Flue Lessons

[tbear853]

Sometimes we learn again, old lessons we once knew.

Lately my stove has been running "poorly", lazy flame, unburned pellets, black sooted door glass shortly after cleaning, you all know. I first thought was a flu issue, was looking to buy parts to change it, looked at correspondence with Bill A. here for ideas. I became convinced that maybe the TC was bad after all. I cleaned the stove, thought maybe was a door seal but tried a dollar bill, it was tight.

In reviewing my notes, etc. I saw where this old stove was running might near perfect last season. I had forgotten just how good. I tested both my TCs, have even got one on order .... but last night I retested them, both test great by testing for signal with changing heat and continuity. I know I can change my combustion blower any time now, it owes me nothing, it has a like new still fore box.

Still, every time we've tried it this season, we've shut it down. I knew was running great last season after some issues.

Yesterday I decided to clean the flue. It's out a wall behind the stove 3-1/4 feet counting a 45* adapter, a tee with cleanout cap outside, 5 feet straight up, a 90* turn and a horizontal termination. I was thinking of adding more vertical pipe. I have a 13 or so amp Craftsman 2 speed leaf blower / vacuum / mulcher, it's a two hand deal.

My cleanout cap is easily 5 feet off the ground. First I put the vacuum on the clean out, and my goodness, the huge black cloud that exited the blower nozzle. Then I put a round blower extension on it and stuck it up the cleanout well past the stove branch, hit high. 2nd cloud out the flu termination. I meant to vacuum it with stove doors open, but I can do the stove with a smaller vac.

Today I did a good stove clean since the stove was cold, vacuumed every thing, heat exchangers, combustion air supply, lower part of burn pot, got the glass squeaky clean, etc.

Stove is running into 4th hour now, there ain't a wooden cooking spoon worth of stuff in the ash pan, and most of what is there is from the starting.

About perfect.

I think part of it is the long non heating seasons allows one to forget the basics is part of it, and then like yesterday took me awhile to get the clean out tee cap off. I think was mainly very slight corrosion of the galvanized steel with the 4 indented slots where you insert and twist it 90 degrees to secure it. I coated all those surfaces with nickel anti seize and just pushed it up into the tee, no twist lock. I'll make a securing strap to make it easier getting off .... and then it'll be an easy 5 minute chore after shutting the stove off for a periodic clean.

 

[tbear853]

Is into hour 11 now, glass looks like I just cleaned it, A coffee cup would hold the ashes twice over. Thursday we were talking about just stop using it, maybe get someone to help move it out. We were talking about no more pellets to be hauled in, etc. Today (well, Friday) it's a different deal, it is good. I can come up with a way to move pellets easier, even if just using buckets so Wife con get them in if need be with no strain. She has brung bags in before, but I know the chore it is for her.

Lesson is "Clean that Flu".

 

[bogieb]

Yeah, we sometimes do need to get back to the basics. Had an oopsie with my P61a when I started it up for the season. I always unhook the OAK and the end with newspaper for the summer as well as bagging up over that. I had gotten the newspaper out when I reattached the OAK, but it was overfilling the firepot with pellets.

Finally decided to go thru the whole thing again (it had been running peachy last spring), so unhooked the OAK, looked up it and saw I'd also put in a piece of insulation prior to installing the newspaper. Once I removed that, it has been running great - imagine that

 

[EatenByLimestone]

Here’s a video of it!

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[tbear853]

That's a lot of dust there ................

 

[Burnin Since 1991]

Here’s a video of it!

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thank goodness no one has to breath that... oh wait

 

[tbear853]

Just thinking, planning. I've got an old round brush, it's a snug sliding fit through a pellet vent flue pipe. I'm not sure of what material the bristles are made of, but it was given to me by that stove dealer when I bought the stove, he didn't give me a pole, and my first flu setups would not have worked with a pole so easily anyway unless disassembled. I cleaned the pipe a few times, but between standing on a roof and disassembling dirty stove pipe, I was always a mess when finished. I even have extension lengths of 2.5" Shop Vac hose that I used a few times pushing upwards from below.

Initially, in 1992, my flu was a temporary assembly and it was a few years before I improved it as I enclosed the open carport leaving only one open end at the opposite side. Flu then was easily 12 feet straight up first through a roof and then past a second roof as it passed through a ring like bracket, and before I could clean it, had to take some of it apart to lower the vent cap just to remove it from the pipe.

The carports 3.5L12 roof was then easy to walk on shingles & I was younger. Sure ... it made for a good draft ... but cleaning it was a Royal PITA. I know I didn't clean it out every year, likely not even every second year at times. The carports 3.5L12 roof is now slick steel & I'm now older.

I now only have a 5 foot vertical flu pipe from the tee up, and then there is an easily removable terminating elbow. It turns 90* and terminates before reaching the first roof, easily reached on a ladder as it is maybe just over 11 feet from the ground below.

I could tie a 7+ foot piece rope to the brush, drop the rope through the pipe and tee with the bottom of tee clean out cap removed, then climb down the ladder, wrap an old tee shirt or other rag around the rope where it exits at the cleanout cap, secure the rag to the tee (string, zip tie, etc), and pull the brush downwards through the pipe, the rag controlling the flu dust. When the brush has been pulled through to the rag, simply let it and the rope and the rag drop into a pail held up underneath.

With the cleanout where it's at, I can also run one of the 2.5" flex hoses of my big shop vac into the branch that goes to the stove. Follow up with the big blower / vacuum .... & trash the by then black sooty rag.
Seams easier and safer to me.

 

[tbear853]

And yesterday I swapped on a box like horizontal flu cap in place of the old round tapered one, and the stove is breathing even better now. I did it as a test as no matter which way the round one was pointed, wind was fighting the stove. This new one has a sloped side facing any wind coming straight in at where the opening was, and I guess that slope deflects the wind up and over. Was a test, but looks like I'll add a brace now, it works so well.

I added the expanded mesh to keep birds out, it was painted already when I found it on the road side all those years ago.

 

[tbear853]

Water in clean out cap?

We were away for the Christmas with family, but just before Christmas, when I wrote the above post (#8), I forgot to ask about others maybe finding water in the SS clean out cap. I know moisture is a byproduct of combustion, I know it will condense on cold surfaces, like exhaust piping.

On the day I swapped that pictured vent cap up top, I had removed the SS cap on the lower end of my clean out tee. I neglected to say that I found that cap full of water, like you filled it under a faucet.

I had just had that cap off maybe 3 weeks earlier in first of December, cleaned it, and reinstalled it with the nickel anti seize on it, and we had run the stove on low maybe 2 weeks total since. If not for a cleanout tee, it'd been a mess. Attached for reference is a picture as it's existed since at least 2020 (changed after we re-roofed). I had a tapered horizontal termination on it, had experimented with a longer horizontal run (over that open carport window), but this what is now except the new "rectangle/trapezoid" horizontal cap that is now facing the camera (and which I braced before leaving)

Anyway, it surprised me at the quantity of water accumulation in just a few weeks, and I wondered if anyone else had seen such in such a short time? My old clean out cap had a couple small holes in it that let water drain, maybe I added them and simply forgot, you certainly would not want holes draining black sooty water in a house.

 

[Whitenuckler]

I could tie a 7+ foot piece rope to the brush, drop the rope through the pipe and tee with the bottom of tee clean out cap removed, then climb down the ladder, wrap an old tee shirt or other rag around the rope where it exits at the cleanout cap, secure the rag to the tee (string, zip tie, etc), and pull the brush downwards through the pipe, the rag controlling the flu dust. When the brush has been pulled through to the rag, simply let it and the rope and the rag drop into a pail held up underneath.

I cleaned my stove pipe for the first time since new this fall. I have a tee behind the stove (which is tucked into a corner of the basement) and a tee out side that is fairly low to the ground. I had bought a duct cleaning brush with rods kit (the type you screw together, then tape) and could be used in a drill. I tried it out but it was almost impossible to use it with just the caps off the cleanouts. No way I could use the drill. The only place I could use it easily was from the nozzle down. Next year I'm going to find a 4" SS brush (or synthetic??) and rig up a pull rope system. It's only a fine dust in there. I just want to make sure I clean and inspect every inch of it. For me the delicate part is past the combustion blower, and being careful arounf the ESP probe. I have bottle cleaning brush for there, and my small size shop vac hose can pass by to go into the tee.

 

[EatenByLimestone]

Maybe your stove isn’t on long enough to heat the pipe long enough to evaporate the water? Does it short cycle a lot?

 

[tbear853]

Maybe your stove isn’t on long enough to heat the pipe long enough to evaporate the water? Does it short cycle a lot?

No, it's on until we turn it off. I understand it existing, it just surprised me how much. Like I said, old clean out had a couple drain holes. Being stainless, not a rust issue, and might be over time it will evaporate.

We are back home, and stove is running like a top. I just a minute ago pulled the cap off, it is dry as a bone bleached in the desert.

 

[NS P-68]

I think you will get less water with the new style cap you installed...

 

[tbear853]

I think you will get less water with the new style cap you installed...

That thought occurred to me too, we had had some serious wind and some rain just before that, was why I had gone to town and got the new termination piece / cap.

Stove for darn sure likes this new cap.

 

[Whitenuckler]

That thought occurred to me too, we had had some serious wind and some rain just before that, was why I had gone to town and got the new termination piece / cap.

Stove for darn sure likes this new cap.

Here is my type. I believe they call it a nozzle? It has a good slope and it's on the north side of the house under the soffits. There is a house further north which would block the wind a bit. I did not see any evidence of water in the tee next to the house.

 

[tbear853]

Here is my type. I believe they call it a nozzle? It has a good slope and it's on the north side of the house under the soffits. There is a house further north which would block the wind a bit. I did not see any evidence of water in the tee next to the house.

Might be the name for sure. Mine was under the overhang of the attached carport, it too was sloped downward, worked
ok I thought, but the new one is better. No matter which way is pointed, it has the house or carport from the south east to the north west behind it as that side of the structures face south west, and prevailing winds here come out of the west to south west. I built my house in 1990 not planning for a pellet stove with nozzle. For years had a 360 degree vent cap, but put a metal roof on in '17 and decided no piercing. Even with a sloped nozzle, any wind hitting it at the opening will fight the combustion fan. We had some serious rain with wind, might have blown some in.

Tomorrow is gonna get real windy, it'll be a real test of this horizontal cap that only has a big bottom opening, with the slopped face above it. If needed, if it doesn't work as I think it will, I can next add a longer sloped face panel for that surface that will only extend below the opening on the wind facing side. We'll see.

 

[Whitenuckler]

Might be the name for sure. Mine was under the overhang of the attached carport, it too was sloped downward, worked
ok I thought, but the new one is better. No matter which way is pointed, it has the house or carport from the south east to the north west behind it as that side of the structures face south west, and prevailing winds here come out of the west to south west. I built my house in 1990 not planning for a pellet stove with nozzle. For years had a 360 degree vent cap, but put a metal roof on in '17 and decided no piercing. Even with a sloped nozzle, any wind hitting it at the opening will fight the combustion fan. We had some serious rain with wind, might have blown some in.

Tomorrow is gonna get real windy, it'll be a real test of this horizontal cap that only has a big bottom opening, with the slopped face above it. If needed, if it doesn't work as I think it will, I can next add a longer sloped face panel for that surface that will only extend below the opening on the wind facing side. We'll see.

I like the new one, but it's going to restrict the flow more than your old one I think. You do have a good vertical rise though. Are you using 4 inch?

 

[tbear853]

Just 3", all I've ever run.

 

[Whitenuckler]

Just 3", all I've ever run.

I didn't pick the size myself, I probably designed it with 3", but my installer picked 4 inch as it's in the basement with 3 90's. I think he said he had 4inch in stock. Anyway, I'm happy. I like the silicon inner seals on mine too. Very tight.

 

[tbear853]

Yeah, my old flue had the high temp rope like seals but I've now got all newer flu pieces and they have the silicone seals. Ain't but a few inches of flue in the house, at the stove back .... all other joints are outside. Stove has a 3" OD steel exhaust pipe, and I don't recall hearing of 4" pellet vent back then.

About the nozzle type flu cap, I couldn't tell about yours, but mine was tapered and said to be to increase velocity of flu gasses. Maybe it did, but to boost speed it requires push, plus was downward at an angle. It too is Dura Vent, but this on there now has no reduced diameter, it's full size until the exhaust gasses empty into the trapezoid rectangle chamber. If wind is blowing it'll miss the outlet and may even create a vacuum as it goes by?

Anyway, I'm not trying to sell anyone on them, I just happily found it working better for my situation.

 

[tbear853]

About the new cap, I had for several years stuck with the long downward sloped tapered vent cap advertised as horizontal, but I'm sure glad I bought this one trapezoid rectangle chamber like one to try. Weve had 40 mph winds today, and they come inwards might near like the angle I took this picture, just not from the ground up. My wife and I both have watched today, not once have we either one seen the stove flame act lazy like it would have been with the round one. Stove glass has stayed clean, and pellet ash is just ash, no partial burnt pellets. To refresh, 3 feet horizontal pipe from stove to the tee outside, then 5 feet pipe up side of tee (cleanout side of tee points down), then a single 90* and this new vent cap as seen. This thing "rocks".

Just came in, took delivery of 2 tons Hamer's Hot Ones.

About the nozzle type flu cap, I couldn't tell about yours, but mine was tapered and said to be to increase velocity of flu gasses. Maybe it did, but to boost speed it requires push, plus was downward at an angle. It too is Dura Vent, but this on there now has no reduced diameter, it's full size until the exhaust gasses empty into the trapezoid rectangle chamber. If wind is blowing it'll miss the outlet and may even create a vacuum as it goes by?

I sharpened a fuzzy picture and it added some black splotches, might be too sharpened, my bad.

 

[tbear853]

Last night, like early this AM, winds woke me up a couple times. Got up this morning half expecting smudged glass and not completely burnt pellets in the ash pan due to a reduced air flow due to those winds.

Surprised I was. 😆 Flame was very lively, glass still looked clean, nothing but burnt ash in the ash pan, and not a lot of pellets used.

Forgive my boring post, but as long as I've run this stove, the many winters, I don't recall it ever doing any better. I do recall times it didn't run so well though.

 

[bogieb]

Last night, like early this AM, winds woke me up a couple times. Got up this morning half expecting smudged glass and not completely burnt pellets in the ash pan due to a reduced air flow due to those winds.

Surprised I was. 😆 Flame was very lively, glass still looked clean, nothing but burnt ash in the ash pan, and not a lot of pellets used.

Forgive my boring post, but as long as I've run this stove, the many winters, I don't recall it ever doing any better. I do recall times it didn't run so well though.

That is an awesome result from such a simple change. Glad it is working well for you!

 

[tbear853]

I promise, unless asked a question, this will be my last post in this thread as I'm sure it is getting old by now.😆

Since long ago, like 1992, I've had a cold air inlet made of 2" OD (same as stove inlet) car exhaust pipe (for combustion air), it goes through the same wall thimble as the flue, over at the upper corner, it has a screen on the outside end, and it comes out of the house and turns 90 degrees and is secured to a log end at a very slight downward angle.

Today, wind is up still, and I heard a big long gust hitting the house as I was watching the stove, thinking how well the stove was doing, etc .... and suddenly the stove flame became more intense, livelier too, like it got a good dose of oxygen .... then I sniffed a trace of smoke. We had long gotten used to it, was very faint and we figured was smoke from outside maybe hitting the house, maybe a seep through a joint? For some reason today, I gave it more thought, then reflected on the cold air inlet.

Then it hit me. When I put the stove in and all that goes with it, I was focused on not letting rain or bugs in (slight grade of pipe, screen, etc) and keeping the inlet away from exhaust. I never considered that I had pointed the pipe right into the prevailing winds here.

So today went downstairs, grabbed an extension hose for my big shop vac, and slipped it over the end, looped it through the porch railing, and pointed it straight down, secured to the rail and the inlet pipe with zip ties. Since then this morning, no smell at all and the stove flame appears unaffected by wind. I think maybe the wind was like super charging the air inlet and reducing vacuum in the stove that pulls combustion air in (thanks to the exhaust blower) momentarily pressurizing the fire box, maybe the whiffs of smoke were through a door seal. Fire would still get more oxygen, but it being pushed instead of sucked in, like adding oxygen to a torch?

Tomorrow I'll stop by a car parts place and get me a turn down. Really old picture used to explain.