# Question About Stove Pipe Air Flow

### Question about stove pipe air flow

I'm planning on installing a DS Kozy King 400 furnace and have a question about the stove pipe's air flow. Does anyone know how the air flow of the pipe is affected if one end is round and the other end has to be rectangular where it fits into the thimble? I would imagine that the flow would be adversely affected but I'm not sure by how much. The furnace end of the pipe will be an 8" diameter (34.26 square inches) and I was thinking of making the thimble end about 10.5" x 6.25" (65.62 square inches). The stove pipe would be about 4' long, have about a 2.5" rise per foot, without any elbows. I have to change my round thimble which has a 7.25" interior diameter to a rectangular one because my vertical flue pipe has an interior size of 11.5" by 6.5", but unfortunately it's faced in the chimney so that the narrow side is where the stove pipe would connect to it. I look forward to your responses...Gary
Gary1

### Re: Question about stove pipe air flow

If the chimney's drafting is good to begin w/...then it will not be degraded enough to be concerned about.
McGiever

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

### Re: Question about stove pipe air flow

I've never been accused of being a math wiz. (That's an understatement.) But I get a different figure for your vent pipe area.
Pi x radius squared should give the area. So 3.14 x 16 (4" squared)= 50.24". Besides being lousy at math, I did not stay in a holiday Inn Express last night but I did sit at a outdoor bonfire drinking Yuenglings until way too late so my math could be wrong.

As to the air flow questions, I don't think it will hurt it much. Short run, good rise. Make a provision to clean out flyash. Others who did stay at a holiday Inn will chime in soon.
coalkirk

Stoker Coal Boiler: 1981 EFM DF520
Coal Size/Type: anthracite/rice coal

### Re: Question about stove pipe air flow

a little larger opening shouldn't hurt anything. as long you have a good draft on the chimney, round or square and as long as it's equal to or greater then the outlet of the stove. should work.
WNY

Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker, LL & CoalTrol
Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon

### Re: Question about stove pipe air flow

I've seen the Holiday Inn thing crop up a few times on here. Do they have coal stoves at Holiday Inns? Or programs on how to operate them?

Should I go stay at a Holiday Inn?
Lightning

Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

### Re: Question about stove pipe air flow

Thanks for your input. My mistake, Pi is 3.14, and not the 2.14 I used. Also, my chimney draft is very good. Talk to you later...Gary
Gary1