Vermont Casting Aspen C3 - How hot should it run

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wjohn

Member
Jul 27, 2021
164
KS
I think the steel top hit 900-950 easily at the hottest point, but the glass top hits above 1000f. My Morso gets up to 800 sometimes, but I've stopped measuring STT and just go by flue temps now, and I don't measure anything on my cooker. The Morso has an insulated blanket over the whole length of the firebox, so I'm not surprised I have a bit lower temps despite having such a similar design.
The Aspen C3 has a single piece cast stovetop. There is an insulation blanket under it except for the front, where it has a cutout that matches the shape and size of the cooktop circle, so that area gets direct heat as it comes up around the baffle. Your 800 on your 2B lines up pretty nicely with the hottest stovetop temp I have measured over the insulated area.

Sounds like maybe the temps aren't unreasonable when compared to what you have seen on your stoves. It would still be good for us Aspen C3 owners if we could get confirmation from VC/HHT on where to measure stovetop temps and what is acceptable.
 

Todd

Minister of Fire
Nov 19, 2005
9,499
NW Wisconsin
My little 602 has seen hot plate temps of 900+ and is usually 100-150 degrees less between it and the flue collar.
 
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72Rover

Member
Dec 29, 2011
57
East VA
While I have no knowledge of the Aspen and it's operating temps, 750 seems pretty hot. I have been using a VC Resolute for 42+ years and by my estimates, it has consumed 80+ cords of wood. (It stands inside my fireplace, with a little VC-branded 'muffin' fan moving air around the firebox. The still-working fan is also 42 years old....) More important would be the stack temp - or even the areas behind the insulation, as opposed to the cooktop itself.

What were the fuel and draft conditions when running hot? Small, very dry wood with a brisk breeze increasing draft? From what I gather from a cursory search of the web is that the Aspen's major complaint is that the air damper came improperly adjusted *from the factory*. Only a few factors can cause any stove to run too hot: an increased draft, too much air or tinder-dry wood. Many folks bought their Aspens when the original owner had no idea how to adjust/fix the draft issue. The automatic air damper on my Resolute is it's *best* feature. When properly 'tuned', I only see wiggles of heat vapors and an occasional wisp of smoke exiting the stack. I've got 20+ feet of stainless pipe inside a tile-lined brick chimney, so draft is outstanding....

Other than my '72 Land-Rover, the Resolute is the best purchase I have even made. Bought it even before I closed on the house. I did have to do a major rebuild three years ago, but I'd expect it would be good for another 40 years. Me, not so much....

Cheers
 

wjohn

Member
Jul 27, 2021
164
KS
While I have no knowledge of the Aspen and it's operating temps, 750 seems pretty hot. I have been using a VC Resolute for 42+ years and by my estimates, it has consumed 80+ cords of wood. (It stands inside my fireplace, with a little VC-branded 'muffin' fan moving air around the firebox. The still-working fan is also 42 years old....) More important would be the stack temp - or even the areas behind the insulation, as opposed to the cooktop itself.

What were the fuel and draft conditions when running hot? Small, very dry wood with a brisk breeze increasing draft? From what I gather from a cursory search of the web is that the Aspen's major complaint is that the air damper came improperly adjusted *from the factory*. Only a few factors can cause any stove to run too hot: an increased draft, too much air or tinder-dry wood. Many folks bought their Aspens when the original owner had no idea how to adjust/fix the draft issue. The automatic air damper on my Resolute is it's *best* feature. When properly 'tuned', I only see wiggles of heat vapors and an occasional wisp of smoke exiting the stack. I've got 20+ feet of stainless pipe inside a tile-lined brick chimney, so draft is outstanding....

Other than my '72 Land-Rover, the Resolute is the best purchase I have even made. Bought it even before I closed on the house. I did have to do a major rebuild three years ago, but I'd expect it would be good for another 40 years. Me, not so much....

Cheers
72Rover, you can read back through the posts to see the conditions. Nothing that should've caused this if it is indeed too high of a temp - low wind, actually short on flue length, etc. for my setup and it's even happened with some ~30% MC wood I tried just for kicks to see if it made a difference. There are two other guys who also posted on here who have different setups than I do.

But, hearing how hot the Jotul F602 and Morso 2B are getting from the above posts makes me think this may not be totally out of line. Maybe these small NS loading cast stoves are just designed for it?
 

SpaceBus

Minister of Fire
Nov 18, 2018
6,428
Downeast Maine
The Aspen C3 has a single piece cast stovetop. There is an insulation blanket under it except for the front, where it has a cutout that matches the shape and size of the cooktop circle, so that area gets direct heat as it comes up around the baffle. Your 800 on your 2B lines up pretty nicely with the hottest stovetop temp I have measured over the insulated area.

Sounds like maybe the temps aren't unreasonable when compared to what you have seen on your stoves. It would still be good for us Aspen C3 owners if we could get confirmation from VC/HHT on where to measure stovetop temps and what is acceptable.
When I first installed the Morso I was hitting it with my IR laser and checking magnetic thermos constantly. I even emailed the customer support at Morso NA and they gave me basically the same answer as HHT gave you.

I do think our narrow box stoves are just going to burn hotter than a larger stove. I think that is also part of the higher efficiency our small stoves enjoy over larger stoves, especially cat stoves. I can't recall exactly, but I think the Aspen C3 is rated 80% for efficiency, and my 2b classic is 85%, I think because of the large heat exchanger.

My stove also has the single piece cast top, albeit with holes on either end for the arch. My stove peaks right where the flames go around the baffle, usually a good 50-100f hotter than even just a few inches closer to the back of the stove. Unless you see it glowing I think you are good to go.

Speaking of glowing, my adapter from the double wall chimney pipe to my appliance collar on my cookstove was glowing in a few spots not long ago. With the high wind some embers set the film of creosote on the inside of the pipe alight. I'm glad I cleaned my chimney last week and installed everything to code!
 
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wjohn

Member
Jul 27, 2021
164
KS
I can't find the 2020 2B Classic in the EPA database, or least not any test recent enough to have an efficiency value listed. The 2B Standard shows 80% HHV vs. 75% for the Aspen C3. Definitely impressive values for non-cat stoves. I bet the LHV lined up with the numbers you're remembering. I wouldn't doubt that the Classic could be even higher. I don't regret getting the Aspen C3 but would've loved to take a look at a 2B standard if we'd had a dealer around here.

The Aspen C3 manual just says stop if things start to glow. Guess I will keep on burning.
 
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SpaceBus

Minister of Fire
Nov 18, 2018
6,428
Downeast Maine
I can't find the 2020 2B Classic in the EPA database, or least not any test recent enough to have an efficiency value listed. The 2B Standard shows 80% HHV vs. 75% for the Aspen C3. Definitely impressive values for non-cat stoves. I bet the LHV lined up with the numbers you're remembering. I wouldn't doubt that the Classic could be even higher. I don't regret getting the Aspen C3 but would've loved to take a look at a 2B standard if we'd had a dealer around here.

The Aspen C3 manual just says stop if things start to glow. Guess I will keep on burning.

I love the vagueness in a manual for a box that holds literal fire.
 
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wjohn

Member
Jul 27, 2021
164
KS
I am at the winding down stage of "hitting it constantly with the IR thermometer" and saw 920 at the cooktop last night and 475 on the exterior of the stove pipe. We had 25 MPH sustained winds with 50 MPH gusts, so obviously I expect the stove to be cranking and I was keeping a close eye on things. I shut the blast gate I added on the intake down totally at that point until it dropped to 800 and then cracked it back open.

At 900 plus degrees at night with all other lights off, you can just barely make out a faint orange/red glow from the cooktop area. Everything else is ~800 or less and not glowing at that point. I think I'd prefer to keep it under 900 (and therefore not starting to glow) so that may be what I target as my max temp there going forward.
 
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SpaceBus

Minister of Fire
Nov 18, 2018
6,428
Downeast Maine
I am at the winding down stage of "hitting it constantly with the IR thermometer" and saw 920 at the cooktop last night and 475 on the exterior of the stove pipe. We had 25 MPH sustained winds with 50 MPH gusts, so obviously I expect the stove to be cranking and I was keeping a close eye on things. I shut the blast gate I added on the intake down totally at that point until it dropped to 800 and then cracked it back open.

At 900 plus degrees at night with all other lights off, you can just barely make out a faint orange/red glow from the cooktop area. Everything else is ~800 or less and not glowing at that point. I think I'd prefer to keep it under 900 (and therefore not starting to glow) so that may be what I target as my max temp there going forward.
It was a windy night and it's just now calming down a bit. This morning I got distracted after reloading the stove and the flue got a bit hotter than I normally like. It's hard to manage a stove when it's constantly pushing 25 mph for hours on end. Sounds like you have a good system with the blast gate preventing the thermostat from letting things go too crazy. At least you get a quick response from adjusting the gate.
 
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