Running my Alderlea T6

[Stover4Life]

Hello all, I recently designed and built my very first house. It is a ranch style home utilizing a closed loop geo-thermal heat pump system. The house is a walk-out style house and I purchased an Alderlea T6 which I built a slate hearth on the lower level. The house is 2,000 sqft upstairs and 2,000 sqft downstairs. Installed the main return trunk so it ended directly above the unit on the lower level. The duct sits about 10 feet above the stove itself. I have temperature sensors located in the return duct to sense when I have the wood burner on. If the return duct senses any return air temperature above 90 degrees a controller disengages the variable speed compressors on the heat pump and turns on the main supply fan. I oversized my stairwell width and have it at 5 foot wide. I manually will close the return air ducts upstairs and force the cooler air to funnel down the stairwell. It works well for the most part. Now my problem.

I burn seasoned Osage Orange (Hedge Apple Trees) only. Our farm is littered with them. My stove will heat up easily enough but will burn through a full load of hedge in a matter or hours, approximately 2 hours until I would have to go down and reload it. I am seeing temperatures on the top of the stove around 600-700, the return air duct temperature sensor says that the air temperature is approximately 105-110 degrees F. I can't go any higher than that because my heat pump refrigerant coil is in the same air stream and I run the risk of boiling my refrigerant if I go any higher. My flue temperature is hovering right around 700 degrees. I believe this stove has a EBT (extended burn time) unit built into it for allowing overnight burns. I have yet to even come close to get a 5 hour burn off a full load. I do have what I believe to be the optimal burn setting marked on the damper. This where I can re-stoke the fire and the stove will stay at a surface temperature of 700 degrees and my flue temperature will not increase either. My questions are:

1. How hot should I be running this stove, what should I see for a surface temperature?
2. Has anyone ever gotten this ETB device to work?
3. How hot before over-fire happens on this stove?
4. Would a fan help move the heat? If so where should it face? (Remember the return duct is located directly above the unit, so I don't think a fan will do anything special?
5. When I do get the upstairs heated from circulating the air from downstairs up the lower level is really uncomfortable.....Does this really need to be this way or can I move air better?

Thanks for the input.

 

[jeff_t]

Are you closing the air down once it gets going? Any secondary action at the top of the fire box? Your stove top temps are on the high side, but okay.

How are you reading the flue temp? If a probe, it's a little high. If magnetic, it is way high. Single or double wall pipe? Flue temps should drop as the primary air is closed down, and stove top temps should rise as the secondary burn takes over. This keeps heat in the stove instead of up the chimney.

How long has the wood been split and stacked? A load of hedge should be an all nighter.

Try putting a fan on the floor, at the top of the stairs and pointing down. It will help set up some convection by blowing cool air down the stairs, and replacing it with warm air. A small desk fan works well.

 

[Stover4Life]

Let me try and answer your questions one by one...

The way I run the stove is to get a fire going strong, with the main damper fully open. once the flue temperature reaches 400-500 deg F and the surface temperature is around 300 deg F, I usually back the main control damper down to 1/3 open. Seems to work the best.

Secondary fire usually only comes on when I have it closed at the 1/3 position but it doesn't last more than an hour, mostly because the hedge load is needing to be restocked.

The flue temperature is monitored using a probe type thermometer.

The flue is double wall construction.

The wood is split and stacked and then stored in a firewood shed. That split wood would sit for at least 1 year before its used. I have checked moisture content in the wood and its always lower than 10%.

I don't think a fan at the top of the stairs will help much and the reason is that if person was to sit at the bottom of the stairs the draft of cold air barreling down the stairs has some serious velocity, enough to blow paper around.

This stove just devours hedge like nobodies business.

 

[Grisu]

The startup sounds ok but I would try to close the air control more than just down to 1/3. You may still have too much heat escape up the chimney. Maybe try to close it completely or almost completely next time.

How tall is your chimney? How many splits do you load for an overnight burn? Do you fill up the firebox? When you say the moisture content is 10%, did you split a few pieces and check the center of the freshly exposed surface?

 

[begreen]

This stove is being pushed hard. It's not surprising that the burn times are short. It is being asked to heat twice the area that we are heating.

 

[Stover4Life]

See thats what thought so I have tried that also. I have let the fire heat the box and flue up the same as I have stated previously. But when I move the main damper all the way to its lowest setting it basically kills my fire. No secondary fire just basically smolders the splits. This is where I ask the question about Pacific Energy's EBT device. Why doesn't that take over when the main damper is moved to the lowest position, after all the EBT is basically a crude bi-metal thermostat. The 1/3 position is the stoves sweet spot, at least thats what I think.

 

[Stover4Life]

To answer the question about my chimney, its approx. 25 feet straight up right out of the top of the unit. No elbows or fittings.

I usually throw 5 or 6 pieces in for night burn around 9pm then get up around 12 and reload the stove with the same amount. Thats when I pretty much let it burn till 6 am.

I check moisture content when I pull split wood from the shed.

 

[Grisu]

When the fire goes out completely when you close the air it probably means your wood is not dry enough. (Other option would be not enough draft but with 25 ft chimney that is unlikely.) When you check the wood are you re-splitting a few pieces? The outside of the splits will be plenty dry but you need to check the center of the wood. Split it in half and check the center of the fresh surface.

 

[Seanm]

To answer the question about my chimney, its approx. 25 feet straight up right out of the top of the unit. No elbows or fittings.

I usually throw 5 or 6 pieces in for night burn around 9pm then get up around 12 and reload the stove with the same amount. Thats when I pretty much let it burn till 6 am.

I check moisture content when I pull split wood from the shed.

So when you load it up around 12 is there anything left at 6 am or does it burn down in three hours? I checked osage orange on chimneysweeponline.com and it has 30 MBTU per cord. During the day I burn Lodgepole Pine in my super 27 and don't even have to try and I get 4 hours of burn time and its only 15.3 MBTU per cord so something is off here. At night I fill the box with Larch (19.5 MBTU per cord) and there are still coals at 8 am for a reload. Definitely do as Grisu says and check the inside of a freshly split round. When I do this I test it immediately as it wont give you an accurate reading once its been exposed to the air for even a short while. How big are the splits you are putting in? If they are more like kindling then you will get hot temperatures quickly as there is more surface area of the wood exposed to flame. FYI I would love to have access to the kind of wood you are burning it sounds great!

 

[begreen]

See thats what thought so I have tried that also. I have let the fire heat the box and flue up the same as I have stated previously. But when I move the main damper all the way to its lowest setting it basically kills my fire. No secondary fire just basically smolders the splits. This is where I ask the question about Pacific Energy's EBT device. Why doesn't that take over when the main damper is moved to the lowest position, after all the EBT is basically a crude bi-metal thermostat. The 1/3 position is the stoves sweet spot, at least thats what I think.

Sounds like the wood is not fully seasoned or draft is not that strong. When was the wood split and stacked? How tall is the flue system? Even with locust I can take the air control all the way over once the wood is fully burning.

But truth be told this sounds like a 2 stove house. Or one that needs a wood furnace.

 

[BrowningBAR]

It was 52 today in Lincoln, Nebraska. With a low tonight of 31. If you are burning that hard and fast now, there is absolutely no way that stove is going to be able to keep up in January and February.

At 4,000 sq ft you will either need a second stove, or switch to a wood burning furnace/boiler/outside wood burner.

 

[mfetcho]

I agree, that is a lot of house to heat. I am heating 2500 sq/ft with my T6 and I run it hot to maintain a good house temp. I could run it a little cooler if I had better air circulation. After 9 hours I have a little coals, but I still have to use kindling to get her going.

I like the design of your house. How is the stove functioning with your geothermal? Are you running them separate?

 

[Sprinter]

But when I move the main damper all the way to its lowest setting it basically kills my fire. No secondary fire just basically smolders the splits.

This makes the wood sound suspect as mentioned by others. It seems very unlikely that the wood is at 10% especially after only a year. If osage orange is at 30 MBTU/cord, it's probably very dense and slow to dry like oak is, which can take up to three years just to get to 20%. Do you measure the MC on a freshly split face and can you confirm the accuracy of the meter? This is very rough, but if you put the pins on the palm of your hand (not sweaty), it should measure in the low 30's.

.

 

[thechimneysweep]

A couple thoughts: if you're trying for an all-night burn, why are you loading just five or six splits? To maximize burn time, pack as much wood in there as the firebox will hold, and once the fire is kindled, turn the draft control down as far as it will go (the EBT will provide enough air for secondary combustion at this setting). That said, I know of two situations that could describe your lack of secondary burn on the low draft setting, both related to the fuel wood, and both already mentioned above.

Scenario A: The wood could be too wet. If water is vaporizing along with the wood resins, it mixes with the exhaust and interferes with secondary combustion. This forces you to open the draft control to get the gasified resins to burn at all, which shortens your burn time.
Scenario B: The wood could be too dry. If a freshly-split piece registers just 10% moisture content, your wood has very little resin content left. When the resin content is gone, there is little fuel left for the secondary burn. Kind of like mill ends, which have had much of the resin content removed during the kilning process: as a result, they burn up fast.

Of the two, Scenario B is the least likely: by all reports, super-tight-grained Osage Orange seasons extremely slowly. Split a piece and test immediately in the center of the split, and I'm betting you'll find your wood isn't as dry as you think it is.

 

[jeff_t]

Another question- is the wood split and stackd outside for a year, then moved to the shed? Or split then stacked right into the shed?
Wind and sun are your friends when drying wood.

 

[madison]

? is the 25 foot chimney 6" double wall, than 6" Class A once it leaves the room? (by your description it does not dump into a tile lined chimney)

? any chance the air intake OR rear channel up to the baffle is clogged?

Osage split size (L and Diamter)? Loading E/W or N/S

Stove blower can help increase heat output (will not help your burn time)

Hopefully Hogwildz can link or post some pictures of his old summit pack to the gills.

 

[madison]

Found the pictures:
Load it like this for longer burn time:
reply # 21 https://www.hearth.com/talk/threads...le-gasket-shes-cooking-now.23717/#post-325226

 

[Hogwildz]

Load that puppy with large splits, pack it to the gills. Large on the bottom, filling in the top with mediums and smalls as needed to fill her up.
If your only using 5 or 6 splits, they should be large like the ones in the photos in the thread Madison posted links to.

I also bet your wood is not quite as dry as you think it is.
We all been there. It makes a huge difference.

Granted it wasn't frigid cold here today, but was in the low to mid 30's when I got home around 3:00 PM. Loaded at about 2:00 this morn, and didn't stir the colas and reload till 5:00 PM.
And that was not loaded completely full.... 15hrs on a 3/4 full load is not absurd.
12 hours on colder days is more typical. You have the same firebox as my Summit has.
Of course every set up is different and performs different at times, but you should do 8 - 10 hrs no problem, unless you burning soft wood. You should do 8+ hrs on a full packed load even if soft stuff. If it is wet, forget it.

 

[Dave A.]

After that picture, now when Dennis says he puts 3 splits in for overnight and keeps his place in the 80's, I don't think he's just BS'ing anymore.

 

[begreen]

3 splits may work in October, but in January are not going to keep the place at 80F unless the area is small or very well insulated or the oven is running round the clock. It's basic math.