Help with Tarm Boiler Install

D. Burch

I am located in NC and plan to install HS Tarm 2200 boiler with 920 gal heat storage tank. I am having difficulty with getting estimates on labor involved as I am purchasing parts through dealer. Anyone who is familiar with these units and the time a typical install takes when tying into radiant floor (manifold brought to heat tank), a forced air heat exchanger and household hot water I would appreciate your insight.
Also, given my climate as mild/moderate is this a worthwhile investment, considering that I am looking for a dual fuel type system that these units are? This unit is wood & LP gas.

Steve Eayrs

Tarm and most other multi-fuel boilers...

will not give you as good efficiency as two seperate units (say a gas boiler & wood boiler), piped together. I don't know the exact size of the Tarm you are talking about, but they are overkill for most houses. Both in price and btu output. A gas boiler sized for your house, and a wood for backup may combined not cost that much different than the Tarm.
I have only installed 2 tarm boilers, both around 15 years ago. These were oil-fired/wood boilers, and both had problems setting up for proper draft on the wood side and still run efficient on the oil. One of these has now been replace by an oil-fired boiler.
If by chance you determine you don't want to use the wood side anymore, (say your wood splitting son moves away), you will be stuck with a less efficient boiler.
Also as far as costs involved......they will vary a lot. Lots of ways to pipe all your concerns. What kind fo tubing is installed in the slab? If there is no oxygen barrier, forget the steel tarm boiler. If I was you I would automatically throw out the low bids, and talk to the guys in your area who know whats up.
If you are going with the Tarm, I would personally want to talk you into using Tekmar controls, with injection pump for the radiant side, and oudoor reset for the mass of the boiler. This would also prevent overheating the radiant floor. Another concern with the wood side of the boiler.....You need to pick a big zone, (have a need for a snow/ice melt system on your driveway?), to dump the excess boiler heat, in case of too big a fire, and the boiler overheats.
Any cost (excluding the boiler and including the material and labor in the boiler room ONLY), should be at least $6000-9000.... maybe more. May I ask why you are buying this boiler yourself? You should realize most contractors will not cover any warranty work if you do. A contractor should be able to buy this for less than you, mark it up to cover labor for misc. small warranty issues for a year or so, and not be that much higher than what you are paying....Or is the bunch you are buying this from going to show up at your house and fix it if it breaks.??
You also need to realize the boiler is just the biggest component to your system. There are lots of other things needed to make it work good. Don't hire someone who plans on leaving about 1/2 of them out.
Hope this helps,
Steve

Steve Eayrs

I should let you know....

That I live and work in Homer, Alaska....Even here I have seen these things be oversized.
One more thing. I don't know who your dealer is, but my experience is they know how to sell parts...that most of the time they could not put together themselves. Maybe their different than usual, but don't be surprised if you end up needing a lot more than they gave you.
No offense intended, but I can understand very well why you would have a hard time finding someone to install this for you and stand behind it, when a salesman is picking our what you need to make it work right. If you were to turn these choises over to the right professional, you could spend less and get more.!!
Steve

John Madden

Tarm Multi-Fuel

Steve has it all right. If a boiler is designed to burn solid fuel, and you burn a liquid fuel(oil) or worse yet a gaseous fuel(LP or Natural Gas) the flue passages are much too large to get any sort of efficiency. Also when comparing fuels remember that a) no fuel can be burned at 100% efficiency. That being said 1 gal #2 fuel oil @ 100% =140,000 BTU's. 1 gal. LP Gas @100%=91,690 BTU's (approx.25% less potential heat from LP than Oil) check your cost per gal in your area.
I live,work, design. install, repair, maintain all types heating systems in the "Frozen North Country" (Northwestern Vermont on the Canadian Border) where we get dips to-30°F and can tell you from experience you need a "BIG" dump zone to get rid of excess heat generated from a solid fuel unit. You are probably going to use the "storage" system that Tarm is selling and that is OK but unless you are real careful about firing the boiler you can and will still get into trouble.
Many people are fooled into believing that heat will be available from a solid fuel unit in a power failure situation. NOT! unless you have power to run circulators the only heat you'll get is when you pull the burning wood out of the firebox.
Installation by persons unfamiliar with solid fuel appliances should be avoided at all costs. Unlike Oil or Gas units, once a fire is lit, the unit will generate heat wether you want it or not!! If for any reason (and there can be many) you can't get rid of that heat you will be forced into "drawing the fire". That last resort when the boiler room is full of steam and scalding hot water from the relief valve. And of course you will now add a pile of wood smoke from the camp fire which is now burning on the boiler room floor. (Been there and done that for an unwary customer when it was -22°F) because of a siezed circulator.
Find someone QUALIFIED in your area to talk too before embarking on this journey. Check out systems they have put in. Then check with the system owners to see if they still burn solid fuel. Ask them questions, LOTS of questions! then evaluate your situation again before plunging in head first. Fifty pounds of wood makes a LOT of HOT WATER.

Mark Hunt

Steve is right. I would add that in order to get the maximum efficiency out of the wood side, you need to burn it as hot as possible.

One of the biggest problems with wood burning devices is that when folks try to throttle down the air the wood smolders and the combustion chamber and connected flue piping will get lined with creosote very quickly.

You need to burn the wood flat out and store the heat in the storage tank. When you first start the system this won't be a problem because of all of the thermal mass you will have in the tank.

Once you have the tank heated you may not require all of the btu's that a good fire will produce. What to do with all those "extra" btu's?

You will need to build smaller fires and burn them HOT. The near boiler piping will need special attention and be piped so that the boiler is protected from the low return water temps coming back from you radiant floor system. This is EXTREMELY important.

The Tarm boiler, unlike other dual fuel units, has seperate combustion chambers for the wood and oil. That's a good thing. But they both vent through the same breeching and setting up the draft can be tricky at best. And since they use a common vent, it is doubly important to keep it CLEAN.

In the area I live in there has been an increased interest in wood as an alternative fuel. I try to educate my customers as to what they are getting themselves into. Wood systems are high maintenance and require that you be more familiar with the combustion process.

I hope everything comes together for you.

Mark H

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hr

A good wood burning article

This goes into some of the points of wood fired boilers. As the others indicated a buffer tank is an important piece of the puzzle. The piping that will provide adequate return temperature protection, buffer capacity, and over heat dump zone can be a bit involved. Best to find someone who has experience in this arrangement.
Although often sold as a DIY package, my experience indicates the safe workable installation and set up is a bit beyond the average homeowner. Plan on spending thousands to have a qualified boiler piping person supply and install all the appropiate piping and controls.

I currently have two wood boilers at my home and shop, I'm still searching for the ideal piping and control arrangement. Wood burning is work! If you have the time and energy it's a fun hobby, or job

All in all a wood burning stove in the home would be the simpliest way to wood heat.

Here are a couple links for more info, cut and paste them into search.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,4498,00.html

Also try www.woodheat.org

Good luck

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George Peteya

Even HS Tarm will...

... tell you that if you ever get lazy and let the gas backup take over, you will have a very inefficient gas boiler. Do the mirror test. Look in the mirror and tell yourself that you'll keep that wood fire burning at least 99% of the time. If not, go for separate wood and gas boilers and get the best of both worlds. Oh, and Tarm says you need to install a heat dump loop, capable of taking 10% of the boiler's rated output, or no warranty. For the 2200, I think that's 14,000 Btuh of dump capacity.

Scott Nichols

wood burning boiler myths

I would like to dispel a few myths about wood burning boilers. Not all wood burning boilers burn with the same technology. Tarm boilers are one of the few that have, since their introduction to the North American market in the 1970s, changed combustion designs as technology improved. Tarm USA now offers multi fuel wood burning Tarm boilers with completely seperate wood and liquid fuel chambers. Heat exchange is also completely seperate. This allows high efficiencies for all fuels. We obtain 80% wood efficiency, 87% oil efficiency, and 83% gas efficiency. These boilers also effectively control operating temperature to a degree that over-heating and triggering of dump zones is almost unheard of. (Of course, a dump zone is always required.) Today's Tarm boilers burn downward with a fan assist. When the boiler reaches operating temperature the fan assist shuts off. Without this fan pushing the exhaust from the chamber, no fresh air for combustion can enter the firebox. Combustion decreases to a dormant bed of coals extremely quickly. We operate our boilers at 180 degrees. While burning with a full load of wood, if the boiler reaches 180 deg. and our fan shuts off, we will normally see a 5 to 10 degree temperature creep. within about an hour the boiler temperature normally begins to drop. Coincidentally, as the boiler temperature decreases, it will reach a point when the fan will be turned on and the dormant fire will be reignited. In other words, these boilers cycle on and off as would a liquid fuel boiler. These boilers produce virtually no soot outside of the firebox. I have burned approximately 25 cords without a chimney cleaning and I can still see the steel on the inside of my chimney. As for the heat storage tank, we are using these to store heat, which allows a continuous burn. This style of wood burning allows even higher combustion efficiency. It also allows 4 season wood use, enormous burning flexibility (one fire per day in cold seasons, one fire per week in warm seasons), and takes away the guess work of when to fire the boiler. We usually size a heat storage tank so that it will be able to absorb all of the heat the boiler can produce when a full load of wood is burned. Finally, we encourage heating professionals to install AND PURCHASE these boilers. There is no substitute for a properly trained, educated, and up to date heating professional.

Steve Eayrs

technology improved on Tarm

I am glad to hear that there have been improvements on the Tarm multi-fuel boilers......but I believe we both realize that the real myths are not the things that have been said in all of the above messages, but Tarms claims that all of these complaints are not valid. In the real world, with the real consumers, these boilers have not worked too well. I would have to say that my biggest complaint (when I had Tarm problems years ago), was not that there were design flaws, but that when Tarm was approached with these very real problems, (not myths!), they spent all of their energy trying to convince the owners that the only possible problem must be the way its installed.....Which means I spent a lot of unpaid time trying to make something work, and trying to convince the owners that I was not an idiot. The only concern Tarm had was to look good, regardless of the facts. The improvements sound great, 25 cords of wood and still running clean sounds like a miracle (or perfect lab conditions), but I would conclude that they are the real myth, until proven otherwise, not the other way around.

Steve

JerryJ

Tarm boilers

We have a few around here that will not soot up the chimny regardlessof what type wood is burned. The new series is completly different from the first ones