Had to call the fire department last night...

[CowboyAndy]

So it was about midnight when we were woken up by the smoke alarms. I hop out of bed and start looking around. Imediatly I smelled smoke. I made a beeline for the basement where the furnace is. As I came around the corner I heard this loud "woosh" sound, and a crapload of smoke came shooting out of the draft fan. it was NOT running at the time, as the thermostat was satisfied. Not knowing what to do (1st year burner) I shut off all the air asap and called the fire department. I would rather be apologizing to the firemen for dragging them out of bed in the middle of the night if it was nothing compared to if it were some type of major problem... as my kids were all still asleep at the time.

So they get there, and I explained what I experienced. They started in the basement, and when the door to the furnace was opened the smoke came out so fast and so heavy imediatly. up to the roof they went. "chimney all clear, no fire no blockage.
There is smoke coming out, but not alot." One of the firemen who is a wood burner himself said to me that what he feels is going on is that given the outside temp (was 40 at the time) and the idling conditions of the furnace at the time, combined with some creosote build up in the stove pipe that the draft was not enough to carry all the smoke out of the firebox, which led to the pressure building up and finally "releasing" via the draft fan.

So they recommended that I either empty the firebox contents (not feasable) or run it wide open until its out. we chose the later, and within a short time the inside temp was 80. Low was 28 last night, so it was down to 68ish this morning when i left.


Now, anyone have any input on this, like why it happened and how i can prevent it?

 

[EatenByLimestone]

Glad you're save.

Matt

 

[jtp10181]

Clean your chimney.

What quality is the wood? More moisture = much more smoke.

I would guess less than optimal wood combined with a slow burn and warmer outside temps is what did it.

 

[savageactor7]

Well better safe than sorry as for your system I dunno. Best of luck with it though.

 

[CowboyAndy]

Clean your chimney.

What quality is the wood? More moisture = much more smoke.

I would guess less than optimal wood combined with a slow burn and warmer outside temps is what did it.

They said the chimney looked okay at the top, minimal creosote. it was just cleaned in january. as for the wood, 21% mc. doesnt sizzle.

my guess, like i said, is the stove pipe going from the furnace to the liner. it doesnt have much of an angle to it... almost horizontal. Im thinking that needs to be cleaned twice as often as the flue itself.

and yes, it was a slow burn, system was at idle when it happened.

 

[Wet1]

I don't know that I'm buying what the guy at the FD said. If the top of the chimney is clean and the outside temp was 40 (cool), I think you have some type of underlying issues with your system...

How long is that nearly horizontal run? Any way to give it some more pitch?

 

[CowboyAndy]

its about 4ft, and no there is no wat to change it... it goes through a concrete wall. and the ceiling in the basement is really low, only about 6 1/2 feet. there is just enough room between the stovepipe and the floor joists to meet clearence with a spaced heat shield.

 

[Jags]

Hmmm....System at idle, mild temps outside, 4 ft horizontal run, 21% wood. Not the ideal condition for a good draft. Throw in some other item, like a water heater venting outside, or a strange wind direction and you could have a negative pressure situation pretty quick. Just food for thought.

 

[CowboyAndy]

FYI, its not completly horizontal, but doesnt have much of an angle to it.

the first thought i had was wind, but when i went outside it wasnt windy at all. was pretty calm. when i get home today im going to take off the stove pipe and see how much creosote there is in there.

 

[johnn]

Not sure what it takes to get the house up to 80,,,but keep in mind you may have burned off any tall tale signs when you go to remove the stove pipe

 

[Highbeam]

Can you move the stove closer to the wall to reduce the 4' horizontal run's length? Given the same elevation change you would end up with more grade in your pipe. Can you cut out the floor and lower the furnace to gain more grade.

40 degrees is plenty cold when it is a normal temp in the house. I started a fresh fire in a cold stone stove last night when it was more than 55 degrees outside since it was only about 63 inside. Is there a way to increase the "idle" air supply to the furnace to let it maintain a little more fire which should maintain the draft a bit better.

Sounds like your house was a better chimney than your chimney.

 

[firefighterjake]

No answers . . . but I can say if you really want to meet the nice, neighborhood firefighters there are a lot more easier ways . . . like just stopping by the fire station on a meeting night or training night if they're volunteers or anytime if they're career.

As for being apologetic . . . there is rarely a need to apologize . . . even if someone has done something bone-headed . . . which clearly is not the case here. It's their "job" (whether career or volunteer) to respond day or night whenever anyone calls -- it's one of the reasons for why you pay taxes (most are funded from taxes) and responding to calls is the reason that they volunteer or work.

If you really want to go above and beyond the call of duty so to speak, we always appreciate home-made cookies and/or thank you notes . . . this applies to career and volunteer firefighters . . . and volunteer FDs are often raising money for special tools/equipment if you are so inclined . . . but quite honestly . . . nothing is really needed . . . well except for the cookies . . . please send some my way for official tasting.

 

[mike1234]

Do you have any kind of outside air intake so you don't end up with negative pressure in the house? A smoky smoldering fire happens sometimes, but with any kind of make up air in the house and the temp at 40 outside, it should flow out. It sure sounds like you need some kind of outside air supply.

 

[Backwoods Savage]

When the temperature is over 35 degrees we usually leave our draft open further than we do when it is colder.

I agree with the firemen. Because yours is a thermostatic controlled draft it was closed because the house was warm enough. Therefore there was not much pushing that smoke out of the chimney. Because it cleared out when you opened the draft, that further agrees with the theory.

Sure glad this turned out okay Andy. Next time set that thermostat higher and put less wood in.

 

[CowboyAndy]

Do you have any kind of outside air intake so you don't end up with negative pressure in the house? A smoky smoldering fire happens sometimes, but with any kind of make up air in the house and the temp at 40 outside, it should flow out. It sure sounds like you need some kind of outside air supply.

When we installed the furnace we decided we did not need outside air because out house is an 1890s farmhouse on a flatrock foundation with gaps all over the place. the door to the basement is outside, and is just a homemade wooden door. there is plenty of places for air. not to mention that there is no access from inside the house to the basement.

No answers . . . but I can say if you really want to meet the nice, neighborhood firefighters there are a lot more easier ways . . . like just stopping by the fire station on a meeting night or training night if they're volunteers or anytime if they're career.

As for being apologetic . . . there is rarely a need to apologize . . . even if someone has done something bone-headed . . . which clearly is not the case here. It's their "job" (whether career or volunteer) to respond day or night whenever anyone calls -- it's one of the reasons for why you pay taxes (most are funded from taxes) and responding to calls is the reason that they volunteer or work.

If you really want to go above and beyond the call of duty so to speak, we always appreciate home-made cookies and/or thank you notes . . . this applies to career and volunteer firefighters . . . and volunteer FDs are often raising money for special tools/equipment if you are so inclined . . . but quite honestly . . . nothing is really needed . . . well except for the cookies . . . please send some my way for official tasting.

I guess i am just one of those people that feel bad for getting them out of bed in the middle of the night for something like that. id rather be safe than sorry though... and yes a thank you note is in order for them. this is the 3rd time ive met up with several of them in the last few months... back in september when my wife got out of bed and collapsed at 4am, another when my son got into a car accident when he was with a friend and again last night. One of them that my wife knows actually said to us "we gotta stop meeting up this way! If you want to hang out, just say so!"

we live in a small town so everyone knows everyone.

Can you move the stove closer to the wall to reduce the 4' horizontal run's length? Given the same elevation change you would end up with more grade in your pipe. Can you cut out the floor and lower the furnace to gain more grade.

40 degrees is plenty cold when it is a normal temp in the house. I started a fresh fire in a cold stone stove last night when it was more than 55 degrees outside since it was only about 63 inside. Is there a way to increase the "idle" air supply to the furnace to let it maintain a little more fire which should maintain the draft a bit better.

Sounds like your house was a better chimney than your chimney.

Moving the stove is not feasable, its a forced air system and would require EXTENSIVE modification (ie re piping all or most of the duct runs including 25 year old custom built cold air return lines).

in terms of idle air supply, there is an air control on the door of the furnace, but the manual says to use it ONLY in the event of a power outage.


Maybe I could shut down the tstat and open the other air control when the weather is milder out?

I also have made arrangements to clean the stove pipe and chimney today. last time i paid someone to do it, but have had the intentions of getting the stuff i need to do it myself. i found a family friend who is going to let me borrow his brush and rods. I am going to plan on cleaning the stove pipe once a month and the flue every other month.

 

[Backroads]

4' Horizontal, slow burn, 21% and mild temps could all be contributing factors. I ask, "What is the overall height of the chimney?", and "What is the chimney flue size in relation to the stove outlet?" These dimensions could also be a factor. There is a formula (I don't have it but someone here may be a pro on the subject) to determine proper Height based on Horizontal distance, amount of 90* angles and flue size. IMHO I would clean the 4' horizontal several times through out the year, personally I think it is too long of a horizontal run. Smoke doesn't like to travel horizontally and if there is going to be build up that's exactly where it's going to be the worst. When I had my chimney cleaned last year by a pro (I didn't want to drag a ladder on the roof, plus I wanted a lesson on chimney design for when I build our house) he explained all the in's and outs of how creasote is made and why, also the key factors in a chimney that will cause it. You could have excellent seasoned wood, a great EPA stove and still get creasote build up with a poor chimney design. Again, I'm not a pro but recommend you have one access your set up. When I mean pro, I don't mean the average chimney sweep, but somebody certified in installation also. It can be very educational, I know it was for me. IMHO I think you have a chimney design problem rather than a wood/stove problem.

Glad everyone is safe. Let this serve as a good reminder for us all to check out smoke detectors every year.

 

[blades]

Glad everyone ok, I clean mine every month, from the bottom up once the snow is on the roof (little to slippery up there for these old bones).

 

[CowboyAndy]

4' Horizontal, slow burn, 21% and mild temps could all be contributing factors. I ask, "What is the overall height of the chimney?", and "What is the chimney flue size in relation to the stove outlet?" These dimensions could also be a factor. There is a formula (I don't have it but someone here may be a pro on the subject) to determine proper Height based on Horizontal distance, amount of 90* angles and flue size. IMHO I would clean the 4' horizontal several times through out the year, personally I think it is too long of a horizontal run. Smoke doesn't like to travel horizontally and if there is going to be build up that's exactly where it's going to be the worst. When I had my chimney cleaned last year by a pro (I didn't want to drag a ladder on the roof, plus I wanted a lesson on chimney design for when I build our house) he explained all the in's and outs of how creasote is made and why, also the key factors in a chimney that will cause it. You could have excellent seasoned wood, a great EPA stove and still get creasote build up with a poor chimney design. Again, I'm not a pro but recommend you have one access your set up. When I mean pro, I don't mean the average chimney sweep, but somebody certified in installation also. It can be very educational, I know it was for me. IMHO I think you have a chimney design problem rather than a wood/stove problem.

Glad everyone is safe. Let this serve as a good reminder for us all to check out smoke detectors every year.

to answer your questions, total chimney height is 29'. size is 8" all the way, which is the size of the outlet on the furnace. now again, its not a completly horizontal. it rises about 18" over 4'.

 

[Backwoods Savage]

Andy, that is plenty of rise for 4' of pipe. I would not worry too much about that.

 

[Backroads]

now again, its not a completly horizontal. it rises about 18" over 4'.

An 18" is more that what you originally described.

FYI, its not completly horizontal, but doesnt have much of an angle to it.

How much creasote was in the 4' run? Like 10-20-30% blockage?

If it was me I'd still see if a pro will come out and do the dimensions to see if there is anyway to make any improvements. It would make me sleep better at night.

 

[stoveguy2esw]

standard up pitch is 1/4 inch to the foot so you are definately good there, im thinking low stack temps not exactly afrigid day , wind possibly could be playing with it as well , was it a "dreary" day? low clouds? low barometric pressure days can have an effect on draw as well. with a large chimney (29 ft at 8" is a bit large though suited for your stove) burning a protracted low fire can reduce stack temps , and remember , the thing that makes draw is temp differential between inside the flue and outside the flue , the closer they are the lesser the draft effect. i like your thought on going to manual controls on the unit in the shoulder seasons, and i like the recommendation of smaller loads, burn shorter brisk fires when just keeping the chill off, a little more work but a safer practice than a long smoulder.

 

[LeonMSPT]

Stood right there and watched the New Yorker do the same thing one morning, and would never have believed it if you told me it would happen.

Woke up to the oil boiler firing at about 4:30 am. Went down, shut off the draft fan, opening the loading door... decent bed of coals left, but not making enough heat to keep up. Put some smaller kindling in, over it was some medium splits, then three larger chunks of wood...

Closed her up and flipped the blower on. Now, I am a bit of a pragmatist when it comes to burning wood. I don't care what time of night it is. I don't care what else is going on. I have a portable phone on the wall beside the boiler, and sometimes I don't even answer it. Depends what's going on at the time. I watch it until the stack temperature peaks and begins to drop. Once it's peaked and falling off, I can walk away and pretty much plan on things just getting cooler. If something is going to go "wrong" it will be on the rise and peak, usually.

Anyway, flipped the blower on and sat on my stump... hmmm, no fire yet... peak in the barometric damper... straight column of heavy smoke and condensate... crap. I stepped back toward my stump, and WHOOOOSH! SMOKE! Shot out of everywhere... little vents in the door, barometric damper... "OH (#($_@#$ What the @(#*$# is going on here?" as I opened the overhead door halfway, cold air comes in the bottom and forces smoke out the top....

As near as I can calculate... heavy smoke column from smoldering fire in chimney and stack and firebox... hot gasses accumulating around fuel... suddenly a flame... oh an ignition source for all the flammable gasses built up in there. Minor "explosion" of sorts, resulting in positive pressure in the boiler. With a stack and chimney filled with a column of not so hot, wet, heavy smoke... where's the extra pressure to go?

Where ever it can is the short answer, and guess what? It's going to happen again, and again, until actual open flame and fire generate enough lift in the chimney to move it out of the system.

Seen entire houses do the same thing during a structure fire. Not quite the same as a "backdraft" because the power of it isn't much due to the small area and relative lack of air and fuel... not sure you'd want to ever open the loading door during an event like this. I cracked the shutter open on the blower to give it more air, and held the barometric damper shut with a stick... want maximum draft anyway under the circumstances. It puffed a couple more times, and once good flames were present in the firebox it stabilized and took off no problem... reset the air shutter to "normal" and went back to bed.

I knew the chimney and pipe were clean... I check it weekly with a mirror through the cleanout, or an unused thimble on the other side of the boiler. Stack gets cleaned every couple of weeks when I am burning alot of wood. Takes about ten minutes from start of cleaning to fire. No big deal.

So it was about midnight when we were woken up by the smoke alarms. I hop out of bed and start looking around. Imediatly I smelled smoke. I made a beeline for the basement where the furnace is. As I came around the corner I heard this loud "woosh" sound, and a crapload of smoke came shooting out of the draft fan. it was NOT running at the time, as the thermostat was satisfied. Not knowing what to do (1st year burner) I shut off all the air asap and called the fire department. I would rather be apologizing to the firemen for dragging them out of bed in the middle of the night if it was nothing compared to if it were some type of major problem... as my kids were all still asleep at the time.

So they get there, and I explained what I experienced. They started in the basement, and when the door to the furnace was opened the smoke came out so fast and so heavy imediatly. up to the roof they went. "chimney all clear, no fire no blockage.
There is smoke coming out, but not alot." One of the firemen who is a wood burner himself said to me that what he feels is going on is that given the outside temp (was 40 at the time) and the idling conditions of the furnace at the time, combined with some creosote build up in the stove pipe that the draft was not enough to carry all the smoke out of the firebox, which led to the pressure building up and finally "releasing" via the draft fan.

So they recommended that I either empty the firebox contents (not feasable) or run it wide open until its out. we chose the later, and within a short time the inside temp was 80. Low was 28 last night, so it was down to 68ish this morning when i left.


Now, anyone have any input on this, like why it happened and how i can prevent it?

 

[LeonMSPT]

Once outside temperatures go above 30 degrees or so... the insert in the living room becomes the make-up and supplemental heat until it cools back off again outside... heavy fuel load, low draft, air restricted... going to have these incidents... if you're firing the boiler. Only way is loading often and lightly... let it burn and don't overload it when you do add wood.

 

[CowboyAndy]

I had my brother in law clean the flue for me last night, and it was in pretty good shape. not much out of it.


So i guess I learned a valuable lesson out of all this. in temps above 40 the fire needs to burn hot at all times.

i tried manually controlling the air, but it didnt work out so well. the fire kept going to a smoldering state even with it all the way open. so i have been leaving the blower on, tstat set to 90. havent had any problems thus far.


Thanks for all the input here, and Leon, glad to see i'm not the only one!

 

[LeonMSPT]

I am pretty sure it happens in any boiler to a degree during certain burning conditions and parameters. However, the owners only smell a little smoke, and don't become alarmed because it was not large enough.

I come to a point where I question the worth of maintaining a wood or coal fire. The "idle" time of the heating and hot water system is so great when the weather is 3-/35 plus outdoors I think it's more efficient and less costly to let the oil burner do the work when it needs to. Only exception is maintaining the entire system at 140 degrees or so with a small but hot fire. Need to be on it about every two hours or so to make it work. Smallish wood and smallish charges.

Picked this up yesterday and just got done unloading it...

The coal, 2,400 pounds of it. Takes up less room, burns longer, doesn't make smoke or creosote... and can burn it during 30 degree weather out and don't gob up the works.

The truck, I picked up three days ago... yesterday the dealership put a "Simonize" treatment in and out, then I went and loaded it with coal.

I had my brother in law clean the flue for me last night, and it was in pretty good shape. not much out of it.


So i guess I learned a valuable lesson out of all this. in temps above 40 the fire needs to burn hot at all times.

i tried manually controlling the air, but it didnt work out so well. the fire kept going to a smoldering state even with it all the way open. so i have been leaving the blower on, tstat set to 90. havent had any problems thus far.


Thanks for all the input here, and Leon, glad to see i'm not the only one!