# Effects (if any) of adding a larger blower fan



## ikessky (Oct 11, 2011)

I'm adding a larger blower to my indoor wood furnace because I added on to my house.  I'm going from ~550 cfm to ~1100 cfm.  I got into a discussion with a friend from work as to the effects it will have on the burn cycles and cleanliness of the burns.  Now, my furnace is controlled by a bi-metal thermostat located on the front.  It has infinite adjustments from "Off" to "High".  As the fire and furnace cool, the t-stat opens a draft door and lets more air in.  With the small blower, the blower would run until the coals were out.  The furnace is designed to shut down the blower when the air jacket drops to less than like 90 degrees or something like that.

Now, my friend says that the increase in air is going to cool things off too much and I'm going to make more creasote.  I am saying that the temps will swing more and will allow the t-stat to open sooner and open more, which will create hotter burns than I've usually maintained.  So I am saying that I will either burn cleaner or the same.

Anyone care to enter a comment?


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## laynes69 (Oct 12, 2011)

There should be a significant difference with a larger blower, both heat and volume of air. I don't think the larger blower will cool the furnace too quick, or affect the burn. I had the old furnace setup in series with a blower of at least 1800 Cfms and it worked well.


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## DoubleClutch (Oct 12, 2011)

Seems to me that if doubling the volume of air forced into the unit was desirable, the engineers who designed it would have specked it that way.

I rarely get good results when I radically change something in a system that's undergone as much R&D as that...

Good luck


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## ikessky (Oct 12, 2011)

It's an add on blower kit from the manufacturer.  It is recommended when the furnace is a central furnace and not just an add on.  The manufacturer offers three different options:  a 550 cfm (standard), an additional 550 cfm blower (to get the 1100 cfm), and then a 1600 cfm.  So, I'm not reinventing the wheel as the manufacturer has already tested and approved my install.

Regardless of if the burn cycles or emissions output remains the same or changes, I can say that the temps in the house should be better regulated with what I am doing.  The furnace was oversized for my house, but should be perfect now that I've added 500+ square feet of living space.


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## DoubleClutch (Oct 12, 2011)

ikessky said:
			
		

> It's an add on blower kit from the manufacturer.



Ah. Well, that's a horse of a different color!

Let us know how it works out...seems like an awful big change to me but presumably they know what they're doing.

Is there any way to get the thing to burn fuel faster, so as to "keep up" with the chilling effect of the bigger blower? Any way to monitor your stack temps?


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## ikessky (Oct 12, 2011)

The blowers turn on with a snap disc t-stat.  When the temp of the air jacket hits 110 degrees, the blowers kit on.  When it drops to 90 degrees, they kick back off.  So the furnace is actually designed to have the blowers cycle on and off.  With just the one 550 cfm blower, the blower never shuts off until the coals are almost burned out.  The bi-metal t-stat that controls the intake air has infinite adjustment up to a designated "HIGH" point.  If you need more heat output, just turn that up.

I don't think I'll need to crank the heat up though.  I just need the extra cfm to get the heat through a longer duct run.  The extra space I added is completely open to the original house, so it will not be hard to evenly distribute the heat.


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## laynes69 (Oct 12, 2011)

You will find a bigger blower will work wonders. It will probably run you out of the home. Is there a large plenum opening on the furnace? If not you'll only be able to squeeze so many cfms from a small hole, or a couple. Our furnace has a 1300 cfm blower and we dont run high, just med high. If anything the larger blower will extract more btus and decrease flue temps which is a good thing.


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## ikessky (Oct 13, 2011)

The furnace has two 8" ducts coming out of the top of it.  I might build a sheetmetal plenum to sit on top and then put the 8" ducts off of that, but I'll see how it does this way first.


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## ikessky (Jan 3, 2012)

Well, I'm going to revive my old post.

Got my first real taste of "winter" here.  Temps this AM were -11.  When I started the wood furnace last night, it was 62 in the house.  Temps got up to about 64 before I went to bed and were back to about 62-63 when I woke up.  Doesn't look like the small 550cfm blower can handle below zero temps by itself.  I'm guessing it would have been fine had I built my fire when it was 68 in the house and it could have maintained that.  Now that I know what it's doing, I guess it's time to order the additional blower.


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## laynes69 (Jan 3, 2012)

I would go with the 1600 cfm fan. It will make a huge difference.


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## ikessky (Jan 4, 2012)

I found a honey of a deal on another 550cfm blower that is exactly the same as DAKA sells.  That should get me to 1100cfm.  If that doesn't do it, I believe my FIL has a few old blowers from some old furnaces that I could try out, but I think this one will do.  Stay tuned!


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## kschweitzer69 (Jan 15, 2012)

Could you share where you found a similar blower to the daka at a discounted price? Is this part cross referanced with other companies? I'm considering adding a second blower to mine. Thanks.


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## ikessky (Jan 17, 2012)

Daka's kit consists of a Dayton 1TDT2 blower, some wire, and some conduit and costs $199 plus shipping.  I already have wire and conduit, so all I really needed was the blower.  I found the blower on ebay for $100 to my door.  Now I see that someone has some cold air/filter boxes on ebay for a little cheaper than Daka retails them for.  Maybe I'll just spend the extra $100 and pick one up rather than fiddling around with making my own.


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