HI, I'M A NEW MEMBER, BUT HAVE BEEN VERY INTERESTED IN THE "GARN" SYSTEM FOR THE LAST 5 YEARS OR SO......BUT THERE ARE STILL A COUPLE OF ISSUES THAT I NEED TO GET COMFORTABLE WITH BEFORE TAKING THE PLUNGE............I KNOW THAT THERE ARE NO ANSWERS THAT FIT ALL APPLICATIONS, BUT I'M GETTING MIXED THOUGHTS AS TO HOW MANY TIMES A DAY ONE WOULD NEED TO START A FIRE.  FROM THE "GARN VIDEO" IT SOUNDS LIKE ONCE IN 24 HOURS (AND THATS WAY UP NORTH ON  LAKE SUPERIOR) THEN I'M READING WHERE TWICE A DAY  BURNS IN A  MORE SOUTHERNLY CLIMATE, SEEMS TO BE THE "NORM"....... ANY ONE CARE TO ELABORATE AS TO WHAT THEIR HABITS HAVE BEEN.******  I ALSO HAVE READ ON THIS FORM THAT IT IS NORMAL TO GET SMOKE FOR THE FIRST TEN TO FIFTEEN MINUETS AFTER STARTING A FIRE...........THE "GARN VIDEO" DOESN'T SUGGEST THAT... ******AS I UNDERSTAND IT, ONE WOULD NEED TO BE AVALIBLE TO TEND THE FIRE FOR 2 1/2 TO 3 HOURS AFTER IT IS STARTED, I'M TRYING TO FIGURE WHEN THAT WOULD FIT INTO A DAILY ROUTINE (TWICE A DAY). ******* I DON'T HAVE TO BUY WOOD AT THIS POINT AND DON'T THINK THAT I WILL HAVE TO FOR ANY FORESEEABLE TIME, THAT BEING SAID,(WITH THE HIGH COST OF THE UNIT), WHAT MIGHT THE PAY BACK TIME BE. MY HOUSE IS APPROXIMATLY 2500 SQ. FT. I CURRENTLY HAVE A 100 GAL WOODMASTER THAT NEEDS FEEDING 2 TO 3 TIMES A DAY (DEPENDING ON THE TEMP.) I'M BURNING SEASONED MAPLE; SOME BIRCH; SOME OAK; AND A MIXTURE OF OTHER  WOOD.  SO FAR THIS SEASON I'VE CONSUMED ABOUT 10 FULL CORD OF WOOD. I HAVE RADIANT INFLOOR HEAT AND INSULATED FOR THE AREA(MID MICHIGAN).  THANKS IN ADVANCE FOR ANY ANSWERS TO THESE CONCERNS............LARRY

 Larry, welcome to the forum. 

 One point of etiquette - please turn off your caps lock. Using all caps is the equivalent of SHOUTING in a forum message or email.  Thanks.

Frequency of burn is dependant on how much of a heat load you have and the temperature of the water you need to heat your house.  If you are using radiant tubing in or under your floors, you can run water temps as low as 120-130.  If you are using baseboard rads, you can only probably go as low 140-150 to keep comfortable.  The GARN can comfortably be heated to 195-200 easy, which gives you a 50-75 degree "window" of heat.  So the anwer to your question is, "it depends".  You need to do a heat loss calculation for your house to get an accurate estimate of your input needs. 

 If the temps are below freezing, I burn twice a day.  I am heating a drafty farmhouse of about 2700 sq. ft. to about 70, as well as the ground floor of my 26x38 garage/woodshop to about 50 (that is uninsulated).  The burns are usually 2+ hours long.  You do NOT need to be there for the whole burn.  In the morning I light it at about 6:30, go take a shower, then add wood at about 7:15, then leave for work.  In the evening I light it at about 6:30 (after dinner) and reload at about 7:30 then forget about it.  The GARN is eeeeeasy to operate, believe me.

If you have burned 10 full cords of wood already, you will be amazed at how much less wood you will use with the GARN.  I go through less than a half cord/week.  Therefore, I estimate that would be at about 2-3 cords at this point in the season given the temps we have had (I live in the mountains of northeast PA).

BTW - I had cataract surgery last week and was "not allowed" to operate my GARN.  My wife and two teenage sons had absolutely no problem firing and loading it for the last week.   

Be aware of the large size of these units, and the need to build a well insulated structure to house it in.  The form factor is the only disadvantage of the GARN.  However, it is worth the time, effort and $$ to build a shelter to accomodate it.

Keep the questions coming!

jim,

thanks for the reply.....sorry about the CAPS thing, i never relized that.(i do it all the time ..wonder how many others i have offended????)    any way back to the issues....yes i'm using radiant heat in the floor on the main floor and the upper floor, the basement has baseboard but we don't use it so it is only set at 60 degrees. i also am heating my side walk(3"x200') but only to just melt the snow about 35 degrees .  i guess i need to get steve to come do a loss calculation.....he said he would.

yeh, i guess it sounds different when one talks about a 2 1/2 to 3 hour burn, but in reality one only needs to be around to reload and not until it is finished.  also i forgot to ask about what if you reach 200 degrees and there is still a fire going....what is the safety valve?.......i have  guessed that is why there are ashes when there aren't suspose to be any. i usally get up at 6;30 and leave at about 7;15 only thing different would be i would have to start the fire as soon as i get out of bed and maybe get up 20 minuets earlier, in order to stay on time. where as now i just take 5 minuets -just as i'm ready to leave- to stir the ashes and load the stove.

did i mis understand the video with "ernie "as to his temps and his frequence between burn cycles. i thought he  had 20 degree weather and 24 hour cycles. .......our temps have been mostly in the lower teens to upper 20's during  a 24 hour period........ what have your temps been this year, like ours????

why doesn't it matter ,what kind of wood one burns....does it only amount to the lenth of time between reloads?

what about ear corn...any info or anyone using it?

i under stand about the shelter thing....my stove i have now is in a leanto off my garage and that is where i also store my wood (15x32) . i have already measured as to a GARN fitting in there as well, i would only have to insulate around it ,which would be no trouble.  i already have the rolmax and studs are no problem.

what do you mean "the form factor"     

 thanks for the reply, and all the anwsers, 

 larry

Hello Larry:

If you are working with Steve, you are in great hands!

Burn time is how long the unit will be burning, NOT how long you need to be there.  Jim (and others) often "top off" their load part way into a burn, but you don't have to do that.  So the amount of time you need to start the unit is the length of time to put in the wood, light it and close the door.  That's it. You don't need to be there when it's done.  It really is pretty much "load and go".

There is no "safety valve" on a GARN unit for when the temperature gets up to 200 degrees.  The worst that could happen is that your water will boil when you get to 212 (depending on your altitude).  That's actually very hard to do and the only real consequence is that you might have to add some water to the tank.

Time between burns is all about sizing and application.  That's why you hear such variations from people.  To keep it simple:  If you need  120 degree water for your heating system and you burn enough wood to get the tank temperature to 200 degrees, you will have about 920,000 btu's stored in our WHS 1500.  If your heat load on the coldest day of the year is 100,000 btu/hr (which is probably high for you), you will get just over 9 hours of heat before you have to burn again.  You can burn sooner.  When it is not your coldest day of the year, your heat load will be much less and it could actually be days between the need to burn.  This is why you need to have some idea what your heat load is - if Steve has offered to do a calculation for you, then by all means, let him do it.

This means you can decide how often you want to burn by sizing the unit accordingly.  If you have the time and energy, you can go with a smaller unit and burn more often.  If you want to burn less often you can get a larger unit.  So Ernie's burn times and frequency are acurate for his heat load and Jim's are acurate for his - different heat loads, applications, and delivery systems.

The type of wood only makes a difference in how much you need.  Wood has the same btu content per pound no matter what the species, but the density varies.  Why this can be confusing is that wood is measured in volume.  A cord of oak is heavier than a cord of birch.  So a pound of oak has the same btu content as a pound of birch, but a cord of oak has more btu content than a cord of birch.

Ear Corn - GARN units are certified to burn air dried corn on the cob.  The btu content is low in that so you will need a lot of it, and at prices approaching $8 per bushel these days it's no longer a popular thing to burn.  

Thanks for the great questions.  Please keep asking.  As you can see, there are lots of good people here who will be happy to answer anything you want to know.

 Greg - thanks for the excellent clarifications.  I have been very curious about the ear corn potential, and you have given the first info I have found other than the brief mention in the manual.  I may have access to some farmland to grow my own ear corn on soon, so I am considering that as a possible supplement to the wood, especially when temps are not so cold.  What is the Btu/lb rating for dried corn on the cob?

Larry - Let me give you a real life example of todays GARN usage for my situation.  I fired my GARN this AM starting at about 5:45.  I burned for about 2.5 hours with one partial reload to get the tank temp over 180.  Starting temp was about 155 and ending temp was about 185+ (I left for work with almost an hour left on the fan timer).  It is now almost 8PM, over 12 hours later, and my tank temp is back down to about 155.  For 1860 gallons of water that is in my GARN, I have used about 465,000 Btus over more than 12 hours.  That means I have used about 38,000 Btu/hr.  Now, today has been fairly mild, right about the freezing mark with cloudy/rainy conditions (actually a nasty little ice storm), so there was no measurable solar gain.  On colder days/nights I only get about 8 hours between burns, which is a heat load of about 55,000 Btu/hr for the same 30 degree temperature change in the GARN.  So far I have kept my GARN temp above 150 because below that my oil furnace kicks on (my crappy aquastat on the old oil burner will not allow me to go lower).  I have all baseboard convectors, but I have more linear footage than I need in most of the house so I could actually run the GARN temps down to 140 and still get decent heating out of my radiators.  With radiant, you can go lower, as I mentioned before.

Jim:

The subject hasn't come up in while, but you made me curious so I did some thumbnail calculations.  I should probably point out that I may have some of the information wrong and this is not an official Dectra posting...  

This is what I recall for base info:

Btu content for wood is about 8500 btu/lb.
A Cord of wood is about 5600 lbs.
A Cord of wood is about 128 cubic feet.
A Cord of wood will cost between $100 - $200 depending on your location.

Btu content for Corn-on-the-cob is about 7000 btu/lb
A bushel of Corn-on-the-Cob (undried) is about 70 lbs.
Moisture content of Corn-on-the-Cob (undried) is about 75%.
Dried to 25% Moisture Content that would give you about 35 lbs/bushel.
A bushel is 1.24 cubic feet.
A bushel of Corn-on-the-Cob is going for about $8/bushel.

SO.....

The btu content of a cord of wood is about 47,600,000.
The btu content of a bushel of Corn-on-the-cob is about 245,000.

The equivalent amount of Corn-on-the-cob to a cord of wood for btu content is 194.28 bushels.

The wood takes up 128 cubic feet of storage space.
The Corn-on-the-cob takes up about 241 cubic feet of storage space.

The wood will cost you about $150.
The corn will cost you about $1555.

Plus - you need to burn about twice as much corn so you'll be burning twice as often.

My advice - Sell the corn for $1500 and buy 10 cords of wood and spend less time burning.   

Thanks for the question - that was a fun little excercise!

Larry,

This is my first heating season with my Garn (2000 gal unit) and actually my first time heating with a wood boiler.  I have to second and third everything that everyone is telling you.  It's simple, it's easy, and it's efficient. 

I'm located about 40 miles north of you, about 20 miles east of Cadillac so our operating conditions would be very similar.  After going through my learning curve on burning times and amounts, I'm currently buring approx. 1 face cord/week, give or take on the outdoor temps.  I'm heating approx. 5000 sq ft (all radiant floors and wall mount radiators) plus domestic hot water as well as keeping the barn where the Garn is housed around 45-50 degrees.  I've been buring the unit once a day.  I generally start my fire around 5:00pm with the water temp somewhere around 120-130 degrees.  Usually set the blower timer for about 3 1/2 hrs and load the unit about half full.  After an hour or so, I go back out and fill the unit close to full.  This will generally get ending water temp in the 185-190 degree area.  Sometimes, if I started with water temp at the low end, I might have to throw in a few more pieces and another hour or so on the blower.  In general, one burn in the evening will last me until late afternoon/early evening the next day.  But that is the beauty of these units, the water/btu storage to draw off of and the options of how you want to burn, 2 smaller burns throughout the day, morning and evening, or 1 bigger extended burn (at least that is what has worked for me). 

At any rate, all I can say is that I am extremely happy with the unit.  If you'd like to make the trip north sometime, just let me know and you are more than welcome to stop by our place to see our's face-to-face in operation.  I also continue to learn from everyone here on the forums, so keep asking questions as we all appreciate the insight everyone has to offter.

Mike   

Thanks Greg.  That was a perfect explanation and comparison.  Now it would not COST me $1550 to produce the corn, but if the price of corn stays at the record highs it is at now, that would be close to my opportunity cost.  However, I do not know how many bushels/acre to expect, so the yield per acre for each fuel must also be considered.  Either way, it appears that wood is hands down the way to go.

Greg:

Jim:

The subject hasn't come up in while, but you made me curious so I did some thumbnail calculations.  I should probably point out that I may have some of the information wrong and this is not an official Dectra posting...  

<Snip>

The wood takes up 128 cubic feet of storage space.
The Corn-on-the-cob takes up about 241 cubic feet of storage space.

The wood will cost you about $150.
The corn will cost you about $1555.

Plus - you need to burn about twice as much corn so you'll be burning twice as often.

My advice - Sell the corn for $1500 and buy 10 cords of wood and spend less time burning.   

Thanks for the question - that was a fun little excercise!

Mike,

Thanks for the invite I would love to take you up on your offer......The more I think about the GARN the more question I seem to think of. I woke up this morning thinking about the water testing and also the flue cleaning.....What can you tell me about these issues? Or maybe we can talk about it when I come up to your place.  Please let me know when it would me convient for you, maybe  on the weekend.       

THANKS, 

Larry 

Jim,

Thanks for the walk thru.....that helps me put it into perspective.  I'm guessing you have the "2000" model, by your mention of gallons. I'm thinking thats the one I might be leaning towards. I know "they" say not to over size, but I think it was Greg that said "decide how often you want to burn". I realize that there are more cost for the 2000 vs 1500, but I'm pushing the limit with what I have now and it isn't a good feeling. Maybe Steve will convince me otherwise when he does a load calculation.   Thanks again,   Larry

 Larry:

Garn has a program set up with a water treatment company that works like this. Initial water treatment for the Garn is sold with the unit and it in is packaged in concentrated powder form for easy handling. Along with that you'll receive a sample bottle that you fill and send back to the chem treatment company for analysis after letting things circulate and stabilize for a couple weeks. The chem company will scope out your water sample and send back any recommendations they have for further treatment. Once you are up and running they will continue to send a sample bottle to you every 6 months to keep tabs on your water quality for you and spot any issues that may arise. You don't lose a lot of water from a Garn because of the design so further treatment is usually minimal unless you have some very nasty fill water. Some users have asked me about using De-Ionized water or distilled water thinking it would be more pure and that is true. The fact is though that D.I and distilled water are actually more agressive than tap water and the chem company guy I spoke with recommends the initial fill be no more than half of either type. The only thing I would recommend is to avoid water that has been chlorinated such as a municipal water supply would be.  

Hi Steve,

I understand that part Iv'e read that somewhere, but how do you get a sample?  Just dip it out of the top? Is there a cover tha tkeeps stuff out of the tank?   From what I can guess from the diagram on the web site I'm mistified as how to clean the flues. Maybe things will be clearer when I go to see Mikes GARN. Let me know when we can do a load calculation.

Thanks.
Larry 

 Typically there will be boiler drains installed in the piping at various locations at the time of installation for accessing the system when needed.  There's another string of posts on here somewhere in which cleaning was discussed. Cleaning the flue tubes isn't something that you have to do very often and it's not all that difficult. The Garn has bolt on cleanout caps at the end of each tube which are accessible right on the front of the unit. I spoke with an owner who has a Garn installed in 1983 and he said he had cleaned the flue tubes 3X in all those years. It's not like a downdraft gasifier such as EKO or Tarm which have very small diameter flue tubes you may have to clean multiple times per season.

JERGY2.0:

Jim,

Thanks for the walk thru.....that helps me put it into perspective.  I'm guessing you have the "2000" model, by your mention of gallons. I'm thinking thats the one I might be leaning towards. I know "they" say not to over size, but I think it was Greg that said "decide how often you want to burn". I realize that there are more cost for the 2000 vs 1500, but I'm pushing the limit with what I have now and it isn't a good feeling. Maybe Steve will convince me otherwise when he does a load calculation.   Thanks again,   Larry

You're quite welcome Larry.  Yes, I have the WHS2000, which has an operating capacity of 1860 gallons according to Dectra Specs.  With the unique, integral storage design of the GARN, "oversizing" is a misnomer.  In reality, too much storage will mean potentially more standby losses, but between a 1500 and a 2000, that is negligible.  If you are just heating your house the 1500 should be fine.  If you are heating multiple residential sized buildings, a 2000 will be a better option to reduce burn frequency.  If you are heating a commercial space, the 3200 "whopper" is your machine.  The 2000 cost about 25% more than a 1500 last June when I ordered mine.  Check with your dealer for current pricing and steel surcharges (if there any now).

Gotta go do my morning burn.  It's been over 12 hours since the last burn, with overnight temps in the low 20s.