Ductwork Question

Ductwork Question

PostBy: Kungur On: Sat Oct 04, 2008 6:07 pm

Well I orderd my Alaska 140 furnace today! Fortuanely my supplier had the foresight to order quite a few in May. So maybe 3 weeks!!
Anyway here is my question. He the supplier recommended ducting the unit into the return air on my exsisting furnace, then use a relay to have both blowers come on at the same time. He also said to run a 8" round into the return air,of the exsisting furnace,. Use no dampers.
So, what do you guys, the experts!!, think?
Stove/Furnace Make: Keystoker
Stove/Furnace Model: K-2

Re: Ductwork Question

PostBy: Blackdiamonddoug On: Sun Oct 12, 2008 6:02 pm

running the 140 into the return side is a good idear.
I would run the 140 full blast so the fan on all the time this will deliver heat through your existing duct work.
Stove/Furnace Make: axemen 260 rebuilt by Matt
Stove/Furnace Model: stoker AA 260

Re: Ductwork Question

PostBy: Vernoncoaler On: Tue Oct 21, 2008 2:41 pm

That is what I did with my koker. Talk with a HAVC guy and he told me that the return ducts should be twice the size of your heat ducts (heat is 8" then returns should be 16"). I have 8" heat ducts and 12" returns, could not get 16" and works great. It will keep my 2400 sq ft home at 72 with out a problem. I also installed the relay into the regular furnace and it blower comes on when the coal stove's blower comes on. Can send you the number for the relay later, wiring it is real simple. You can get it @ Grainger cheap. I have attached pictures of my set up.

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Hot Air Coal Stoker Furnace: Keystoker Koker
Coal Size/Type: Rice
Other Heating: Propane Forced Air

Re: Ductwork Question

PostBy: coalishot On: Tue Oct 21, 2008 2:56 pm

Return and supply should be sized for equal cfm.
If I knew your blower cfm rating i could tell u exactly.
8" is good for 240 cfm at 1.0 s.p.
16" is good for 1400 cfm at 1.0 s.p.
see the huge difference.
Stove/Furnace Make: ALASKA
Stove/Furnace Model: LIBERTY

Re: Ductwork Question

PostBy: coalishot On: Tue Oct 21, 2008 2:59 pm

10" is 400 cfm at 1.0 s.p.
12" is 600 cfm at 1.0 s.p.
16" seems way over sized. however an over sized return should not hurt you.
Stove/Furnace Make: ALASKA
Stove/Furnace Model: LIBERTY

Re: Ductwork Question

PostBy: LsFarm On: Sun Oct 26, 2008 1:41 am

Now THAT'S a cold air return system...

Vernon, everytime you see a thread or topic about cold air return ducting please post the photos of your returns and box around your distribution fan. that is what turns a stove into a furnace..

Really nice job.

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

Re: Ductwork Question

PostBy: McGiever On: Tue Nov 02, 2010 10:31 am

Very clever...just noticed radiant fins on flue/vent pipe run to chimney in 3rd photo. :idea: ;)
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Coal Size/Type: PEA / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek