Heat Commander - Weld spots in firebox causing bricks to break?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

sleewok

Member
Jan 27, 2021
80
USA
Hey everyone, I recently did a deep clean of my Drolet Heat Commander. I pulled all the bricks out and repaired several that were cracked. As I was getting ready to reinstall them in the firebox I noticed that there are several weld spots that are raised up maybe 1/8" to 1/4" (see photo). They do not allow the bricks to lay flat against the bottom. I wonder if this will cause bricks to break since there is a very small point of pressure. Should I grind down the weld spots? Or should I put down a layer of ash on the bottom? Or just not worry about it? Thoughts?

[Hearth.com] Heat Commander - Weld spots in firebox causing bricks to break?
 
Update: After some research I decided to use sand as a base for the brick. It worked out really well. I also packed the gaps between the bricks with sand. The bricks are now tight against the walls of the firebox and I was able to fill the larger gaps in the front. Considering that sand will hold the heat I imagine I will get even better performance than previous years.
 
  • Like
Reactions: salecker
It’s super easy to grind out little reliefs in the firebricks.
 
Has anyone else had issues with their heat commander firebricks? Were yours swollen at all or just cracked? I'm having issues with the firebricks near the grate expanding/swelling and crumbling. I've had the heat commander for a year and put less than 3 cords of dry wood through it. I first noticed this issue this fall while cleaning out the firebox. It continues to get worse. I contacted sbi and they said it looked like normal wear and that it wasn't covered under warranty. I'm not an expert but I don't think having to replace firebricks after burning a cord of wood is normal. Pictures are of the firebox after sweeping it clean with a brush. The raised areas are swollen bricks, not leftover ash. The chunk of brick pictured is a piece that I found blocking the air intake grate. I was having issues with the glass sooting up and found one of the firebricks had swelled so much that it was blocking the air intake grate. The piece shown is what was blocking the grate.
 

Attachments

  • [Hearth.com] Heat Commander - Weld spots in firebox causing bricks to break?
    20250124_090226.webp
    246.4 KB · Views: 26
  • [Hearth.com] Heat Commander - Weld spots in firebox causing bricks to break?
    20250124_094630.webp
    474.3 KB · Views: 21
  • [Hearth.com] Heat Commander - Weld spots in firebox causing bricks to break?
    20250124_090840.webp
    167 KB · Views: 22
Has anyone else had issues with their heat commander firebricks? Were yours swollen at all or just cracked? I'm having issues with the firebricks near the grate expanding/swelling and crumbling. I've had the heat commander for a year and put less than 3 cords of dry wood through it. I first noticed this issue this fall while cleaning out the firebox. It continues to get worse. I contacted sbi and they said it looked like normal wear and that it wasn't covered under warranty. I'm not an expert but I don't think having to replace firebricks after burning a cord of wood is normal. Pictures are of the firebox after sweeping it clean with a brush. The raised areas are swollen bricks, not leftover ash. The chunk of brick pictured is a piece that I found blocking the air intake grate. I was having issues with the glass sooting up and found one of the firebricks had swelled so much that it was blocking the air intake grate. The piece shown is what was blocking the grate.
I have not seen that. Infact my firebricks look essentially perfect and im in my third year on my unit. Id estimate ive burned 12 cords in it
 
I have not seen that. Infact my firebricks look essentially perfect and im in my third year on my unit. Id estimate ive burned 12 cords in it
Ok, so something must be going on with mine. Now to figure out what the cause is. My unit is installed in my basement and I do get a downdraft if I haven't had a fire for a day or so and we have rainy weather. I have a chimney cap but I wonder if the downdraft is bringing in humid air and the firebricks are absorbing it. Seems like a stretch though.
Only other thing I can think of is that I rake coals over the grate when the fire is dying down. I do this in an attempt to get the coals to burn down completely and quickly so they don't smolder and cause creosote/unclean burn.
 
Not ideal, but firebricks are what $3-4 each...meh...
 
Has anyone else had issues with their heat commander firebricks? Were yours swollen at all or just cracked? I'm having issues with the firebricks near the grate expanding/swelling and crumbling. I've had the heat commander for a year and put less than 3 cords of dry wood through it. I first noticed this issue this fall while cleaning out the firebox. It continues to get worse. I contacted sbi and they said it looked like normal wear and that it wasn't covered under warranty. I'm not an expert but I don't think having to replace firebricks after burning a cord of wood is normal. Pictures are of the firebox after sweeping it clean with a brush. The raised areas are swollen bricks, not leftover ash. The chunk of brick pictured is a piece that I found blocking the air intake grate. I was having issues with the glass sooting up and found one of the firebricks had swelled so much that it was blocking the air intake grate. The piece shown is what was blocking the grate.
Yes, I had major issues with mine. I had a few crumbling (not as bad as yours) and at least 7 or 8 cracked. I ended up cementing them back together and so far that has worked out great. My HC is from 2020, so 4 years on my bricks isn't bad.

The one thing is I learned to be more careful when loading. I would pack it as tight as possible and often I think that would damage the bricks.
 
Im careful as far as loading the firebox goes, I dont want to damage bricks or secondary air tubes and I dont have any cracked bricks so far. Good to know you can cement them back together though. Did you use regular cement?

It was $72 to replace the bottom layer of bricks through drolet which isnt the end of the world. More so just wondering why the bricks are swelling if it isnt normal. I would thrilled to get 4 years of use out of them.
 
I think that swelling is clinkers, ashes fused together onto the brick.
I don't think it's the bricks swelling.

Those can form when the mineral content of the wood (or bark!) is amenable to that, and then especially when burning hot - indeed right next to the air intake...
 
  • Like
Reactions: brenndatomu
Ok, so something must be going on with mine. Now to figure out what the cause is. My unit is installed in my basement and I do get a downdraft if I haven't had a fire for a day or so and we have rainy weather. I have a chimney cap but I wonder if the downdraft is bringing in humid air and the firebricks are absorbing it. Seems like a stretch though.
Only other thing I can think of is that I rake coals over the grate when the fire is dying down. I do this in an attempt to get the coals to burn down completely and quickly so they don't smolder and cause creosote/unclean burn.
I know once my stove goes cold i have a big downdraft into my heat commander to. I can open the door and feel the cold air flowing in. But no issues with a fire going and once i start burning, the fire doesnt go out completely until the weather starts to consistently be warm. Then ill just run the oil furnace
 
Good to know furnace cement will hold up. As far as clinkers go, that would make sense seeing as most of the issue is where I push the coals towards. Still not sure why the bricks are crumbling away in those areas though.
Maybe ill try raking the coals towards the front of the firebox to see if that helps. Not a fan of how much smoke comes the door opening and goes into the house when I rake the coals forward but at least I would figure out if it solves the crumbling brick problem.
On damp days that cause downdraft I've been opening the heat exchanger door and sliding a piece of sheet metal in front of the center heat exchanger tube to block air flow. Doesn't fully stop air flow but slows it down a good bit and keeps moisture out of the rest of the furnace.
 
In my stove,clinkers can adhere to the bricks and when either reloading or my little toothless rake contact them, they can break off taking small parts of brick with them. Doing that often can result in crumbling bricks.

Your system likely sees a bit different conditions, so things may behave differently than mine though.
 
True, I would just have to keep track of where they go when I do a deep clean. The sand has been working really well.
I honestly have never pulled the bricks on any stove or furnace to do a deep clean. I see no benifit in it.
 
In my stove,clinkers can adhere to the bricks and when either reloading or my little toothless rake contact them, they can break off taking small parts of brick with them. Doing that often can result in crumbling bricks.

Your system likely sees a bit different conditions, so things may behave differently than mine though.
I have tried to be careful when raking coals since I first noticed the bricks crumbling but that's the best theory I've heard so far so ill go with that! 🤷
There are two heavy bricks in the back of the firebox that are made from a denser material than the pumice bricks that I'm having issues with. Might be time to find more of those style bricks and be done with the issue.
 
  • Like
Reactions: stoveliker
  • Like
Reactions: brenndatomu