How much air space under the rear pan?

[cpmaple]

Hello traders,
Well i got my arch lengthen and 8" stack on it now i have just one more question to finish it off. I have flat pans and wondering how much space should be between the firebrick and bottom of pan? I was gonna go 2 inches and yes i has force air from the back. Please get back to me with ideas thanks in advance cpmaple

[Dennis H.]

Whats the width of the arch?

Techicnally you only need the same square inches as your stack. So for an 8" stack that will work out to about 50 1/4" square inches.
So if you have a 24" wide arch I would go 2" or just over that maybe 2 1/4".

If you have a larger stack than you would have to add some depth under the pan.

Just my 2cents

[cpmaple]

Whats the width of the arch?

Techicnally you only need the same square inches as your stack. So for an 8" stack that will work out to about 50 1/4" square inches.
So if you have a 24" wide arch I would go 2" or just over that maybe 2 1/4".

If you have a larger stack than you would have to add some depth under the pan.

Just my 2cents

Dennis H thanks for the input and yes i have a 24" by 6' arch everyone on this site is so helpful cpmaple

[maple flats]

I'm not sure about your formula, but I have 1/4" under my raised flue pans, plus the raised flue channels. It works great. When I had drop flue I left about 1/2" under the drop flues, plus the flues channels, that worked good too. I think 2" under the pan loses too much heat transfer potential.