Not getting the heat I expected--any suggestions?

Nonprophet · Feb 5, 2009

Recently installed our used Vermont Castings Encore 2550 in our yurt. Had the second burn last night. All seems to be going well in that I'm getting long burns and the cat is activating for nice clean burns--I'm just not getting as much as heat I would have expected. With the griddle temp at 550, I engage the cat, but even with the primary air open all the way, I can't get it to go over 600--which I guess isn't a bad thing as I don't want to over-fire (and I guess a little ironic in that there are others who can't keep the Encore from getting too hot!!)

Overnight temps have been in the low 30's, but I'm only maintaining inside temps of 72-75 or so whereas our older steel stove would get up to 80+ with no problem--even fully damped down.

I'm burning very well seasoned (2-3 years) oak and madrone, so that shouldn't be the problem. With our older steel "smoke dragon" I would usually burn the oak at night because the madrone just put off too much heat--the yurt would quickly get up to 80 or so inside and stay that way for many hours. I guess I'm just surprised that the older non-epa steel stove put out so much more heat than the Encore does......

Current stack set up is 3' of 8" single wall, into a 90, into a 3' SS Selco double wall piece that goes through the yurt wall, into a T, and then 8' of 8" single wall with a china hat on top. I realize I may need to increase draft, as I should be able to get this stove up to 700 or so wide open, and right now I can't. I'll add another 2-4 feet to our stack today and see if that helps, but if I'm getting a 550 degree griddle temp (recommended in the owner's manual and by others here) and I'm using good, dry/seasoned wood and but it's just not heating up the yurt that well, what could be the problem? Is this just as hot as this stove will run?? I was initially afraid that this stove might put out too much heat and cook us out (rated for 1900 sq ft), now I'm worried that when the temps drop into the teens that we might not have enough heat.........

Many thanks for any suggestions!

NP

Jags · Feb 5, 2009

Nonprophet said:
Current stack set up is 3' of 8" single wall, into a 90, into a 3' SS Selco double wall piece that goes through the yurt wall, into a T, and then 8' of 8" single wall with a china hat on top.

Am I reading this correctly? Are you saying that you have 8' of single wall outside?

Nonprophet · Feb 5, 2009

Yes--that's the setup.

Jags · Feb 5, 2009

Nonprophet said:
Yes--that's the setup.

Walk to the nearest wall and bang head a minimum of 3 times. :mad:

Single wall outside is not a good idea. The pipe will cool very quickly and in turn cool the exhaust gasses. This will not only have an effect on reducing draft, but can be a major source of creosote.

Outside pipe should be double wall (at least thats my opinion.)

Nonprophet · Feb 5, 2009

Jags,

Thanks for the advice. We've been burning this way for two years and not had any problems--I pull the bottom plate off the T every month or so during burning season and inspect everything and so far never more than a 1/4" or so of dry black soot on the inside of the pipe. We got excellent draft this way with our older non-certified stove, but I'm wondering if we need more height to get the downdraft cat stove to produce as much heat as we'd like.

KarlP · Feb 5, 2009

Nonprophet said:
even with the primary air open all the way, I can't get it to go over 600

What about with the primary air 70% closed? Its hard to get my stove over 500 wide open as well. If I close it down so I'm not sending all the heat up the chimney the stove temperature climbs.

begreen · Feb 5, 2009

The newer stove is likely extracting more heat from the wood and putting less up the flue. Adding more flue pipe may help. What is the current length? More flue length may not solve this issue as it may just provide more cooling to the flue gases. If so, it may be time to invest in some double-wall pipe.

As a first try solution, you could change the interior pipe to double-wall connector pipe and replace the 90 with 2 - 45's.

Here's a link to a yurt stove install I helped with this fall. It has double-wall all the way and illustrates the 2-45s

https://www.hearth.com/econtent/index.php/forums/viewthread/27154/

Nonprophet · Feb 5, 2009

KarlP said:
Nonprophet said:

even with the primary air open all the way, I can't get it to go over 600

Click to expand...

What about with the primary air 70% closed? Its hard to get my stove over 500 wide open as well. If I close it down so I'm not sending all the heat up the chimney the stove temperature climbs.

Hi Karl,

I'm a little confused about this--doesn't having the primary air open all the way INCREASE the stove temp? That's what the VC Encore 2550 manual says anyway........

We have a flue damper that we used with our older stove and that would "keep the heat from going up the chimney" when we damped it down, but it seems counter-intuitive to me that reducing the air entering the firebox on the Encore would reduce the amount of heat going up the chimney--but then again I'm totally new to cat stoves !!!

NP

Nonprophet · Feb 5, 2009

BeGreen said:
The newer stove is likely extracting more heat from the wood and putting less up the flue. Adding more flue pipe may help. What is the current length? More flue length may not solve this issue as it may just provide more cooling to the flue gases. If so, it may be time to invest in some double-wall pipe.

As a first try solution, you could change the interior pipe to double-wall connector pipe and replace the 90 with 2 - 45's.

Here's a link to a yurt stove install I helped with this fall. It has double-wall all the way and illustrates the 2-45s

https://www.hearth.com/econtent/index.php/forums/viewthread/27154/

Hi BeGreen,

Thanks for your comments. The current height of the chimney rises a total of 11.5 from the stove flue outlet--3' inside and 8.5' outside.

I guess I don't understand what you're saying about the "newer stove is likely extracting more heat from the wood and putting less up the flue." I can get griddle temps of 550-600 degrees with the bypass damper closed and the primary air open all the way--it just seems like the stove doesn't produce as much heat as our older steel one, maybe because cast iron just heats slower and more steadily? But then again even after a few hours with the cat engaged and the primary air wide open (the owner's manual says that the primary air wide open is how you get the highest heat......) it will still only heat the yurt up to 75 or so with a 30 +/- outside temp......whereas the older steel stove would put it up to 90 if we left the flue damper shut and the door dampers open with dry wood.......

Thanks for the link on your yurt/morso install!!

NP

Bigg_Redd · Feb 5, 2009

Nonprophet said:
Recently installed our used Vermont Castings Encore 2550 in our yurt. Had the second burn last night. All seems to be going well in that I'm getting long burns and the cat is activating for nice clean burns--I'm just not getting as much as heat I would have expected. With the griddle temp at 550, I engage the cat, but even with the primary air open all the way, I can't get it to go over 600--which I guess isn't a bad thing as I don't want to over-fire (and I guess a little ironic in that there are others who can't keep the Encore from getting too hot!!)

Overnight temps have been in the low 30's, but I'm only maintaining inside temps of 72-75 or so whereas our older steel stove would get up to 80+ with no problem--even fully damped down.

I'm burning very well seasoned (2-3 years) oak and madrone, so that shouldn't be the problem. With our older steel "smoke dragon" I would usually burn the oak at night because the madrone just put off too much heat--the yurt would quickly get up to 80 or so inside and stay that way for many hours. I guess I'm just surprised that the older non-epa steel stove put out so much more heat than the Encore does......

Current stack set up is 3' of 8" single wall, into a 90, into a 3' SS Selco double wall piece that goes through the yurt wall, into a T, and then 8' of 8" single wall with a china hat on top. I realize I may need to increase draft, as I should be able to get this stove up to 700 or so wide open, and right now I can't. I'll add another 2-4 feet to our stack today and see if that helps, but if I'm getting a 550 degree griddle temp (recommended in the owner's manual and by others here) and I'm using good, dry/seasoned wood and but it's just not heating up the yurt that well, what could be the problem? Is this just as hot as this stove will run?? I was initially afraid that this stove might put out too much heat and cook us out (rated for 1900 sq ft), now I'm worried that when the temps drop into the teens that we might not have enough heat.........

Many thanks for any suggestions!

NP

I think I found the problem.

Nonprophet · Feb 5, 2009

Bigg_Redd said:
Nonprophet said:

Recently installed our used Vermont Castings Encore 2550 in our yurt. Had the second burn last night. All seems to be going well in that I'm getting long burns and the cat is activating for nice clean burns--I'm just not getting as much as heat I would have expected. With the griddle temp at 550, I engage the cat, but even with the primary air open all the way, I can't get it to go over 600--which I guess isn't a bad thing as I don't want to over-fire (and I guess a little ironic in that there are others who can't keep the Encore from getting too hot!!)

Click to expand...

I think I found the problem.

Hi Redd,

Why would that be the problem? Our older "smoke dragon" would heat the yurt up to 85+ on a 15 degree day, with the same wood and stack setup that we're using with the Encore--so why do you think the yurt is "the problem?"

Thanks!

NP

Jerry_NJ · Feb 5, 2009

Sorry for the dumb question: what is a "yurt"? Could that be the problem. Another: what's wrong with 70 degrees, did you grow up in the tropics?

begreen · Feb 5, 2009

I don't have the manual for the stove on this Mac, but 11' seems very short for the Encore and the interior 90 isn't helping. I would expect minimum mfg recommendation to be up around 15'. Stronger draft will occur with a hotter flue and more length could help. If you have an extra 4 ft to try temporarily go for it.

FWIW, my observation with the Morso in the yurt with 12' exterior flue pipe and about another 3 feet inside, all double wall, was that there was just enough draft and definitely not too much.

Jerry, look at the thread I posted for a picture inside and out of a yurt. That isn't the problem. Low draft most likely is.

Jerry_NJ · Feb 5, 2009

BG, thanks .. live and learn.

So, what do you do about the plumbing :>?

Todd · Feb 6, 2009

CZARCAR said:
Nonprophet said:

KarlP said:

Nonprophet said:

even with the primary air open all the way, I can't get it to go over 600

Click to expand...

What about with the primary air 70% closed? Its hard to get my stove over 500 wide open as well. If I close it down so I'm not sending all the heat up the chimney the stove temperature climbs.

Click to expand...

Hi Karl,

I'm a little confused about this--doesn't having the primary air open all the way INCREASE the stove temp? We have a flue damper that we used with our older stove and that would "keep the heat from going up the chimney" when we damped it down, but it seems counter-intuitive to me that reducing the air entering the firebox on the Encore would reduce the amount of heat going up the chimney--but then again I'm totally new to cat stoves

NP

Click to expand...

cat stove = get it up to operating temp , exhaust thru heated cat as primary air is closed which allows for longer cleaner burn. secondary air should not aggravate fire further but only provide enough air to mix with fumes which go thru cat & flash...i thinx

I agree, you need to slow down the air a little while after lite off. The cat needs time to burn going though the honey comb. If the draft is too strong, like wide open air it will suck the smoke through and not give it time to burn.

Also look into a proper chimney. These newer EPA stove have much less heat going up the chimney so the draft can be very tempormental.

begreen · Feb 6, 2009

Jerry_NJ said:
BG, thanks .. live and learn.

So, what do you do about the plumbing :>?

Our friend's spot has the classiest outhouse you have ever seen, but they can be plumbed if you desire. They are thinking of putting a bathhouse extension on the yurt this summer. We'll see.

Nonprophet · Feb 11, 2009

Just wanted to post an update to this thread.

Last week I went ahead and added another 4' of single wall 8" pipe to our flue for a total of 15' now. Truth be told, I don't really think it made much difference, though I did replace the spark screen while I was at it.

I think that the problem was simply that we're not used to a cast iron cat stove! It just takes longer to heat up (though it retains heat much longer), and it's a little bit more "finicky" than our older steel "smoke dragon" stove in terms of needing a sufficient coal bed before closing the damper and reducing the primary air while still maintaining 5-600 degree griddle temps. It does light very easily, and, by keeping the ash door cracked open a little when lighting and then closing the ash door and using the flue damper at about 50% to keep more of the heat in the stove in the early stages of a new burn, we're now able to get our Encore up to 650-750 without too much effort, and then it's pretty easy to maintain 500 degrees or so all night. Once the cat is engaged and burning well we open the flue damper and it burns long, slow, and clean--just what we wanted!

NP

stovetop · Feb 11, 2009

Jags said:
Nonprophet said:

Yes--that's the setup.

Click to expand...

Walk to the nearest wall and bang head a minimum of 3 times.

Single wall outside is not a good idea. The pipe will cool very quickly and in turn cool the exhaust gasses. This will not only have an effect on reducing draft, but can be a major source of creosote.

Outside pipe should be double wall (at least thats my opinion.)

once you go through the ceiling support box you need to switch to double wall stainless pipe for the rest of the way..Pretty sure that is code around here. Really would not recommend single wall on the exterior of a house

North of 60 · Feb 11, 2009

stovetop its a YURT. A real fancy wall tent so to speak. Google it. They are awsome.
N of 60

WOODBUTCHER · Feb 11, 2009

BeGreen said:
Jerry_NJ said:

BG, thanks .. live and learn.

So, what do you do about the plumbing :>?

Click to expand...

Our friend's spot has the classiest outhouse you have ever seen, but they can be plumbed if you desire. They are thinking of putting a bathhouse extension on the yurt this summer. We'll see.

classiest "Privy"
I actually had the kids thinking it was something really cool to say... till I told them what a privy was.

WB

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