New Lopi Answer- Questions

[brenndatomu]

I leave the air supply to the stove wide open all day

If you slowly, and in stages, close the intake air control down (say 75%-50%-25%-0%(if the flame will stay) over a period of 20-30 minutes (after the fire is well established) that will put much more heat to the house than leaving the air open...that just warms the chimney.
If you were reading 300* on the outside of the doublewall pipe, then the internal temp was to the moon!

 

[wagne223]

I am not an expert stove operator so I may have missed something, but there are a couple things that stand out to me in this thread.
1. Flue temp is given, but this looks like double wall pipe and there is no probe in the pipe.
2. The door is open for 30 minutes or more on startup.
3. The image looks like a good fire.
4. Mention of adding "one more log" "added 2 more logs"
5. Stove acted the same with lumber.

My thoughts are that the flue temp is higher than the OP thinks.
The stove is not achieving secondary burn because the door is open too long at start, and being opened during the cycle to add wood.

I would like to see a video of the stove operation from cold start.

 

[Rose Lane]

All great points.
I had not realized that one needs a probe to measure flue temp with double wall pipe.

Generally speaking, it is very hard to even get a kindling fire going, which is why I've been leaving the door open. Closing the door, or closing down the air supply snuffs it out. The airsupply is very sensitive, and only has about 3/4" of an inch to play with.

For kindling I am using 2x6 dimensional lumber that I cut on a chopsaw to 1" wide. It's always been inside, so I'm optimistic the kindling is dry.

I just got some pressed logs (Home Depot did not have Bio Bricks.)

I will make a timelapse of startup tomorrow; unable to work in the space today.

Thank you!

 

[stoveliker]

hard to get kindling going even with the window cracked?
There are two issues when this happens; not enough draft (blockage in the flue - unlikely in new construction - or too tight a building envelope), or wet kindling. The latter seems hard to do, given that kindling is split so small...

 

[DBoon]

I leave the air supply to the stove wide open all day (both of the test days have it wide open.). The stove door is left open about 1/2" to 1" during startup, i.e. 30 minutes to 45 minutes while I am actively monitoring

Generally speaking, it is very hard to even get a kindling fire going, which is why I've been leaving the door open. Closing the door, or closing down the air supply snuffs it out.

These are all symptoms of wet wood. On my Lopi Answer, I might leave the door open 5-10 minutes on cooler, smaller piles of coals (200-250 degree stovetop), then close it. When my stovetop hits 350 degrees, I close the primary air 75% open. When it hits 500 degrees, I close the primary air to 50%. When its going well (maybe at stovetop 550 degrees), I close the primary air to 25% open. What happens next depends on the wood (hickory burns differently than cherry) and the outside air temperature. If you can't operate your stove this way, then the wood is likely too wet.

 

[Rose Lane]

Day 3 Test: Pressed Logs + Video

Confirmed, the stove pipe is 22”, thus double walled. I don’t have a probe thermometer currently, so stopped collecting that information.

The only decent looking pressed logs at Home Depot were brand Green Mountain.

This is what I did differently this time:

Started fire with two pressed logs and dimensional lumber kindling. I only used two pressed logs based on prior commenter’s note that more could be too much for a stove. I think, in this case, more would be necessary.

I closed the stove door right away.

Airflow was tamped 25% after 1.5 hours, and 50% after two hours (the theory being it would keep more heat in the room.)

Over the course of the test, used 3 pressed logs (total) and 1 piece of 2x4 scrap, plus the regular kiln dried wood which probably tests 25% moisture.

This is a video of 3.5 hours of this, sped up 40x to 7 minutes.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

No real improvements on interior temperature data.

The next test will be using ONLY pressed logs and dry dimensional lumber.

Any other suggestions welcome. Thank you all for the input!

 

[stoveliker]

Closing the air after 1.5 and 2 hrs is way too late. Think 10-30 minutes max

 

[EbS-P]

My only suggest is to fill the firebox clear full each load. When I start top down I start with two medium splits on bottom two small on those then kindling all the up to touching the baffle. Your manual might say not to load above the firebrick. I would respect that but put a couple pieces of kindling in the middle a bit higher.

Put the pressed logs on a two pieces front to back of scrap when you cold start.

It’s hard to secondary combustion happening in the video was it??

I’m in a 700 sq ft basement and I can only move the temps about 2-2 degrees an hour with a 2.4 cu ft stove. Takes a lot of heat to warm up but much much less to stay at temp.

Keep at it.

 

[Rose Lane]

Closing the air after 1.5 and 2 hrs is way too late. Think 10-30 minutes max

It takes 30 minutes to get the kindling going! Do you mean 10-30 minutes after the logs are burning?

 

[Rose Lane]

My only suggest is to fill the firebox clear full each load.

It’s hard to secondary combustion happening in the video was it??

I have not seen the secondary combustion working until the entire space is up around 65.

In fact, when it's colder, the fire actually avoids the secondary combustion holes- it travels around them, like they are blowing out something not flammable.

Agreed, I'm going back to top-down fire building, regardless of what the manual says.

 

[stoveliker]

It takes 30 minutes to get the kindling going! Do you mean 10-30 minutes after the logs are burning?

Kindling is supposed to get going in 30 seconds. That's what it's for.
So (again), your kindling is (also) too wet and/or you don't have enough draft.

It doesn't make sense otherwise.
Not being able to start a fire on a reasonable way has to be either one of these things.or both.

Did you make kindling from some 2*4 scrap lumber?

If the open window doesn't help, I'd consider adding height to the chimney.

 

[ctyankee]

You have to tamp air down 90% or more. Within 20 minutes (this includes the kindling period) you should be able to do this. I start with a smallish load, but by 20 minutes I'm ready to stuff it full if that's what I want to do. Let it rip a bit with air open, then put down to 90% or more. A stone cold stove with no coals could take longer on average. These stoves are made to run hard --- as long as you what the temp is more or less. I have temp on top of stove near pipe, 700 degrees is an ideal temp I think. Secondaries are triggered by very little to no primary air. Also, I use newspaper, twigs paper towel roll etc if I have to for kindling. I don't want to mess around with the kindling phase.

 

[stoveliker]

I see you did use 2*4 scrap kindling.

But I see moisture on your window evaporating. Something is quite wet there.

 

[DuaeGuttae]

We used to run a Lopi Revere insert in a walk-out basement in a well insulated and air-sealed house. There was slight negative pressure in the basement, not enough ever to cause a backdraft, but it was something we need to pay attention to, especially starting a fire in a cold stove. The problems the OP is describing do sound very strange, definitely worse than anything we experienced. One thing that did help us, though, was being willing to use firestarters instead of just a match or kindling. We found that burning a quarter of a super-cedar while starting a fire from cold helped keep the flu warm enough to overcome slight negative pressure. We did crack a window open if we had to, but having more heat inside the stove (even just the little heat from a fire starter and paper) definitely helped.

It was surprising to me when we first got the Lopi that we had to keep the stove door cracked to light it off because we had never done that in the stove we had in my childhood home. I came to understand that it was part of how the Lopi was designed, but it should not take even 10 minutes to get kindling going, much less 30. I would say 10 minutes would be about the max to have the stove open at all, like when building a full load top down.

 

[Rose Lane]

Kindling is supposed to get going in 30 seconds. That's what it's for.
So (again), your kindling is (also) too wet and/or you don't have enough draft.

It doesn't make sense otherwise.
Not being able to start a fire on a reasonable way has to be either one of these things.or both.

Did you make kindling from some 2*4 scrap lumber?

If the open window doesn't help, I'd consider adding height to the chimney.

The kindling is made from 2x6 lumber chopsawed into one inch thick chunks.
It's been stored 100% inside.

Could it be that the stove's built in airflow is just not adequate?

 

[stoveliker]

The kindling is made from 2x6 lumber chopsawed into one inch thick chunks.
It's been stored 100% inside.

Could it be that the stove's built in airflow is just not adequate?

I have not seen others with that issue. A design problem would often result in quite a few folks with consistent issues.

If flow is an issue here, a taller chimney could very well help .

 

[Rose Lane]

I see you did use 2*4 scrap kindling.

But I see moisture on your window evaporating. Something is quite wet there.

That's a really interesting point about the moisture. I just scrubbed through the beginning of the video and see it too- I hadn't noticed before.
That was a cold morning startup, nothing hot in the stove. And typically, the interior moisture of the room is reading 16% or so. So what could it be? It also hasn't been precipitating.

 

[DuaeGuttae]

I just went back and reread the whole thread and watched the videos again to see what I am missing. I admire your perseverance and sure hope this thread will help you get warm sooner rather than later.

Did you ever nail down an exact height on the flue? At one point early on you suggested that it was actually too short, but I missed any follow up on that. Insufficient flue height can certainly affect draft. The stove has to have enough draft for its own airflow to work properly.

You also mention getting surface readings of 18 to 25 percent on your wood. I think you know by now that that’s definitely too wet as the internal readings will be higher. Also, if the wood is cold, it will read falsely low. At one point in your last video after you tamped down the stove to 50 percent, it kept burning for a while, and then a while later it picked up signficantly. That looked like a symptom of wet wood where you evaporated the excess moisture, and then the stove managed better.

You mention that you don’t get secondaries till your room temperature is about 65 degrees. It’s the temperature inside the stove that matters for secondaries, but in my stove, if I keep the primary air open too much, I’ll cut down on the secondary action. I need to tamp it down fully or almost fully to maximize my secondaries. If you are having to keep the primary air open to get excess moisture out of the wood, you’ve really lost a lot of btu‘s and particulates up the chimney before you’ll even get to the temperatures that would allow secondary combustion.

Have you ever put a full load of bricks (not jam packed full but reasonably full) on top of coals to see how it burns? It’s hard to start bricks in a cold stove. They do better on coals.

I know your firebox is small, but your loads look small inside it, too.

I’m thinking that you need to verify that you meet the specs for flue height first, then work on burning bio bricks (not the wood you know is too wet) in larger batches to get the space heated and keep it heated. Do you burn a fire a night ever so that you’re not starting at such a low temperature in the morning?

You also mention not being able to insulate the floor. Even putting a throw rug down under your feet will help you feel warmer, and covering more area would help even if it’s not professional insulation.

When you open a window, does air rush in like a fan, or does it not do much? That little test helps you know how tight your building is.

 

[DuaeGuttae]

I found myself thinking over this thread and talking with my husband about it while we were preparing dinner this evening? I have a couple more questions.

1) Have you looked at your chimney and cap recently to make sure that you aren’t getting creosote buildup that is affecting draft. I know you aren’t having problems with smoke, but with what sounds like wet wood, it’s a safety as well as performance issue.

2) Is your workshop elevated so that the uninsulated floor is in contact with the air rather than the ground?

 

[wagne223]

Some observations from your video. Everyone is going to have a little different procedure. I'm comparing yours to mine.

1. Not enough kindling and what you have is too big for a fast light. I like kindling to be a mix of log length and 6" long so I can build an openly spaced pile across the stove. I like my piece's to start at 1/2" x 1/2" and be no bigger then 1/2" x 1. I will sometimes put a few large chunks like yours on top. I probably use 5x the amount of kindling you show. I build my kindling structure on top of 4 or 5 small to medium splits.

2. All your heat is going up the flue. There is a point in your video that the fire is going really strong and the logs are starting to ash and your note said 25% tamped. That far into the burn you should be cruising with the primary air just cracked or completely closed. I could be wrong, but with the fire going that good at that point there does not seem to be an issue with the stove or the flue.

Keep the following in mind:
The kindling needs to heat up the flue, heat up the firebox and start the logs.

The flue is completely open to the outside. The only way to keep heat in the firebox is to reduce the airflow through the stove by closing the door and reducing the primary air as quickly as the fire will allow.

Heat in the firebox transfers to the stove top and body which warms the room.

My suggestions would be.
Put 2 or 3 pieces of your big kindling on the bottom of the stove N/S. Place 2 or 3 of the pressed logs or known dry splits on top of those. This allows hot air to flow under and around.

Openly stack 20- 30 pieces of smaller kindling on top of the logs. My favorite is pallet slats split with a hatchet.

Crack open a window (to eliminate the building airflow being an issue).

Be sure the primary air control is fully open.

Light the kindling, leave door open 1 inch.
In 5 minutes the kindling should be fully engulfed. Since you don't have a flue probe, give it another 2 minutes then close the door.

The fire will drastically slow down. Allow it to recover. After 5 more minutes, it should be be burning good but the flames will be slow compared to when the door was open.
Reduce primary air by 1/4 allow fire to recover for 5 minutes.
Reduce another 1/4 and repeat.
You should be down to only 1/4 open, secondary combustion should be visible and the stove top temp should be climbing.

The logs should be starting to burn and secondary combustion increasing until it looks like all the air in the stove is on fire.

Should be getting warm now.

If this does not work for you, then I suggest you find someone that has experience with EPA stoves to come check it out. The dealer or a qualified sweep maybe.

 

[brenndatomu]

I would say not nearly enough wood being loaded to get the firebox up to a good operating temp, and then not closing the air down anywhere near soon enough, which results in no secondary combustion, and poor heat to the house (chimney is warm though!)
Maybe try loading log cabin style...bottom 2 logs N/S, next layer E/W, and so on...then put a bunch on kinlin in the middle of the "cabin" and drop a match on 'er!

 

[DBoon]

Hi Rose Lane,

First, that's a great video. You are going to figure this out. The video is a huge help.

I think the biggest problem you are experiencing is that you are not putting enough wood in the stove and it is not reaching critical mass so it can run the way it wants to and throw off some serious heat. It is a tough stove - don't worry about the stove top getting pretty hot. I've had mine to 800 degrees and it is ok (I don't like it being there, but it's been there and it can take that heat).

Also, if it is a new stove, the firebrick probably has a lot of moisture in it that will take about one week of solid burning to really evaporate out. I go through this with my stove every fall after a humid summer. So keep at it and when that moisture gets evaporated out of that firebrick, it will seem like a different stove.

Lastly, your firewood might be a little wet - hard to tell. But you seem to be getting a pretty good light off on pieces you put in. You just need to put more in.

Your first load of the day (cold start) needs to be about 10 times that quantity of wood you are using. Use the 2x4 pieces about the size in your video to create a stack of wood in the stove as tall as the stove allows and as wide and deep. Load the kindling/2x4s front to back, a piece on the left and a piece on the right. Place some very small splits (about 1" across) of cordwood or kindling over them in one layer, then another layer of kindling/2x4s front to back, and some small splits over that, and keep repeating. Start that with paper and a firestarter underneath that stack and light it off. Keep the door open for about the first 5 minutes or until there is a good fire going in there (no more than 10 minutes should do it). Close the door. When your stove top reaches 350 degrees, pull the air lever out 25%. When it reaches 400 degrees, pull it out 50%, when it reaches 550 degrees, pull it out 75%. Leave it there and let it burn - you should see a lot of secondary combustion. If not, it's because your wood is too wet. But I think you will be fine with this approach as your first fire and you'll see some secondaries, but you have to pull the air lever out to get the secondaries (and to get the heat - the heat is in the secondaries and the gases from the wood).

Then, let that first fire burn down to coals. You want to reload when there is about 2 cups of coals (just coals - not unburned wood) and the stove top is about 300 degrees. Rake the coals forward into the front half of the stove and create a level layer of coals. Create a trench in the middle of it (front to back) for the air to flow from front to back after you load it up. Then, fill the stove 3/4 full with wood splits - this should mean about 5 or 6 splits 4" or so on a side. Try to stack it so that there is a little room between what is in back and what is in front. It helps to use a flat piece in the front bottom to hold a log on top. You should probably buy some elbow length welder's gloves at your local hearth store to stack the wood in the stove with. Once stacked on top of the coals, close the door almost all the way but leave it open a crack until flames get going. When you see good flames in the firebox, close the door all the way (handle down). When stove top reaches 400 degrees and there are good flames, pull air control out 25%. When stove reaches 550 degrees (and good flames) pull air control out 50%. When stove reaches 600 degrees or 10 minutes later, pull air control out to 75%. You should see good secondaries at 50% and 75% air. If the flames die out, push air back in 25% and wait 5 or 10 minutes for flames to return vigorously and then pull air out 25% more again. If you wood is good and dry, you should be able to get the air control out 100% and let it cruise for a couple of hours at 500 to 600 degrees stove top. If your wood is slightly wet, then you might struggle to get to 500 degrees with air control between 50 and 75%. If wood is really wet, you may struggle to get past 25% air control and 500 degrees.

As your firebrick and wood gets drier, you will need to modify the instructions I gave above by turning down the first faster at lower temperatures. You'll get the feel of it in no time. The key is to get a sustained secondary combustion.

So, to summarize:

1. You need a lot more wood
2. Keep at it - you need to drive the moisture out of the firebrick
3. Get to know your air control and how the fire responds to it.

 

[wagne223]

Here is an example of my stove loaded for a cold start.
I typically cut pine short so I can load it N/S in my shallow stove.
On the very bottom in the ash is two pieces of pine N/S to allow air to flow under the load.
On bottom is 2 medium oak splits E/W. On top of the oak is 4 small pine splits N/S.
Then some larger pieces of pine bark. On top is the cut an split pallet kindling.
I also throw some pieces of bark and wood slivers from splitting in wherever they will fit.

 

[bholler]

It takes 30 minutes to get the kindling going! Do you mean 10-30 minutes after the logs are burning?

No if working properly it should be 10-30 mins from striking the match.

 

[wagne223]

Here is that load 5 minutes after lighting.
The door is open 1 inch during this time.

At 5 minutes, the flue is up to temp so I closed the door. Notice the fire slowed way down upon closing the door. You can also see the secondary burn starts immediately when closing the door.

2 minutes later (7 mins from start) the fire has recovered so I close primary air to 50%. You can see the fire is being forced down and heat is warming up the bottom logs.