Blower for evaporator

[Outdoorsman0490]

Hey all,

Currently I am running a 2'/4' divided pan with my 1'/2' preheater directly behind it. What cam blower would one put on this set up? I see them from less than 100 cfm all the way to 550 cfm like on my wood furnace. At what point would you want to have a multi speed switch other than just unplugging when going to put wood on. Thanks for the help.

[nymapleguy607]

100 cfm is probably plenty of air for that size arch. You might get away with a larger blower but if your arch has any air leaks you will be blowing ash and debris out.

[RileySugarbush]

For air through your grate, I suggest a 100 (minimum) to 200 (better) CFM squirrel cage blower. Less than 1/4 hp is needed for these low pressure blowers. Adjust flow with a baffle over the inlet of the blower to where you get a hot fire and now ashes blowing out the seams of your arch. Simple on/off switch for loading wood.

[BreezyHill]

the more air tight your arch is the less you will leak out of the arch. The use of a dimmer switch works best as you can turn the know/slide the lever to adjust the speed as needed...ie: batch draw off, adding wood, starting the fire, etc. The baffle control is much less adjustable and is generally needs more attention to adjust. Check out ebay and clist for fans. To large can be throttled down by partially covering the inlet. I have 400 cfm on a 2x6, but will be adding Air Over Fire from a stack heater for next season.
This originally had a 170 cfm on it but piggy backed another fan to get the 400. The new system will still have the dual fan and the AOF system. Trials will tell what the end result will be for most efficient boiling.

Ben