@trevj, you and I have a lot in common in regards to our stove setup and also for our heating demand. I found out we really have a lot working against us with the stove configured like we have and I've had my own struggles I could share. In my opinion there is no conceivable way you are going to get the heat you need without making some significant changes to your stove configuration and I think you still might need to put to bed the question of moisture in your wood. I don't believe your stove is operating at its full potential and if it was, its still uncertain in my mind that it will give you the heat you need. Regarding stove configuration, things you should consider addressing in order of priority are;
1) Raising your thimble above the stove to the maximum while complying with code regarding minimal clearance to combustibles to the floor joist is a good start. At that point I would install a 8" round thimble to maximize the available flow area.
2) Use a double wall close clearance pipe between the stove and thimble in place of that single wall you have now. DuraVent makes a "DVL" connector pipe you might want to look into. (Search the internet, you can usually find it cheaper with free delivery than local dealers sell it for.)
The purpose for the double wall pipe is to help maintain the flue temperature which is the primary factor that creates draft. A higher flue temp also will help mitigate creosote buildup which I suspect you will have an issue with at the top of your chimney.
3) Lastly, consider installing an
insulated liner in your existing chimney. Easier said than done because you may not have the minimum required space for the size liner needed to satisfy the stove requirements, even if you bust out the existing clay liner.
There are two primary considerations for needing/having an insulated liner installed; 1. after performing the above recommendations you still cannot obtain the necessary draft as spec'ed in the manual (0.05 inches of WC operating on HIGH) or, 2. you are having a creosote buildup issue.
Insulated liners will reduce the heat loss to the chimney (into the masonry) and will ensure the proper draft and mitigate creosote by maintaining the flue temperature so the condensable gasses stay a gas while in the pipe.
Even if you are able to are able to achieve the 0.05" of WC draft as spec'ed in the manual without a liner you might (likely in my opinion) will have creosote formation in the top of your chimney. The exact amount of buildup will be highly dependent on how much heat remains in the flue gas by the time it reaches the top.
Depending on how much work you plan to tackle yourself, you could do #1 and #2 on your own. I did and it cost my approximately $5-600 USD. The cost of the DVL pipe was about approximately $480 and consisted of a 24" straight, two 45 elbows, a 12 telescoping section (always include a telescoping section, ALWAYS!), an adapter and a thimble connector. The rest of the cost was a new thimble, thimble cement, motor mix, 4" masonry cutting wheel, a 12" long 3/8" masonry drill bit, and a couple trowels.
I believe even your existing single wall pipe could be arraigned in a better configuration. The horizontal piece between the thimble your upper 45 elbow is killing you. I highly recommend you connect your upper 45 elbow directly to the thimble and add length between the two 45 elbows to compensate for the removed horizontal. While I wouldn't want you to minimize the vertical rise section any, you should attempt to minimize that horizontal run at all costs. The more vertical rise straight out the top of the stove the less smoke spillage you will get during reload.
I hope you're still with us here I know this is getting lengthy.
All of that aside, take a dive into your manual to the back and review the trouble shooting section. Lets look for commonality among the issues you described, primarily smoke spillage and poor output of the stove.
I previously mention smoke spillage and vertical rise out of the stove... Not much else to discuss other than that's why I recommend raising the thimble. Also the poor draft of the chimney or a cold chimney is a commonality for poor output of the stove, see below.
Poor draft can be caused by an oversized flue but it can also be cause by low flue gas temperatures. The thermal mass of the masonry chimney will absorb the heat from the flue gas. You have a large heat sink that is going to consume heat and cause poor draft (and creosote). My chimney is the same height as yours but its only one core of blocks to support one 8x8 inch clay liner. Your chimney not only has the masonry block around your 6x10 liner but it appears you also have an adjacent liner in the chimney for your fireplace. Additionally, the top 8 feet or so is exposed directly to the ambient air where mine is in a chase-way all the way to the cap. This keeps the cold wind off the masonry an slows the heat transfer taking place. I'll spare you further rambling about this.
I quickly will mention that I also bought my stove with no fans and operated it for several weeks/couple of months without them. The most notable thing I found was by having the actual BK fans on the stove the thermostat damper seemed to open more and could burn the wood s little faster and get more hear out of the stove. The thermostat seems to operate based partially on the metal temperature of the stove. Without the fans stripping the heat off the stove the stove seemed to close down that damper sooner as compared to having them on. Plain and simple, more heat is able to be transferred to the living space with the fans. The heat will not roll off the stove and go straight up like your old stove could (natural convection), this stove needs forced convection, i.e. fans. I run my stove flat out on high heat non stop and I know what you are going through.
See any other similarities here with creosote buildup?
I strongly suggest you get your hands on some of those compressed wood blocks mentioned earlier and load the stove to the gills with them and see if there is any improvement in your stove output. If there is then you need to realize that your wood is not dry enough. If there is no significant change in the stoves performance then you can conclude the stove has poor draft and need to get a draft measurement. If you can get your hands on a bunch of kiln dried 2x4 scraps then use those. If your cat probe thermometer is not going higher than half into the active range then this supports the theory of wet wood. It should be no problem for that needle to reach the top of the active zone.
