Hi. I have a newmac wb100 wood furnace up in my shop. There is approx 2' of horizontal flue coming out of the back of the furnace, then a 45 degree elbow which takes the flue straight up and out through the attic and roof. I don't have any problem with draft (no smoke ever coming out the door or anything), but I'd like to know if there is a proper way to monitor the burn in a furnace like this in order to achieve optimal heat and burn times. I have a thermocouple probe mounted in hole that I drilled into the vertical section of my flue about 16" above the 45 degree elbow, wired to a digital readout, that gives me some idea about how hot the flue gasses are running. On startup I generally run the forced draft fan for about 15 minutes (with the combustion air draft slide fully open) so that I can get the flue temps up to 600 or 700 degrees Fahrenheit, but I notice that as soon as I shut down the forced draft fan the flue temps start dropping (pretty fast too) and when I start closing the combustion air draft slide (after around 30 minutes) towards the minimum setting the temps really drop (I'm usually looking at between 200 - 300 degrees Fahrenheit). The only way to keep the flue temps up and burning nice and hot is to leave the combustion air draft slide pretty much open, but then the furnace just gobbles the wood like some kind of glutton
Is there some other way that I can monitor the burn on this furnace? For instance how can I use my IR gun to monitor surface temps on the door or on the plenum to figure out that I've got a good burn going? Or maybe I need to be putting an Outdoor Air Kit on the furnace to help with combustion air??? (my shop is a pretty leaky old building, but the furnace is located in a kind of alcove nook enclosed by cinder block walls...... Any help or advice is certainly appreciated.
Cheers,
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Cheers,