Blower Question

[tappin&sappin]

I've recently added a "blower" to the rear of the arch on my 2x6. The blower is nothing more than an old fan, but it seems to produce a harder boil.

Up until this weekend, I always just had the draft door beneath the grates open. Problem now is, with the fan running, ash and sparks are being blown out the draft door on the front of the arch. I've got a row of bricks in the ash pit built up to the bottom of the grates to try and deflect the air up into the fire.

Would it be okay if I now sealed off the draft door on the front of the arch since air is being fed in from the back? Or should I leave it open so the fire can draw air from the front of the arch as well? What does everyone else do that has forced air in the rear of the arch.

I'd like to limit the amount of ash floating around in the air. Makes a real mess. Good thing for filters! :)

[RileySugarbush]

If your blower is sized for good combustion you should absolutely close the draft door. Since ash is being blown out, it sounds like the blower is plenty big. Closing the door will keep that air in and should improve the combustion air flow. Seal it up as best you can to keep the ash from blowing out the edges

[Russ]

Yes, seal the front draft, but be carefull when opening your doors for firing. You don't want to get a blowback of flames in your face. Kind of hard to explain the "sunburn" in March, especially if accompanied by lack of eyebrows. We mounted a switch on the wall near our firing doors that turned off the fan prior to firing. That was before putting the induction fan on the chimney; now everything just gets sucked in, along with a little help from fans pumping air into the firebox.

[sweetwoodmaple]

I just added a blower as well to my arch (3 x 10).

I've been struggling to get it just right. I sealed up my front draft doors by putting up a row of bricks and some insulation blanket.

I had mine turned up too much so ash was blowing everywhere. Yes, the fire was hotter and had a slightly harder boil, but I was using oak like it was pine!

So, I slowed it down and now I can fire without shutting the fan off. Basically, I tried to match the best hot fire I every built with natural draft, only it happens all the time.

I also found the blower helps if you have dry or green wood. You still loose the BTU's with the water and steam, but you can still keep the fire hot.

[maplehound]

Alright guy's, with those new fans don;t be afraid to start out with a slow fan speed at first. then after the stack gets hot turn them up. You will get more assh blowing when the stack is cold but once it warms up it will draw better and then you can get more air to it.

[Justin Turco]

I too have been experimenting with a new homemade blower. At the recomendation of another maple trader, I covered one side of the blower to limit the amount of air that could feed into it. This cut down / stopped the ashes from getting kicked out. I can actually open the firebox doors without making a big mess. Though I do shut the fan off for firing. If I had an airtight front I would certainly crank up the airflow to the point that it would breath fire in your face if you opened the doors without shutting the fan off. Note: My home depot rheostat, which is made for a ceiling fan will not turn on my blower in the low and medium speeds. It was about 20.00. A regular on off switch would have done the trick in my case. I see more steam out the roof now and my damp wood burns a lot better. Can't wait to see what she does with good wood next year.

Where can we buy a stack temp that reads higher than 800. (Though I'm going to shoot for 800 degrees stack temp.) Can't buy one in my town. Can't find one on ebay.

Edit: here is a link for the "condar" brand that Westvirginiamapler uses. http://www.condar.com/meters.html

[Father & Son]

Dependng on the type of blower motor you have there are two options for controling the amount of air.
1) You can put the blower on a rheostat and adjust to the speed you need but I have been told the blower motors last longer if runs at full power.
2) You can put a damper in the plenum connecting the blower to the arch. This allows the blower motor to run at full power and gives you the control of the flow. With the air flow dampered down alittle the motor runs against alittle back pressure like they are supposed to.
This is not my expertice, just what I have been told. Hope it helps.

Jim

[tappin&sappin]

Guys, thanks for all the responses.

I still have some rope gasket material laying around, so I'll take that and try to seal up that draft door on the front of the arch. I'm glad I can close that, because all that ash was kind of messy!

For draft control, I have a piece of tin that I put in front of the fan before I fire. Otherwise I would definetely have lost some eyebrows.

Thanks again for the advice.

Jim - I talked to Casbohm the other night and he said you had trouble w/ yours but got it figured out and was doing 45gph... Awesome.

[Father & Son]

Jake,

It still needs some tweaking and I have to try things one at a time, but it's getting better. Still need to try to get it to it's rating - 55/hr. I'm running it with the blower on and the draft door open so I still don't have it figured out.

Jim

[WESTVIRGINIAMAPLER]

I use the 3-39 fluegard and it works great. I usually run from 1400 to 1650 in stack temps. Be interested to see how long this thermometer works at those high of stack temps.

[Justin Turco]

I just ordered the 3-39 flue temp guage from condar. WestVirginiaMapler, what is your rig rated at (gph) What are you getting? I wonder what kind of stack temps the factory was running when they rate these evaporators. I'll bet pretty high. Under ideal conditions.

[WESTVIRGINIAMAPLER]

Justin,

Mine is rate around 45gph I think. I can get it to 60 or more per hour. The 2 times I checked it this year I ran 62 and 65 gph but that was on long boils, the 62 gph was 640 gallon of sap and the 65 gph was 850 gallon of sap.

As far as stack temps, I would guess Leader would tell me 800 to 1000 max. They would think I am an idiot for running 1600+ stack temps, but it works for me. I have ceramic blanket all around the trusses and roof around the stack, so if I don't catch anything on fire, then that is the main thing and so far in 3 years in my new sugarhouse, I haven't had any problem.