Does your rocket smokes back on windy days?

Mine does, and it's a pish!

Somewhere in my reading I saw that another person had trouble with that as well. They were talking about adding a T to the top of the exhaust stack, but there wasn't any follow up as to whether that helped or not. I was wondering about the round caps that are sort of scalloped. According to the business website where I found one pictured they are called "wind turbine" vents. http://www.lowes.com/pd_30996-228-52604_4294765330_4294937087_?productId=3032372&Ns=p_product_prd_lis_ord_nbr|0||p_product_qty_sales_dollar|1&pl=1¤tURL=%2Fpl_Roof%2BAttic%2BVentilation_4294765330_4294937087_%3FNs%3Dp_product_prd_lis_ord_nbr|0||p_product_qty_sales_dollar|1&facetInfo=

Thanks a lot Lolly.

I have one, but haven't managed to mounnt it yet. It's very big compared to my flue tube. And i'm a bit stuck, i can't find 9 inch elbow to fit it.

Is it possible/practical to enlarge the last few inches of the exhaust to give a cap something to fit to? I know assume the exhaust is the same of smaller size than the riser and the vent used to transfer the heat to the mass. I've seen some adapters used to change the size of venting as it gets smaller. Why not use something like that to enlarge the end to fit the cap?

Those wind turbine vents are great at sucking hot air out of a space. They will work in a dead calm: as the hot air rises, it will drive the turbine, thereby creating a suction draft...self perpetuating.

If mounted at the high point of a chicken coop, they will provide a nice ventilation on a warm day.

Satamax McCoy wrote:Mine does, and it's a pish!

I built a small rocket stove heater for my 35 foot motor home in which we live in full time, during the filming of my video we had winds gusts of up to thirty five miles an hour, I had no problems with back drafts from my very first wind storm due to the chimney cap I built.

Take a look at the video I posted, I show the stove installed and then take you outside to see the chimney cap in action in 35 mile an hour winds.

http://www.youtube.com/watch?v=GSsJZ3ru0ME&feature=plcp&context=C3592efdUDOEgsToPDskJuN-zMPLvkYjGcxOzGUbiA

Great video, Dale! I just fired the link off to some folks that usually help me with projects. I have a Class C RV at the farm that will see something like this before next winter. It sat near a body of water too long and isn't road worthy any longer due to rusting of the wheel assemblies. I acquired it as additional living space for the campsite nearly two years ago however winter usage hasn't been possible so far. Once it is moved into a final position we might even be able to add some mass. BTW, the cap is great!

Lolly K wrote:Great video, Dale! I just fired the link off to some folks that usually help me with projects. I have a Class C RV at the farm that will see something like this before next winter. It sat near a body of water too long and isn't road worthy any longer due to rusting of the wheel assemblies. I acquired it as additional living space for the campsite nearly two years ago however winter usage hasn't been possible so far. Once it is moved into a final position we might even be able to add some mass. BTW, the cap is great!

Thanks for the compliment, I cannot take full credit for the idea, I did get the idea from the fella that posted it in a link below that is a much larger version than mine that he built for his home.

Sitting here by a nice warm fire as I type.

http://www.iwilltry.org/b/build-a-rocket-stove-for-home-heating/

Lolly K wrote:Great video, Dale! I just fired the link off to some folks that usually help me with projects. I have a Class C RV at the farm that will see something like this before next winter. It sat near a body of water too long and isn't road worthy any longer due to rusting of the wheel assemblies. I acquired it as additional living space for the campsite nearly two years ago however winter usage hasn't been possible so far. Once it is moved into a final position we might even be able to add some mass. BTW, the cap is great!

I also have a much clear video of the stove in testing that I did outside the RV, you can view it in the link below.

http://www.youtube.com/watch?v=sJOVG71YiJI&feature=plcp&context=C39b4552UDOEgsToPDskJjWGM3guOfo8Tsz2R-3Evc

great videos Dale really like the wind cowl - I'll be working out how to make one soon

Satamax - spent an irritating smoky day with loads of smoke back. Figured it was the wind and spent ages messing with the exhaust. Much swearing later and just as it was going dark found that there was a tiny crack in the cob surround to my burn feed tube - blocked it up and no more smoke back !! How such a small leak caused such a problem I don't know, but it did. So check for that before you try anything else

I reckon I do need a cowl on the vent though because if the wind swings around it does cause a slight smokeback or more often just a slow down in the rocket effect.

the temperature at the vent is really low - which is great for efficiency but maybe causing problems with condensation within the duct.... can't do much at the moment , we've had so much rain the greenhouse has flooded !!

Roger

I used a cheap steel ball bearing wheel caster for my piece that the chimney cap sits on, I cut the wheel out, turned the steel caster upside down and made a cross bracket, you have to make sure your bracket you make to secure the wheel caster to allows sufficient air flow, my first try was a bit of a failure due to my cross bracket being too wide which constricted the air flow, I quickly too my grinding wheel and cut much of it down to to open up the air passage.

I have some very good photos and a video of how he assembly works, I will do my best to get them up in another video so you can see clearly how I did this.

I did find that where I welded my chimney hood to the caster that my welds were not so good, I had created leaks in places, so I used high temp silicone to seal them, even in high windy rains no water gets down the chimney pipe, I did a test with the water hose before doing the install.

A number ten can with a few tabs cut works a treat. What the heck is it with folks not putting a defuser/chimney cap on the chimney? Am i missing something? i know the book says to put one on I bloody dictated that part.

Couldn't have that translated into English could I ? "A number 10 can" ? You Colonials have some jolly odd expressions ....... took ages to figure out that "hardware cloth" is actually wire mesh.............. so is the can in question merely an appropriately sized ex food container or some as yet unknown product or perhaps a particular size of lavatory ........... if the latter I fear there may be complaints if I fix one to the roof !!

Thanks in advance

Roger

Roger Merry wrote: Couldn't have that translated into English could I ? "A number 10 can" ? You Colonials have some jolly odd expressions ....... took ages to figure out that "hardware cloth" is actually wire mesh.............. so is the can in question merely an appropriately sized ex food container or some as yet unknown product or perhaps a particular size of lavatory ........... if the latter I fear there may be complaints if I fix one to the roof !!

Thanks in advance

Roger

number ten can is a food service size steel container.
for the life of me i cant remember the European name for it.
I do like the large crapper idea; I am a big guy i think a number ten crapper sounds kinda nice.

There is a trick in the marine trades for dealing with pressure differentials between intake and exhaust of finicky systems. In addition to the Charlie Noble, which is the "H" shaped cap which creates draw in almost any wind condition, installers will often plump an intake to the same location as the exhaust. That way they both see the same pressure variations due to wind direction and aspect. So, if you are continuing to have trouble, consider providing a fresh air supply from the same location as the exhaust.

I attached a 12" Whirley bird (Mushroom Vent) to my rocket stove because I had SEVERE BLOWBACK PROBLEMS on an 8" system using a 8-10" and also a 10-12" REDUCER to fit an 8" exhaust pipe and it WORKS GREAT! We live on a hill with tall trees so the blowback caused a lot of smoke to reverse and fill our room with smoke. We considered removing the rocket stove filled with cob, concrete, rocks but the vent is working great and now we have no smoke in our room. I have 20 years experience as a HVAC contractor and came up with the same solutions as you did! Even if the turbine does not turn, it still keeps air from blowing back through the rocket stove system. www.majorsway.org - EARTHBAG HOME BUILDERS - ARK

I haven't made mine yet but I've read about blowback and someone suggested this and I'm thinking a dryer vent would work awesome. Anyone tried this?

the flaps are to heavy but the old style with the louvers might work.