Fly Ash in Flue Outet?

I just did a clean out on my Juniata and had a question about the flue exit. The flue gasses exit the top of the stove and I know the design of the internal flue system creates a place that fly ash can accumulate. My question is given the velocity that the gasses are traveling through the pipes, how likely is it that fly ash will block this area? When I have the cap off my clean out tee, the smoke from the starter bag is really coming out of the stove and through the pipes on up the chimney. I just ran my vacuum hose down the flue pipe in to the stove and then up the flue from inside the stove. I am guessing that since I am still registering a -.02/.03 draft over the fire that I shouldn't worry about it much.

If you can get your vacuum into those internal pipes and your draft is not changing for the worse, I would think you are good to go.

-Don

You can get the same draft reading through a soda straw as through a 12X12 flue...which one will carry the most gases away?

The point is, don't wait for big draft reading changes before thinking your stove pipe is filling up and partially blocked with fly ash.
Airborne fly ash can and will be different size/weight particles. The heavier particles settle/fall sooner/closer while the lighter particles will go further. Depending on velocity, some of the tinyest might be carried far enough to exit the chimney...maybe???

That's why I have 2 clean out tees installed.

McGiever wrote:The point is, don't wait for big draft reading changes before thinking your stove pipe is filling up and partially blocked with fly ash.

I agree, waiting could mean the flue shuts down when yer not home to solve the issue.

I wish there was an easier way to clean that section out other than removing the pipe from the top of the stove. I think I could come up with something but not until spring when I no longer need the stove.

Can I use any vacuum to clean up fly ash. Will it make it airborne ?

longislandsteve wrote:Can I use any vacuum to clean up fly ash. Will it make it airborne ?

you can use any vacuum that is capable of filtering very fine particles. It also needs a large filtering area to avoid fast clogging. I would not recommend any bagless vacuum.

I've been using the bags made for in shop vacs and they work good with no mess at all.

Best to use a drywall bag in the vac, it catches the tiniest particles. Any horizontal run is going to collect ash, just a matter of how often.

I am going to be paying much closer attention to the build up of flyash in the flue outlet on my Juniata. Yesterday when I got home from work, my wife had turned the thermostat up to 85 (max it would go to) while cleaning up around the house and couldn't figure out why the house was so hot. I figured it would be a good time to shut the stove down and give it a good cleaning while letting the house cool down a little. I pulled the pipe from the top of the stove, and much to my surprise, the opening was almost blocked completely with flyash. I cleaned it all out and the rest of my horizontal pipes and fired it back up. The coal is burning much better now as a result, stove puts out better heat, and I used a good bit less coal last night and today. I am going to check it again next week around this time to get an idea how quick the ash builds up there compared to the amount in the horizontal pipes so I have an idea how often I need to pull it apart and clean it.

How long has the stove been running since that area has been cleaned?

I half a$$ed cleaned it about a month ago, but I stuck my vacuum hose down through a clean out tee into the top of the stove. I will be taking it apart on a regular basis to clean it from here on out, I just need to figure out what "regularly" is for my setup. The way I have my pipes mounted makes it easy to just pull it out of the collar and move it to the side. I'll get a schedule down for cleaning before too long, but I'm thinking once a month should be pretty sufficient.

I vacuum my pipes once, mid season. I've never come close to having more than inch in my near horizontal run (which is 3.5ft worth of pipe). That's crazy ash build-up.

My pipes could probably due with only cleaning mid season and at the end, but the flue outlet on top of the stove will not last that long. The flue gasses in the Reading Juniata exit the fire box through an L shaped section of square tube. It starts about half way down in the fire box travels up the side, sharp 90 deg turn along the top then another sharp 90 to the collar. There is not any kind of radius to the flue path inside the stove at all, just square boxed turns and a squared off closed end where the flyash builds up under the flue collar. The square tubes are only 3 to 4 inches in size as well.