Hot Burn and Secondary Air Tubes

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
F

fxdwg

New Member
Nov 16, 2008
4
SW WA
Hello,

I'm glad I found this place, I'm hoping maybe someone out there can help me out.

I've got a Lopi Answer wood stove that was installed during construction in 1996. This is my fourth Winter in the house. It took me a some time to get used to getting this stove going with a good burn, with some hints from the chimney sweep guy, I figured it out (I'm a city guy that has never had a wood stove before).

I typically get burns going that regsiter up in the 500/600 temp range (based on this magnetic thermo the chimney guy sold me that is on the outside of the unit).

Suddenly I am having serious issues with the stove and I cannot get a burn over 400, and that is very brief. Its been going for two hours this morning and it is around 300. I'm in the middle of the same cord I got at the beginning of the season, and it was burning fine, so I don't think this is a green wood issue. I've even been using some of the wood from last season I had left over and it won't get going either.
I have to keep the vent open all the way to get anything to burn at all. If I get a good coal base going, I normally close the vent down to about an inch and get a nice hot/long burn, but now when it do that eveything just completely shuts down.

Last Tuesday (which is right around when this started happening), I noticed the middle of the three secondary air tubes has deteriorated and there is about a three inch hole in the middle of the tube.
I visited a local fireplace store yesterday and asked about this tube, its purpose, etc. This guy said it shouldn't be the cause of the problems I am having. He suggested I am not getting good air flow and should clean the stove out real good.

Yesterday I took all the firebrick out, clened it out as good as I can. I noticed whoever did this last didn't put the top bricks back correctly. there is this front flange that holds the bricks in place. I re-assembled based on the instructions - at least now when I open the stove door, I don't fill the house with smoke. The flange was put back in a way where it was blocking a two inch gap all along the front of the stove, blocking flow to the chimney.
Anyway, now I can get stuff started a lot faster, kindling and small pieces burn like crazy, and I get coals. As soon as I sit a larger pieice on the coals, at first it flames up, but then it just dwindles down to a smolder.

I'm at the point where I am not even going to bother using the stove. I am burning wood but not heating the house. I realize these tubes need to be replaced for the stove to function properly, but my question to you all is do you think this is part of what is causing my problems?

Thanks for your input.

- Brad
 
Have you inspected/swept the chimney/stovepipe system and cleaned the cap (& screen, if installed)? Rick
 
Have you checked to see if you have an air pressure balance problem in the house? Stack effect? Makeup air vent clog? Maybe it's just the barometer?

Can you plug the hole in the tube temporarily until you get a replacement?
 
Have you inspected/swept the chimney/stovepipe system and cleaned the cap (& screen, if installed)?
Click to expand...

The previous three seasons I had the chimney sweep guy out for inspection and he always says everything is very clean. I haven't had him out this season yet, but based on previous years, I am "assuming" the pipe is in pretty good shape.

Have you checked to see if you have an air pressure balance problem in the house? Stack effect? Makeup air vent clog? Maybe it’s just the barometer?

Can you plug the hole in the tube temporarily until you get a replacement?
Click to expand...

You will have to forgive me on some of your verbiage, I'm not sure I fully understand your questions.

air pressure balance problem - well, I know I have a cold chimney and if I haven't burned in a few days, and the house heat is running, I do have issues with smoke being drawn into the house. Typically I try to pre heat the chimney with a little fire starter block and if it is really cold I will open a window so the draw comes from there instead of the chimney.

stack effect? not sure what this means.

makeup aire vent clog? again, not sure what you mean.

barometer? Well, I know what a barometer is, but not sure how it relates to a wood stove

plug the tube - I could probably do this. Does your question suggest you think this is part of the problem, or just a suggestion to see if conditions change?

Sorry for my ignorance. Again, I appreciate your input.

- Brad
 
Sorry about the nomenclature...

Stack effect - Warm air rises. If an upstairs window is open or there are leaks up high, air exits, leaving a low pressure downstairs.

Makeup air - Many homes provide some means of bringing in outside air. If your intake vents or HRV filters clog, it can cause an inbalance. Some people in their zeal to conserve heat, block all the cold drafts and in so doing cut off a supply to makeup air. Better to seal where the air is leaking out. Exhaust fans and clothes dryers can also affect the pressure balance.

Barometer - The density of the air affects how well smoke rises which affects the chimney draft. You can tell when you look outside and the smoke from the chimney tends to fall rather than rise.

Plugging the tubes - Yes, I think it would help and you can probably do a quick test with coarse steel wool.

Lastly, not all wood from the same cord would be equal. Wood stored closer to the ground retains more moisture. I can tell just by the weight of it when I move my wood from outside into my woodshed, that the stuff laying closer to the ground has a long way to go before it is ready for burning. When stacking in my woodshed, I put it off to the other side for later use. Inversely, I always set aside (up high) a bit from the prior season to chop up as kindling or to resort to if having any burning issues.
 
I get back to the point you made that the sweep said everything is good so you did not have him back out this year. Thats what I heard. Good chance your cap or at least your screen on the cap is partially plugged. Many times a loss of draw is caused by creosote accumulation on cap. Go outside with a pair of binoculars and look at the cap. Better yet have your chimney swept every year whether it was ok last year or not.
 
I vote for plugged cap too with a second guess at wet wood. Either way, you should plug the broken tube. The stove is 12 years old but I wonder if those tubes are warrantied for life? I burnt out and had to replace some Lopi stove parts on my freedom bay that were nearly 20 years old. They were cheap.
 
I realize it is a good idea to have inspection/cleaning on a regular basis, but I just haven't gotten it done this year yet.

I just went up on the roof and took a look myself. The screen/cap is totally clean. The pipe itself has some dry crusty buildup, but I was able to see all the way down the tube and it is wide open.
 
Try checking the air intake, I have 2 dogs and a cat and have to vaccum mine out once in a while. Every rear I try to blow it out with an air line before the season starts. What happens if you leave the stove door cracked open?
 
fxdwg said:
I realize it is a good idea to have inspection/cleaning on a regular basis, but I just haven't gotten it done this year yet.

I just went up on the roof and took a look myself. The screen/cap is totally clean. The pipe itself has some dry crusty buildup, but I was able to see all the way down the tube and it is wide open.
Click to expand...

Since you have checked that the chimney is clear you can check it off your list. If you know that your wood is dry and that your current setup has worked much better in the past then I would wait until tonight. I live north of you and up at 700 feet above sea level with a current 61 degree outside temp and no wind. My fire is going right now and is being fed the small stuff. 3-4 inchers just to keep it ripping and since I don't need or want it to last that long. These mild temps make for poorer than usual draft. Tonght when it cools into the low 40s you should be much better off.
 
I have seen what you are describing (sudden drop in burn performance) when the pipe from the stove to the chimney pulled out of the chimney just a little bit. That allows room air to get into the chimney and really kills the draft thru the stove.
 
I replaced the air tubes two nights ago and fired up last night. everything seems to be back to normal.

Thanks for all the input and suggestions for things to look at.
 
Status
Not open for further replies.

Similar threads

IDfamforest
Shop stove build and buffeting/back puff from the air intakes- ideas?
Replies
20
Views
745
The Hearth Room - Wood Stoves and Fireplaces
bholler
B
jwoair23
Heritage 8024 - Secondary Burn Tubes Cracked?
Replies
6
Views
263
HearthStone
begreen
begreen
J
Pre 1990 Lopi 520 secondary air tubes
Replies
4
Views
409
Classic Wood Stove Forums (prior to approx. 1993)
begreen
begreen
D
Newbie with a chimney question
Replies
6
Views
305
The Hearth Room - Wood Stoves and Fireplaces
bholler
B
R
Regency F3100 air tubes - homemade
Replies
2
Views
1K
The Hearth Room - Wood Stoves and Fireplaces
richard1988
R
Top Bottom
Back