Addition of wood fired boiler.

Tom R.

I added an H.S.Tarm (Denmark) wood hot water generator to a 110,000 BTU oil fired system two years ago. Works great. Two items: (1)size the new mains and circ pump large enough to get as close to 5 deg. delta T as you can at the new unit. (2)Install lines with normally open solenoid valves directly from the new supply mains to the zones to bypass the flow control/zone valves so that convection will keep up flow after power failure. Don't recommend this with the PEX and the fan coil will need power to dissipate the heat. Failure to do this will surely cause a relief valve to lift if power is cut off while the unit is firing. Doesn't look like it will work without emergency backup power.

devo

Addition of wood fired boiler.

Hello , I am interested in adding a Buderus(recently acquired) wood fired boiler to my existing system. My existing system consist of a Buderus G124 (79,000 BTU output) boiler with 1 zone ( high temp fan coil) & 3 zones (low temp radiant) plumbed with P/S piping with the low temp controlled by a Wirsbo 101( Tekmar w/Bellisimo 3 way valve). This system has worked flawlessly for me for almost 3 years. The only thing I would have done differntly,retrospectively, would have been to use injection mixing. I had installed,what I believe, to be the better quality components ( IE: Buderus, Wirsbo, Grundfos,Tekmar,Bell&Gossett, Hydrolevel,Sparco etc) I am looking for the MOST RELIABLE setup that can be recommend to me because I have never studied wood fired boiler installations before and I am definitely one to want to learn the absolute proper methods. I would prefer simplicity over complexity but I am open to any and all responses to my inquiry. P.S. For all the contributors to "The Wall" I'd like to say Thank You for your opinions because when I first designed my system, there weren't many people in my area to consult with on hydronics/radiant. One or two wouldn't talk with me or even sell me equipment, knowing I was going to do the install myself.

devo

response to suggestion

Thanks for the input Tom! By the way; How do you like the Tarm? I just helped a close friend ( owner of a tree business) install a Pacific Western OUTDOOR/OPEN system (hydro coil and DHW heat exchanger) VERY BASIC setup! I had received a DVD from Tarm and tried to convince my friend that this was the way to go ( wood gasification). After spending approx. $5400.00(wood stove) $1200.00 ( 100 ft. insulated piping) $300.00(hydro-coil) $120.00( 1" PEX inside supply/return) $600.00 ( concrete pad and retaining wall) untold other expenses ie. pump, heat exchanger, pipe, fittings, rebar,forming lumber(concrete), gas( runnung around in a F-350(parts getter/GAS GUZZLER) and any and all other misc. plumbing items you can possibly think of, AND ALSO let's not forget ! NO LABOR! " FRIEND" ( Point!!! Me installing a WOOD boiler/ free wood /WHOOPS!!!!! Let me restate that "NO DIRECT OUT OF POCKET EXPENSES" I feel better!!!! I believe he figured he has between $9000-$10,000 in this setup. I was told the Tarm is "too expensive" That's right! I was at friends house last night and he had to "go for a walk" at 11PM to stoke the behemouth, walk down over the hill,in the snow/cold, fell on his ****, tear up the yard ( unload wood) If I didn't get the Buderus for the "right price" I would have been purchasing a Tarm. I plan on using the Buderus for only 1 or 2 seasons. There is another way to generate heat with the G124 unit beside using natural gas in this unit, I have been theorizing and experimenting with this for a while with an old gas boiler .

Tom R.

Glad to help

Good to hear you liked the suggestions - now:
Tarm was $4200 2 years ago. Picked it up in NH from the distributor. Comes with all controls mounted (except those I mentioned as add-on). It was installed in an existing chimney previously used for a wood stove. Inspection and repair= $500. Circulating pump, piping, fittings and insulation $245. Cellar holds 4 cords of wood, so I load wood inside I want to. Keeps 3000 sq. ft. warm (including attached garage kept @ 55 deg.) Next sring, we will install a 600 gal. open storage tank for buffer (for domestic H/W during summer and mild weather).
If I can find a 1946 Volvo from Sweden (they were made with CO generators burning wood) I can kiss the oil people goodbye for good.
For those who own outdoor furnaces - is there nothing better than going outside in subzero weather to load the thing, so that you can come back in again to get warm?

Tom R.

More wood

Did your friend tell you that he now has to build a shed to keep his wood dry? The Tarm does everything the factory says. No smoke except when starting cold, no creosote except INSIDE the firebox, and when running the combustion chamber looks like a blast furnace, just like in their video. And they hydro test these things at 65 psi! We are installing a 600 gal. open tank and submerged heat exchanger next spring to enable long burn times and extended periods without firing. In summer we expect to heat enough water in one day to supply domestic hot water for the rest of the week. By the way, the Tarm cost $4200 2 years ago, came with complete integrated control panel and external pipe mounted controls (including wells), temperature/pressure relief valve, tube cleaning brush and fire rake. Design and workmanship are outstanding.

Lloyd Nichols

Less wood, more heat easier...

That's what you get with wood gasification, as you have learned Tom. Thanks for the good words. Call anytime if we can help.

Lloyd

jim post

Tarm Addition

Add me to the list of gasification enthusiasts. I put a Tarm in my attached garage this past summer. The garage has proven to be an excellant location for the boiler. I piped the Tarm to our existing 3 zone hot water baseboard system. It has been working great. Without storage, it requires stoking 3 times a day in cold weather. It was down to 0 last night and the house stayed right at 70 degrees. Better yet, the garage was 55 degrees. Last year we kept the house at 62 to save on LP...And soda would freeze in the garage. Needless to say we are very happy with the Tarm.

jp

hr

Some gasification notes

I'm running a 40KW EKO Vimar. Important! a buffer tank is critical. These boilers like to run hard and hot. Hard to match the homes heat load to the boilers output.

I matched a 500 gallon LP tank to mine. This allows me to burn hot and store heat until it is needed.

Need to watch return temperatures to the boiler when you have that much buffer tank. I like the variable speed circulator method better than thermostatic valves, personally.

Dry wood is also important, perhaps some coal tossed in is also another tip.

hot rod

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jim post

storage

It's true matching the wood charge to the heat loss requires some effort...especially in the shoulder seasons...but right now with temps around here in the single digits...we load 'er up and she burns! We keep the tstats set at 70 and we end up loading every 8 hours or so depending on the temp outside. For us storage added compexity and cost to the already expensive proposition of a Tarm...We may go to storage in the future, but right now we don't mind tending our heat source.

jp

Keith W.

No s*&#t! That's a primary loop?!

That's a very funny picture. Artistry in primary/secondary design. Now, you don't have any thermal traps on your secondaries or anything, but... that looks very cool. Hah!

(Please correct me if I'm misinterpreting)

Tom R.

One exception

I agree with everything you said but the variable speed circulator. I prefer to pump constant volume and use a thermostatic mix valve to control return water temperature to the boiler. This assures that there are no hot or cool spots.

hr

a 3 way thermostic mix valve is

a flow restricting device As the port to the boiler closes based on temperature, it reduces flow through the boiler.

A variable speed circ, installed as in figure 3 of this article, actually assures the boiler has the exact flow required. The boiler circ, properly sized, handles this.

The VS circ just moves temperature from the boiler loop to the primary loop.

No Cv to watch out for as in a 3 way thermostatic.

Just another way to manage return protection.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,128051,00.html

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hr

Grundfos Super Brutes

with built in checks handle the protection to and from that primary loop. Good eye to catch that!

I actually removed the check from the circ to the buffer tank, to encourage some ghost flow. That allows a little bleed through, which is fine since that circ fires when the boiler gets to 160° anyway

hot rod

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Tom R.

3 way valve

Tarm supplies a mix valve which does not throttle the return water. Having a thermostat inside similar to an automobile (but acting in reverse - it closes on rise) it allows supply water to be introduced into the return to maintain temperature. Recirculating this way actually increases flow since the head is reduced to almost zero.

jim post

Tarm Set-up Photos

Ok, HR has inspired me to share some photos of my Tarm set up. I had a local dealer (Burner Boys) assemble, set the Tarm in place and install the chimney in July. I did the piping and controls with the help of the manual, the Burner Boys, and The Wall. I tied into my existing boilers return with a couple of closely spaced Tees. Seems to work very well.

jp

John Abbott

Tarm........

> Tarm supplies a mix valve which does not throttle

> the return water. Having a thermostat inside

> similar to an automobile (but acting in reverse -

> it closes on rise) it allows supply water to be

> introduced into the return to maintain

> temperature. Recirculating this way actually

> increases flow since the head is reduced to

> almost zero.



Is definitly the way to go.I installed a Tarm Gasification boiler with 600 gallon storage,separate oil back up,in a P/S piping arrangement and it works like a charm. After a week of firing we had two coffee cans of ash. The customer is thrilled and so am I.The Tarm Boiler exceeds my wildest expectations.

Tom R.

Boiler placement

Should you or the Burner Boys happen to install another Tarm, set it on 8" lightweight solid concrete block as in the attached photo. The ash container fits nicely under the ashpit door so you can rake the ashes directly into it.

jim post

8\" blocks

I would have liked to use concrete blocks since they would have matched the ashod better. In my garage install I tucked the boiler into an alcove and I had to match the elevation of the alcove floor. The alcove is directly above the landing of my basement stairs and decreases the amount of space the Tarm takes up in the garage. With clearances it fits very snuggly in the alcove which makes anything I have to do at the rear of the Tarm a bit of a hassle. I am willing to hassle so I don't lose much floor space in the garage and any smoke spillage and wood debris are not in the house. Plus I can check things out and restoke the boiler without having to go outside. Additionally, at -2 outside last night the unheated garage was down to 50 this AM.

jp

hr

In a garage, the code

requires the boiler be elevated 18" above the floor.

hot rod

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Tom R.

Wood

Yes it does! Ours is in a basement. By the way, I couldn't help noticing the wood supply alongside your boiler. Does the manufacturer recommend that small a size or do you moonlight installing flooring?

jim post

One other note...

on my install is the location of the Tarm boiler drain...It's not ideal...since I stuck the boiler mostly in an alcove and the back is difficult to get to, I have the boiler drain in a tapping in the lower left corner on the front...this fitting could get broken by a dropped piece of firewood while loading and create a bad situation. I need to come up with a way to protect it. Any ideas?

Thanks,

jp