New stove, liner, and a chimney fire

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JPS

New Member
Dec 12, 2022
14
RI
Hi all,

I moved to a new (to me) house a couple years ago. The house came with an old pre-EPA stove and has an interior masonry chimney with 3 flues. 1 served a basement gas hot water heater, the 2nd has an outlet on the first floor for the pre-EPA stove they used, and the 3rd goes to a 2nd floor fireplace. All flues have a 7"x7" interior dimension. We enjoy the heat of the fire, and have ready access to all the wood I can cut. split, and stack; but the old stove wasn't doing that great in terms of heating us out of the house in shoulder season or more mild winter days, and a really short burn time that wasn't great for 2 working people away from the house 9+ hours a day.

After a fair amount of research here on stove options and proper steps to take, I found a good deal on a barely used Blaze King Princess (PE32), and we found a sweep to install a 6" liner and insulation in the first floor flue, which is approximately 25' from the tee to the top of the chimney, about 12' in conditioned space, 13' in unheated attic and exposed chimney on the roof. Install for both the stove and liner was done in mid-October this year, we started burning around a week later. From the start, the performance of the stove has been ok. Getting the fire started and going being the the biggest issue, as the draft wasn't awful, but not what I would have hoped for until it got up into the active zone on the cat. Other than a couple really warm days, we've kept it running 24/7 and the heat has been good and the time between reloads about 7-14 hours. A higher setting with mostly pine yields those 7 hour burns, a lower setting with oak gets us about 14 hours between reloads. All our wood has been under cover in a shed for about 14-18 months. If I split a large pine piece that is at room temp, it measures around 17% on a moisture meter, and splitting a large oak will yield around 19%, so our wood is maybe not ideally dry, but nothing I've tested has been above 20%. The only other thing that seems notable to me about its operation is that the usable range of the thermostat was only from full blast at 100% open to around 75% open, anything lower than that seemed to choke the fire out, though I didn't experiment with it too much, as within that top 25% of the dial was meeting my needs. If we left it up near full temp on the controls, the cat probe would get to 80-90% of the way to its max heat reading, and a surface temperature reading would be at 600+, so at least outwardly the stove seemed to be functioning fine.

Fast forward to yesterday, and we had a small(?) chimney fire. We had been out for a while and the cat had moved down into inactive, but there was still a healthy bed of coals, so I turned on the bypass, loaded the firebox, closed the door, and went for a shower, thinking 10 minutes would be perfect to get the cat back into the active range. When I got out, I could hear loud crackling coming from the stove pipe or flue and could see smoke billowing from the top of the chimney when I popped my head outside to look (way, way more than a normal fire starting process makes). I immediately closed the stove's air intake/thermostat all the way. Within a minute or two, the loudness of the crackling subsided, gradually, and the smoke even more gradually subsided. Based on noise level, the chimney fire must have been out or nearly out 10-15 minutes after I shut the air intake off. I was hopping between inside and outside this whole time, and at no point did I see flames or sparks coming out the top of the chimney (I saw a neighbor's chimney fire years ago and theirs looked like a sparkler at the top, which I was expecting/fearing for ours).

Since I had a brand new full load roaring when I closed the air intake, it wasn't until today that all the ashes and smoke in the firebox were done enough to remove the stove pipe and inspect (there is also snow on the roof, so I'm not going up there until it melts and is dry). Judging by the pictures online, the stove pipe had/has level 2 creosote build-up, as there was some thin flaky expanded creosote sitting off the walls of the pipe, but there was still a relatively thin layer of crunchy granola-like black stuff well-adhered to the walls. It was not at all glossy or smooth, which is what I understand stage 3 to be like. After I brushed out the stove pipe, I looked at the horizontal part of the tee connection, which looked the same as the pipe. I stuck a cellphone up to see if there was anything of note up, and just saw mostly more of the same. When I spun the phone to look down, I could see that there wasn't any cap on the lower section of the tee, just open air 15' down to the unheated basement where the cleanout is.

The last bit of information is that I had a tough time getting a chimney sweep to do this job originally. I called at least 6 sweeps in our general area, 2 wouldn't travel this far, 3+ never returned messages, and only the one we ended up having do the liner install actually came to give a quote. They came weeks after they said they would, left trash in my yard, damaged shingles and didn't say anything about it, and when they repaired some of the chimney surface and flashing they hosed a bunch of leftover concrete onto our deck and in our gutters. I'll be calling around again to have a different Sweep inspect our chimney to make sure its still safe and the original install was done correctly, but I'm worried I may have weeks of waiting to get someone out here.

With all that in mind, I'd like to know as much as I can before trying to address the issues with the original installer or a new Chimney Sweep. Is no cap on the bottom of the tee/cleanout the cause of that much creosote build-up in about 6 weeks of consistent usage? If that is the cause, Is a cap required as part of an installation, or am I just a sucker for not making sure that was part of their install? If that is the cause, is there a cap that can be installed after the fact, or is the liner going to have to be pulled up to access the bottom in order to install one? If that tee/cleanout cap isn't the problem, what should I be looking for in terms of other causes for that build-up of creosote?

Thanks in advance, sorry for the novel, but I tried to include everything of relevance.
 
Yes you definitely need a cap on the bottom of the cleanout tee. This robs your draft and cools your exhaust gases significantly, which is probably the cause for your creosote buildup. Get that cleanout capped ASP
 
Wow.... im surprised the stove worked at all with no cap. You just sucking cold air up diluting your draft and cooling the flue gases till they condensed. I would be pissed at that installer.

Im sure one of our local installers on these forums can tell you, but I would assume the cap on the bottom of your T would be included in a install.
 
a lower setting with oak gets us about 14 hours between reloads. All our wood has been under cover in a shed for about 14-18 months.
First, glad it wasn't worse, but this really sounds like a case of wet wood. There's just no way short of a kiln to make any oak ready to burn with 1 summer of drying, You want to get yourself some ash or conifer woods, if you need it ready at that speed. Set that oak aside until 2024/25, or build one of @Poindexter's or @Woodsplitter67's solar kilns, if you want it ready for the 2023/24 season.

At 25 feet of pipe, it would be very unusual for you to not have too much draft, rather than too little. I have just over 25 feet on one of my stoves, and it pulls 0.2" water column, roughly 4x the optimum draft for this stove, so I have a key damper installed to reduce draft. You saying you have poor draft and trouble getting started is another dead give-away for wet wood, we see this every week on this forum.

High draft does lead to a hotter pipe, so the combination of creosote deposited during start-up with wet wood, with the expected strong draft of a tall pipe, might have lead to the fire.
 
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Cap your clean out prior to using again.
Using only a limited portion of your stat range is completely normal.
After capping the clean out your useable stat range/position is likely to change a bit. Running this stove "choked out" is par for the course as long as the Cat stays active. 90% of my burn has zero flame. Good luck.
 
I appreciate everyone's responses so far.

Calling around today I was able to get one Chimney sweep who might be able to do an inspection in 10 days, but he wasn't certain about that so it may be 2+ weeks, especially complicated with the holidays coming up.

Some people's opinion here is that the lack of a cap could explain my problems, and certainly it needs to be fixed asap. Do they make tee/cleanout caps that can be installed after the fact, or will I need to have the liner pulled up to access the bottom of the tee? If this can be done relatively painlessly and the new Chimney Sweep gives the rest of the flue liner a seal of approval, I'd just as soon not have to deal with the original installer.

First, glad it wasn't worse, but this really sounds like a case of wet wood. There's just no way short of a kiln to make any oak ready to burn with 1 summer of drying, You want to get yourself some ash or conifer woods, if you need it ready at that speed. Set that oak aside until 2024/25, or build one of @Poindexter's or @Woodsplitter67's solar kilns, if you want it ready for the 2023/24 season.

At 25 feet of pipe, it would be very unusual for you to not have too much draft, rather than too little. I have just over 25 feet on one of my stoves, and it pulls 0.2" water column, roughly 4x the optimum draft for this stove, so I have a key damper installed to reduce draft. You saying you have poor draft and trouble getting started is another dead give-away for wet wood, we see this every week on this forum.

High draft does lead to a hotter pipe, so the combination of creosote deposited during start-up with wet wood, with the expected strong draft of a tall pipe, might have lead to the fire.
The oak I'm using was dead standing for a number of years before I cut/split/stacked it in late summer of 2021. I have a pretty large property, and probably have 5+ years of dead standing or hangups I can use for firewood before I need to even think about cutting down a live one. I can't say how long they were dead standing since it was dead when I acquired the property, but they had zero branches smaller than about a 3" diameter left attached, so it had to be several years. I understand dead standing isn't going to be as dry as cut/split/stacked under cover for an equal amount of time, but I'd tend to assume it was at a considerably lower moisture content before stacking than if I had cut down a live one. More importantly, I've checked a half-dozen of the fattest splits I had in October, at room temperature, on a fresh split, with a moisture meter, going with the grain, sinking the pins all the way, and everything came up in the 18-19.5% range. Checking again yesterday on another 5 pieces of the oak, I've gotten about the same readings, with none above 20%. So, if wet wood is the problem, either my moisture meter isn't accurate, which is certainly possible, or sub-20% moisture content isn't actually good enough for my stove/flue. I don't mean to dismiss this possibility, but I spent enough time on this forum when I was looking at stove options to know how important dry wood is, and have done my best to ensure what I put in it is appropriate.
 
Welcome to the forum! I’m glad that you are all okay. @bholler and other people are going to check in and offer advice. I don’t think the installer/sweep did right by you and could be reported to the BBB for a start.
 
The cap on the tee is not optional. The installer messed up. The liner needs to be inspected after the chimney fire.
I'm curious how they got a 6" insulated liner in a 7" flue.
It wouldn't surprise me if there was no insulation.
 
The cap on the tee is not optional. The installer messed up. The liner needs to be inspected after the chimney fire.

It wouldn't surprise me if there was no insulation.
I appreciate the responses again from everyone.

I should have stated at the beginning, the installer quoted us for removing the old tile liner and said they would be using a pour-in insulation. If the cap on the tee isn't optional it certainly does make me wonder what other corners (like insulation) may have been cut on the job.

I tentatively have another Sweep coming out to inspect the flue next week, but it is very tentative at this point and haven't had much luck getting a hold of any other ones.

Is there a tee cap product that can go in after the fact, or will the liner have to be pulled up to get that cap in?
 
Is there a tee cap product that can go in after the fact, or will the liner have to be pulled up to get that cap in?
Not that I know of. It should be pulled.
 
Oh and if they did pour in insulation with a light wall liner it will need to be destroyed to pull it out. Heavy wall or midweight will pull out
 
A 6" liner in a 7" flue with pour in insulation means you got the corners insulated, if that.
The tiles were supposed to have been removed. Still, unless spacers were attached to the liner, it can be contacting the chimney brick which is not acceptable.
 
Fellow RIer here. Sorry you are dealing with that stuff. Seems like something is off or the installer was cutting corners. I know theres some snow but with the rain coming it'll be gone. If you get on the roof can you remove the cap and see the insulation they installed? For future cleanings, look into the sooteater. Jealous you have the land for all that firewood gathering. My next house hopefully will be better.
 
Update: I was able to get on the roof today and get a look at the flue from that end. My chimney has 3 flues that exit the crown close together. When they installed the stainless liner, they did not remove the top clay flue tile, I'm assuming because it would have meant the top plate would not have fit next to the other flue tiles without modifying the plate. The top plate is about 6" wide outside of the 6" hole for the flue, which means a bunch of it is just sitting over air, but the part that borders another clay flue overhangs that flue by an inch or two. We don't use that flue, so I'm not worried about it at the moment, but that seems like a pretty big red flag since obviously it would be causing a partial blockage of that other flue if we did use it.

For the flue that was lined, they did use the pour in insulation, which makes it impossible to tell from the top if they removed the clay tiles below the top one. I can see that on one side of the flue the insulation comes up to within 2-3" of the top of the liner/clay tile, while on the other there is at least a 12" gap from the top of the flue until the insulation actually fills the gap between the liner and clay tiles. The liner is reasonably centered on the masonry in that top 12" I can see.

Two things I'm not sure the relevance of:
The underside of the cap, the visible top 12" or so of the liner, and the plate for the top of the flue all has a thin layer/film of sticky creosote, and none of the granola-like stuff I saw lower in the flue. I'm assuming the fire never got near the top, as I could never see flames or sparks coming from the top during the fire. Is creosote more apt to accumulate near the top or bottom of a flue, or is that more dependent on the specific circumstance?

The other bit of info I didn't really explain in previous posts. The bottom of the tee connector seems to be resting on the edge of the very bottom original clay flue liner. Below that last clay liner piece it widens to just the cinder block masonry. Elevation wise the tee seems fine, and it means I know for sure 1 clay tile was removed, but it seemed like an odd thing, no idea if its of significance to this story.

I won't be able to get another Chimney Sweep to look at it before the New Year, despite calling quite a few of them. Of the two I spoke with for a while about the problem, 1 seemed to think a missing cap on the tee wasn't ideal, but shouldn't be causing major issues like this, while the other said it absolutely could cause major problems. I have contacted the original installer and he said he would be out to take a look at things this week. Anything else I should be keeping in mind when he comes?

Thanks again to everyone who's given input.
 
Did you take any pictures while up there?

What separates the clay liners in this chimney? Is there a brick wythe dividing them? If not, what is containing the poured in insulation?
 
Did you take any pictures while up there?

What separates the clay liners in this chimney? Is there a brick wythe dividing them? If not, what is containing the poured in insulation?
I did not think to get any pictures, I was even using my phone for the flashlight to see down between the liner and clay tiles, duh.

There is essentially no separation between the clay liners of the 3 flues, which I see is improper construction. Since the top clay tile is still in place on the liner, that clay tile is what is containing the insulation. Right around the point where that first tile ends (based on the other 2 flues) is where the insulation starts to fully surround the SS liner. I can't say for sure what is containing it below that, though it you read on, I'd assume the tiles just keep going all the way.

I poked around a little more down at the tee, and found much more interesting stuff there, though none of it is good news, I don't think. A little above the tee to liner connection, the lined flue tilts to the left at maybe a 45* angle, and then after a foot or so turns back up to vertical. The connection between the tee and the liner didn't seem appropriately tight, and when I felt that spot, there must have been a 1/2" gap from the liner to the tee on one side. I could stick my fingers in the gap and feel a clay tile right against the tee, and creosote build-up in that small gap on both the clay tile and outside of the SS liner. So now I know they didn't take out the clay tiles, there is no insulation between the tile and SS liner there, and the liner isn't properly connected to the tee.

Here's a crudely drawn visualization of the three flues in the chimney, as best I can make and as best I can tell.
left to right at the chimney cap is: basement vent flue, 2nd floor fireplace flue, 1st floor stove flue

III Roof level
III 2nd floor level
I/ Between 1st and 2nd floor
II 1st floor
II basement
in the basement the left side has a cleanout for the hot water heater vent, and the center is the cleanout for the 1st floor fireplace, there is no cleanout or opening on the right side of the chimney in the basement.
Note the flue from the 1st floor stove is dead center on the chimney at the tee and below, but between the 1st and 2nd floor it shifts to the right, presumably to accommodate the 2nd floor fireplace flue.
 
That's a bummer. Based on what has been posted, it sounds like the job needs to be done over with an insulation-wrapped liner and capped tee.
 
That's a bummer. Based on what has been posted, it sounds like the job needs to be done over with an insulation-wrapped liner and capped tee.
If so, make sure the new guy allows you to collect evidence of why it was wrong and needed to be re-done, in case you want to recoup the cost of the original (wrong) install. I'm not sue happy, but I would be pissed if I paid someone to do a pretty well-defined job, and then within a year had to pay a second person to undo it and redo it right.