new piping for Eko 40 install

[powerspec]

I hope to get this Eko 40 going soon. Will this piping arrangement work? Is there a chance that the load circs will short circuit cold water from the Eko (or the electric heater) when the boiler is off instead of drawing hot water from the storage? The connection tees for the loads and storage are 3 feet vertical above the top of the tank and the Eko. I have only these two connection points for the pressure storage tank.
The piping will be 1.25 inch steel pipe.
Comments welcome, this is a great web site!

 

[stee6043]

I'd move your primary circ to be "after" the Danfoss valve. Everything looks okay to me. The short circuit issue with the boiler is prevented by the Danfoss valve. If you're running water through the boiler eventually it will cool and the Danfoss will close. This will force your flow through storage. Even though I'm not sure that would ever happen to begin with...

 

[Bricks]

Correct me if I am wrong but on your waste heat valve is that for boiler protection ..loss of power if it is would that not be normally closed valve?

 

[DaveBP]

Where does the return water from the building come in to the boiler/storage part of the system?

And yes, the circulator does need to be between the Danfoss and the boiler.

Edit: Oh now I see it.

 

[WoodNotOil]

When the pump runs to supply zones it seems to me like it will be trying to pull water from all three heat sources (Wood, Storage, & Backup). What controls which source is being used? Usually there are additional zone valves or pumps used to turn flow on and off. I don't see anything like that on your schematic. Am I missing something?

 

[powerspec]

No you are seeing what I hope to build. The idea I have is that the hot water from storge will be lighter and faster to move than the cold water in the shut down boiler so that the load circ will alway be drawing in hot water. When the boiler is firing there is no problem. It's just when the boiler is off and cold I need some assurance that this scenario will not mix hot storage water with cold boiler/ electric heater water. Avoiding large zone valves at each heat source and unneeded circs is the idea. Will it work?

 

[DaveBP]

You could fudge the flow resistance in the pipes to your favor.

If the return from building zone valves were tee'd into the top of the tank there would just be a lot less friction for the flow to go through the tank than through the boiler or electric heater. You'll never have zero flow through the other routes but you can cheat as much as possible, insulate the pipes to minimize actual loss from the water.

 

[Gooserider]

1. I would move the control valve for your dump zone to just above the tee on the boiler outlet - otherwise you are likely to get a lot of ghost flow in the dump zone. You might also need a flow check on the return side to keep from getting ghost flow there as well.

2. I don't see how you can get charging in the storage tank - or return from the house zones. If I'm reading your diagram properly, when the boiler heats up and the bypass valve closes, then the boiler pump will be pushing water out the return side into the storage tank, possibly mixing with the house zone return feed. I think the pump needs to move a bit, so it's on the supply line to the storage tank, and with a zone valve between the boiler and the storage tank. You want the pump to push water into the loads and the storage tank when the boiler is running. When the boiler is out, close a zone valve to cut it out, and the house boilers will pull from the storage tank. Maybe add a second ZV on the return line to the storage tank and boiler so that when it is closed flow is forced through your backup heater.

3. Don't forget your expansion tank and fill / purge plumbing.

Gooserider