ducting blower fan directly to furnace

ducting blower fan directly to furnace

PostBy: Duengeon master On: Sun Feb 10, 2008 10:04 am

Will a blower on a harmon mark III make it more efficient? I use it to heat my basement then it heats my whole house. My oil burner sits right next to it, and is very jelous of the stove. :cry2: Can I duct the back of the stove where the fan mounts to the stove and pipe it directly to the cold air side of the furnace, or do you think the heat may hurt the furnace fan assembly? Then I want to hook up the fan only swich that is on my oil burner's thermostat to make use of the basement heat. :)
Duengeon master
 
Hand Fed Coal Stove: Harmon Mark III
Coal Size/Type: Anthracite pea and nut mix. Bituminous lump

Re: ducting blower fan directly to furnace

PostBy: coaledsweat On: Sun Feb 10, 2008 10:35 am

Sounds like a plan, how about pics? That should generate a plethora of ideas to chose from.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: ducting blower fan directly to furnace

PostBy: Dallas On: Sun Feb 10, 2008 10:46 am

Here are my thoughts on that, after having tried using the furnace system as an air circulator.

While the furnace fan will circulate the air, it also passes the "hot stove air" over the furnace heat exchanger. When the air passes over the furnace heat exchanger, it loses a lot of it's heat to the furnace, probably going out the furnace flue. The end result being, any air coming out of the furnace system is too cool to assist warming the house. "Very inefficient"!

If you were to use a separate fan and plumb the stove heat into the hot air plenum of the furnace, it would probably do a better job.

Edit: It should probably have a return to the stove, as well.
Dallas
 
Hand Fed Coal Stove: Modified Russo C-35
Other Heating: Oil Hot Air
Stove/Furnace Make: Russo
Stove/Furnace Model: Modified C-35

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Re: ducting blower fan directly to furnace

PostBy: LsFarm On: Sun Feb 10, 2008 11:38 am

Dallas has it right. the heat exchanger in the furnace will work in reverse, and it will heat the air in the furnace's burn chamber and flue, so it's not a good way to do it.

Put a fan on the MarkIII, this will make it MUCH more efficient, make a duct top like Dallas did for his coal stove, and duct the heat into the upper part of the house.. Put a cold air return duct to the inlet of the distribution fan on the MarkIII, and you will have a little coal burning furnace setup, and working right..

You will still get plenty of radiant heat off the stove's body to heat the basement.

Maybe you can talk Dallas into making you one of his custom stove top heat ducts?? :D :D :lol: :lol: :? :) ??

Greg L
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Re: ducting blower fan directly to furnace

PostBy: LsFarm On: Sun Feb 10, 2008 11:40 am

Here is Dallas's custom stove top heat reclaimer: Really temperamental stove/draft !!

Nice metal-bending !!

Greg L
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Re: ducting blower fan directly to furnace

PostBy: butchs37 On: Sun Feb 10, 2008 4:34 pm

I have mine set up with the furnace blower on a thermostat with relays. When thermostat calls for heat stove will come off of idle and blower will not come on until the fan limiter on stove switches on. I have 1 cold air return in the center of the house piped directly to the stove. All cold air returns on the furnace are shut off via a piece of sheet metal over the air filter. Temps blowing out of the vents are lower than directly off stove about 105 deg. but the house is evenly heated.
butchs37
 
Hot Air Coal Stoker Furnace: Alaska 140 dual feed

Re: ducting blower fan directly to furnace

PostBy: Dallas On: Sun Feb 10, 2008 5:51 pm

Butch, where do you have the stove heat entering the furnace system?
Dallas
 
Hand Fed Coal Stove: Modified Russo C-35
Other Heating: Oil Hot Air
Stove/Furnace Make: Russo
Stove/Furnace Model: Modified C-35

Re: ducting blower fan directly to furnace

PostBy: butchs37 On: Sun Feb 10, 2008 6:42 pm

through the access cover for the blower. The blower draws the air through the stove then blows it through the furnace and into ducts.
butchs37
 
Hot Air Coal Stoker Furnace: Alaska 140 dual feed

Re: ducting blower fan directly to furnace

PostBy: Duengeon master On: Mon Feb 11, 2008 8:33 pm

LsFarm wrote:Here is Dallas's custom stove top heat reclaimer: Really temperamental stove/draft !!

Nice metal-bending !!

Greg L
Dallas's heat reclaimer is awesome. 8-) :up: It's more than I can make. I will go out to buy the blower for a mark III.
Duengeon master
 
Hand Fed Coal Stove: Harmon Mark III
Coal Size/Type: Anthracite pea and nut mix. Bituminous lump

Re: ducting blower fan directly to furnace

PostBy: Wood'nCoal On: Mon Feb 11, 2008 10:41 pm

Sounds like something similar to what I plan to do with the Alaska. I'm going to duct the hot air into the hot air plenum after the oil furnace's heat exchanger. I'm sure it won't produce the same effect as the actual oil burner running, but it will supplement the heat from the Harman.
Wood'nCoal
 
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert

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