How full is too full?

[kieth4548]

Have a curious question. I have an england 28-3500 furnace add on. How much wood do you load. Is there a thing where to much wood makes it not as efficent? I read somewhere that people fill them to the top but when I do that it seems that the fire is gettting snuffed out by all the wood and not enough air is getting to the coals on the bottom. Is there a point that to much wood is to much if that makes sence.

Thanks
kieth

 

[jebatty]

Good question - one that I have too - and interested in responses. Mine is a Tarm Solo Plus 40, where the manual says to pack it tightly. I burn mostly slabwood, which is flat on one side, and occasionally both sides. There are times when I think it is too full, or too tightly packed, at least so full that it blocks the downdraft to the secondary burn/gassification tunnel. This seems to happen after the burn starts and then the pile collapses on itself. Then I have a struggle to free up some space to restart the gassification.

Experience of others?

 

[Eric Johnson]

I have heard about Tarms bridging up in the firebox, leading to a premature shutdown of the blower and causing the low fuel light to come on, even though there's wood in the stove. Everything I've read on gasifiers says to load them right up, however. I would only load a conventional boiler or furnace up to the hilt on very cold nights. The rest of the time, you're ahead, both from an emissions and an efficiency point of view, to make as many small, hot fires as possible. But when it's below zero outside, I've found that you can jam them full of wood and they'll pretty much take care of themselves.

 

[kieth4548]

My manual just says to fill it with wood. Tech support had no answer to this question. They said they didn't really know how full to fill it. This is the only problem that I have with england is when I call tech support so far on every question they said they didn't know so I am left to figure it out. I am hoping to get some good answers and also I understand there are some england engineers on here that can shed some light.

 

[SeanD]

I also have the 28-3500. Never had a problem with to much wood, although I also don't force it in. Open the door, rake down the coals and put in as much wood as easily fits through the door. Usually about 6-8 splits, each 20" long and roughly 5" diameter. Loaded this way it burns 8 hours and leaves hot coals for the next load.

 

[kieth4548]

I also have the 28-3500. Never had a problem with to much wood, although I also don't force it in. Open the door, rake down the coals and put in as much wood as easily fits through the door. Usually about 6-8 splits, each 20" long and roughly 5" diameter. Loaded this way it burns 8 hours and leaves hot coals for the next load.

Can I ask where do you set your dampers? Do you use the bottom damper also? I know this may very based on the type of wood you burn but I figure it can give me some kind of gauge.

 

[SeanD]

Here's how I use the dampers:
1. To start a fire from scratch open the top damper all the way to the left. Bottom damper open some. This is pretty much the only time I open the bottom. I do not like to leave the stove unattended with the bottom open because the fire will burn like a blast furnace.
2. To build the fire on hot coals in the morning or upon return from work I open the top all the way to left. Leave all the way open until the fire is well established. Then close the damper to about 1/4 from the right.

Now comes the challenge of temperature management in the house. If the house is cold, I pack the stove and open the damper anywhere from all the way to 1/2. I turn the 28-3500's blower fan on continuously and turn on my forced air furnace fan to help move the air. As the house warms I back it off - creep the damper towards 1/4, put the blower on thermostatic control and turn off the gas furnace fan. There is a lot of trial and error here. Our first winter I burned a LOT of wood and had my windows open half the time. Now, in our third year, we keep the house temp right where we want it.

 

[kieth4548]

Thanks Sean.
When I load the wood full and I open the top damper all the way open I notice the flames get huge very fast. I see them wrapping around the baffle plate on top and through the front edge opening leading to the open chamber going to the stove pipe and then the stove pipe gets very hot. Once that happens I quickly cut the damper back but it seems like the wood needs to get hotter but I'm afraid to leave it open with the flames leading back to the stove pipe and then cause fire in my pipe.

 

[Eric Johnson]

That's the catch 22 of most wood burning--you need to get that pipe nice and hot at least once a day for it to stay clean, but you run the risk of torching off a chimney fire when you do if the pipe has creosote growing in it. If you get lax in your daily "maintenance," in other words, the whole process can get out of whack and you will either wind up cleaning your chimney with a brush or with a chimney fire.

But it usually takes awhile for that much creosote to form in the first place, so you've got some flexibility.

What most people do is make their first fire in the morning a small, hot one, letting the stove pipe get nice and hot. After that, you can load it up and damp it down for a longer burn. It also doesn't hurt to inspect and/or clean your chimney once a month, at least at first with a new stove.

 

[jebatty]

Chiming in again because in 17 years of burning wood in a traditional air-tight wood stove and 3 months with a Tarm boiler, we never have had a creosote problem. With the wood stove we clean the chimney only once each year before the start of the heating season. Very minimal ash build-up in stainless 6" chimney, and two brush runs restores to bare metal. We always burn dry wood, mostly aspen (popple) with birch, ash, and oak in the wood stove and mostly pine in the boiler. After three months of burning pine in the boiler, same as the wood stove - nearly no build-up (bare metal clearly visible) in the 6" stainless chimney.

All of our wood is DRY. We burn wood which has dried at least two full seasons (3rd year wood). All cut/split wood is stored covered with good air circulation. The wood stove has a surface thermometer on the stovepipe about 18" above the top of the stove. Temperatures are kept minimum 250, preferably 300-350, and 400 maximum, except lower of course for initial start-up and burn down.

The boiler is wood gassification and is burned to maintain good gassification. Stack temperature with a probe thermometer now is 400-600, with the higher temp on the initial loading, and then gradually falling with steady temp around 400-450.

I think the key points are to know and pay attention to the stack temperature, adjust draft accordingly, and burn dry wood. My wife is attentive as I am with the wood stove, because it needs attention (draft control and wood loading) to maintain what I think is proper stack temperature. The boiler, once adjusted (which has taken considerable effort, witnessed by my prior posts), now is self-regulating and needs little attention.

 

[Reggie Dunlap]

I've been filling my Tarm as full as possible. It was 15 below here last night and I shoved just as much wood into it as I could. I put the big stuff in the bottom and the smaller pieces on top as I run out of room. As long as the fan shuts off at 190 like it's supposed to it should never overheat unless the power goes out.

In milder weather I think I will probably not have to load as much to keep my tank up to temp.

reggie

 

[Eric Johnson]

Interesting thing about creosote. I haven't quite figured it out.

As noted, the gasifier produces no creosote except in the primary burn firebox. I was amazed to wake up this morning at 6:30 to a warm house. I loaded the boiler up pretty good last night around 11:00. The house was around 75 and the boiler still had a nice bed of coals. It was about 5 below zero and hasn't been out of the single digits all day. So I guess it works OK.

My previous boiler was a 150,000 btu/hour Royall, which ate wood at an alarming rate and couldn't keep the house warm for any length of time near zero. The longer it stayed cold, the colder we got. After a few days, I'd usually be forced to turn the gas back on to get the place back up to temp. That boiler had a blower and produced zero creosote except at the cap. And it was burning like 15-20 full cords a winter. I think most of my heat was going right up the stack. Running through an unheated barn attic, that 8" Duratech should have been a creosote factory. I ran that boiler for 4 seasons, progressively burning less wood as I made improvements to the piping and burned drier wood.

For 9 years prior to that, in another house about 60 miles north of here, we had a Marathon Logwood 24 in the basement of a two-story house and connected to a 7" insulated ss flex liner. The chimney ran right up through the middle of the house. My wood was usually pretty dry because I would generally cut it the previous winter, leave it stacked outside all summer and fall and then move it all into the basement around the end of October. Bring it Own! That boiler produced some creosote. But I could run a brush up and back down the chimney liner easily from the basement in about 15 minutes, so I started doing that once a week--whether it needed it or not. I spent at least five seasons analyzing everything I could, and still can't explain why some weeks it made creosote and other weeks it didn't. Maybe a moisture meter would have been helpful. But making note of weather conditions or boiler temp was no help.

That's a long way of saying not to take anything for granted. Know the status of your chimney.

 

[kieth4548]

I've been filling my Tarm as full as possible. It was 15 below here last night and I shoved just as much wood into it as I could. I put the big stuff in the bottom and the smaller pieces on top as I run out of room. As long as the fan shuts off at 190 like it's supposed to it should never overheat unless the power goes out.

In milder weather I think I will probably not have to load as much to keep my tank up to temp.

reggie

Reggie do you mean the fan should kick on at 190 not off? Mine is set at 150 from the factory and it runs all the time.

 

[Eric Johnson]

He's got a boiler, kieth. The fan he's talking about is the draft blower. It gets the water temp up to 190 and then shuts off so the boiler doesn't overheat. The fan you're talking about is presumably the blower for the forced hot air. With a boiler, you use a pump for that.

 

[Reggie Dunlap]

Kieth,

Eric's got it right as usual. 10 below here now and dropping fast.

Reggie

 

[kieth4548]

OK.. that makes sence.. thanks.