Smoke in the House Trouble Shooting

[mudpacker]

We have started 4 test fires. All resulted in a smoky mess. We believe this is due to a weak draft. We have already checked the book's suggestions on this topic and found them to be inconclusive.Here are our concerns: In general…
1)The exit flue's (vertical stack or chimney) position out of the house?
2)The difficult pressure zone issues inside and ouside of the house?
3) The height of the piping outside of the building?
4) Our piping's lack of thermal insulation?

1) We installed the exit in the low pressure side of the basement of a two story house. The south prevailing winds are on the opposite side of the room/ house which has a drafty door. Also we have a Vacu Stack as the cap. SO we believe wind issues are not the problem. But maybe pressure?

2) We are currently installing an additional 20 feet of uninsulated(?) steel piping a few feet above the eave, before the next test. We are not convinced this will help since we are not over the peak. The book suggests to exit at the eave, but this conflicts with pressure zone issues, right?

3) Also of interest, the number of 90 degree bends and the slowing of draft pulling as a result? We have 8. Our local code says we need a two foot height from the peak of the house PLUS 9 inches for each bend, 72 inches means a six foot extension from the roof. That's an 8 foot chimney from our peak!

4) We live in a cold climate, temps at below-15F are not uncommon. SO having the stack outside is of concern since it will be cold and slow the draft, right?There is 27 feet of piping in the RMH so if we have a twenty five foot outdoor chimney, then what? 50+ feet overall? The book suggested to go outside with the chimney, but now we are not so sure.

We are considering the option of going through our existing chimney with, of course, a new liner. It was originally for a wood stove and now gas. It is located in the middle of the house. I have attached pictures since they are worth more than words:)

[rectifier]

Anyone with much stove experience will tell you outdoor stacks (esp. in a cold climate) are CRAP. That stack is colder than your house, and the cold air in it will sink into your house/stove. It will be a bitch to start, and when you aren't running the stove, it will blow a steady stream of creosote-y air out of the stove and stink up the place (in my experience).

Try priming it with a couple pieces of newspaper stuck in the cleanout port I see next to the wall there, that always got our old chimney going. If the newspaper won't go, then the stack is really cold, give it a blast from a propane tiger torch, that'll get it going! Once it's primed (warmer than ambient) it should work OK.

Is the existing chimney internal? If so, use it. By the way, vertical feet don't really count towards 'overall' length as they increase draft where horizontal feet decrease it.

Of course welcome to the Rocket forums, it's always good to see more cold-climate rocketeers, your stove/bench flue look well built and I hope it works out for you!

[peterberg]

mudpacker,
Rectifier is right, use your internal chimney if at all possible. With a new liner and properly insulated it is by far the best choice.

The stack effect of the house itself is difficult to deal with, keep in mind that Ianto Evans is running his stove inside a one-storey building. Your stove is much more likely to suffer from a contra-stack effect.
The extra 20 feet of uninsulated stovepipe won't help to my knowledge, it's still stone cold inside that pipe.

There's another fact, however. Your stove isn't finished yet and the bench is virtually non-existent. So, there's a bare stove pipe with a length of 27 feet over the floor which is dissipating heat quickly. Very much more than the completed bench would do. I do expect you will have a puddle of condensation fluid at the lowest point. For a real test, it might be sensible to cover the horizontal flue with insulation material or the like.

[mudpacker]

Do not know what it is yet? Wood or chimney? Wood yes but, chimney? We'd like the chimney in case of a fire. It would clear the second floor and is in code. Still, it may not need it? And, is fighting a cold sink possible? We had a warm sunny day at 45 degrees F. But with a different wood (ja, dryer too) and the one line Chimney, that was probably heated by the Sun and just two feet above Eve, it was a great firing. Thanks for the support! Peterburg, we actually had installed a layer of insulation before the tests, that was an older photo. Here is an updated one. And yes lots of water works:) We changed wood, shortly into the firing, and it was a completely different stove! Amazing? We will see manana… Can you hear somebody giving a big sigh of relief? That's us, smokeless today.

[mudpacker]

Bench covered.

[rectifier]

Good to see you got it working for you. When you say you may not need the chimney, are you talking about direct side venting? You need to be very careful with prevailing winds, also a direct vent will usually not meet any code unless it's a 'direct vent appliance' which of course, a rocket stove is not.

I would keep the chimney or use your other chimney.

Fighting a cold sink is usually done in the manner I mentioned, by loosely putting something like a piece of dry newspaper directly at the base of the chimney as a primer fuel. As it burns, some of the heat is pretty much forced to rise up the chimney. Usually the draft will switch over quickly. At that point, close the cleanout and light the main stove. Once it's running, it will not reverse.

A damper right at the chimney base can be very helpful to prevent a cold sink from forming. Close the damper after your fire is out, and no downward flow can develop in the chimney.