How full can I pack my PE Alderlea T6 LE?

[Sean in the woods]

I have a new PE Alderlea T6 LE and will be trying for long burns soon. Those of you who have them:

• How full do you pack them?
• How close to the baffle plate?
• How important is it to carefully choose splits that leave air gaps between them?
• North-South or East-West?

Thanks.

 

[Nigel459]

The quick answer is: it depends... on wood type, size, MC, temp, elevation, etc etc haha...

In a balanced fuel/stove/chimney system you can stuff it chock full and enjoy a long controlled burn. Before you go trying it, my first question would be how is your draft? If you have excessive draft, which is likely with a longish flue system (~>14') in the cold U.P., you can be fighting runaway fires if you put in too much fuel without a damper or some measure.

Have you measured your draft? What's your flue/chimney system like?

 

[Sean in the woods]

The quick answer is: it depends... on wood type, size, MC, temp, elevation, etc etc haha...

In a balanced fuel/stove/chimney system you can stuff it chock full and enjoy a long controlled burn. Before you go trying it, my first question would be how is your draft? If you have excessive draft, which is likely with a longish flue system (~>14') in the cold U.P., you can be fighting runaway fires if you put in too much fuel without a damper or some measure.

Have you measured your draft? What's your flue/chimney system like?

The draft should be good but I don’t know how to measure it. Is there a tool?
I have a 6” double wall flue that is ~24’ from stove to cap. It has two 45 degree bends in it forming a “dog leg” about 5’ above the stove then straight up the rest of the way.
What are the symptoms of over fire? I assume too high a flue temp but how high is too high and how long can it spike into that range, if at all?

 

[begreen]

I have a new PE Alderlea T6 LE and will be trying for long burns soon. Those of you who have them:

• How full do you pack them?
• How close to the baffle plate?
• How important is it to carefully choose splits that leave air gaps between them?
• North-South or East-West?

Thanks.

Go for it. You will be burning hundreds of fires over the years so don't get too obsessed. If the goal is maximum burn time or maximum heat, then fill it up close to but not lifting the baffle. I usually leave about an inch clear and I do not obsess about a perfect packing job. Our splits are too varied for me to be fussing trying to get a perfect packing job, especially when reloading on hot coals. Sometimes it will work out well with little gaps and other times the gaps will be there due to a knot or something. No worries. It's more important to learn how to quickly reduce the air without smoldering the fire.

With a cold start, I usually leave a valley in the top middle for the top-down start with kindling. Then once the fire is burning strongly I insert a split to fill the valley. It sounds like your draft will be good. You have the same setup as we do with the offset, but we have a little shorter, 20' tall flue system. Draft has never been an issue for us.

This is a typical full load for our stove.

 

[begreen]

What are the symptoms of over fire? I assume too high a flue temp but how high is too high and how long can it spike into that range, if at all?

How are you measuring temperature now? Have you seen the "Starting a fire" thread up in the stickies section? That shows the T6 through a burn. I will say that since getting a digital flue thermometer, I rarely use anything else except maybe my eyes. It provides real-time guidance vs a long lag time with other instrumentation. With the digital probe I have the alarm set at 900º. Normal digital flue temps range around 450-650º, depending on the stage and size of the fire.

On the stovetop I usually see between 500º and 700º SST. 450-500º would be with smaller, shoulder season burns and 700º would be with a fresh reload when I am pushing the stove for heat. If you keep the stovetop temp below 750º it will be fine.

 

[Nigel459]

Agree with the “go for it” sentiment.

It sounds like your draft will be good. You have the same setup as we do with the offset, but we have a little shorter, 20' tall flue system. Draft has never been an issue for us.
....

The few times draft has been an issue for me it has been too strong, leading to hotter and shorter burns. One time was scary hot, so I guess that’s where I’m coming from. @Sean in the woods this is what I mean, since your chimney is longer and your climate colder than BG. Do you have a key damper?

But as BG says, you’ll figure it out. Good luck!

 

[Sean in the woods]

Just coming down from a scary burn.

Loaded 5 large oak splits and a stick N/S onto hot a coal bed in a warm stove. Followed the instructions and waited to turn the air down till the wood began to char (I interpreted that as began to turn brown). Turned it to just a little open (1/8?). After 10 minutes the flames were darker so. I checked outside. There was a fair amount of smoke. Inside, I saw the secondaries had gone out. So I turned the air up to a quarter. In a minute, the secondaries had come on. I turned the air to the minimum and the secondaries stayed on.

After a little while, the flue temp began to climb. I use an Auber probe monitor.In 1/2 an hour it was905 and still climbing. When it crossed 1025. I started felling the walls of the chase that the liner goes though on the way to the roof. It was not too warm. When it crossed 1040 degrees I started clearing furniture and tying back curtains getting ready to grab logs from the fire and toss them out the window. It topped out at 1054 held it for 10 minutes and came down steadily. It declined more slowly after it got below 980. An hour and a half after I put the wood in, the flue temp is in the low 700’s and the wood has burned off a little over half of it’s volume.

So. Questions.
Was I over reacting? Was 1050 dangerous?

 

[begreen]

Was I over reacting? Was 1050 dangerous?

The system can handle that temperature for short durations like you experienced. This has happened to me on an odd occasion. If you are really concerned, open the stove door. It will be a strong fire, but the rush of cool air will break secondary combustion and cool down the fire within a minute. You will see this in the flue temp almost immediately.

 

[Sean in the woods]

The system can handle that temperature for short durations like you experienced.

Good! I’ll chalk it up to noob nerves. Thanks.

 

[Nigel459]

Great that you have a nice flue thermometer, this will really help! To me, the event you describe could be one of a couple of things:

1. You reloaded when things were still way too hot. If you do this there’s really no stopping off gassing going way too quickly and things getting out of control in most stoves.

or 2. If you reloaded and things weren’t too hot then you may have too-strong draft...

When you’re cruising for a long burn, your flue temp could/should be way lower than 700. Sounds like way too much heat going up the stack. I think in BGs great thread his stove top is usually a good 100 higher than his flue, which runs around 400 I think, maybe even lower when cruising.

 

[SpaceBus]

You may want or need a key damper in the flue system.

 

[Sean in the woods]

If you are really concerned, open the stove door. It will be a strong fire, but the rush of cool air will break secondary combustion and cool down the fire within a minute. You will see this in the flue temp almost immediately.

I thought that the inrush of air would make matters worse. Glad to know that there is something more I can do. Thanks again.

 

[Sean in the woods]

Great that you have a nice flue thermometer, this will really help! To me, the event you describe could be one of a couple of things:

1. You reloaded when things were still way too hot. If you do this there’s really no stopping off gassing going way too quickly and things getting out of control in most stoves.

or 2. If you reloaded and things weren’t too hot then you may have too-strong draft...

When you’re cruising for a long burn, your flue temp could/should be way lower than 700. Sounds like way too much heat going up the stack. I think in BGs great thread his stove top is usually a good 100 higher than his flue, which runs around 400 I think, maybe even lower when cruising.

I hadn’t thought about the premature gasification. Makes sense. It was a very hot coal bed.

How do I determine if I have too much draft for the stove?

 

[Sean in the woods]

You may want or need a key damper in the flue system.

I may. Got to find out if the draft is too strong somehow.

 

[SpaceBus]

I may. Got to find out if the draft is too strong somehow.

The tool is called a manometer or a magnehelic gauge. I believe the manometers are less expensive. Guys with wood burning forced air heaters tend to use them along with a barometric damper.

 

[Sean in the woods]

The tool is called a manometer or a magnehelic gauge. I believe the manometers are less expensive. Guys with wood burning forced air heaters tend to use them along with a barometric damper.

Thanks. Now that I know what to search for, I’m off to the races.

 

[Sean in the woods]

How are you measuring temperature now? Have you seen the "Starting a fire" thread up in the stickies section? That shows the T6 through a burn. I will say that since getting a digital flue thermometer, I rarely use anything else except maybe my eyes. It provides real-time guidance vs a long lag time with other instrumentation. With the digital probe I have the alarm set at 900º. Normal digital flue temps range around 450-650º, depending on the stage and size of the fire.

On the stovetop I usually see between 500º and 700º SST. 450-500º would be with smaller, shoulder season burns and 700º would be with a fresh reload when I am pushing the stove for heat. If you keep the stovetop temp below 750º it will be fine.

I just went back and re-read your excellent starting a Fire thread. Makes more sense now.

Quick question: My Auber probe is mounted 15 inches above the stoves collar. Is that too low? Could it be giving me faulty readings?

 

[mar13]

Just coming down from a scary burn.

Loaded 5 large oak splits and a stick N/S onto hot a coal bed in a warm stove. Followed the instructions and waited to turn the air down till the wood began to char (I interpreted that as began to turn brown). Turned it to just a little open (1/8?). After 10 minutes the flames were darker so. I checked outside. There was a fair amount of smoke. Inside, I saw the secondaries had gone out. So I turned the air up to a quarter. In a minute, the secondaries had come on. I turned the air to the minimum and the secondaries stayed on.

After a little while, the flue temp began to climb. I use an Auber probe monitor.In 1/2 an hour it was905 and still climbing. When it crossed 1025. I started felling the walls of the chase that the liner goes though on the way to the roof. It was not too warm. When it crossed 1040 degrees I started clearing furniture and tying back curtains getting ready to grab logs from the fire and toss them out the window. It topped out at 1054 held it for 10 minutes and came down steadily. It declined more slowly after it got below 980. An hour and a half after I put the wood in, the flue temp is in the low 700’s and the wood has burned off a little over half of it’s volume.

So. Questions.
Was I over reacting? Was 1050 dangerous?

I'd follow Begreen's fire starting thread. I do recall the Pacific Energy stove manual states to turn down the stove once the wood is charred. I find that if I wait that long, the fire may already have too much momentum, especially if on hot coals, even if raked forward. But turning it down too much too early may still squelch the fire if not enough momentum. The turn-it-down incrementally is perhaps analogous to piloting an oil tanker or 747 (of which I have no experience) .

 

[Sean in the woods]

I'd follow Begreen's fire starting thread. I do recall the Pacific Energy stove manual states to turn down the stove once the wood is charred. I find that if I wait that long, the fire may already have too much momentum, especially if on hot coals, even if raked forward. But turning it down too much too early may still squelch the fire if not enough momentum. The turn-it-down incrementally is perhaps analogous to piloting an oil tanker or 747 (of which I have no experience) .

Yeppers. I just re-read @begreen ’s fine tutorial. Learned lots. Again. From this thread too.

I think I understand what you are saying re the ship and plane analogy. I shouldn’t always expect an immediate response.

 

[Nigel459]

I may. Got to find out if the draft is too strong somehow.

I’d try a relatively full load again, but from a cold start. Try a top down fire, follow the “how to start a fire” process. If it “runs away” again and you can’t keep things relatively controlled then yeah, a key damper would be a good first measure to try and likely solve it.

 

[Sean in the woods]

I’d try a relatively full load again, but from a cold start. Try a top down fire, follow the “how to start a fire” process. If it “runs away” again and you can’t keep things relatively controlled then yeah, a key damper would be a good first measure to try and likely solve it.

Thanks. Doing it now.

 

[Highbeam]

I run a noncat really hard in my shop for real heat.

I have found that leaving space above the fuel load, 1-2”, allows some space for secondary combustion to occur without just creating a second primary combustion area where the tube air hits the wood. That second primary fire on the top is being fed by full throttle secondary air and really burns fast and shoots up the stack. I believe that filling wood to the tubes is usually safe but wastes wood. It get the same burn times and heat output with less fuel when I maintain space for secondary combustion above the fuel load.

Turns out, some owners manuals even specify not to load above the bricks.

 

[Sean in the woods]

I run a noncat really hard in my shop for real heat.

I have found that leaving space above the fuel load, 1-2”, allows some space for secondary combustion to occur without just creating a second primary combustion area where the tube air hits the wood. That second primary fire on the top is being fed by full throttle secondary air and really burns fast and shoots up the stack. I believe that filling wood to the tubes is usually safe but wastes wood. It get the same burn times and heat output with less fuel when I maintain space for secondary combustion above the fuel load.

Turns out, some owners manuals even specify not to load above the bricks.

Excellent advice. Thanks.

 

[Sean in the woods]

Yay!

This morning, from a cold stove, I followed instructions using an almost full load of oak. It did not run away. Looks like I don’t need a damper after all. Here are the times and temps of today’s burn.

Time	Flue	Stove Top
6:30AM	000	000	Started
7:30AM	826	615
8:00AM	730	500
9:00AM	624	421
10:00AM	374	246
11:00AM	464	257
12:00PM	376	257
1:00PM	342	225
3:00PM	336	199

Next thing to learn is how to properly start a full load from coals of the previous burn.

Thanks again everyone.

 

[begreen]

Congratulations. You will do fine. The stovetop temps seem on the low side, especially with oak. When I am burning locust they often top off in the 650 to 700º range. What is being used to measure them and where?