Progress Hybrid/need a damper

[rideau]

Tried a burn with small ironwood rounds today...47 pounds of Ironwood, 5 of apple, 9 rounds total. Pretty cold out...around 0*F - with the air completely closed flue temps were 600 - 700*F for over 5 hours. About 6 1/2 hrs into the burn flue was down to 500F. Had a really active fire for the five hours. Stovetop temps, as read on cast iron next to flue discharge, never went over 450*F. 9 1/2 hours and down to large coal bed, stove 260, flue 350F.

Could not close the air more, and so lost a lot of heat up the chimney. Spoke with Woodstock and they said to get a damper...which I expected but didn't really want to hear. Am not looking forward to the way it will look. One more thing when cleaning the pipe too. Oh, well. Should be my biggest problem.

Woodstock would like to see the flue temp at 350 to 400 degrees. I'm a long way from that when I burn smaller wood. Large splits I can burn with an internal flue temp about 450 (if it isn't too cold or windy out), and I get a much longer burn time.

So, I'll give ICC some business, get a damper, and have a new toy to play with. Wouldn't be surprised to find I can actually get a good deal more heat out of this stove than I have been, which would be pretty remarkable considering the heating job it is already doing.

Anyone else having trouble keeping internal flue temps down? I have an internal chimney, and a long straight run of ICC chimney...a good 30 feet.

 

[rdust]

Anyone else having trouble keeping internal flue temps down?

No issues here, my stove is a cat stove without as much unregulated air as a hybrid. I've always been able to dial mine down to anything I want no matter what with a simple turn of the knob.

My last stove with tubes was impossible to burn where I wanted it when the temps hit the single digits.

 

[corey21]

Tried a burn with small ironwood rounds today...47 pounds of Ironwood, 5 of apple, 9 rounds total. Pretty cold out...around 0*F - with the air completely closed flue temps were 600 - 700*F for over 5 hours. About 6 1/2 hrs into the burn flue was down to 500F. Had a really active fire for the five hours. Stovetop temps, as read on cast iron next to flue discharge, never went over 450*F. 9 1/2 hours and down to large coal bed, stove 260, flue 350F.

Could not close the air more, and so lost a lot of heat up the chimney. Spoke with Woodstock and they said to get a damper...which I expected but didn't really want to hear. Am not looking forward to the way it will look. One more thing when cleaning the pipe too. Oh, well. Should be my biggest problem.

Woodstock would like to see the flue temp at 350 to 400 degrees. I'm a long way from that when I burn smaller wood. Large splits I can burn with an internal flue temp about 450 (if it isn't too cold or windy out), and I get a much longer burn time.

So, I'll give ICC some business, get a damper, and have a new toy to play with. Wouldn't be surprised to find I can actually get a good deal more heat out of this stove than I have been, which would be pretty remarkable considering the heating job it is already doing.

Anyone else having trouble keeping internal flue temps down? I have an internal chimney, and a long straight run of ICC chimney...a good 30 feet.

I have a 14 foot chimney straight up and when it is real cold and windy my pipe damper comes in handy. I don't use it all the time just when i need to reduce the draft.

 

[Waulie]

I don't remember, what's your chimney like?

I would question your flue probe as well. Not saying you don't need a damper, but those flue probes can be tricky to get accurate readings from. I forget the PH owner who was using a series of thermocouples and reported flue temps consistently at 400. I only have a surface thermo and it almost always reads 320 on the single wall pipe about 10 inches above the stove. They say external pipe temps should be half of interior temps, but I know I'm getting a whole lot of heat from the top of the stove that has to affect the temps I'm seeing. I mean, the actual flue temps could be zero and I'd probably still register close to 300 measuring the way I am.

I have a hard time seeing how your flue temps could still be so high after 9.5 hours with your stove down to 260 already. Again, I think your probe might be a little out of whack.

I still think a damper could help you for these super cold days. I assume that you had a pretty full load in there and it does seem that it burned up fast.

 

[fire_man]

Tried a burn with small ironwood rounds today...47 pounds of Ironwood, 5 of apple, 9 rounds total. Pretty cold out...around 0*F - with the air completely closed flue temps were 600 - 700*F for over 5 hours. About 6 1/2 hrs into the burn flue was down to 500F. Had a really active fire for the five hours. Stovetop temps, as read on cast iron next to flue discharge, never went over 450*F. 9 1/2 hours and down to large coal bed, stove 260, flue 350F.

I have to agree with Waulie on this - those flue temps seem unlikely - especially with the draft closed and the stovetop temps below 450F.
How exactly did you measure the flue temp? I cannot imagine a flue temp of 350 after 9.5 hours with only a coal bed burning.

I measure the exit temp of the stove on the rear Progress plate (mine is a rear vent application) and the plate almost never reads higher than the stovetop temp. - usually it's 100F lower. I don't have 30 feet of internal chimney, but your temps seem unreal. Can you double check with another thermometer?

 

[chipsoflyin]

At the peak of the full load burn, secondaries active, with ash and mushroom oak, we are seeing 450-500 stove top near exit collar, 18 inches up single wall 250-300 external, cat probe at 750-800. With a dark stove, prior to secondaries firing, cat probe 1000-1100, single wall 350-400, stove top 500-550. Woodstock must be refering to external pipe temps(350-400). After 9 hours, huge coal bed, reload at 12.

 

[rideau]

Tony, I'm reading on the cast iron next to where your plate is.

Waulie, I have double wall ICC pipe, have a magnetic thermometer on the exterior of the pipe next to the internal probe, and it is consistently reading almost exactly 1/3 of the flue probe. Both probe and magnetic thermometer are 14 inches above the stove. While the pipe is hot, I can touch my hand to it for an instant without getting burned. I have just moved the magnetic thermometer to the rear of the pipe, at 14 inches. If you are right, Waulie, the temp should drop, because there is far less heat radiated off the top of the stove to the back than to the front.

Right now I am burning a load that is two splits: sugar maple, 1/2 of an 11 inch round, 18 inches long, and 1/2 of an 8 inch beech round, 18 inches long. Put them in the stove at 8:10 or so. It is now 11:06, cast iron top reading 350, flue 550, air completely closed, blue flames. Constant flames, but wispy. Not putting a ton of heat in the room. Really cold out. Just checked, and in the shelter of the house it is 6degrees F out. Crazy draft. If I open the air at all, the pipe whistles.

11:20, cast iron 350, probe 550, magnetic thermometer 170. It's down maybe 10 degrees in the back. So there is perhaps a slight effect on the magnetic thermometer in the front. Doesn't surprise me too much because it is reading surface temps...its gauge is external. The probe is reading internal temps, and I would not expect it to be influenced by the exterior temp...wouldn't make much sense to design it that way. I'll run the magnetic thermometer in the back for a while.

11:30: 350, 560, 170. I really do think my flue is pretty hot and that a lot of heat is going up the chimney.

Have a new cat. installed it Sunday night, 1 week ago. Before that, external magnetic thermometer was reading between 150 and 200, usually lit off at 150, went up to 200, then back down to about 140 - 160. Which I would translate to 420 to 480 degrees. Now at 170, I'd translate to 510. But that is 170 0n the back of the flue, and I was reading temps on the front of the flue previously. AM going to move magnetic thermometer back to front and see if it goes back up...And after I read that, I am going to move the magnetic thermometer a few feet up the flue. If you are right, there should be a dramatic drop in the temperature of the magnetic thermometer. I'd expect a much bigger drop in air than in internal flue temp as one moves away from the stove top.

OK. Magnetic thermometer on the front is reading 190 now. The other magnetic thermometer I put another 14 inches higher on the flue. It is also reading 190. It was 350 when I put it here a few minutes ago, the reading of the cast stovetop. So it may still be dropping.

HOWEVERlightbulbs went off. I have had the stovetop soapstone in the raised position for cooking since yesterday. Just closed the center top and the internal probe went down IMMEDIATELY and is now reading 445, the magnetic thermometer next to it is reading 185, and the one higher up is reading 150.

100 degrees cooler on the probe, with the soapstone down! So, you are obviously right Waulie. The stove top does dramatically influence the reading on the probe thermometer. I have no idea how much of the temp now being read is the result of exterior heat. Guess I'll do some experimenting, moving the magnetic flue thermometer to the back, and to different heights on the back, of the flue.

But, thanks all. I feel much more comfortable about the flue temps now, and will open the air a bit and see what happens. Maybe I don't need a damper after all.....

Waulie, it was a quick burn, but I was using smallish rounds. 52 pounds of wood, but the firebox was not full by any means. I took a picture, and may post it....This present fire is two large splits, as noted above. Much less wood than the small rounds, but I bet it burns longer. I am now four hours into the burn.

Chipsoflying, Woodstock was definitely talking about internal flue temps. The cast on my stove by the exit plate reads about 450 for hours when I have active secondaries going also.

What has been really bugging me is that the Flue temps are supposed to go down as the stovetop temps and cat temps go up...and mine was not. It was going up a lot after the cat was engaged, and staying up. BUT...it was the cast iron cooktop. And I'm an idiot, because I had left the top up in between cooking on purpose because I think it radiates more heat into the room and it is cold out...Didn't put two and two together.

Again, thanks all, for your time and thoughts.

To close, it is midnight, the probe has gone back up to 500, the magnetic thermometer next to it 190, and the one 14 inches higher 150.

About to open the air. Just crack it open. Will post again in a bit, or tomorrow, re what happens.

 

[Waulie]

It sounds like it's not as bad as you though, but still running a bit high. I'm sure a damper would help you out in the super cold but probably not a must have item for now.

I did an experiment last night. It was low single digits and I had a large (full but with short splits) load cranking away with the air almost a quarter open. The stove looked like the gates of hell and was throwing tremendous heat. I burned it that way for an hour or so and then turned the draft all the way down. I got lazy secondaries for a bit then it went to a no flame at all cat burn. So, even in this cold and with the stove raging hot I am able to kill things by closing the draft. I have a tall, but oversized chimney. I turned the air back up before bed because it was just darn cold!

 

[doug60]

I have a damper & only use it when is really cold out. What I found is when using the damper you will wind up with too many coals & not enough heat output per load. That is if you over dampen. you will have to find a sweet spot. My chimney is about 23 feet tall. Hope this helps .

 

[BrowningBAR]

Rideau, thanks for the post. Stuff like this interests me. The Progress is still top of the list as the replacement stove in the future.

That being said, this thread is a good example of how a cat stove is more complicated to run than a non-cat stove.

 

[Machria]

Rideau,
My flue is straight up, 26' from the stove top collar, with only a slight 30* bend coming off the top to line it up with the chimney. My magnetic Woodstock temp gauge is about 12" above stove stuck to the single wall pipe. It ALWAYS stays between 200 and 400, MOST of the time with the CAT engaged, it stays between 250 and 325, regardless of what is going on in the stove (raging or smoldering, lots of wood, no wood left...).

I wonder if your house is pressurized? If you crack a small window, do you hear air rushing out? If so, this would be forcing air into the stove and up the chimney.... which a damper would help fix....

 

[rideau]

My house isn't pressurized. It's well built, mid-1970's, with the best that was available to me at the time and location. Shipped all the wood from lower NYS, where the hardwoods were milled for the home. Doug Fir came from BC via NYS because I couldn't get it in Ontario. Pella windows. 2x6 studs, 2x12 joists. Good insultaion but just before wrapping was available. Anyway, air tightness is not the problem. Just have an amazing draft because at the top of a cliff just off the lake, at the south end of the lake where the wind howls across a big open lake from the North...and I have a tall interior chimney.

My flue isn't hotter than yours...300 to 400 on the outside of single wall translates to 400 to 800, and anything above about 450 is hotter than I want my flue when in cat burn mode. 325 translates to 650, and I surely don't want that, and especially I don't want 800. Mine tends to sit at about 550 to 600 internal probe temp, when in the lowest burn I can achieve. And that is also my problem. I can't cut the air down enough to get rid of flames in my firebox, so I cannot get as slow a cat burn as I would like. The only way to approximate one is to shut everything down immediately, and let the stove take its time getting to operating temps, rather than charring the wood before engaging the cat. Even then, eventually I get active secondaries. I'd like to be able to slow sown the air flow. Woodstock has recommended that I get the damper. I guess I'll have to install it at the top of the double wall adjustable pipe, but it's going to be a pain adjusting, if I need to do much adjusting. Hopefully, I'll be able to set it at one setting, and adjust the air from the aiir control on the stove.

 

[Machria]

Gotcha, I forgot your talking probe. Anyway, I was referring to your house being too insulated and air tight for the stove, I did not mean not well built.... That would make it "pressurized", meaning it is so air tight, it is pushing air out cause the warm air inside is a higher pressure than the cold air outside. Most houses leak enough to equalize enough, but maybe yours is so well built the air has nowhere to go but up the chimney? Just a thought. In anycase, I would think the damper would help/solve that problem.

 

[rdust]

can't cut the air down enough to get rid of flames in my firebox, so I cannot get as slow a cat burn as I would like.

This is as designed we all knew it from the start. Even with the air shut down you have that pesky secondary air to deal with. If you can access the secondary air maybe you can restrict it some or build something that closes it when you close down the primary air.

When someone builds a hybrid that closes the secondary/unregulated air down on a low burn I'll be super interested.

 

[Waulie]

This is as designed we all knew it from the start. Even with the air shut down you have that pesky secondary air to deal with. If you can access the secondary air maybe you can restrict it some or build something that closes it when you close down the primary air.

When someone builds a hybrid that closes the secondary/unregulated air down on a low burn I'll be super interested.

It really depends on the draft. I can usually close mine down for basically a no flame burn. Actually, it's more like a no flame for a while, lazy flame for a while burn. I'm sure that's why WS is recommending a pipe damper for Rideau.

The secondary air for the Progress does close down, just not all the way. It can't close all the way because even an all cat burn needs air. The secondary air feeds the cat as well as the secondaries. I think that's why people have such difference experiences. With a ton of draft, you can pull enough air to get the stove up to secondary temps, even with the draft closed. Maybe you could design a hybrid that has the a separate, small inlet for a low cat burn and have everything else close down completely, but I wonder if it's kind of the nature of the beast. Any inlet is going to let different amount of air in for different draft situations. If you pull enough air to get the stove hot enough, the secondaries are going to fire.

 

[rideau]

And that is fine. I'd like the air to go through my stove more slowly so there is more time for the heaat to transfer into the stove and through the window into the room. Less up the flue to heat the great outdoors.

 

[Machria]

It really depends on the draft. I can usually close mine down for basically a no flame burn. Actually, it's more like a no flame for a while, lazy flame for a while burn. I'm sure that's why WS is recommending a pipe damper for Rideau.

Yep, if I close my air all the way down with raging secondaries going, in 2 or 3 minutes it is black in the stove with just smoldering coals in the bottom. I actually had my first flame-out with this stove yesterday. I reloaded on a very small coal bed, and had to run out in a hurry. So I waited about 2 minutes, and a very small flame started up, but the pipe was only at 150 - 175 degrees. Well, I couldn't wait, so I flipped the bypass and closed down the air and took off. When I got home 3 hours later, the fire was completely out, only a few smoldering ashes in the bottom bassicaly doing nothing, with ALL the wood still left. So I threw in a 1/2 a sup[er cedar and restarted. That had never happen to me before. But it shows how much I can shut down the stove.