Fisher Fireplace Insert Baffle

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scotbro59

New Member
Jan 3, 2018
2
Virginia
I recently purchased a home that had a 1980 Fisher Fireplace Insert. I used the insert for the first time in November, and although it's my first wood insert or wood stove, I noticed immediately the flames (and heat) going straight up the flue and the smoke coming out of my chimney.

I was lucky to find my way to Hearth.com and this Forum, where I saw pictures of homemade baffles. I went to a local metal fabricator to find a piece of steel 20"x 15" but they were very busy with commercial customers. They sent someone to look with me for 'scraps' and the best we found was this 1/4" 20"x 13" steel tread. I bought it and placed it on two firebricks. It extends about 4" in front of the front end of the 8" flue and is about 3.5" from the top. It is flush against the rear of the insert.

It works great. The insert now uses less wood, puts out more heat, and there is much less smoke from the chimney. Ideally it would be about two inches longer and have the 2" x 3" notches at the corners, but it's fine for now.

Attached is a picture after I had my first chimney cleaning yesterday. They vacuumed out all the ashes.

Baffle copy.jpg Insert copy.jpg
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,230
NE PA
The critical measurement is from the bottom of outlet pipe to baffle plate. The opening (or smoke space) must not be any smaller than the square inch area of the chimney flue. In your case that would be the square inch area of 8 inch pipe which is 50.24 square inches. The circumference of 8 inches is 25.12 which at one inch opening would be 25.12 square inches, so you need 2 inches from plate to outlet pipe for 50.24 square inches.
You'll find it works better by dropping the rear of baffle so it is not level. This will also give you the correct smoke space if it is too close to outlet pipe now.

I don't see the damper control in your picture. (lever) Unless this is an early insert with a chain control that won't work without the right side fireplace cover plate. You will need this control for open door burning with screen in place and you should use it to an extent if the flue liner is insulated with doors closed.

Always burn on a minimum of one inch of ashes.
 

scotbro59

New Member
Jan 3, 2018
2
Virginia
The critical measurement is from the bottom of outlet pipe to baffle plate. The opening (or smoke space) must not be any smaller than the square inch area of the chimney flue. In your case that would be the square inch area of 8 inch pipe which is 50.24 square inches. The circumference of 8 inches is 25.12 which at one inch opening would be 25.12 square inches, so you need 2 inches from plate to outlet pipe for 50.24 square inches.
You'll find it works better by dropping the rear of baffle so it is not level. This will also give you the correct smoke space if it is too close to outlet pipe now.

I don't see the damper control in your picture. (lever) Unless this is an early insert with a chain control that won't work without the right side fireplace cover plate. You will need this control for open door burning with screen in place and you should use it to an extent if the flue liner is insulated with doors closed.

Always burn on a minimum of one inch of ashes.

Thanks for your reply! I will try tilting the baffle down in the back so it's at an angle. The opening is larger than the sq. in. area of the 8" flue as it's about 3" from the plate to outlet pipe.

There is no damper or control installed, and the fireplace cover plates and angled deflector are not there either. What's the best way for me to install a damper and control? The flue liner is not insulated except for a short distance above the visible pipe. I do need a way to control the fire for open door burning.
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,230
NE PA
With the baffle plate flat across the outlet, the smoke space between baffle and firebox top is not the factor. The limiting opening in your case is the perimeter of the 8 inch outlet pipe extending down into the firebox. Your square inch opening area would be the circumference of 8 inch pipe which is 25.12 X the height from plate to pipe. When you angle the plate, that will not be the limiting factor, then you go by square inch area the smoke travels through the area above plate.
Does the insulated pipe at the bottom connect to a masonry liner or does it stay the same pipe size to the top? You may not need a damper for closed door burning without an insulated liner. If you are going to close off the front area making the pipe inaccessible for a damper, you would need the correct parts or make them. Below is the damper with connecting rod.

Insert Damper 3.jpg

Insert Damper 10-28-80.jpg