Marc said:
I have had two new stoves in our home and both, one CAT and one non-CAT w/secondary burn, have proven incapable of a slow burn. My dealer and I have worked on this for two seasons. My system begins with 12 feet of double wall 8" flue pipe. Overall stack is approximately 28 feet. We are at 3K foot elevation. It has been impossible to load either stove with more than two splits without stove top temps rising to 700 or beyond and controls being incapable of slowing the burn. A 2/3rds load would be imprudent.
If I were to replace the 12' section with 6" pipe, what would be the probable result?
GEEZE , lets professorate on a therey or 12, why don't we?? Well, all you guys are right but I actually did it ,so here is my real live experience.
I have the 8 inch stove pipe with both the in line damper and the tee draft dump to outside air & I use both controls for almost 3 years now, on each & every load of wood i burn.
i have the infamous 1970- 1/4 in plate steel ex smoking dragon stove of 12 cubic foot firebox
that I very sucessfully converted DIY style to secondary burn & am enjoying at least a 50 % wood savings because of it as well as a 36% estimated smoke reduction up the chimney.
The stove sits in the basement at the bottom of a 44 ft interior chimney with several tons of excessive draft, on MOST DAYS, although about 5 days a year ,I have poor draft, probably due to weather conditions,prevailing wind,or whatever.
Marc, I hope you realize that when you turn off your primary air , that it is not at all off, but meerly set to the factory stop that still leaves your primary air between 10% to 20 % open.
This is designed into the stove so that there will always be some live flame on the wood & to prevent the stove from a smoldering burn so that it can more easily pass epa requirements.
I think you must already know about this ,as you threatened to file off the factory preset primary air stop ,allowing the primary air to close fully.
But,before you do this, please consider the tee with suction dump to room air. The tee cost 12.00 & the damper cost 9.oo but it has that hole in the middle that you would have to bolt a piece of sheet metal across or buy a manual draft dump (Manual barametric pressure regulator) that Craig mentioned earlier. It is the same piece of equipment,just without the hole in the middle. You will probably have to order it to the tune of $20.oo & ship
So, to kill extra draft you can close off a in line damper, but only so far , as then smoke backs up in the stove & you can get the campfire smell.
Better than this ,is to open the draft dump to room air,letting room air into your stove pipe to kill the suction & lower the draft.
The interaction of the two controls opperating at once gives an amazing degree of control to your stove than can not be achieved in any other way.
On a cold start,I close the draft dump to room air & open the inline damper for max suction & now I am able to put 4in x 4in splits, as well as a few larger ones into the stove & load the last foot by the door with crumpled newspaper & just touch a match to the paper & in 6 to 10 minutes, all my wood is engaged & starting to char with no kindling at all.
The same teqnique will start a load of wood from almost dead coals, with no kindling & often no newspapers although I have to hoe the ashes to expose the embers & liven them up a bit with a electric hairdryer, before & sometimes after,laying the wood.
For calming down the stove, the draft dump to room air is opened fully & the in line damper is closed about 1/8 from fully opened. I could close it 1/4 or 3/8ths from full open , but risk the chance of campfire smell in the basement,so I tend to use the draft dump to outside air more, as it never gives a smell.
Of couse, my stove has fully closable primary air & secondary air controls, so I have pretty good control on all aspects of the burn. The one thing I regret is not having a window in the door to actually see what the flames are doing. I have to opperate my stove by way of a stove pipe thermometer & a stove top thermometer, without any way to see the flames.
The window is inpossible because I have a primary intake air preheat grate just 3/8th in offset from the inside of the loading door. It is actually a thin steel plate with 12 holes drilled in it to let primary air enter the firebox but the air picks up the heat from the steel plate before getting into the firebox.
How good can this stove be controled ? I maintained a 175 deg burn for over two hours
to cure some fireplace masionary cement that I did not want to reach 212 deg so that water would not boil out and the released steam preferate the patch job.
The patch is good & holding, for now, but in april,the stove gets a new 8 inch elbow on the back wall of the stove. acid had corroded some pin holes thru the sheet metal of the elbow
& from then on, the inside of the elbow gets baking soda applied to it ,once a week to neutralize any acid build up. The elbob is only offset from the firebox by 2 inches & ashes collect at the bottom of the elbow causing premature rust thru in only 3 yrs.
So,I recommend for Marc to install a tee in his 8 inch stove pipe & a manual draft dump to room air. If this don't work well enough,then marc will have to modify his primary air so that it can close fully as well as installing close off valves on the secondary air pipes,too.
I used old plumbing water valves for my secondary air adjusting valves & they work great.
But then,my secondary air pipes are old plumbing pipes that I drilled holes in every inch,so they were already threaded to accept the water valves.
No bragging here,just the plain & simple truth.Corrie, from englanderstoves, helped me in the design of the stove & i was so pleased that I bought a new summersheat stove (englander) that I didn't really need, yet, but sooner or later ,it will get installed.