The old hotblast

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grizzerbar

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Been hanging around reading your forum for a few years now, actually about 6 yrs. I think. I am not very computer savvy actually try to avoid them when I can. I have followed a lot of the advice on using a hotblast that has been posted here Thanks. Pretty much resigned myself to burning a lot of wood and waking up to no fire though, never could get more than 4 or 5 hrs out of her yet. I have a 2 story home and have a stove in the livingroom also. Been thinking about how the stove operates burning wood from top. I always avoided using the feed door damper on my hotblast though because of all the well known issues with it. I have seen posts about removing plug in back to get air over top of fire. My question is why not just modify the door damper and make it a manual damper for air over fire. The reason I am asking is I have just completed just that. I removed bi-metal spring and then weighted cheap thin flapper for a more positive feel and not so touchy or bouncy now. Also tightened up the knob mechanism so it locks in place where I set it. I apologize if this has been covered in previous posts. Do you guys see any issues with going this route? Just trying to get a little better burn time. I have no other problems with the furnace, it has actually served me well and I don't regret installing it at all. My plan is to close down spinner on ash door and try to burn from top down using modified feed door damper.
 
When I had my hot blast I modified the door similar to what you are saying. Went from 4-5 hour burns that were uncontrollable to 8 hour or so controllable burns. Much better being able to manually control the air flow to the firebox
 
Been hanging around reading your forum for a few years now, actually about 6 yrs. I think. I am not very computer savvy actually try to avoid them when I can. I have followed a lot of the advice on using a hotblast that has been posted here Thanks. Pretty much resigned myself to burning a lot of wood and waking up to no fire though, never could get more than 4 or 5 hrs out of her yet. I have a 2 story home and have a stove in the livingroom also. Been thinking about how the stove operates burning wood from top. I always avoided using the feed door damper on my hotblast though because of all the well known issues with it. I have seen posts about removing plug in back to get air over top of fire. My question is why not just modify the door damper and make it a manual damper for air over fire. The reason I am asking is I have just completed just that. I removed bi-metal spring and then weighted cheap thin flapper for a more positive feel and not so touchy or bouncy now. Also tightened up the knob mechanism so it locks in place where I set it. I apologize if this has been covered in previous posts. Do you guys see any issues with going this route? Just trying to get a little better burn time. I have no other problems with the furnace, it has actually served me well and I don't regret installing it at all. My plan is to close down spinner on ash door and try to burn from top down using modified feed door damper.
I took the plug out of the back with 2 elbows and 2 pipes. I have 2 plastic plugs with different holes drilled in them or I can put the plug that came out of the back. I also have the induction blower from the back mounted in the ash door that's on a thermostat to help the fire start better,works great! I can get 10-12 hrs burn time.
 
I have one in my shop and get 4-6 hour burn times with coals lasting up to 3 days if filled with hard wood after a load of soft wood. It should be noted that I can not get these kind of results with soft wood or if I'm only burning the stove for one load of wood. It requires at least 2-3 loads over the course of a day working in the shop to get lasting coals.

The first thing I did was to sh*t can that bi-metal spring and make the door flapper manual. Second I modified the ash pan door air dampener to close fully and tight, then marked it so I could know where it is adjusted to. Third thing was to remove the back plug and install an 8" chunk of pipe with a ball valve on the end to meter the flow. The pipe was just to keep the valve away from the heat so it wouldn't melt the nylon bushings that seal the ball inside.

Now my burning process is as follows:
Starting from a cold, bunt out stove, I will rake the ashes around in the bottom to remove any excess ash. I always leave about 1-2" of ash in the bottom to plug the grates and insulate. Next I open the ash door, dump the ash pan, replace, and then scrape a small hole in the front of the ashes to allow air from the bottom for starting. Now the stove is ready to fill.

I usually keep a good mix of hard and soft wood on hand so usually I'll start the stove with soft wood. Load two large chunks on each side as far back as possible leaving a gap in the middle. Fill the middle with thinner splits of dry soft wood or kindling. Continue to fill the stove 1/2 way making sure to leave the front open and keeping the smaller dry stuff in the middle. Now fill the front with your starting material. For me it's paper then splitter scraps, bark, or small (1/4-3/4") pine or cedar chunks cut at about 2-4" long placed vertically. I keep some 1" square chunks of Ash, Oak, or anything straight grained to place above this. Next I'll toss a couple more thin splits in the middle/front above this to catch when the kindling is lit. Top it off with one more big split and light.

To light I close off all the top fire air and light the paper at the bottom with the ash door open. Let things roar as the kindling catches with the ash door open. After a couple minutes I'll close the ash door and open the ash door dampener one full turn. Open the feed door draft flapper fully and let the fire catch. I have a thermometer in the chimney that I'll moniter from here. When the inside stack temp gets up to about 1000*F, I'll close the feed door draft flapper and fully open the rear air valve that I previously mentioned. This is where the stove runs most of the time. When it is below zero outside I will have to close the rear air and the ash door air to 3/4 to slow down the draft some. Leaving ash in the bottom of the fire box prevents most of the air from coming in the bottom. After the first load, the bottom grate is usually completely plugged leaving only the rear air valve as the inlet. I have found this to be the most efficient I can get the stove to burn.
 
I guess my big question is what is the difference whether you let your combustion air in the front through modified controllable door damper or in the back through the forced draft inlet?
 
I tried the front a few different times and usually had an over-fire condition. With the rear air inlet I find its less fussy and can usually be left open
 
Ok here is an update. I was thinking about removing the plug in the back of unit and adding pipe to introduce combustion air. When I looked at how my unit is designed I decided not to. I have the HB1300 there smallest unit as my house is only a little over 1300 sq. ft. Anyway the plug is mounted low on the back of unit at about the level of the grates. Inside there is a baffle that directs the incoming air underneath the grates. I feel that is ok for coal but I wanted to try to burn wood from top down. I lit furnace this morning with spinner on ash door wide open and modified door damper about 1/2 open. Once I got a good hot fire I completely closed off spinner (ground off tits) and left door damper open. I can't believe it, I had a good controlled fire all day and I didn't have to open doors and windows because of heat. I have used about 6 or 7 large splits in the last 10 hrs which is less than half of what I normally use to maintain fire. I am amazed, I normally wouldn't burn with temps in mid 30's because of too much heat but I won't hesitate now. Can't wait to see how it does when it gets cold, I have a lot of room to back down the stack damper yet so I think it is going to be ok. I sometimes burn a small stove in my living room on warmer days 30's & 40's but I was constantly feeding that also. Now I think I may have solved the problem. Will still use the stove once in a while for aesthetics though.
 
Hey Pagie I think there are pics posted on this forum. Just Type hotblast into the search function. I will post a picture of mine tomorrow if you still can't locate them.
 
One more update especially for Jakers. Well last night I found out you have to be perfect on your feed door damper setting(got a little hot!) Once again you guys have proved smarter than I am so I went out to garage grabbed a couple 1.5" X 12" black iron nipples and an elbow. Went to hardware store bought a 1.5" ball valve, then I removed plug for force draft inducer and screwed the piping and valve in there. Should have listened to you guys in the first place this is much easier than trying to mess with the door damper. Pulled a chair up to furnace with couple of magazines and a coffee and began to tune the furnace. I can still get a nice controlled burn that will last for longer than 3 or 4 hours and I don't have to worry about getting the door damper perfect. By the way Jakers my settings are exactly the same as yours, works great THANKS
 
Awesome. Glad to hear you are getting better results from the old "smoke dragon" as they have been nicknamed. I sure am happy for the folks that informed me of the ins and outs of getting the best the hotblast can offer. I'm glad to help others in the same ways, along with any knowledge I've acquired along the way. Happy burning and keep your chimney clean

Merry Christmas and happy holiday season
 
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