What is the ideal space between the flues and the arch

[Thiems sugarshack]

How much space should you have between the flues and the arch on a drope flue evaporator I would think the least amount of space the better

[Bucket Head]

The ideal amount of space would be none. Well, almost none. You don't want your flues touching the arch/insulation/firebricks, but you want it close. Mine is a raised flue and I have 1/4" to 1/2" of space under the pan. You want to force every bit of flame/heat through those flues. Make all that heating surface area the flues provide work for you!

Steve

[maple flats]

as little as possible without touching. You want to force the heat thru the flues, for both drop or raised flue.