Ideal temps

[Millertime_9]

Hi, what's maybe confusing me is degrees celsius vs fahreneit!

Can someone tell me the ideal temp to have my nestor martin 33 harmony burner at?

I've read 250deg celsius, at the flue pipe

But a lot of stove thermometers I've seen range wildly with the "efficient" spot

Some say 250deg c is max "safe" temp, but others say 350degc! It's confusing

Anyone know what the ideal or max temp should be on the glass, or on the stovetop using my IR thermometer?

Thank you

 

[begreen]

Some thermometers are made to go on the stovetop and others are made to go on the stovepipe. The "safe" ranges are different with the stovetop one having the higher "safe" range. On the stovetop keep it below 400ºC with 250º to 350º as a typical operating range. Glass readings are not too helpful and can be inaccurate.

 

[Millertime_9]

Some thermometers are made to go on the stovetop and others are made to go on the stovepipe. The "safe" ranges are different with the stovetop one having the higher "safe" range. On the stovetop keep it below 400ºC with 250º to 350º as a typical operating range. Glass readings are not too helpful and can be inaccurate.

Thank you
I think I'm maybe not even firing it to max potential then

Hottest it's ever been is 300 deg celsius, not fahrenheit, on the stove pipe, the flue

And 250deg c stovetop
So I can go higher, safely?

 

[Prometeo]

in my opinion your draft is too strong, 300c flue should correspond to a much hotter stove top. Can you show a video when burn ?

 

[Millertime_9]

Hiya thanks for your reply
I've managed to get it better

Flue pipe, using an IR thermometer, c150deg and the magnetic thermometer (on the side there) about 230deg, does that sound more right?

My main issue is I don't seem to be able to get the stove itself above 230deg

Am I maybe simply not putting enough smokeless in?

Should it be filled entirely up to the top of the grate, covering the entirety of the grate?

I'm maybe wondering if I'm doing the air controls wrong too

I always thought you don't want the flue going below 150 deg as that's when creosote forms, but to do that, I can't close my air control right down, otherwise the flue does than start going below the 150?

 

[begreen]

That looks like a small fire. A larger fuel load will provide more heat. What is actually in "smokeless" fuel?

 

[joop]

gumdrops and rainbows

 

[joop]

google translate?

 

[begreen]

It depends on the specific product. There are many sold in the UK. If the smokeless coal is made from anthracite dust then creosote is not a worry.
@Millertime_9 what product are you currently burning?

 

[Millertime_9]

It depends on the specific product. There are many sold in the UK. If the smokeless coal is made from anthracite dust then creosote is not a worry.
@Millertime_9 what product are you currently burning?

Hiya, yeah it's "smokeless ovals"

I think the issue might simply be not enough fuel!

Should I be properly filling the entire stove up to the grate level?

That would give roughly 2.5 inches of fuel?

And what do you think re the air flows... am I being daft thinking I need to maintain the flue at 150deg min?

Or, surely, the higher the flue temp, the higher its heating up the stove itself?

Ps, I got some "colombian coal", proper "house coal" and the Heat difference off that was noticeable, but its quite messy!

 

[joop]

add some more see how it goes.don't have any idea what it is lol.

 

[Millertime_9]

add some more see how it goes.don't have any idea what it is lol.

Haha can't go wrong
My only worry is overfiring but if the stove itself doesn't get above 230 degrees celsius (not fahrenheit) then I'm miles away from worrying about that?

When's the key to lowering the air controls, once you get to what temp in flue?

 

[joop]

i go by eye.check manual should state temps

 

[begreen]

And what do you think re the air flows... am I being daft thinking I need to maintain the flue at 150deg min?

Depends on the brand of the smokeless ovals. Many look like they are made from coal dust. If so, no worry about the lower flue temp. Coal doesn't make creosote.

For Homefire smokeless ovals:

comprise anthracite duff (as to approximately 57% of the total weight), petroleum coke (as to approximately 17% of the total weight), bituminous coal (as to approximately 13% of the total weight) and molasses and phosphoric acid as binder (as to the remaining weight)

My only worry is overfiring but if the stove itself doesn't get above 230 degrees celsius (not fahrenheit) then I'm miles away from worrying about that?

That's more than ample headroom. If the stove stays below 370ºC it will be fine.

 

[I Love A Country Life]

Greetings, all! I have similar questions about "ideal temps" and this thread has been helpful, but I also wonder if it might vary by individual stove or not. So just curious your thoughts on the topic. My apologies in advance, but I want to provide a detailed description of our stove and the background for why I'm asking.

We purchased our home 4 years ago and it already had installed in it a Grand Wood Cook Stove (link here, or photo is attached). This is a non-powered unit (no electric controls or dampers, no fans, etc). Very basic in design. Firebox is the top half with the two air inlets you see on the door - just manually turn open or shut. Handle on top of the stove opens/closes the damper (I'm calling it a damper, but might not be the correct term). It is either all open or all closed. When open, the exhaust goes straight up the flue. When closed, it forces the exhaust into openings located along the top of the sidewalls at the back of the firebox. Between the firebox sidewall and the outside of the stove is a "void" of a couple inches where the air circulates down the side of the unit, into the bottom of the unit (under the bottom box you see, which is an oven), and up the back of all of that where it then goes up the flue. I hope that description makes sense.

Furthermore, in our particular setup, the stove is enclosed within a soapstone structure built all around it. The stone is about 3 inches thick, and as you might assume, absorbs the heat and then radiates it for a longer period of time than what the stove might otherwise do if it were left exposed. Of note, this soapstone enclosure we believe (but do not know for certain) was constructed by the prior homeowner, not necessarily something offered by the stove manufacturer or retailer.

Every season, we've learned more as we adjust how much wood we load and how open or closed we run the air inlets. But we've yet to make it through a full season without creosote buildup at the top of the flue...thick enough we have to stop burning and do a mid-season clean. Good news is it isn't the sticky tar consistency, but rather dry and brittle. But nonetheless, enough builds up that it doesn't exhaust well enough to keep burning and when it gets windy outside, gets a reverse draft to where it "burps" smoke out of the air inlets and into the house.

The flue has a 45 degree bend just a few inches above the top of the stove, then another 45 about 12 inches later where it then goes straight up to the top of the chimney. There is approximately 6 feet of flue pipe exposed in the house (before it passes into the ceiling), and then is approximately 15-18 feet from ceiling to top of chimney. The chimney is framed/siding (not masonry or stone). Flue inside the house is double-wall and then from ceiling to top of chimney is the insulated pipe (which we had replaced new after we bought the home).

Wood we burn is mostly ash, which we cut, split, and stack ourselves. You might argue it is too seasoned, as we have a 2-year supply ready and what we're now cutting and stacking will be for the 2026-2027 season. My point is it is plenty dry - no green wood! And if it matters, when we stack it, is done so within a variety of woodsheds so it has roof covering over it all as well.

So we're trying to figure out how to get through a season without needing to stop to clean. We have a professional clean and inspection prior to each season's start, so we're starting fresh. It just seems as if we have to be doing something wrong to not be able to make it through an entire season.

I've heard it explained as an old carburetor - there are 2 variables in the equation....fuel and air. For creosote to build, you are running too rich - either too much fuel or not enough air (or both). I've read plenty about burning smaller hotter fires. But I also have read in plenty of these forums about folks who set their fire at bedtime and it lasts all night long. Maybe that is a difference in individual stoves and their load capacities, but we've never gotten anywhere near that. When we thought we were burning well and had the air inlets cranked closed a bit, we'd get a good solid 4 to 5 hour burn. Waiting much longer than 5 hours required a fair amount of bellows work to get the coals to light the next load (couldn't just place the wood in and expect it to take off on its own). However, at that air setting, we were experiencing the buildup described above.

So this year, we started burning a bit in late October or early November, but as the weather transitioned, it was on again off again based on temps. We didn't get into a constant round-the-clock-all-week burn until mid-November. Wouldn't you know it, by mid-December we already had the buildup to the point of needing to stop and clean. So since then, we've been burning with the air inlets wide-open. It is resulting in a noticeably hotter fire, to the point I wonder if it might be too hot. No signs of creosote buildup yet, although out of precaution and curiosity, in a few days I'm going to let it go out and then climb up to check the top of the chimney and see how things look. Oh, but the downside to this is requiring reload about every 3 hours. That doesn't make for a good restful night's sleep!

So all of that to lead to the eventual question - is there an "ideal" temperature on the surface of the stove to know we're doing things "right?"

As you'll see in the pic, I have two of the magnetic thermometers on the front of the unit. I know, those aren't the most accurate and I also know the temperature of the steel can vary greatly in just an inch or so. But I see on those the "overfire" zone and to stay below that results in the creosote buildup. With the air inlets wide open to where I feel things are burning cleaner, they can get to near 600 degrees. And that is on the front of the unit. The top where the flames actually hit is hard saying since it is under the soapstone. But the portion exposed right around the flue pipe connection exceeds 615 (as that is the limit on my IR gun). I wonder if I'm putting too much stock into what zones are listed on these magnetic things and just need to remove them to remove that visual/mental "limit" I'm aiming for.
The flue pipe itself will read around 400 right at the connection to the stove, 285 by the 2nd 45 bend where it then heads straight up, and just under 200 where it enters the connection box at the ceiling.

Lastly, I've checked the manual to see what it says about target/ideal temperatures. The manual is very basic, and you can read it here if you are curious. But basically the only thing it says about burning temperatures is "do not overfire. If it glows, you have overfired." Pretty helpful, huh?! I've never gotten it that hot, so from that piece of instruction, I'm "safe." But I have a hard time just following instruction so basic as "make sure it doesn't glow and you'll be fine."

All temps above are Fahrenheit, and I hope I've given enough information to offer good advice from this group. I've only posted a few times, but have enjoyed lots of reading and appreciate all I've learned from this group. In the end, I'm just looking for that sweet spot of a hot enough burn to avoid the creosote buildup, but maximizing the length of time for the burn. It sure would be nice to sleep through the night, or even only have to get up once for any reloads.

Thanks in advance!

 

[begreen]

A good temperature for one stove is not necessarily ideal for another. The flue temp can be a helpful guide. Does the stove connect with single-wall or double wall stovepipe? If single wall, reading about ~18" up from the flue collar is recommended. A surface temp of around 200-300º is normal.

 

[I Love A Country Life]

A good temperature for one stove is not necessarily ideal for another. The flue temp can be a helpful guide. Does the stove connect with single-wall or double wall stovepipe? If single wall, reading about ~18" up from the flue collar is recommended. A surface temp of around 200-300º is normal.

That’s a good question. I assume it is double wall since the complete vertical piece is. But perhaps the initial connection and possibly the 45s are single. Is there an easy way to tell? It all looks the same from the exterior - black, size, etc. And when sending a brush through, do not feel any changes at the joints or in the diameter.

 

[begreen]

If it is double-wall stove pipe, surface readings are not valid or too meaningful. A surface reading of 285 on double-wall stove pipe would have me concerned. If the stovepipe is double-walled it needs a probe thermometer for a meaningful reading.

I just measured our stove which has been burning for a few hours now. Our system has double-walled stovepipe with a 45º offset off the stove. With a flue temp of 645º (digital probe measured) the surface temp on the stovepipe above the offset is 213º and at the connection to the support box, 168º.

 

[I Love A Country Life]

If it is double-wall stove pipe, surface readings are not valid or too meaningful. A surface reading of 285 on double-wall stove pipe would have me concerned. If the stovepipe is double-walled it needs a probe thermometer for a meaningful reading.

I just measured our stove which has been burning for a few hours now. Our system has double-walled stovepipe with a 45º offset off the stove. With a flue temp of 645º (digital probe measured) the surface temp on the stovepipe above the offset is 213º and at the connection to the support box, 168º.

Thanks for that info. Helpful reference given we don’t have a probe. Guess that should be an addition before next season.