Stack size?

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stefan66

Member
Hearth Supporter
Nov 26, 2010
65
ThunderBay Ontario
Thinking of purchasing an Echo25 but only have 6 inch stack.
I know I'ts not recommended.
Anyone doing it out there?
 
Yup! Talked to Mark at AHONA about it and he said to make my 90 degree bend right out of the boiler 8 inch and as much 8 inch as possible before entering chimney. I actually have too much draft. 21 feet to top of 6 inch Metalbestos stack.
 
I'm sure it will work. And I've reduced a woodstoce flue myself in the past without problems. But reducing a flue will not pass code and will fail an inspection. Insurance companies won't like it either.

Tarm, woodgun and biomass boilers all have 6" flues. May be others.
 
I have been using my EKO 25 with a 6" flue for 4 years now,

The EKO's heat exchanger consist of 6 -1 3/4" tubes which would allow it to have a total flue capacity of 14.4 sq. inches.

Area = pi x radius x radius x 6 = 3.14 x .875 x .875 x 6 = 14.424

6" flue has a total capacity of 28 sq. inches - (double that of heat exchanger)

Area = pi x radius x radius =3.14 x 3 x 3 =28.26

The way I see it if there was any kind of bottleneck in the flue system it would be in the heat exchanger itself,that's why its so important to keep them tubes clean.

The Eko 25 has actually been over built,even your pipe connections are 2" which could handle a boiler with a 450,000 BTU capacity ,since the EKO 25 is only a 80,000 BTU unit a 1" connection would have been adequate.
 
It seems like most manufacturers have chosen to use one flue size and pipe sizes to streamline their manufacturing process. I can't see any other reason to have the same size flue and pipes on 25,40,60 and 80 kw boilers.
 
My eko40 runs fine with a 6 inch flue. what are you using now to heat.[/quote]

Currently using an old "Franks Piping?" boiler.
Basically a dutch oven design.
Lots of radiant heat off of it,which is great for heating the garage it's located in.
Thanks for the replys.
 
It seems like most manufacturers have chosen to use one flue size and pipe sizes to streamline their manufacturing process. I can't see any other reason to have the same size flue and pipes on 25,40,60 and 80 kw boilers.

Completly agree Mike, it does make it harder for the end user, and limit their options due to code requirements. One would think that they would go 6" all the way as pointed out in the HX firetube openings. This way all would work with 6" (more the standard now anyway) then if someone had a 6" flue or chimney breech it would work. Then if there were an existing 8" breech/chimney one could neck it up and be legit as well.

TS
 
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