Drolet Heat Commander Potential Heat Issues

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chadcj7

Member
Oct 27, 2020
18
Alexandria, KY
I have had a HC in the house for about 2 weeks now. After doing some additional reading on here, I am starting to wonder if I am not getting the most out of my unit. I have it installed in my basement next to my central heating/cooling unit for the house. I have a pipe running into the unit, and it is distributing throughout the house. I run the central unit fan on low throughout the entire year and I am doing so with the HC running as well.

I have a exhaust running up through the house, so it is at least 20 feet long. I feel I am burning wood pretty fast and getting good heat but not sure if I am getting the whole advantage of the heat. I may be overthinking this as well. I checked the external temp on my exhaust pipe and when I have a good bed of coals and running a solid flame, I am only getting to about 230 degrees, and that is within 1 foot of the exhaust pipe before the elbow up. I do have things connected to a thermostat and the fan is running on the HC. When I read the manual, they say the pipe should be at least 250 degrees or higher. I also have a manul damper at this time and it is wide open.

I'm trying to make sure that I am getting the most out of my HC. This is my first wood burning furnace. Any help is appreciated. Thanks
 
230 external is roughly 460 internal...plenty... actually a bit high if you are looking for efficiency.
IMO you need a manometer...the Dwyer Mark ll model 25 is one that is cheap simple reliable and used by many here. That way you can actually set you damper to a proper setting...or personally I think a barometric damper is the best option on a modern wood furnace.
Also when did you last clean the heat exchanger tubes? Should be at least weekly IMO.
Another thing that will affect efficiency big time is if the baffles in the fire box are not properly in place...should be flat on the secondary air tubes, and slid clear to the back.
 
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As brenndatomu said, check exhaust draft. If exhaust draft is excessive your heat from the fire is going out the chimney before it has time to be absorbed by the heat exchanger tubes. If you get the dwyer mark II you can also use it to verify your duct work is at the correct pressure if you care to get that technical. Baffles being in the right spot also seemed to make a difference for me efficiency wise. I also try to make sure my secondary air injection tubes are rotated all the way down, they like to rotate up if you slide the baffles on top of them.

I never thought to clean the heat exchanger tubes that often. Easy enough to do and can't hurt, adding it to my maintenance list!
 
When I had my Caddy ( same HX design as yours ) I'd clean my heat exchanger once a month or so. A few folks on here mentioned to clean them every week or more, after starting to do that I definitely noticed more heat going into the house vs up the chimney.
 
I had temp sensors on the plenum and stovepipe...you could see in the temp trends when it was time to clean...it's just so darn easy to do on those SBI furnaces, no sense in blowing your hard earned heat out the chimney when you can prevent it in literally a couple minutes!
 
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All great advice. Assuming the best way to clean is just get a wire chimney brush? Do I need to vacuum it out or just use the brush? How do you adjust the baffles? I will check the manual as well. Also what are the secondary air injection tubes? Sorry if these are dumb questions. As I mentioned earlier, this si the first wood burner I have had for a house. I also went back and checked my temps again, and it appears that I am realistically running around 150 - 175 more consistently. Final question. If I get a Barometric damper, will that take the guesswork out of things?

Thanks
 
It came with the scraper to clean it.
Sounds like a good reading of the manual is in order...it explains all this very well.
Baro damper, yes it pretty much automates keeping the "hot flue" draft at a steady state...but will not change anything when cold. The Fields RC damper is most commonly used...best bang for the buck too... don't buy one of those cheap ones at the big box or farm store...total crap.
 
After writing my response, I went back and read the manual closely. I have been using the scrapper to move the hot coals around. I then looked at things since my fire was burned down and realized that the baffles were moved forward. I pushed them back, and now I will see if I run a little more efficiently.

Can you help me better understand what you mean by how it won't help when things are cold.
 
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chadcj7 said:
Can you help me better understand what you mean by how it won't help when things are cold.
Click to expand...
The warmer your flue gets the more the draft increases. A cold flue might have little to no draft or even a reversed draft when there is no fire. Once things heat up, hot air wants to rise so draft increases. Thats where the baro comes into play and starts opening up to let air into the flue to decrease the amount of draft that the stove sees.
 
chadcj7 said:
That makes sense. What is an ideal external temp on the flue, as I know the internal will be higher.
Click to expand...
Double wall of single wall? You should be able to hold your hand on double wall.

As mentioned before, anything above 400F internal and you are wasting heat up the chimney. When I had my Caddy, I'd shoot for temperatures between 350F and 400F. I had a temperature probe in single wall right after it exited the furnace hooked to a PID controller to display the temperature.
 
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chadcj7 said:
It is single-walled. I am registering around 125-175 on the external temp with it near the exit. If I close the damper down, will that help lower this temp?
Click to expand...
Yes, but you don't want it too low because you'll end up making creosote.

If you are new to running the furnace, I'd highly recommend spending the $30 on a cheap Chinese PID controller, and RTD probe so you can learn how to run the furnace correctly and not possibly burn your house down because you are running it too low and plugging the chimney pipe up with creosote. As others have said, spend the money on a good baro, set it and forget it. The only reason you should have a key damper on a wood furnace is because the baro can't slow the draft down enough.
 
 
 
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