Physical location of dump zone, need for glycol, etc.

[horrocksd]

I plan to locate my Econoburn 150 in the far end of my barn which will put the boiler 90' from the house. I plan to install the boiler in a fully insulated and fire-stop sheetrocked and externally-vented boiler room framed within the barn (I have 8 restored collector cars in the barn and don't want to risk an explosion if one of those old gas tanks springs a leak, plus my insurance company won't insure the barn and contents if I don't have a code-spec boiler room). For the sake of preserving barn space I'd like to keep the boiler room to a minimum size with adequate clearances to the boiler and that would make the room 6' x 10'. I'd been thinking that I'd run glycol in the system just to be on the safe side and because I'd planned to run the overheat dump zone outside of the boiler room in the unheated barn space so that it could shed heat at maximum efficiency if the need arose.

Now that I'm planning 500 gallons of storage, the cost of glycol in the system looks to be prohibitive. If I understand correctly, the necessary mixture would be about 40% glycol and my full loop and storage capacity would require 224 gallons of glycol at around $15/gallon. Holy crap! That's $3300 just for the glycol, plus the thought of that much toxic stuff roaming around just waiting for a leak scares the hell out of me. Anyway, I'm wondering if I put the dump zone inside the small boiler room if it would shed heat adequately, and if not, are there any inexpensive options to isolate the dump zone so I could run glycol in just that loop? I can't see how since it would mix with water in the boiler jacket once it was activated. Any ideas and opinions would be greatly appreciated.

 

[webie]

Sometimes this is the case like me I use unpressurized storage . So even tho I have 1200 gals of storage I only am actually useing about 30 gallons of glycol . Un less you are really rich and burning wood ??? I wouldnt even think about a system useing glycol and large capacity pressurized storage .
You could run the dump zone in the house . I doubt a 6 by 10 room would be big enough for a dunp zone . I also think a 6 by 10 room is not big enough for your boiler . You will want some storage for wood in that room .
There is a way you could make it work . You could use a side arm and run a boiler loop dump through that then you run an isolated loop of say baseboard with a few gallons of glycol in it . This loop would need its own expansion tank and fill parts just like a heating system .

 

[horrocksd]

Webie,

Thanks for the reply, but the house is 100' away and I'm wondering how I would run a dump zone to it and hope the convection worked properly within the dump loop, and in the basement which is below the level of the barn. I guess I could run two un-insulated pex lines from the barn to the dump zone, but would convection drive that adequately if the power went off?

 

[ewdudley]

..
For the sake of preserving barn space I'd like to keep the boiler room to a minimum size with adequate clearances to the boiler and that would make the room 6' x 10'. I'd been thinking that I'd run glycol in the system just to be on the safe side and because I'd planned to run the overheat dump zone outside of the boiler room in the unheated barn space so that it could shed heat at maximum efficiency if the need arose.
..

If you've got headroom available a dump tank instead of a dump zone might work for you. I don't think it would need to be too large, maybe 100 gallons.

In case of a runaway boiler with a full load of fuel you would need enough water such that when converted to steam it would account comfortably for all the heat the boiler could possibly produce. If the boiler was blowing off and you were relying on the dump tank to replenish the boiler you'd need a vacuum break for the dump tank.

--ewd

 

[Tony H]

For dump you could do as Webie suggests just make sure you can shed heat fast enough ie have enough baseboard.
Where is the storage ? If it's in the house you can run with no glycol as long as you set it up with a power backup and keep the pump running. You could do the same if it's in the shed and you setup a backup heat source to keep the boiler room warm. It works nice with an HX and using gas/oil backup as this will warm the water as it pumps thru the furnace .
The other option would be the unpressurized storage.

 

[Trzebs13]

For a Safety dump zone. I used a 40 gallon hot water heater tank and that was more than plenty. If you get good thermal sphoning going it will work just fine.

Here is a thread to take a look at.
https://www.hearth.com/econtent/index.php/forums/viewthread/47187/

 

[horrocksd]

TRZEBS13,

Thanks for the suggestion, this looks like the way to go. It looks from the pics like you plumbed this in with 1 1/4 inch pipe. I would have thought standard hot water heaters would be plumbed for 3/4 inch. Did you have to do anything special to the heater tank to plumb this size? Also, I scrounged 40 feet of 1 1/4 fin tube which I'm thinking I could use as plumbing pipe to and from the tank.

 

[Trzebs13]

Actually I used 1" copper and Yes the tank has 3/4" NPT threads. You could drill those out and weld a larger nipple to it if you wanted, but I didn't. If I has some 1 1/4 finned tubing I would most definitly us that even if you had to reduce it down on the ends. Like I had mentened in that other post. You must put a heat loop in on the back / return side or else you will end up heating the water in the tank as well. I really like this system, it is sympel and very little to go wrong. Works on a little thing called gravity. Any question don't hessitate to ask.

 

[Trzebs13]

I re read your original post. I'm hope you get that this is not my dump zone. It is my safety dump. Or what ever you want to call it. This only activates in the event of a power outage and If there would be a roaring fire going. My dump zone is actually my basement floor. So let run threw it. The house calles for heat, the damper opens and starts the blower or the pump for the basment floor. Then once the house is satisfied the blower or pump shut off. By this time there is still 130,000 BTU's coming out of the boiler. The temp rises to 190 deg and the dump aquastat is tripped which turns on the basement floor pump. Even thou the thermastat says it dosent need heat. The water temp comes down to 170 deg and the dump turns off. Depending on the fire size, amount of wood. This may happen as much as twice before the fire box is cooled down enough with the damper closed. I'm assuming if your planning storage that you would hook up your dump to your storage. But in my opinion you still need a safety. Like you said you would rather not burn the place down. And this certianly helps me sleep at night.