Mark Beard wrote:
Scott Weinberg wrote:I have 38 foot internal and 4 external, it is scary good. Very seldom need to use the bypass, but always like to have it as an option. By seldom, I mean 2-4 times in a entire season. And it is NOT the flue causing the need, but more the climate conditions on that given day.
Tell me more please what is your bypass and when do you use it or what is its roll/purpose/need?
Tagged on my response (or here-
https://permies.com/t/241976/Batch-Rocket-single-bell-build - ) is the beginning of the entire build and based on 7" size dimensions . With the fact that even though there is well past 1000 words in the whole description of what I did in this series, the photos will TELL MORE on how it looks and how I did.
Now, for and how it works.
if your facing one of those questionable days (for me, it would be about 40 degrees F, very high humidity, and low barometric pressure) When you lite the stove, you can tell it wants to work, but just doesn't want to take off readily.
With the bypass at the top of the Mass Bell, open and going directly to the flue, The freshly lit hot gases, go up the riser and into your bell, seeking to keep going up as they are so much hotter than anything else, thus the 4" bypass, at the top of your bell, is a easy exit for these gases.
In less than two minutes, the bypass is to hot to touch, and if it is that hot, the gases are going right where you want them, up the flue.
When the direction is established, and this does not take long, in just minutes, the bypass can be closed, and if you feel your main exit flue pipe, it will slightly warm right away. Exactly what you want. Again this is meaning, that everything is flowing in the right direction. You can experiment, by partially closing the by pass and then completely in a few minutes.
Long story short, you want this by pass to completely be closed,
when not in use, so it will only be room temp. It's job is done.
There are those that have posted how they installed the bypass AFTER the build was done, and the work is far greater than if you build initially. Mine is not at the very top, but very close, with only one brick layer above it. It has but one goal, and that is to establish direction and movement of flue gases, thus keeping chances of back drafting to near zero.
Best of success.
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