rocket mass heater rebuild because of some back draft

This was an question that was posed to Paul on his kickstarter page and he said to post it here.

Thanks for any help.

CRay


Hi Paul,

I can't wait to get all the DVDs. I am in the process of rebuilding my 55 gal. version rocket stove.
I got a new drum with the bolt on lid. I followed Darfield Green Building plans. I have 25 foot of 8' inch pipe. I have been happy but not much rocketee pull. It has some back draft and smoking

What should I try to get more Rocket pull,

Thanks for any input you can get me at this time.

I was wondering if installing a draw collar is a viable solution for some RMH systems

For example: http://www.drawcollar.com/, tho this is an electric solution.

Although, a simple little box in flue with a little door where you can burn some paper seems like a good non electric solution.

That seems to be a great idea.
On the meantime, it suggests that one may be able to use to wire that were mean to heat up the copper water piping (used for warming up the house) to prevent freeze and burst during winter for, say when one need to go on to a trip.

Something like this or something more powerful:
http://www.chromalox.com/productcatalog/Heat+Tracing+Products/Light+Commercial+Cables+and+Controls/Heating+Cable+-+ThermWire+Pipe+Freeze+Protection/product-details.aspx?p=316&gclid=CM6lh-KM4bUCFUWd4AodqW0AGw

It is outside, so it will not subject of smoke deposit. Just need to be of high enough heating, I suppose.

Should this work? if this wire heat up large section of the chimney pipe, it should still work?

NF

This is a difficult question to answer without seeing the stove. There are a handful of issues that might be taking place. For starters, it is always best to check the height between the top of the heat riser from the barrel surface before mortar is put in place. Build a mockup outside and mark the height on the heat riser that gives the best draw for your fire breathing dragon. Also, the area around the heat riser where the barrel hits the flue should be designed to slowly bottleneck the smoke into your exhaust/flue. Is the heat riser tall enough? Are you overstoking your stove without allowing enough air in for combustion? I would recommend checking out Donkey's forum at http://donkey32.proboards.com/index.cgi for all your rocket stove questions.