New Furnace Day: Drolet Heat Commander

[laynes69]

The furnace doesn't burn wide open when there's a call for heat. The dampers adjust to maintain maximum efficiency and heat output. The temperature settings for the blower change based on the call for heat. It's not an on/off combustion system. There's numerous stages that the dampers can adjust the fire to.

 

[JRHAWK9]

The furnace doesn't burn wide open when there's a call for heat. The dampers adjust to maintain maximum efficiency and heat output. The temperature settings for the blower change based on the call for heat. It's not an on/off combustion system. There's numerous stages that the dampers can adjust the fire to.

Understand that, burning wide open is burning dirty. I was under the assumption the call for heat will have some effect on the rate of wood consumption.....? A constant call for heat would burn the wood quicker, right? That's all I meant.

 

[Highbeam]

The dampers adjust to maintain maximum efficiency and heat output.

I propose that these two things do not happen at the same time. Flue temps rise, emissions rise, efficiency falls as maximum output is reached.

I believe that there is a sweet spot of maximum efficiency somewhat lower than maximum output but above minimum clean burn rate.

Good stuff folks.

 

[laynes69]

I believe that there is a sweet spot of maximum efficiency somewhat lower than maximum output but above minimum clean burn rate.

I agree completely, however an on/off system would burn wide open and do so indefinitely. Using thermocouples, they can detect surges in temperature and maintain a burn that's clean and efficient. Maybe not full efficiency no, but much more efficient than an off/on system.

 

[trx250r87]

I guess I was wrong on my statement about the thermostat condition not being relevant.

I usually just set the HC thermostat and forget it. I rarely pay attention to if it is calling for heat or not.

I just came home from work and as of 4:45pm after loading the furnace (half full of soft maple) this morning at 6:15am the fan was turning on about every 10-15 minutes. I'm assuming the thermostat was calling for heat. Up stairs thermostat was still 69 degrees and it was in the mid/upper teens this morning. Attached is a photo of the amount of hot coals left in the firebox.


Eric

That does not seem right. My HC fan cycles once I am at the coaling stage if there is enough plenum temperature to kick the fan on, regardless of thermostat condition. This often happens for hours.

Eric

 

[Highbeam]

I guess I was wrong on my statement about the thermostat condition not being relevant.

I usually just set the HC thermostat and forget it. I rarely pay attention to if it is calling for heat or not.

I just came home from work and as of 4:45pm after loading the furnace (half full of soft maple) this morning at 6:15am the fan was turning on about every 10-15 minutes. I'm assuming the thermostat was calling for heat. Up stairs thermostat was still 69 degrees and it was in the mid/upper teens this morning. Attached is a photo of the amount of hot coals left in the firebox.


Eric






View attachment 286168

Is that the under grate air supply kicked on making the coals white?

 

[trx250r87]

I did hit the reload button, crack the door and open the manual damper for a few minutes and the coals started glowing pretty good.

The grate air supply is not fed by any forced air, just natural draft.

Eric

 

[laynes69]

If the house drops in temp and the thermostat has a heating demand, the grate air opens and burns white hot. I've came downstairs after an overnight fire thinking there were alot of coals in the firebox, just to find a small amount of ashed over coals. The units really do extract a bit of heat.

 

[JRHAWK9]

North-South or Log cabin style loadings?

That's funny you asked...but seeing you went there. Of course everyone is building a crib. It's how SBI instructed Intertek to load it and it's how it was certified. It's why the manual has to recommend it. They seem to have gotten away with it.

If the house drops in temp and the thermostat has a heating demand, the grate air opens and burns white hot. I've came downstairs after an overnight fire thinking there were alot of coals in the firebox, just to find a small amount of ashed over coals.

That is one feature that would be nice to have. I'd only need it a handful of days a winter, but it would be nice to have that option available. In terms of efficiency though, you are sacrificing overall BTU's long term (by way of chimney) for short term heat output.

 

[Pflum]

I believe the manual instructs to load crib style for max heat output, but also instructs to pack tightly North/South for max burn time. I'll check the manual when I go downstairs.

 

[laynes69]

That's funny you asked...but seeing you went there. Of course everyone is building a crib.

That is one feature that would be nice to have. I'd only need it a handful of days a winter, but it would be nice to have that option available. In terms of efficiency though, you are sacrificing overall BTU's long term (by way of chimney) for short term heat output.

I'm not going to lie, 4 large splits in a crib actually put out a ton of heat and last for hours.

As for the sacrificing BTU's the heat exchanger does well to extract the heat from the fire. I'll take a small reduction in efficiency in order to maintain a comfortable temperature in the home.

 

[JRHAWK9]

I'll take a small reduction in efficiency in order to maintain a comfortable temperature in the home.

Agreed, there are a few times when we have those numerous 70-80 HDD's in a row where I would find it helpful to be able to burn down the coals quick and keep supply temps high in order to load the next load faster. I have a way I do it, but it's manually, not automatic. LOL

 

[JRHAWK9]

I believe the manual instructs to load crib style for max heat output, but also instructs to pack tightly North/South for max burn time. I'll check the manual when I go downstairs.

Seeing it was instructed for Intertek to load that way and that's the way it passed and was certified, they have to make it part of the manual.

 

[woodey]

I believe the manual instructs to load crib style for max heat output

So to achieve the "max heat output " loading crib style, am I right to assume you need 2 different lengths of splits to do this?

 

[sloeffle]

I've been burning mine for a few weeks now; I don't have my return air hooked up yet, hope to have it hooked up next week. Overall I'm happy with the HC, my biggest gripe is probably that when the thermostat is satisfied, the blower cycles a lot. The blower is really quiet, so the sound doesn't bother me. The computer raises the cut in/cut off temp when the thermostat is satisfied, but if there's a decent fire going the thing cycles a lot, sometimes every couple minutes. To me its not lessening the amount of heat being delivered, its giving a blast of hotter air every few minutes versus a steady supply of cooler air. It doesn't seem like the air controls are choking down the fire a lot, but I know they are trying to keep the burn clean too

My Caddy did the same thing until I added the blower mod to mine. It's miserable listening to it kick off and on all of the time. IMHO the blower mod makes the furnace heat the house so much better, especially at the end of the burn when the house is up to temp, or getting close.

 

[brenndatomu]

IMHO the blower mod makes the furnace heat the house so much better, especially at the end of the burn when the house is up to temp, or getting close.

True story

 

[laynes69]

So to achieve the "max heat output " loading crib style, am I right to assume you need 2 different lengths of splits to do this?

So to achieve the "max heat output " loading crib style, am I right to assume you need 2 different lengths of splits to do this?

No, I just take 2 splits corner to corner and 2 offset from those. My wood is still the same as before.....18" to 20".

 

[sleewok]

I did hit the reload button, crack the door and open the manual damper for a few minutes and the coals started glowing pretty good.

The grate air supply is not fed by any forced air, just natural draft.

Eric

Wait, there's a manual damper on the HC? Where is it located?

 

[trx250r87]

Wait, there's a manual damper on the HC? Where is it located?

Negative, I have a manual/key damper installed on my flue.

Eric

 

[FixedGearFlyer]

I’m late to this season’s party, but we are still thrilled with the HC. Last winter was an absolutely game changer in both comfort and convenience and this year is shaping up to be the same.

We dropped a 6” stainless liner down our 7”x7” masonry flue in early fall and that’s improved burn times and heat output over last winter’s fantastic performance.

We’ve been getting 12+ hour burns with the firebox about 2/3 full and keeping the house within a degree or two of the thermostat setting (70*F) for that entire time. Outside temps have been in the upper 20s during the day and the lower 20s to mid-teens during the nights, so we’re still in “One Fire Per Day” land. We usually burn around 8:00am and the fan is still cycling occasionally when we go to bed around 10, though the house is starting to cool at that point. By morning, it’s around 60 and we do it again. Our shoulder-season pellet stove takes up the slack if it drops below 60 during the night.

So far, we don’t have any complaints about the HC. Even in the depths of last winter when we kept the furnace burning 24/7, we only had to go down to the basement twice per day - once in the morning and then once in the evening.

 

[Rockstar1346]

From my first few weeks with it I have found crib style gets a quick hot fire burning and gets the plenum up to temp. But I only load maybe 4 splits in this way then let it burn down to coals then load north south on top I find that works best for me. There’s definitely more I need to do to make it more efficient, but this year was more about getting it installed before snow flies.

 

[Rockstar1346]

I just wanted to post a picture this morning because I never really get to see it as I go to work in the dark and get home in the dark. But how on earth do these stoves burn with no smoke what’s so ever!?

 

[brenndatomu]

But how on earth do these stoves burn with no smoke what’s so ever!?

Canadian elfin magic...

 

[JRHAWK9]

Welcome to the 21st century. If it did smoke, it's not efficient. Smoke IS your fuel, so sending it up the chimney is like poking a hole in your gas tank of your vehicle as you drive down the road.

Once you get below freezing temps, you will see water vapor condensing in the air.

I was just over at the neighbors a couple days ago picking up some poplar he cut down and didn't want. Lucky for me ( ) it was near his OWB. So I got to smell/inhale that horrible smelling smoke while I was there. He burns well seasoned oak, but those OWB are just nasty. The top of his stack was just covered in black gooey creosote. Nasty!

 

[brenndatomu]

Smoke IS your fuel, so sending it up the chimney is like poking a hole in your gas tank of your vehicle as you drive down the road.

Good analogy.

I was just over at the neighbors a couple days ago picking up some poplar he cut down and didn't want. Lucky for me ( ) it was near his OWB. So I got to smell/inhale that horrible smelling smoke while I was there. He burns well seasoned oak, but those OWB are just nasty. The top of his stack was just covered in black gooey creosote. Nasty!

Agreed, that's a nasty stench being downwind of those things!
But the newer OWB's (some of them anyways) burn as clean as your Kuuma! 👍👍
My folks just installed a new HeatMaster G series (this is for those reading along, JR already knows about it) and the difference between it and their old Central Boiler is like an ox cart with stone wheels vs a new Tesla!