hook it up in series because I have a DHW coil in my boiler. The diagram in my attachment seems to fit my needs. However, I do not have an indirect water heater. Does anyone know if this would work? What zone valves, pump switches, three way zone valves, etc would I need? Any comments or input is appreciated. Thanks!
In series water storage diagram.
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![[Hearth.com] In series water storage diagram.](/talk/data/attachments/10/10157-aed63fb945d6ae500fe74001c15856d9.jpg?hash=t-ubdHkc1P)
![[Hearth.com] In series water storage diagram.](/talk/data/attachments/10/10158-bc38c8739178f89ad9e594351a924e0b.jpg?hash=KnoUyKQSmF)
Now I can read it. My eyes are fine, but my head hurts 
I've seen this setup before, and I can't figure out what's happening in this diagram. I've puzzled 'till my puzzler is sore.
Let's say for the sake of the argument that all the circs are the same size, and to make life simple, the indirect and its circ are gone.
Let's say that the EKO is active and its circ is putting out 10gpm at 180 degrees, and that the zones create a 20 degree drop.
There's a circ between the EKO and the oil boiler, so I'll assume that there's no flow into storage from the EKO at this point. The Oil boiler has another circ on the return from the zones - perhaps we can assume 10gpm for that as well, lacking any other data. That would put 20gpm through the oil boiler - half hot water from the EKO, and half cold water from the zones.
That means that water coming out of the oil boiler is halfway between the outlet temp of the EKO and the return temp from the zones, and 20 degrees above the zone return temp.
That means the oil boiler outlet would have to be 160, and the zone return would have to be 140. That 20gpm at 160 degrees would then split - 10 to the zones, and 10 back to the EKO via the bottom of storage.
In this scenario, you're only running your zones at 160 - I just don't get it. Am I missing something?
This problem gets even worse running off storage, where your starting temperature is lower and your really want to be returning the coldest possible water to storage.
I've seen this setup before, and I can't figure out what's happening in this diagram. I've puzzled 'till my puzzler is sore.
Let's say for the sake of the argument that all the circs are the same size, and to make life simple, the indirect and its circ are gone.
Let's say that the EKO is active and its circ is putting out 10gpm at 180 degrees, and that the zones create a 20 degree drop.
There's a circ between the EKO and the oil boiler, so I'll assume that there's no flow into storage from the EKO at this point. The Oil boiler has another circ on the return from the zones - perhaps we can assume 10gpm for that as well, lacking any other data. That would put 20gpm through the oil boiler - half hot water from the EKO, and half cold water from the zones.
That means that water coming out of the oil boiler is halfway between the outlet temp of the EKO and the return temp from the zones, and 20 degrees above the zone return temp.
That means the oil boiler outlet would have to be 160, and the zone return would have to be 140. That 20gpm at 160 degrees would then split - 10 to the zones, and 10 back to the EKO via the bottom of storage.
In this scenario, you're only running your zones at 160 - I just don't get it. Am I missing something?
This problem gets even worse running off storage, where your starting temperature is lower and your really want to be returning the coldest possible water to storage.
This setup seems to feed only the storage tank from the EKO and then the oil boiler has to get its heat from the storage. That means if the storage drops to unusable temp then you have to wait for it to charge back up before you have any usuable heat, or maybe burn oil during that time. It can take hours to heat a tank up.
Instead I think that in a series setup the hot water should heat the oil boiler first and then excess heat is transfered to storage. Then when no heat is coming from wood the oil boiler has a way of drawing from storage.
As for controls, there are different ways to do it. Generally aquastats are used on the boilers to turn pumps on and off at the right times. I have an open on decrease aquastat on my Tarm that shuts the charging circ off when the temp drops below a certain unusable temperature. I have an open on rise on the oil boiler that will turn the drawing circ on unless the temp is above a certain temp. You can also put an aquastat on the tank that lets the circs know if there is usable heat there. Mine run through a DPDT relay that won't allow drawing and charging at the same time. I may add a second relay so that it would only draw if the tank was at a usable temp.
I hope that helps some. Hopefully someone else has other opinions and suggestions as well.
Instead I think that in a series setup the hot water should heat the oil boiler first and then excess heat is transfered to storage. Then when no heat is coming from wood the oil boiler has a way of drawing from storage.
As for controls, there are different ways to do it. Generally aquastats are used on the boilers to turn pumps on and off at the right times. I have an open on decrease aquastat on my Tarm that shuts the charging circ off when the temp drops below a certain unusable temperature. I have an open on rise on the oil boiler that will turn the drawing circ on unless the temp is above a certain temp. You can also put an aquastat on the tank that lets the circs know if there is usable heat there. Mine run through a DPDT relay that won't allow drawing and charging at the same time. I may add a second relay so that it would only draw if the tank was at a usable temp.
I hope that helps some. Hopefully someone else has other opinions and suggestions as well.
I think, and it is just my opinion, that in a series hookup the oil boiler needs to be the center that is always hot, not the storage tank. Perhaps the diagram you posted can do that, but I can't tell what is supposed to happen when the circ horizontally oriented on the return side of the oil boiler runs. Does it draw from storage? If it draws from the Eko, how is the water being returned to the Eko? I don't get it.
I think if you are piping this from scratch, it would be to your advantage to pipe it so that it could either be run in series or as a primary secondary. That way you have the option of running more efficiently later when you can add another alternative for DHW other than the coil in the oil furnace. I can't image it would cost much to add that flexibility from the start.
I think if you are piping this from scratch, it would be to your advantage to pipe it so that it could either be run in series or as a primary secondary. That way you have the option of running more efficiently later when you can add another alternative for DHW other than the coil in the oil furnace. I can't image it would cost much to add that flexibility from the start.
I cant seem to wrap my mind around how to do this, does anyone have a diagram for what Im trying to do?
I have a diagram I can modify to show you as an example. However, I need to know if you plan to use 1 pump with zone valves to drive your heating zones or pumps for each zone? Also, you said there are 4 ports on your tank? Where are they located? Is there a link to the tank on the web? I will see what I can do once you get back to me.
Right now, I have 3 zones on my oil boiler each with separate pumps. You can see the tank online at: http://www.newhorizoncorp.com/hotwaterstorage.php There are 4 ports on each end spaced equally top to bottom, 2 ports on top, and 2 ports on the long side top and bottom. There are also two smaller ports on top for pressure gauges I assume. The reason I wasn't originally looking into a parallel set-up is that it seems to require an external DHW heater. I don't have the room to add one to my existing set-up which is why I purchased the tank I did. I have only a very small utility room for my oil furnace and storage tank.
Alright, here is what I think you were asking for. There are two pumps, one for charging and one for drawing. When the pump on the Wood return line runs, hot water is circulated through the oil boiler and then to storage and back to wood. When the wood is under temp, the pump on the storage line comes on and circs hot water from storage through the oil boiler.
I did not include piping to have the additional option of switching to primary/secondary. However, the simplest way would be to pipe a line from the top of storage to feed the zone manifold and then a line from the return manifold to the bottom of storage. These can be in ports or tied into other lines. With the use of ball valves you could simply divert the water that way.
Also, as I said before it may be a good idea to put an aquastat on the tank so that the drawing pump would not come on if the tank is under temp. This would need to be tied into a DPDT relay similar to how I control my drawing and charging pumps. See my system layout page.
I did not include piping to have the additional option of switching to primary/secondary. However, the simplest way would be to pipe a line from the top of storage to feed the zone manifold and then a line from the return manifold to the bottom of storage. These can be in ports or tied into other lines. With the use of ball valves you could simply divert the water that way.
Also, as I said before it may be a good idea to put an aquastat on the tank so that the drawing pump would not come on if the tank is under temp. This would need to be tied into a DPDT relay similar to how I control my drawing and charging pumps. See my system layout page.
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![[Hearth.com] In series water storage diagram.](/talk/data/attachments/10/10174-921e3e7e4f7127d309d4517d4cbb56d8.jpg?hash=kh4-fk9xJ9)
Thankyou very much for your time that is exactly what I was looking for. In your opinion is it that much less efficient to heat thru my oil boiler? I have a newer oil boiler and I heard of leaks from having the oil boiler cold.
I think that efficiency is more of an issue in the off season than during the heating season, so long as the boiler and plumbing are well insulated. It is less efficient, but how much depends on a lot of variables. A newer boiler should help the situation. If space is the issue, then this may be your only alternative. However, you could always locate the indirect water heater somewhere else and pipe to it which would allow you to still do a primary/secondary.
I noticed on second look at the diagram I posted that since there are two lines on the exit pipe from the oil boiler, when the Wood circ runs it would try to pull water through both bringing water into the wrong part of the tank. This could be solved by closing the valve on the cold line or could be automated by putting a Taco EBV in to close when charging is taking place and open when drawing. I hope that makes sense.
It will work in series, but as stated before is more efficient in primary/secondary.
I noticed on second look at the diagram I posted that since there are two lines on the exit pipe from the oil boiler, when the Wood circ runs it would try to pull water through both bringing water into the wrong part of the tank. This could be solved by closing the valve on the cold line or could be automated by putting a Taco EBV in to close when charging is taking place and open when drawing. I hope that makes sense.
It will work in series, but as stated before is more efficient in primary/secondary.
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