blacked out / creosoted fireplace door window?

lumbajac · Oct 30, 2010

I am entering my 2nd season with an RSF Opel III insert. I must say I was very happy with my 1st season of burning last year as the fireplace gave me a good consistent heat that kept my NG forced air furnace pretty much idle. However, last season I did get a lot of blackening of the fireplace door window by creosote. I attributed this to poorly seasoned wood as I only had about 6 months of seasoning time since I cut and split.

I was eagerly anticipating this season as now I am sitting on 2 1/2 cords of 12+ month seasoned red maple, yellow birch, and sugar maple. Much to my disappointment, I again have the heavy black creosote coating my window so much so that I can't even really see the flames, just an orange glow. I haven't even really been able to achieve a good secondary burn this year it seems. I've read on here before (I believe) that the air holes in the secondary tube of these epa burners should be facing the window as to effectively wash it. The holes in my secondary tube are facing towards the window, but up and away from it at an approximate 30 or 45 degree angle. I can't adjust this postion as there is a factory preset tab that sets this position so I am assuming it is correct.

I've read where others on the hearth.com burn their morning stokings of firewood quite hard with wide open air supply for a bit to burn off any light residues left on their windows from an overnight burn - I have tried this with no luck. I'm really thinking something isn't right here or maybe I even need 2+ year seasoned firewood? Anyone have any advice, suggestions, or is this just the way it is (I hope not)?

I'm really happy with my heat output from the Opel, but I need to get this black window issue figured out. I've just sent a similar email into RSF as well, but thought there might be some insight found here over the weekend.

Thanks,
lumbajac
U.P. of Michigan

BrowningBAR · Oct 30, 2010

How hot are you burning?

branchburner · Oct 30, 2010

Not sure about your stove, but the air wash generally is from primary air, so I don't think the placement of secondary tubes is a concern. If you are burning too cool/slow, the glass may be getting too dirty for the airwash to get clean on its own. If my secondary burn stalls and the glass goes black, I need a pretty hot burn to clean it, and it means leaving the primary full open for a good bit.

RNLA · Oct 30, 2010

Funny thing I have had stoves that burn really clean and ones that did not. The really funny thing is they have all been Country wood stoves... I'm now under the firm position that the wood must be seasoned and dry. NO RAIN from top if you can do it. My current stove has had no issues with the window. I probably burn a little hotter than I should, wasting heat. So I'll say to burn a little hotter to keep your glass clean. You may not be able to burn as long if you want clean fire viewing. BETTER WOOD.

lumbajac · Oct 30, 2010

I start out with a hot fire - air wide open. However, I do shut it right down then - if I don't I will cook myself out of the house. I have good, dry wood that was covered on top to prevent rain soakage and dried in a wide open area with good sun for 2 summers and 1 winter. It sounds like I'll have to choose between a long burn and creosote OR a quick hot burn and less creosote?

vvvv · Oct 30, 2010

glass stays clean from airwash, air is driven per bouuoyancy,duh

Backwoods Savage · Oct 30, 2010

lumbajac, for sure that red maple should be really dry in this length of time so that should probably give you the hottest fires. Could this be some of the same thing we see when starting to burn in the fall? We have small fires and sometimes the glass does get dirty. However, when we have a hotter fire the glass does clean itself pretty quickly. Could this be that you are simply shutting it down too far and the fire is just needing more air? Or could this be that you are simply putting in too much wood for burning at this time of year? I do hope you get it figured out.

Hopefully when the weather gets colder it will all straighten up for you. That probably means in about 30 days or less.

lumbajac · Oct 30, 2010

~*~vvv~*~ said:
glass stays clean from airwash, air is driven per bouuoyancy,duh

HUH????

firefighterjake · Nov 1, 2010

lumbajac said:
I start out with a hot fire - air wide open. However, I do shut it right down then - if I don't I will cook myself out of the house. I have good, dry wood that was covered on top to prevent rain soakage and dried in a wide open area with good sun for 2 summers and 1 winter. It sounds like I'll have to choose between a long burn and creosote OR a quick hot burn and less creosote?

Random thoughts . . .

As mentioned earlier the air wash is not in the secondary burn tubes . . . it comes from another place . . . in time and space.

Thermometers . . . do you have 'em . . . saying a fire is hot doesn't truly give much information if you are simply using your sense of feeling (it feels hot) and vision (it looks hot since there are a lot of flames.) You can get a lot better feedback with a thermometer on the stove and flue . . . then you can truly tell if something is really hot, hot or actually running cooler than normal temps.

Air controls . . . leaving the air control open on a modern EPA stove will typically result in a lot of flames in the firebox and there will be some heat -- but most of the heat is going up the chimney and not heating up the woodstove. You want to keep the air open when getting the fire going . . . but the end goal is to get the stove and flue hot enough to burn cleanly . . . and then you start slowly shutting down the air to achieve secondary combustion -- this is where the combustible material in the smoke catches on fire and burns -- in effect you get a second burn which results in more heat . . . providing your stove is hot enough, there is a right amount of oxygen in the firebox and the wood is well seasoned.

Closing the air too much or too soon before the stove has had a chance to heat up will result in the fire smoldering and not burning properly . . . and burning with less than optimal wood will also result in the fire suffocating or going into a slow burn. However, again . . . the desired result for a good, hot burn to heat up the home is not to leave the air control open, but in fact to shut it down . . . this will result in a cleaner, hotter burn.

The reason the glass may not blacken when you have the air open all the way is because all the "dirty" material in the smoke is going up the chimney . . . but if you close down the air too soon before the fire is hot enough or if the wood is not seasoned enough, those "dirty" materials are now sooting up your glass . . . however, if the wood is good and the air/fuel mix is good and things are hot enough to achieve a secondary burn you will burn off those "dirty" materials . . . keeping the glass clean, giving you more heat, giving you a cleaner burn and giving you a long burn.

Choosing: You shouldn't have to choose . . . if your wood is good, the oxygen/fuel mix is good and the temps are hot enough you should be able to bring the stove up to temp, start to close down the air and achieve a secondary burn -- this will be a clean burn (which will keep the glass from blacking) and you will get more heat and at the same time a longer burn.

branchburner · Nov 1, 2010

Dirty glass keeps me honest. If my window is going black, I've been doing one of these naughty things:
- Burning wood slightly too wet/green
- Trying to get a too-long burn by shutting down the air too far or too fast
- Trying to get a too-soon secondary burn by closing my bypass damper early
- Putting a too-large split on a too-small bed of coals

ControlFreak · Nov 1, 2010

LunbaJack,

You need to get a stove thermometer so you can tell what the temperature of your stove is. The temperature of the stove is like taking your pulse.

If you're running the stove with the draft wide open, it should get hot enough to burn off all the creosote on your glass. If you're not burning off the creosote, then you're not getting hot enough. The grand question is why.

There are two basic reasons why you wouldn't be getting hot enough:
1. You still have too much moisture in the wood <<< This is the most likely issue
2. The fire is not getting enough air

The easiest way to troubleshoot this is to get some wood that you know for sure is dry, and see how the stove operates. You could go to the lumber yard and pick up some cheap 2x4's or find some other scrap construction lumber. This stuff is always really dry and should burn hot and lively.

If it doesn't operate well with dry wood, then you're not getting enough air to the fire.

Dan

vvvv · Nov 1, 2010

lumbajac said:
~*~vvv~*~ said:

glass stays clean from airwash, air is driven per bouuoyancy,duh

Click to expand...

HUH????

primary air enters above glass & due to air buoyancy it dives down to get at the hot zone or the coals

Clodhopper · Nov 2, 2010

Interesting thread. I've got 2 Oslos. The one's glass stays clean no matter what I do, the other gets black no matter what I do. The only difference is the length of the chimneys. The dirty one is about 25 feet of stainless in a straight shot, and the clean one is about 14 foot. The wood supply is the same.

vvvv · Nov 2, 2010

Clodhopper said:
Interesting thread. I've got 2 Oslos. The one's glass stays clean no matter what I do, the other gets black no matter what I do. The only difference is the length of the chimneys. The dirty one is about 25 feet of stainless in a straight shot, and the clean one is about 14 foot. The wood supply is the same.

stove locations [n,s,e,w] ? thhhhhis is great puzzle

jotulguy · Nov 2, 2010

Clodhopper said:
Interesting thread. I've got 2 Oslos. The one's glass stays clean no matter what I do, the other gets black no matter what I do. The only difference is the length of the chimneys. The dirty one is about 25 feet of stainless in a straight shot, and the clean one is about 14 foot. The wood supply is the same.

The one with the dirty glass...basement install? And what are the stove top temps on both? The reason i ask is because they are both the same big dumb box(my favorite tech mark from Jotul lovingly calls them that) That being said something different is going on.

lumbajac · Nov 2, 2010

firefighterjake said:
lumbajac said:

I start out with a hot fire - air wide open. However, I do shut it right down then - if I don't I will cook myself out of the house. I have good, dry wood that was covered on top to prevent rain soakage and dried in a wide open area with good sun for 2 summers and 1 winter. It sounds like I'll have to choose between a long burn and creosote OR a quick hot burn and less creosote?

Click to expand...

Random thoughts . . .

As mentioned earlier the air wash is not in the secondary burn tubes . . . it comes from another place . . . in time and space.

Thermometers . . . do you have 'em . . . saying a fire is hot doesn't truly give much information if you are simply using your sense of feeling (it feels hot) and vision (it looks hot since there are a lot of flames.) You can get a lot better feedback with a thermometer on the stove and flue . . . then you can truly tell if something is really hot, hot or actually running cooler than normal temps.

Air controls . . . leaving the air control open on a modern EPA stove will typically result in a lot of flames in the firebox and there will be some heat -- but most of the heat is going up the chimney and not heating up the woodstove. You want to keep the air open when getting the fire going . . . but the end goal is to get the stove and flue hot enough to burn cleanly . . . and then you start slowly shutting down the air to achieve secondary combustion -- this is where the combustible material in the smoke catches on fire and burns -- in effect you get a second burn which results in more heat . . . providing your stove is hot enough, there is a right amount of oxygen in the firebox and the wood is well seasoned.

Closing the air too much or too soon before the stove has had a chance to heat up will result in the fire smoldering and not burning properly . . . and burning with less than optimal wood will also result in the fire suffocating or going into a slow burn. However, again . . . the desired result for a good, hot burn to heat up the home is not to leave the air control open, but in fact to shut it down . . . this will result in a cleaner, hotter burn.

The reason the glass may not blacken when you have the air open all the way is because all the "dirty" material in the smoke is going up the chimney . . . but if you close down the air too soon before the fire is hot enough or if the wood is not seasoned enough, those "dirty" materials are now sooting up your glass . . . however, if the wood is good and the air/fuel mix is good and things are hot enough to achieve a secondary burn you will burn off those "dirty" materials . . . keeping the glass clean, giving you more heat, giving you a cleaner burn and giving you a long burn.

Choosing: You shouldn't have to choose . . . if your wood is good, the oxygen/fuel mix is good and the temps are hot enough you should be able to bring the stove up to temp, start to close down the air and achieve a secondary burn -- this will be a clean burn (which will keep the glass from blacking) and you will get more heat and at the same time a longer burn.

Thanks for the detailed/thorough thoughts... will consider and try them all.

lumbajac · Nov 2, 2010

Clodhopper said:
Interesting thread. I've got 2 Oslos. The one's glass stays clean no matter what I do, the other gets black no matter what I do. The only difference is the length of the chimneys. The dirty one is about 25 feet of stainless in a straight shot, and the clean one is about 14 foot. The wood supply is the same.

Interesting - I've got about 33' with two 30 degree elbows.

lumbajac · Nov 2, 2010

Clodhopper said:
Interesting thread. I've got 2 Oslos. The one's glass stays clean no matter what I do, the other gets black no matter what I do. The only difference is the length of the chimneys. The dirty one is about 25 feet of stainless in a straight shot, and the clean one is about 14 foot. The wood supply is the same.

Interesting - I've got about 33' with two 30 degree elbows... but only one stove. Maybe there is something with the draft?

lumbajac · Nov 2, 2010

ControlFreak said:
LunbaJack,

You need to get a stove thermometer so you can tell what the temperature of your stove is. The temperature of the stove is like taking your pulse.

If you're running the stove with the draft wide open, it should get hot enough to burn off all the creosote on your glass. If you're not burning off the creosote, then you're not getting hot enough. The grand question is why.

There are two basic reasons why you wouldn't be getting hot enough:
1. You still have too much moisture in the wood <<< This is the most likely issue
2. The fire is not getting enough air

The easiest way to troubleshoot this is to get some wood that you know for sure is dry, and see how the stove operates. You could go to the lumber yard and pick up some cheap 2x4's or find some other scrap construction lumber. This stuff is always really dry and should burn hot and lively.

If it doesn't operate well with dry wood, then you're not getting enough air to the fire.

Dan

It may be #2 - the fire is not getting enough air. I read on another recent thread regarding someone with an RSF Opel not burning well. Someone suggested a baffle being partially closed beneath the firebox - I found said baffle on my own stove and it was indeed closed up quite a bit. Haven't tried burning again yet... waiting for colder weather again.

firefighterjake · Nov 2, 2010

lumbajac said:
ControlFreak said:

LunbaJack,

You need to get a stove thermometer so you can tell what the temperature of your stove is. The temperature of the stove is like taking your pulse.

If you're running the stove with the draft wide open, it should get hot enough to burn off all the creosote on your glass. If you're not burning off the creosote, then you're not getting hot enough. The grand question is why.

There are two basic reasons why you wouldn't be getting hot enough:
1. You still have too much moisture in the wood <<< This is the most likely issue
2. The fire is not getting enough air

The easiest way to troubleshoot this is to get some wood that you know for sure is dry, and see how the stove operates. You could go to the lumber yard and pick up some cheap 2x4's or find some other scrap construction lumber. This stuff is always really dry and should burn hot and lively.

If it doesn't operate well with dry wood, then you're not getting enough air to the fire.

Dan

Click to expand...

It may be #2 - the fire is not getting enough air. I read on another recent thread regarding someone with an RSF Opel not burning well. Someone suggested a baffle being partially closed beneath the firebox - I found said baffle on my own stove and it was indeed closed up quite a bit. Haven't tried burning again yet... waiting for colder weather again.

I think you're getting some terms confused here . . the baffle is the wafer-like board above the burn tubes at the top of the fire box . . . are you talking about the primary and/or secondary air inlet?

FixedGearFlyer · Nov 2, 2010

lumbajac said:
Interesting - I've got about 33' with two 30 degree elbows... but only one stove. Maybe there is something with the draft?

Everyone here has missed the obvious, Lumbajac. You live in Copper Country and the smoke in your stove doesn't want to leave, so it grabs onto your glass!

joefrompa · Nov 2, 2010

I noticed far more build-up on my glass when I had the log ends facing the glass or close to it, allowing them to off-gas straight onto the glass.

Pushing them further away, or not facing the glass directly from the log-end, + a very hot fire resulted in substantial air-wash - even with green wood.

I still have creosote baked onto the edges, even after a 650 degree fire than last for hours, but it's thinning.

lumbajac · Nov 2, 2010

FixedGearFlyer said:
lumbajac said:

Interesting - I've got about 33' with two 30 degree elbows... but only one stove. Maybe there is something with the draft?

Click to expand...

Everyone here has missed the obvious, Lumbajac. You live in Copper Country and the smoke in your stove doesn't want to leave, so it grabs onto your glass!

Excellent point FixedGearFlyer - only you and I would probably understand that phenomenon though!

lumbajac · Nov 2, 2010

firefighterjake said:
lumbajac said:

ControlFreak said:

LunbaJack,

You need to get a stove thermometer so you can tell what the temperature of your stove is. The temperature of the stove is like taking your pulse.

If you're running the stove with the draft wide open, it should get hot enough to burn off all the creosote on your glass. If you're not burning off the creosote, then you're not getting hot enough. The grand question is why.

There are two basic reasons why you wouldn't be getting hot enough:
1. You still have too much moisture in the wood <<< This is the most likely issue
2. The fire is not getting enough air

The easiest way to troubleshoot this is to get some wood that you know for sure is dry, and see how the stove operates. You could go to the lumber yard and pick up some cheap 2x4's or find some other scrap construction lumber. This stuff is always really dry and should burn hot and lively.

If it doesn't operate well with dry wood, then you're not getting enough air to the fire.

Dan

Click to expand...

It may be #2 - the fire is not getting enough air. I read on another recent thread regarding someone with an RSF Opel not burning well. Someone suggested a baffle being partially closed beneath the firebox - I found said baffle on my own stove and it was indeed closed up quite a bit. Haven't tried burning again yet... waiting for colder weather again.

Click to expand...

I think you're getting some terms confused here . . the baffle is the wafer-like board above the burn tubes at the top of the fire box . . . are you talking about the primary and/or secondary air inlet?

Yes - after review I do see I am improperly using some terms. I looked back to a previous & similar post to find where a member named hearthnleisure said, "Sounds like an air flow issue. There is an intake air adjustment on the right side of the unit that is accessible behind the bottom louver. Open that up, I think pulling it forward opens it. " This is what I called a baffle for lack of a better term, but should of said air intake adjustment as hearthnleisure speaks of. This air intake adjustment was indeed partially closed - actually a lot closed. I opened this all the way up, but have yet to try burning again - need some cold weather.

56kz2slow · Nov 22, 2010

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blacked out / creosoted fireplace door window?

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