Garn Junior Questions

[huffdawg]

Dectra says the Garn could heat a little over 2000 square feet + a two car garage.. I heat roughly 4600 square feet plus two DHW tanks, 60 and a 40 gal... with me EKO 40. surely the Garn Junior can out perform the eko 40? Our climate here is a lot milder thats for sure.

Also noticed the supply outlet is a lot larger than the return . just curious why?

Huff.

 

[surefire]

The supply outlet (and piping to the pump) is larger to reduce the inlet friction to the pump in order to reduce the risk of cavitation.
Here's some reading:
(broken link removed to http://www.fluidh.com/cmsAdmin/uploads/cih-taco5aselectingthepump-website.pdf)
Check out page 11.

Chris.

 

[surefire]

Are you going to keep your 1000 gal storage if you go with the Garn Jr? With these units it's not a matter of how much it can heat but how long you get to leave it between burns. Unless the load is so huge you're burning continuously...
From the specs:
Eko 40: 137kbtu/hour
Garn Jr: 180kbtu/hour

That tells me that there's more horsepower with the Garn Jr, so it will heat storage faster. As well, if you keep your present 1000 gal storage you'll be effectively doubling your storage and therefore (roughly) doubling your time between burns.

 

[hobbyheater]

(broken link removed).
The website has a customer location (broken link removed) The site shows some of the bigger Garns sold on the Island; a Garn 2000 in Courtenay and Garn Jr in Maple Ridge. Gord Bullen is the owner of Advanced Wood Heat. I'm sure he would help you to go and see one in operation.

Garn on the barge going to Quatsino.

Getting off the Barge.

At the Lodge. Gord standing beside the Garn with one of his children.

 

[Woodfarmer1]

I'm heating 3400sf plus another 1700sf in my basement slab, which I won't heat until the dead of winter.
Right now if I heat the Jr. To 180* it will easily coast 12 hrs between burns. I have in floor and a couple stelrads.
Then my boiler temps are down to about 110*, so I relight and burn a heaping wheelbarrow load of wood, in two shots to bring the temp back to 180*. So that's 40* with each full burn just under two hours a burn.

I started two years ago with a profab empyre elite 100, 60 gallons of water, they said you don't need storage, BS! I digress, now one full season with the Jr. And a very long cold winter it was. As was mentioned above it all about the time you want between firing. I will usually need to fire at least every 6 hours when it gets into the minus temps.

If I want to maintain my system at optimal 160* I'd need to turn my backup propane boiler on, (we won't do that now will we.) our hydro cost keep increasing all the time so I didn't opt for the electric heaters in my Garn, if you have dirt cheap hydro I'd recommend them to keep your water at a constant temp. Which is the only knock against heating by batch burn.

 

[Mike Fromme]

Probably a case of not overstating expectations. But I remember someone saying that you can't burn in a garn 24/7 and expect max output... Need to let the coals burn down from time to time to get max rated output.

 

[huffdawg]

Are you going to keep your 1000 gal storage if you go with the Garn Jr? With these units it's not a matter of how much it can heat but how long you get to leave it between burns. Unless the load is so huge you're burning continuously...
From the specs:
Eko 40: 137kbtu/hour
Garn Jr: 180kbtu/hour

That tells me that there's more horsepower with the Garn Jr, so it will heat storage faster. As well, if you keep your present 1000 gal storage you'll be effectively doubling your storage and therefore (roughly) doubling your time between burns.

Was going to sell the tanks with the boiler but now you got me hummin and hawing... thats a good point. 2000 gals storage would be nice.

 

[huffdawg]

(broken link removed).
The website has a customer location (broken link removed) The site shows some of the bigger Garns sold on the Island; a Garn 2000 in Courtenay and Garn Jr in Maple Ridge. Gord Bullen is the owner of Advanced Wood Heat. I'm sure he would help you to go and see one in operation.

View attachment 168597
Garn on the barge going to Quatsino.

View attachment 168598
Getting off the Barge.

View attachment 168596
At the Lodge. Gord standing beside the Garn with one of his children.

I Luv install pics.. thanks HH. Will contact Gord in the near future.

 

[Buzz Saw]

Was going to sell the tanks with the boiler but now you got me hummin and hawing... thats a good point. 2000 gals storage would be nice.

Does the Jr have a large enough firebox to heat 2000 gallons? Would you have to load twice to heat that many gallons?

 

[mr.fixit]

Not to be to discouraging huffdawg, but seems like you have a nice setup with plumbing and storage as it is now. Seems like it would be a shame to rip it all out because of a couple minor issues.
Have you thought about a hood over the eko loading door to catch some of the smoke?
Do you have adequate draft on your flue?

One downside on the garn is (someone correct me if this is incorrect) the need for a water to water heat exchanger between the garn and the rest of the system.

I think if you were set on changing things you would be better off just replacing the eko with something a bit more sophisticated like the froiling.

 

[surefire]

Extrapolating from what Woodfarmer1 says above, you would probably have to load four times. At two hours a load, that's an eight-hour burn, but after the last loading you wouldn't need to be there, so that's six hours of your time. They say you don't have to babysit it so you could be doing something else between loadings. Or what if you threw a load in after work, then one before bed, then one in the morning as you leave for work?

(I'm no Garn pro, I've just read every single post on Hearth regarding Garns...and hopefully someday I'll be posting install pics here!)

All due respect to the poster above, but I've never heard about having to let the coals burn down once in a while for max output. If you had so much to heat that you had to burn continuously you'd have to stop burning sometime to remove ashes, but that's it. Your point of maximum efficiency is the full-out burn, ie gasification.

 

[surefire]

Not to be to discouraging huffdawg, but seems like you have a nice setup with plumbing and storage as it is now. Seems like it would be a shame to rip it all out because of a couple minor issues.
Have you thought about a hood over the eko loading door to catch some of the smoke?
Do you have adequate draft on your flue?

One downside on the garn is (someone correct me if this is incorrect) the need for a water to water heat exchanger between the garn and the rest of the system.

I think if you were set on changing things you would be better off just replacing the eko with something a bit more sophisticated like the froiling.

There's no need for a heat exchanger. See this recent thread:
https://www.hearth.com/talk/threads/when-to-use-heat-exchanger.149153/#post-2004850

 

[Mike Fromme]

Extrapolating from what Woodfarmer1 says above, you would probably have to load four times. At two hours a load, that's an eight-hour burn, but after the last loading you wouldn't need to be there, so that's six hours of your time. They say you don't have to babysit it so you could be doing something else between loadings. Or what if you threw a load in after work, then one before bed, then one in the morning as you leave for work?

(I'm no Garn pro, I've just read every single post on Hearth regarding Garns...and hopefully someday I'll be posting install pics here!)

All due respect to the poster above, but I've never heard about having to let the coals burn down once in a while for max output. If you had so much to heat that you had to burn continuously you'd have to stop burning sometime to remove ashes, but that's it. Your point of maximum efficiency is the full-out burn, ie gasification.

Guess you haven't read every post then.
https://www.hearth.com/talk/threads/garn-whs3200-wood-gun-e500-part-2.65342/

 

[huffdawg]

Not to be to discouraging huffdawg, but seems like you have a nice setup with plumbing and storage as it is now. Seems like it would be a shame to rip it all out because of a couple minor issues.
Have you thought about a hood over the eko loading door to catch some of the smoke?
Do you have adequate draft on your flue?

One downside on the garn is (someone correct me if this is incorrect) the need for a water to water heat exchanger between the garn and the rest of the system.

I think if you were set on changing things you would be better off just replacing the eko with something a bit more sophisticated like the froiling.

Not discouraging at all. Still not decided anyways.. I actually have a hood that I had made up but I never installed , just open the boiler room door when if I load during a burn. I have thought about a froling also but for the same price I could get a Garn Jr. I think. I was going to make my boiler room bigger anyways so I have space for a half decent mancave in there. Also if I got rid of the two five hundreds I would have a lot more room in my shop.The size of the wood you can burn in the Garn is a huge factor also, got tendonitis in my left arm from splitting all the small splits the EKO needs..

I have good draft when the secondary is open , but when the primary is open the smoke likes to billow out.



D

 

[surefire]

Guess you haven't read every post then.
https://www.hearth.com/talk/threads/garn-whs3200-wood-gun-e500-part-2.65342/

Hey, thanks! That's precisely the post of which I was remembering.

 

[surefire]

The Garn System Design Manual talks about plumbing systems both with and without heat exchangers. Starts on Page 23.

http://www.garn.com/wp-content/uploads/general/manuals/GARN_Design_Manual.pdf

 

[Kwehme09]

I am not sure about the GARN Jr's BTU's and how many your place will require, so I will speak broadly and say this:

Running an undersize GARN sucks. You end up in a weird purgatory where your individual fires blend together, you build up coals and you get none of that sweet coast time. They are meant to be batch fired, and they are meant to utilize their storage and undersizing takes all of that away.

I ran a 3200 for 5 years in the White Mountains. It was grossly undersize for the demand. We had plenty of oil backup, but bouncing between oil/wood on that large a system is a big management headache, even when you are doing it through relatively sophisticated controls.

Someday I'd love to put a GARN on my little homestead. When I do, I will oversize it a little from a BTU standpoint, and put in extra storage and give myself a few places to dump heat if need be.

 

[Woodfarmer1]

It is good to know that the Garn can be fired continuously when required. The other side of the equation though is having enough wood on hand. I'm a one man show so the logging and c/s/s 5-6 cord is about all I have time for. I wouldn't want to run out of wood by the 1st of March either.
As last year was my first year with the the Garn, I'm really going to have to experiment with different fire times. The last fire is usually around 9:30 pm so that doesn't leave much heat in the system by 6am.

 

[Mike Fromme]

In the post I linked @jebatty states that he wasn't able to get the rated btu output when loading every hour due to coal buildup. It was ~30% less. kweheme seems to be saying he had a similar experience...it's best to batch fire to let the coals burn down.

That's not necessarily a bad thing. Just something to keep in mind when sizing the system. And could help explain the OP's initial question/comment. Even though a Garn jr can put out 180k btu intermittently it can't be expected to do it 24/7. 180k btu minus 30 percent would be about what it takes to keep 2000 sq feet warm on a design day around here.

Moral of my comment .... Oversize any gasser a little bit and add plenty of storage, it will just work better.

 

[TCaldwell]

Just for comparison, my garn 1900 holds 1906 gal x 8.43lbs/gal of water=15,896btu/deg raised, per my hundreds of weighed wood burns it averages out to approx 3lbs wood per degree of storage raised. Quick figuring about 1.5 lbs per degree should get you in the ball park for the jr., for 40deg raised= 60lbs wood. I don't know what the jr will hold and 2 how much wood will burn smoothly at a load. This depends on your your wood type and moisture content, dryer smaller splits=smaller load, higher mc and larger splits=larger load will burn smoothly. I have found with the firebox size of mine, same size as a 2000 that I can fit 150 lbs wood, 135lbs if large split is really pushing it, the comfortable spot is between 80/110 lbs wood load. My thought would be to load about 75lbs to start and reload 45 about 1.5 hrs later to charge your 2000 gal 40 deg, and clean the ash out of the firebox with one swipe of a flat shovel before the next firing.
As kwmeh09 states and jebatty will confirm that this can't effectively be operated as a downdrafter with day long occasional loading to keep the fire going for a extended time. In extreme conditions you can add a firing in between you normal schedule.
Id call dectra about how much of a wood load the jr is confortable with and their thoughts on combining with your onsite storage.
On the other hand being a big decision, you really should look at the 02 controlled froling.
I like this thread1

 

[huffdawg]

I am not sure about the GARN Jr's BTU's and how many your place will require, so I will speak broadly and say this:

Running an undersize GARN sucks. You end up in a weird purgatory where your individual fires blend together, you build up coals and you get none of that sweet coast time. They are meant to be batch fired, and they are meant to utilize their storage and undersizing takes all of that away.

I ran a 3200 for 5 years in the White Mountains. It was grossly undersize for the demand. We had plenty of oil backup, but bouncing between oil/wood on that large a system is a big management headache, even when you are doing it through relatively sophisticated controls.

Someday I'd love to put a GARN on my little homestead. When I do, I will oversize it a little from a BTU standpoint, and put in extra storage and give myself a few places to dump heat if need be.

In the coldest part of the winter here I burn 2 to 2-1/2 fireboxes full . for the last few days I have been burning 1-1/2 I mostly burn Fir hemlock and some broadleaf maple...

 

[Karl_northwind]

remember you gotta shovel some ashes out every now and then. every few loads is good I think, because both the primary air inlet and the flue outlet are near the bottom of the firebox. kinda has to be a batch burn for this reason. at least gotta let it die down every day.