Tarm solo 30 or 40

[chuck172]

Solo 30
100,000 btu output, 4.01 cu.ft. firebox, holds 41 gal.

Solo 40 ($600.00 more)
140,000 btu output, 5.35 cu.ft. firebox, holds 54 gal.

Bi-level, 1800 sq. ft. main floor, full,unfinished basement for now, (no baseboard down there yet) I will install fin-tube.
We use plenty of hot water, whirlpool tub.

I'd like to get the boiler soon, no storage this year, probably next spring.
Should I get the 40 to be safe, will I burn more wood with it?
I was told by the tarm people if I choose the 40, I may have to tend the boiler more the first winter, because of no storage, smaller more frequent fires. Next year-with storage, definitely no problem with the bigger unit, as a matter of fact it will be more convenient because I can run full load at max. less times.
Using the slant fin heat loss calculator I came up with:
108,658 heat loss (btu/hr) that's with heating the basement with allot of baseboard.

 

[sweetheat]

Hi Chuck: Just for comparison. 1176 sq. ft radiant slab and 1176 sq. ft. 2nd floor. I purchased the Tarm solo 40 with 806 gal. open storage. Their recommendation. Not installed yet. Will be before next fall/winter. I'd recommend the 40. good luck sweetheat

 

[Reggie Dunlap]

I'd go with the 40. The cost difference is minimal and you'll be OK if you add an addition, a hot tub, or an outbuilding in the future. A slightly oversized boiler has no downside as long as you have adequate storage.

 

[chuck172]

Looks like it will be the 40. I hope nothing comes up to change my mind. I'd really like to be sure of at least one thing with this project.
thanks,

 

[begreen]

I hope nothing comes up to change my mind. I'd really like to be sure of at least one thing with this project.
thanks,

That's easy - Your wallet will be much lighter when it's done! ;-)

 

[sweetheat]

You have to think of the payback. Just imagine the money you will save over time, and the clean burns. Helping us who live downwind breath easier.
If you can afford the heat storage, open or closed, you'll be glad you did it.

 

[chuck172]

Storage is a definite, 800 gal. like yours. Next spring though. For this winter its the solo 40 and reline the chimney. Probably put down the deposit within a week or two. Starting to hash out the piping. I think its all mentally coming together. This forum is great.

 

[jebatty]

When you get your 40 (and all other Tarm users), consider adding the home-made chain turbulators. I got flue temp reduction by about 100F, translating to about a 3% increase in efficiency, for $0, as I had an old chain in the barn.
https://www.hearth.com/econtent/index.php/forums/viewthread/13237/

 

[sweetheat]

thanks Jim: So your leaving the 1/2 inch chain in there all the time? Is'nt that restrictive? By reducing the flue temp your increasing the heat transfer to the tubes? What is it? fly ash? carbon? what do turbulators from tarm cost? what is a turbulator? just a round wire brush?

 

[jebatty]

So your leaving the 1/2 inch chain in there all the time? Is'nt that restrictive? By reducing the flue temp your increasing the heat transfer to the tubes? What is it? fly ash? carbon? what do turbulators from tarm cost? what is a turbulator? just a round wire brush?

I'll take a pix and post later. Yes, leave them in the hx tubes, and just remove and clean them when you clean the hx tubes. Yes, restrictive to some extent, but you likely will have to adjust the draft fan anyway, so just adjust it to get appropriate flue temp with the turbulators in place. I aim for 400-500 on the probe thermometer. Turbulators "turbulate" the hot flue gases, increasing contact with the hx tubes, thus improving heat transfer and efficiency. The 40 has 8 hx tubes, and Tarm-purchase turbulators are about $20 each, I think. The chain turbulators are exactly that, a chain. The chain I used was barn cleaner chain, which has quite large links. I think you want to get chain that leaves a little (1/4") clearance from the hx tubes. Other turbulators come in a variety of designs.

 

[free75degrees]

When you get your 40 (and all other Tarm users), consider adding the home-made chain turbulators. I got flue temp reduction by about 100F, translating to about a 3% increase in efficiency, for $0, as I had an old chain in the barn.
https://www.hearth.com/econtent/index.php/forums/viewthread/13237/

Another great piece of info from the Hearth! I am definitely going to experiment with chain turbulators. How do you measure the flue temp?

 

[Eric Johnson]

You can buy an internal probe stack thermometer for about $25. Condor makes one. Or, you can get a barbeque probe thermometer for a lot less. You drill a small hole in your stove pipe and poke the probe in there.

 

[bbb123]

Here is a picture of the Tarm turbulators. NoFo had some made for his Eco did he ever post any results?

 

[chuck172]

Do the turbulators just slow down the velocity of the hot gases?

 

[free75degrees]

Just a guess, but the intention is probably to avoid laminar airflow, which occurs when a fluid moves in a very orderly manner, which would cause the air near the edges of the tube to cool down as they lost their heat, and for the hotter air in the middle to stay hot. This is a bad scenario because we want to the hottest air near the edges. So the turbulator probably just ensures that the heat is evenly mixed in the tubes (and probably slow the air a bit as a side effect)

 

[bbb123]

Just a guess, but the intention is probably to avoid laminar airflow, which occurs when a fluid moves in a very orderly manner, which would cause the air near the edges of the tube to cool down as they lost their heat, and for the hotter air in the middle to stay hot. This is a bad scenario because we want to the hottest air near the edges. So the turbulator probably just ensures that the heat is evenly mixed in the tubes (and probably slow the air a bit as a side effect)

Yes what he said.

 

[chuck172]

Makes sense.

 

[Eric Johnson]

Just as a point of interest, the turbulators on the EKO, Biomax and Econoburn gasifiers double as heat exchange tube cleaners. When you move a handle on the side of the boiler, a rocking mechanism moves them up and down in the tubes, knocking most of the soot, ash and other crap back down into the ash pit.

 

[bbb123]

Eric do you ever have to take them apart and do a "good cleaning" If you do please take a picture I'd love to see how they work.

 

[Eric Johnson]

I've got better pics somewhere, but can't find them at the moment.

What you're seeing in the first pic is the view into the back of the boiler from the chimney connection, prior to the first firing. The turbulators are the vertical pieces of steel (there are 16 hx tubes and thus, 16 turbs). The horizontal piece with the cotter pins pushes the whole works down or pulls it up, depending on the position of the lever. There's an identical assembly in front of what you see here, (currently below the bypass damper) covering the other 8 tubes. There's a shaft connected to the handle that rocks the whole thing back and forth.

The second pic is my modified snow shovel handle that allows me to do the cleaning operation from the front of my boiler. Because I only have about an inch of clearance on either side, it's a lot easier than walking around to the back. They say to shake the handle every time you load wood. I did that all winter, and it never got jammed up.

 

[jebatty]

Take a look at the chain turbulators I made. The speckled stuff on top of the hx tube box is fly ash from burning jack pine. I clean the top of the hx box each time I brush the hx tubes. No creosote. After a full season of buring, except for a small accumulation of ash at the top of the chimney, the stainless chimney itself is practically clean.