5 inch batch box build smoking issues.

[willypw]

Hi all,

I have just built a 5inch inch batch box to the dimensions using the formula on the batchrocket.edu.

It a brick burn box with a super wool insulated riser which . The whole system is inside 2 x 55 gallon drums with the exit for the flue at the bottom of the lowest drum and no other heat storage apart from the drums/bell.

After firing the heater without the top drum everything seemed to be going well. no smoke and lots of heat.

After sealing the top barrel and trying another burn there was a lot of smoke. I read another thread saying that the exhaust for the flue needed to be bigger so i changed the outlet from a 5inch to a 10 inch opening tapering down to 5.

After re firing it still smoked with little to no change.

I then removed the tapered cone and left the lower barrel with just the 10inch hole and re fired and it still smoked as bad as before.

The wood was bone dry kindling from a hardware shop so shop not have been an issue

Also once the fire is really hot it starts to pulse.

The only part of the system that is not spot on is the riser which is between 140-150mm when it should be 130. This is due to the wool not compacting evenly but i read that the riser diameter did not have to be spot on.

If Anyone has any ideas of what i could try to sort this out i would really appreciate it.

Is it just a case of the smaller heaters not getting hot enough?

     


   

[Dan (Upstate NY, USA)]

Photos of the build?

[peterberg]

Maybe paint in the barrels? That tend to smoke like mad, every time the temperature goes up until it's all burned away. Take a sniff at the exhaust, if it doesn't smell like a wood fire but burning paint instead you know what the problem is.
Food quality, open top barrels tend to be dark red inside, other qualities seem bare metal but usually it isn't but clear laquer instead.

Since the core without barrel burned without smoke I'd say it's the barrel.

[willypw]

Im trying to add photos but keep getting this error coming up.

Error: This forum has exceeded its attachment space limit. Your file cannot be uploaded.

I will try and burn off the top barrel inside by making a fire and see if that changes anything.

A friend had a thought that the top of the barrel may shedding heat to quickly and that it may not be drawing efficiently enough.

I was thinking that if i build the flue into the barrel (ie the bell) and don't have it exiting out the back of the lower barrel but exiting out the top of the top barrel it would create a greater draw.

Just wondering how low to have the exit for the flue and if that might be the issue?  

[Vortex]

The forums picture hosting is full so you have to host them elsewhere and link to them here.

What kind of chimney do you have? What is your stove door like, is it air tight? What size is your primary and secondary air?

[martyn]

Damp bricks and masonry can cause this sort of problem.

[satamax]

Well, first of all, we need to know the gaps between top of the heat riser and barrel. And between heat riser side, And barrel at the flue transition.

Then, how's your chimney?

Hth.

Max.

[drooster]

Aug 15, 2019 12:18:35 GMT -8 satamax said:

Well, first of all, we need to know the gaps between top of the heat riser and barrel. 

He is using two barrels, I assume the gap over the riser is large,
but without more info what can we know?
It does seem strange his setup is smoking,

pictures needed!

[satamax]

Never assume anything!

[whazzatt]

Aug 15, 2019 12:18:35 GMT -8 satamax said:

Then, how's your chimney?

Ja, what's happening downstream? A quick test would be to add a metre or two of additional flue to wherever the chimney/flue exits and see what happens...