2 flues on Fisher Grandpa Bear - do we 'close off' (cap) the other flue that will not be used?

[KMK]

one flue is on top of fire box, other is at back. We are going to use top flue.
Do we cap (close off) other flue at back?
Thanks for any advice you may have about this.

 

[begreen]

Yes, the unused flue outlet must be capped.

 

[bholler]

It is probably one of the ones that had a barometric damper on the back. Which was a horrible idea, cap it

 

[KMK]

Yes, the unused flue outlet must be capped.

Thanks!

 

[KMK]

It is probably one of the ones that had a barometric damper on the back. Which was a horrible idea, cap it

Thanks.