Is exit chimney too short?

Hi! I have an off grid homestead in northeastern Minnesota. I just finished building rocket mass heater core and all the piping. Due to building design heater is under the lowest slope of the building. Hence chimney being 4 ft. under the peak of the building. I just test fired it and was drafting beautifully. Though it is August, I'm worried about possible issues in the winter. Thanks for any information

Please furnish us with pictures of the installation to give us a better idea. Thanks

Here's some photos

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Doesn't look to code to me.  It should be 10' away from the top of the chimney to the roof on a horizontal line.

So should I just add more insulated piping on to it. Possibly secure it to the roof with metal ties?

I have a similar setup with the chimney lower than the peak. For 3 years now it's given me no trouble. The worst that could happen I guess is that a prevailing wind could wrap smoke around the house rather than blowing it away from the peak.

Under certain conditions (depending on wind speed and direction) a small zone of high pressure can build up on one side of the ridgeline. If that happens and the RMH is going, this pressure gradient could possibly kill the draft, making the heater stall and smoke back. The main reason we try to get chimneys up above the ridgeline is to keep them out of the problematic zone.

Thanks for the helpful information

Graham Chiu wrote:Doesn't look to code to me.  It should be 10' away from the top of the chimney to the roof on a horizontal line.

In Massachusetts, I believe the code is 3 feet higher than any part of the building within 10 feet of the chimney (measured horizontally).

I would suggest finding out what your local codes are and following them...

If for no other reason than not inviting a visit from "the Man" to poke around in your business, but also because the codes are often written in response to/for the purpose of avoiding another tragedy.