New to coal - with a shining gem of a base burner: McClary 114 with Piggyback Oven!

I have a portable fog machine that I use for some of my professional work, and it doesn't show any leaks. Very cool to see the fog rise up around the body and through the secondary heat port on top. I wish that could actually be used to send hot air to the upstairs directly, but such installations are illegal now (at least in Canada).

I just recalled that a member in the past solved his oversized chimney problem by simply placing a piece of sheet metal with a 6 inch hole in it, over the existing chimney outlet. It tended to hold heat in and maintain draft. Cheap to try and if it seems to work, more elaborate configurations could be tried as well like a section of smoke pipe extending down into the chimney through the sheet metal.

DonKom wrote: ↑

Wed. Feb. 20, 2019 10:36 am

She's cold at the moment as I plan to replace some mica windows, but I'll fire her up again in a couple days just for the enjoyment of it. Any and all thoughts to get better draft would be appreciated - while cold I'll also be installing the manometer.

One tip that I will share on mica replacement that helped me alot. I was having a hard time lining up the mica on the curved parts of the door. I would get one lined up and started on the next piece and then the first one would move before I could get the inner ring bolted on. I found that a drop of super glue on each corner of the mica held it in place while I lined up the rest of the mica. It made the job a lot easier and you have far more of it to replace that I had.

Randy

franco b wrote: ↑

Wed. Feb. 20, 2019 1:09 pm

I just recalled that a member in the past solved his oversized chimney problem by simply placing a piece of sheet metal with a 6 inch hole in it, over the existing chimney outlet. It tended to hold heat in and maintain draft. Cheap to try and if it seems to work, more elaborate configurations could be tried as well like a section of smoke pipe extending down into the chimney through the sheet metal.

So, Ive see a few places with super short chimneys, im assuming they had issues because they have mortared stainless metelbestos pipe onto the top, for shits and giggles you could achieve the same thing with a few pieces of regular stove pipe and some quick set mortar might help it might not

Okay, I've got the stove fired up for manometer readings! Tried to do this a few days ago but the backdraft was so strong it took 15-20 minutes with a heat gun on the stovepipe to get the air movement neutral - thought I'd wait for colder weather or more wind.

The firepot is full and just about at full burn now, and the reading is: 0.05. From what I gather, that's almost nothing - and I'm in direct draft mode with a window cracked open in the room. I think this will be the last time I fire up the stove this season, with more drastic measures to induce draft to put in place over the warmer months to prepare for next season. I don't want to depend on windy days, I'd like some consistency here... so still muddling over exactly what to do. A lot of options, all of them can help a little.

Currently 10F outside and going down to 0F tonight with wind speeds just over 10 miles an hour.

At the very least, I've learned a lot about the starting and operation of the stove this season... now to get it singing and dancing every night next winter.

It's clearly junk, I'll be happy to scrap it for you.

.05 is an ok draft for a small firepot stove that is idled down. But, for a larger firepot stove in direct draft, that's borderline dangerous.

As the firebed burns down and it's heat volume starts to drop off and it starts to ash up, it won't have a strong enough draft to be sure of not back drafting.

Either there are large air leaks passing, or after the firebed, or the chimney is not sufficiently high enough to keep a healthy draft.

Paul

Thanks Paul,

Yeah, keeping the doors closed in that room and a window open for it to burn down. If 0.05 is as much as I can muster from the stove, I need to adapt the chimney. For the record, the firepot is 14" in diameter.

There is no CO anywhere around the stove once up and running, but I have a 1ppm handheld Co detector I keep on me when the stove is running, and five others in the house including one right next to the stove.

I run my portable fog machine around the stove but can see no activity from leaks anywhere.

Will work on fitting the chimney - which was perfectly fine operating a wood stove for years - with the necessary modifications to get better draft.

Richard S. wrote: ↑

Mon. Mar. 04, 2019 8:00 pm

It's clearly junk, I'll be happy to scrap it for you.

Haha, nice try! Just a design flaw with an incompatible chimney that needs fixing.

.05 is five lines up from zero and is excellent draft. .005 would be half a line up from zero. Lets be sure we understand your reading. An oversize chimney has to be made smaller or steps taken to hold more heat in it, which making it smaller does.

What is the reading with a cold stove and chimney?

franco b wrote: ↑

Mon. Mar. 04, 2019 9:47 pm

.05 is five lines up from zero and is excellent draft. .005 would be half a line up from zero. Lets be sure we understand your reading. An oversize chimney has to be made smaller or steps taken to hold more heat in it, which making it smaller does.

What is the reading with a cold stove and chimney?

Cold stove and chimney could be neutral, could be negative! With every effort to put a stove into an overdraft scenario I can get 0.05. Turn on the base burner? Close the window? These all force that number lower. One of the things I'll be doing in the spring is a chimney liner, still looking into an Enervex RSHT draft inducing fan though... 10 year corrosion warranty and we'll have back-up power for things like this within a year if needed. Huge expense, but reliable beyond adaptations that will provide better but inconsistent draft. I don't know, the cost is the biggest concern but I don't want unpredictable things from an old stove!

If a cold chimney backdrafts it means the house is acting as a chimney and losing air higher up. Enough heat in the chimney and the open window overcomes this as well as fixing the air leaks higher up.

The age of the stove is immaterial.

Good catch Franco, I was missing a zero. .05 is not close to back drafting.

Still, with a full burning firebed in direct draft, the mano reading should be able to get higher than .05,... if the chimney were able to provide a decent draft.

My little firebox range can get up to 1.5 after a few minutes in direct draft, thanks to a tall brick chimney (unlined).

Franco is right, the age of the stove has nothing to do with it. You need a taller chimney to overcome the house wanting to be the chimney (window closed).

And adding height to the chimney is likely cheaper and certainly more reliable than any modern technology. My tall, unlined brick chimneys have been working very well since 1892. Plus, a taller chimney works just as well during a power outage when you really need that stove.

Paul

franco b wrote: ↑

Wed. Feb. 20, 2019 1:09 pm

I just recalled that a member in the past solved his oversized chimney problem by simply placing a piece of sheet metal with a 6 inch hole in it, over the existing chimney outlet. It tended to hold heat in and maintain draft. Cheap to try and if it seems to work, more elaborate configurations could be tried as well like a section of smoke pipe extending down into the chimney through the sheet metal.

This is exactly what I would do.

Running your stove in base burner mode is probably giving you an exit flue temperature under 120* F.

Since its dumping into a short uninsulated masonary chimney with all four sides exposed to the cold, with a large 8" x12" clay tile flue liner, I'm not at all suprised at the lack of a good draft.

I would cut a 6" hole in a 10" ×14" ×1/4" thick steel plate and weld a 4' section of 6" pipe leaving an inch or two sticking out the top, and stick the remaining 46" down the flue. Weld four pins, small blocks or angle iron pieces to the bottom of the plate to keep it centered in your flue.

I didn't notice if you had a mpd in your flue pipe ..... If not I suggest installing one.

As far as changing your 90* elbow to two 45*s or running it at an angle, in my opinion is not worth the effort.

This is a very inexpensive but highly effective an proven solution to slowing down the escaping flue gasses and retaining enough heat in your existing chimney enabling it to draft on its own.

Paulie

Thanks so much for all the feedback everyone!

First step was always going to be a chimney liner - everything I read told me that this helps a fair amount. 316L steel is the best for lower temp exhaust as it resists corrosion at lower temperatures. It's just a more complete solution to the 6"x4' pipe idea. Kits are readily available for exactly this function.

I should be able to force the draft to be something like 1.5, at least I'd like to have that much pull through the chimney and then dampen things down to a comfortable level. After all, it would still be fun to cook on that piggyback oven if I can get it hot enough! Just not happening no matter what I do with my current chimney.

No MPD, though I have a chimney cleanout which can function as a barometric damper if needed. I was actually thinking of designing a cover for it that functions as a damper and have that 3D printed in steel.