My older model Woodchuck 526 is up and running in my 24x24 2 story shop with insulated walls and roof R13. It's maintaining 70-80 in 20-30 degrees outside. The circulation blower mounted on the furnace is a single speed that "seems" to be blowing too much air across the stove and cooling it down too much too quick. I want to maintain 300-600 flue temperature 12" from the stove outlet right below the manual dampener. It will turn on about right around 130" air duct temperature but then run till too cool for the flue to maintain temps to avoid cresote. Because the stove is radiating enough heat to keep the switch in the duct approx 24" above the cast iron top of the actual stove inside the bottom of the duct is my guess why. As is, I run the blower then unplug it when I see the flue temp getting to low. but that means constant monitoring so I usually leave the blower off and treat it like an ordinary stove. So... before I start getting snap switches, 3 speed or variable motors, thermostats and other geeky stuff to play with, I wanted to get some of you guys thoughts on how to correct it. I've read of blocking some of the inlet opening size to slow the cfm being moved but not sure as that would seem to put a larger load and thus energy usage on the motor in theory. The furnace will work as is without blower but this has became one of those "let's make it work the way I want it to" projects. Looking for idle thoughts and ideas. Lenny
I have lots of thoughts on this subject...but the first one, with the time I have at the moment, is doing this will actually lessen the load on the motor as it is moving less air, doing less work, so uses less power.
I've read of blocking some of the inlet opening size to slow the cfm being moved but not sure as that would seem to put a larger load and thus energy usage on the motor in theory. As an HVAC technician I can tell you if you block the intake to a squirrel cage motor the rpms increase and the amps will actually go down. If you block air flow to a bladed fan it will slow the fan down and increase amp draw. I know it sounds weird, but that's the way it is
I blocked it down to about 25% of my original opening of a 20x20 filter size. I then moved the temperature switch up in the air duct about 30” from the stovetop within. It seems to be working well now. The fan (squirrel cage) turns on when the air in the duct reaches approx 100 degrees and off when it cools to about 80. The flue temp stays above 300 12” from the back of the stove unless it’s about time to reload. Damper about half closed and air inlets pretty well open. With a outside temp of 25 a couple of days this week, my 24x24 2 story is maintaining 70-80 downstairs and I have a curtain (canvas drop cloth) blocking the stairs off. Upstairs runs about 60. Don’t quite have all night burns yet but still 50ish or so first thing in the morning. Pretty happy with it now. Sent from my iPhone using Tapatalk
