Fisher Grandpa Bear pre 1980 Flue Problem

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Doc Scholl

New Member
Aug 19, 2016
1
Bloomington, IN
I just purchased a Fisher wood stove that has an (supposedly) 8 inch flue outlet. I need to reduce to 6 inch for my existing chimney. The actual ID inlet is very close to 7 5/8" (or 7 3/4") with the OD being actual 8". There is not a store in town or on the web that offers a 7 5/8" male crimped inlet by a 6" female straight outlet. I have tried 2 standard 8 x 6 reducers and they just get crushed. I can't get a 8 inch pipe into a 7 5/8 inch hole. I understand a standard 8 x 6 reducer could have several extra cuts to the crimped 8 inch but I,m not happy with that as it will leak. Any help would be appreciated.
 
All older stoves had 6 and 8 inch OD before pipe was made to fit stove pipe going by ID.
You didn't mention if this is a top, rear or side vent.
IF top vent; Simply over-crimp the male end smaller until it fits.
With hand crimper, you can bend outward as it is crimped to keep the smaller end straight with the pipe instead of getting funnel shaped. Do this with a piece of 8 inch and put the damper in that section, then reduce as needed.

Pipe Crimper.jpg Photo shows galvanized duct pipe; use only black stove pipe.

There is piece made by Dura-Vent called "stove adapter" made for this purpose, but since most installations require cutting and crimping the cut end, a good set of crimpers is a very good investment.

IF this is a rear or side vent, the OD fits a Tee perfectly and you can cap the bottom end. Slip the tee over the stove vent pipe. Any condensate goes straight down into the cap to be evaporated. You can reduce at top of Tee and again install damper in first section of pipe.
 
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