Lopi Insert Not Putting Off Heat?

[BillinTex]

Boy am I glad I found this place. I am learning so much from the experienced hands here. Tiffany, I hope you get the problem sorted out. I was looking at Lopi inserts last week and they seem to be as well made as they were years ago when I first encountered the brand in Oregon. They are out of my league price-wise, however.

 

[Hobbs]

I have the same medium insert, the firebox shape is challenging with this insert being only 12’’ deep and 24’’ wide. I started cutting my wood at 11’’ so you can load North and south. This is a pain but it will double your burn time and put out more heat. When I loaded 16’’ splits East and West the center of the load burns out and I had to reload and constantly fool with the fire. Also you’re only getting a half loaded firebox.

When I load north and south with 4 large splits the fire is screaming in 20 minutes and I can close down the air control all the way and get 6 hours of great heat, 8-10 hours of coals.

 

[nola mike]

Tough to see how hot you're actually burning. On my insert I have secondaries going even with very low heat output. On my jotul it'll crank with very little secondary action. I'll disagree with the conventional wisdom here that less air=more heat. The lowest air setting without smoldering is the most efficient, but not necessarily highest heat output. Also, it may start to smolder later if turned down too low. There's definitely a sweet spot between closing air and max heat On my insert I use a candy thermometer to see how hot the air is coming out. On mine with the fan on low, it gets to 275-325' during the hot part of the burn. This will be completely stove dependant.

 

[TradEddie]

I'll disagree with the conventional wisdom here that less air=more heat. The lowest air setting without smoldering is the most efficient, but not necessarily highest heat output. Also, it may start to smolder later if turned down too low. There's definitely a sweet spot between closing air and max heat

I think we'd all agree with you, max heat output will be achieved with air slightly open, depending on the "calibration" of any particular unit's air control, but it's a common beginner mistake to think that fully open air and the resulting blazing "traditional" flames give the most heat. With my Lopi, 1/4" from fully closed will quickly hit 700F stovetop or more, the range of happy operation for mine is between there and closed. I've never experienced smouldering with seasoned wood and a properly pre-heated (>400F) firebox, even with fully closed air, which is how I run 99% of the time.

TE

 

[Tiffany and Bartholomew]

I have the same medium insert, the firebox shape is challenging with this insert being only 12’’ deep and 24’’ wide. I started cutting my wood at 11’’ so you can load North and south. This is a pain but it will double your burn time and put out more heat. When I loaded 16’’ splits East and West the center of the load burns out and I had to reload and constantly fool with the fire. Also you’re only getting a half loaded firebox.

When I load north and south with 4 large splits the fire is screaming in 20 minutes and I can close down the air control all the way and get 6 hours of great heat, 8-10 hours of coals.

View attachment 303780

It definitely is difficult to get the wood properly stacked going east/west with the size logs she has. She actually already started cutting them in half so she can load the other direction! So at least we know we’re starting to learn 😅

 

[Tiffany and Bartholomew]

I have the same medium insert, the firebox shape is challenging with this insert being only 12’’ deep and 24’’ wide. I started cutting my wood at 11’’ so you can load North and south. This is a pain but it will double your burn time and put out more heat. When I loaded 16’’ splits East and West the center of the load burns out and I had to reload and constantly fool with the fire. Also you’re only getting a half loaded firebox.

When I load north and south with 4 large splits the fire is screaming in 20 minutes and I can close down the air control all the way and get 6 hours of great heat, 8-10 hours of coals.

View attachment 303780

Oh! Also, how quickly does it take to heat the general area around the stove? I just want to make sure I’m not having unrealistic expectations for how quickly it should heat, especially with those tall ceilings.

At our house with our stove (not an insert), it regularly takes about 3 hours to heat the house 13 degrees on the thermostat around the corner in the hall. I wouldn’t assume it would be that quick for hers, though (our ceilings are only 8 ft tall).

 

[Tiffany and Bartholomew]

I think we'd all agree with you, max heat output will be achieved with air slightly open, depending on the "calibration" of any particular unit's air control, but it's a common beginner mistake to think that fully open air and the resulting blazing "traditional" flames give the most heat. With my Lopi, 1/4" from fully closed will quickly hit 700F stovetop or more, the range of happy operation for mine is between there and closed. I've never experienced smouldering with seasoned wood and a properly pre-heated (>400F) firebox, even with fully closed air, which is how I run 99% of the time.

TE

So, we did have a breakthrough on thanksgiving. We realized all those little air vent things at the bottom of the insert (I think that’s where the stove draws air from) were all clogged up with dust! So we cleaned those out and the fire went much better. We were able to get it closed nearly all the way without it dying out of anything like that.

Also, the temperature in the room finally went up I think about 8 degrees within 4 hours or so. That was really exciting! However, I don’t know if we should attribute that to the cleaned air vent things or the fact that it was substantially warmer outside than it has been all the other times we had tried (I think it was like 58-62 out). What do you guys think made the difference?

 

[Tiffany and Bartholomew]

Boy am I glad I found this place. I am learning so much from the experienced hands here. Tiffany, I hope you get the problem sorted out. I was looking at Lopi inserts last week and they seem to be as well made as they were years ago when I first encountered the brand in Oregon. They are out of my league price-wise, however.

This forum is a blessing! We’ve learned so much from it as well. I honestly don’t know if we would’ve been able to get a fire going the first time without looking things up on here every step of the way!

I was shocked to find out how expensive it was, although it looks really nice and everyone says great things about it!

For us at our house, we bought a $700 stove from Tractor Supply, I forget which brand but I can find it. It’s not an insert, but we love it just as much as I think we would have a more expensive one! Getting the piping and chimney and all that cost more than the actual stove, but well worth every penny.

We were hesitant about getting a wood stove at first, as we never grew up burning. But after the ice storms a few years ago, and being without heat or power for four days, that convinced us pretty quick 😅

 

[begreen]

So, we did have a breakthrough on thanksgiving. We realized all those little air vent things at the bottom of the insert (I think that’s where the stove draws air from) were all clogged up with dust! So we cleaned those out and the fire went much better. We were able to get it closed nearly all the way without it dying out of anything like that.

Also, the temperature in the room finally went up I think about 8 degrees within 4 hours or so. That was really exciting! However, I don’t know if we should attribute that to the cleaned air vent things or the fact that it was substantially warmer outside than it has been all the other times we had tried (I think it was like 58-62 out). What do you guys think made the difference?

Air + Fuel + heat are the essentials for fire.

Flush-mounted inserts tend to pick up more from the floor in front of the stove due to the lack of or a very shallow ashlip. Often the blower intake is right at the hearth level. The blower tends to pull in ash, wood debris, dust, and animal hair, into the vents and blower. To keep this at a minimum, always turn off the blower when loading or cleaning the stove and keep the hearth and the intake ports clean.

Let us know how the insert is working as it gets colder outside.

 

[TradEddie]

Also, the temperature in the room finally went up I think about 8 degrees within 4 hours or so. That was really exciting! However, I don’t know if we should attribute that to the cleaned air vent things or the fact that it was substantially warmer outside than it has been all the other times we had tried (I think it was like 58-62 out). What do you guys think made the difference?

That does sound like poor heating to me, but I don't have your insert, or your home, so I simply don't know. I do know that if you've got secondaries burning like those photos, I'd expect the air coming from the outlet vents to be almost too hot to hold your hand near. If it's not, maybe some more vacuuming is called for, or perhaps there really is some other issue.

On a more positive note, if you've been able to successfully run the insert at 60F, then you'll find that it'll run much, much better when outside temperatures are lower. Colder outside temperature creates more draft, which drives the whole system. I won't run mine above 50F, the lack of draft makes it burn badly and it's extremely difficult to control, below 50F it's not an issue, and by single digits I've got to remember to close down air extra fast, or it'll soon be glowing in places it shouldn't!

TE

 

[Tiffany and Bartholomew]

That does sound like poor heating to me, but I don't have your insert, or your home, so I simply don't know. I do know that if you've got secondaries burning like those photos, I'd expect the air coming from the outlet vents to be almost too hot to hold your hand near. If it's not, maybe some more vacuuming is called for, or perhaps there really is some other issue.

On a more positive note, if you've been able to successfully run the insert at 60F, then you'll find that it'll run much, much better when outside temperatures are lower. Colder outside temperature creates more draft, which drives the whole system. I won't run mine above 50F, the lack of draft makes it burn badly and it's extremely difficult to control, below 50F it's not an issue, and by single digits I've got to remember to close down air extra fast, or it'll soon be glowing in places it shouldn't!

TE

Thank you everyone so much for all your help and tips! Also, glad to know it should be easier to burn when it’s colder out! Tomorrow it will be cold so we plan on going over there and burning to see how it goes.

Unfortunately, we spoke to the company who installed the stove. They said there is “no need” of a block-off plate in the damper area because there is a top plate at the top of the chimney. They also said we “are not losing heat from the chimney.” So, I guess that is out of the question, unless it’s pretty easy to do yourself.

When we mentioned that the fire was going well, but not heating the room well, we were told it is still user error and there is nothing wrong with the stove.

They told us to start the fire and let it burn a solid hour with the bypass open, so that flames are going up into the flue (which you can see a little bit when the bypass is open). After an hour and it has burned down to red hot coals, reload it and close the bypass. Then start closing the air intake until it’s basically closed.

He said unless the air intake is basically completely closed, we will be losing almost all the heat out the chimney (which I thought wasn’t happening, which is why we didn’t need a block off plate).

Also, he said to jam it full all the way to the top, or else we won’t get any heat, either. I think that’s the only thing we haven’t done yet, because loading the size pieces we have (16-18”) makes it difficult to load it 100% full due to the firebox size. But we will try cutting them in half and loading n/s tomorrow.

Anyways, just wanted to get other people’s opinions on that? It seems wrong to me that it should take an hour for the stove to get hot enough to be able to close the bypass?

Also, we plan on bringing an infrared thermometer over to measure the actual temps on the insert. Since it’s flush, where should we take the measurement? Or will it not be accurate enough to really matter?

Thanks again!

 

[TradEddie]

Lots to unpack there.

Strictly speaking, there is no "need" for a block-off plate, so the installer isn't lying, but many here have found that it helps a lot. I personally didn't find it made any noticeable difference at all. Few installers seem to want to offer one, I'd imagine there's not much profit for them.
A DIY block-off plate is not difficult or expensive, some sheet metal, self tapping screws and a tin snips is really all you need. I made mine using the "two halves" method, I made a template using a cardboard box first. I think I used some gasket cement too, and I also stuffed the area above with roxul, and the area between the insert and the old fireplace firebox. Lots of advice on this site about block off plates. Not a beginner project, but not difficult.

There's absolutely no reason to leave the bypass open any longer than is needed to get the fire started. Read the manual, the bypass is opened briefly when starting a fire, and and to prevent smoke entering a room when opening the door on a hot stove. With bypass open, you get no heat into the room and no secondary combustion, lots of smoke annoying your neighbors and lots of creosote on your own chimney liner.

Installer is correct, unless the air is almost completely closed, you lose all the heat out the chimney. The heat from the fire heats the air in the firebox, and all that excess hot air goes straight up the chimney to the outside. That's why open fireplaces don't heat well. That's very different to losing heat by conduction through the brick (both are bad). Any air in excess of what's needed to achieve your required burn rate is wasting heat.

Yes, a full load will burn slightly better, and it's not just the extra fuel burning for longer, less air spaces means more efficient consumption of the air, (or something vaguely scientific like that) meaning less air needed, meaning less wasted energy. But if you can't get enough heat however briefly with a smaller load, a full load is not going to solve the problem.

Being able to monitor the stove top temperature is huge and it really simplifies the process, both for troubleshooting and for daily operation, but I don't think there's any way to do it with a flush insert. Perhaps with a precise IR gun, you can find somewhere good. 400F seems to be the magic number for secondary combustion across many makes and models of stoves.

With active secondary combustion, and primary air control almost completely closed, how hot is the air being blown out by the fan on low speed? How close to the vent can you hold your hand? Could that fan be misaligned and not blowing where it's supposed to?

TE

 

[Tiffany and Bartholomew]

Lots to unpack there.

Strictly speaking, there is no "need" for a block-off plate, so the installer isn't lying, but many here have found that it helps a lot. I personally didn't find it made any noticeable difference at all. Few installers seem to want to offer one, I'd imagine there's not much profit for them.
A DIY block-off plate is not difficult or expensive, some sheet metal, self tapping screws and a tin snips is really all you need. I made mine using the "two halves" method, I made a template using a cardboard box first. I think I used some gasket cement too, and I also stuffed the area above with roxul, and the area between the insert and the old fireplace firebox. Lots of advice on this site about block off plates. Not a beginner project, but not difficult.

There's absolutely no reason to leave the bypass open any longer than is needed to get the fire started. Read the manual, the bypass is opened briefly when starting a fire, and and to prevent smoke entering a room when opening the door on a hot stove. With bypass open, you get no heat into the room and no secondary combustion, lots of smoke annoying your neighbors and lots of creosote on your own chimney liner.

Installer is correct, unless the air is almost completely closed, you lose all the heat out the chimney. The heat from the fire heats the air in the firebox, and all that excess hot air goes straight up the chimney to the outside. That's why open fireplaces don't heat well. That's very different to losing heat by conduction through the brick (both are bad). Any air in excess of what's needed to achieve your required burn rate is wasting heat.

Yes, a full load will burn slightly better, and it's not just the extra fuel burning for longer, less air spaces means more efficient consumption of the air, (or something vaguely scientific like that) meaning less air needed, meaning less wasted energy. But if you can't get enough heat however briefly with a smaller load, a full load is not going to solve the problem.

Being able to monitor the stove top temperature is huge and it really simplifies the process, both for troubleshooting and for daily operation, but I don't think there's any way to do it with a flush insert. Perhaps with a precise IR gun, you can find somewhere good. 400F seems to be the magic number for secondary combustion across many makes and models of stoves.

With active secondary combustion, and primary air control almost completely closed, how hot is the air being blown out by the fan on low speed? How close to the vent can you hold your hand? Could that fan be misaligned and not blowing where it's supposed to?

TE

Thank you for your in-depth response!

We will probably forego the block off plate then. I don’t think we’d feel comfortable installing it ourselves, though it doesn’t seem too hard.

We will try to close the air down as much as we can when we try it next then.

As for the temperature of the air being blown out, we would have to measure it. I know when we are sitting directly in front of it (when it’s going well) without the blower on, it will start to sting your face. but once the blower turns on, it is much more bearable. Maybe we can take a look at the fan? Id assume there’s something in the manual about that?

Thanks again!

 

[brenndatomu]

There's no "need" for double/triple pane windows, or insulation for that matter, but it sure helps!

 

[TradEddie]

For reference, on my Lopi Freedom (non-flush insert), with a stovetop of 500F, the air being blown by the fan at lowest speed is about 210F, when the fan is increased to maximum, the air drops to about 170F, as measure d by a thermocouple in mid-air. That's nowhere near the unit's max output but that's a lot of heat. (150CFM heated 100F is 16,000 BTU/hr by my rough calcs)

TE

 

[TradEddie]

I've got a couple of questions related to the install:
What's that switch on the wall? Is this insert in a "heatilator" type fireplace, i.e. are there vents up high and down low on that wall? Those heatilators may improve the efficiency of a fireplace, but on an outside wall, I found that those vents work very well in the opposite direction, they draw warm air in the top vents, that air is cooled by the cold masonry and flows out the bottom vents. If those vents are there, block them, and if there's a fan in there (not the insert fan), never run it.

Can you actually feel air blowing out the top of the insert, not just rising warm air? Is that air flowing faster when the fan is on higher speed?

Can you look to see the bypass plate is sliding closed properly (with cold fire, use a mirror or phone to look up the back of the firebox), there's a circular opening that should be blocked when the bypass is closed, and open maybe 2/3 of a full circle when the bypass is open. While you have the mirror there, are the firebricks on top of the the secondary air tubes all tight together?

Perhaps you're just expecting too much too quick. To heat a truly cold house takes a lot of energy, running a stove as the sole heating source is a 24/7 operation, easier with long-burning dense wood like oak, but not impossible with pine. Get that stone surround heated up and it'll stay warming the room long after the fire is just embers, but let it go "stone" cold and it's just sucking heat out of the room. I know when I've returned early from vacation in Winter it takes many hours for my furnace to bring the house to 70F, and that's blowing warm air into every room.

TE

 

[Tiffany and Bartholomew]

I've got a couple of questions related to the install:
What's that switch on the wall? Is this insert in a "heatilator" type fireplace, i.e. are there vents up high and down low on that wall? Those heatilators may improve the efficiency of a fireplace, but on an outside wall, I found that those vents work very well in the opposite direction, they draw warm air in the top vents, that air is cooled by the cold masonry and flows out the bottom vents. If those vents are there, block them, and if there's a fan in there (not the insert fan), never run it.

Can you actually feel air blowing out the top of the insert, not just rising warm air? Is that air flowing faster when the fan is on higher speed?

Can you look to see the bypass plate is sliding closed properly (with cold fire, use a mirror or phone to look up the back of the firebox), there's a circular opening that should be blocked when the bypass is closed, and open maybe 2/3 of a full circle when the bypass is open. While you have the mirror there, are the firebricks on top of the the secondary air tubes all tight together?

Perhaps you're just expecting too much too quick. To heat a truly cold house takes a lot of energy, running a stove as the sole heating source is a 24/7 operation, easier with long-burning dense wood like oak, but not impossible with pine. Get that stone surround heated up and it'll stay warming the room long after the fire is just embers, but let it go "stone" cold and it's just sucking heat out of the room. I know when I've returned early from vacation in Winter it takes many hours for my furnace to bring the house to 70F, and that's blowing warm air into every room.

TE

Thank you!

No, there are no other vents on the wall. I think that switch turns on the outlet that the insert is plugged into (I think for the blower).

We checked and yes, the bypass opens and closes fine. But we did notice there were 2 fire bricks that are broken. I don’t know if that’s from us using it or how those break? They’re above the tubes so I would assume we didn’t accidentally hit them when loading. I’ve attached picture.

Everything else, we’ll let you know once we get it started.

And that’s my concern is that we are hoping for too much. Her house thermostat is far from the stove, so it will probably take longest to get that to go up. But we’ll use the portable one to measure that specific room again and see now that it’s a colder day.

 

[Tiffany and Bartholomew]

The firebricks on top

 

[Tiffany and Bartholomew]

So it’s in the 30s outside today.

We got the fire started. Closed bypass at about 4 minutes in. Let the kindling burn and get a bed of red hot coals. Then we filled n/s as full as we could get it, literally no more room (see picture - it’s more full than it looks). It was 63.2 degrees inside when we started it. Oak, fully seasoned, checked with moisture meter.

Slowly pulled air intake out nearly all the way (id say about 90% closed). Secondaries looked like a waterfall - very cool!

After about 2 hours, wood was burned through and we needed to reload. By that time, the portable thermometer read 66.2, so about 3 degrees increase.

The blower was on medium. Temperature of the air being blown was about 250 degrees. We could feel it blowing with our hands.

The hottest the metal got (not the door, but the plate against the wall) was about 250, the door handle got to about 300.

The issue we found was once the blower turns on, it literally blows the heat straight up, not out into the room. When we put the portable thermometer on the mantle above the fireplace (see picture), it’s almost 75. So, are we just losing heat straight up? The loft area is only 68.

When the blower is on, I can sit on the chair near the fireplace and not feel any heat. When the blower is off, I start to feel really hot sitting in that same chair. So it seems to be warming the room better when the blower is off.

Is there an issue with the blower, then? The stove is putting off heat, I just don’t really know where it’s all going.

Also, the ledge closest to the glass on the door was about 600.

Thanks!

 

[begreen]

It looks like the stove is definitely burning better, though I might not have reloaded it for another hour or two. The stove is doing the best it can. It's a bit undersized and has no block-off plate or insulation behind it, so a percent of the heat is going outdoors.

It takes a long time and a lot of BTUs to raise the house temp and all of the mass in it up 5º. Going from 60º to 70º or 75º could take a large part of a day because not only the air needs to be heated, but also all the furniture, the walls, floors, etc. And all the while, the house is losing some heat to outdoors, especially through the windows. Once the room temp has stabilized, then less heat is needed to maintain it.

 

[Tiffany and Bartholomew]

It looks like the stove is definitely burning better, though I might not have reloaded it for another hour or two. The stove is doing the best it can. It's a bit undersized and has no block-off plate or insulation behind it, so a percent of the heat is going outdoors.

It takes a long time and a lot of BTUs to raise the house temp and all of the mass in it up 5º. Going from 60º to 70º or 75º could take a large part of a day because not only the air needs to be heated, but also all the furniture, the walls, floors, etc. And all the while, the house is losing some heat to outdoors, especially through the windows. Once the room temp has stabilized, then less heat is needed to maintain it.

Thank you.

This is a picture of what it was when we reloaded it. I guess we were afraid it would cool down too much since there was no more fire.

She is planning on running it all day and even waking up to keep it going throughout the night, just to really test the theory that it needs to be going long enough to heat the whole room good enough.

Should we have waited longer to reload still?

 

[begreen]

Yes, I would have opened up the air a bit and waited maybe an hour. If you want more heat during this wait, put on a couple skinny (2") splits loaded E/W with the air open about 30%.

 

[TradEddie]

Those cracked firebricks might make some difference, if the cracks are so big that heat is going up there instead of around the baffle but probably not much. Can you try move them, so that the crack is closed as much as possible? If that's a new stove, I'd say it's the installer's responsibility to replace, but firebricks are cheap and although frustrating to replace, you could do it yourself. It's like a puzzle the first time, then once you've got it figured out, not so bad. If you do try yourself, take lots of pictures first so you understand how the bricks and the metal supports are supposed to be.

If I reloaded on those hot coals, I'd expect an almost runaway stove, I too would drag all those to the front and open the air fully, get a blast furnace effect (I actually do use those for some crude forging).

That still doesn't look very full to me, there's still lots of space between splits. There's an art to packing in as much as possible, I don't think it affects heat output much, but it certainly affects burn time.

Lastly, aften ten years with my insert, I still can't decide whether it heats better with or without the fan. You're not nescessarily crazy for thinking that, although with a flush insert, it should be better with the fan on. I think with fan off it heats the surrounding brick better to give a longer slower heat.

TE

 

[joewasilla28]

So much great information. Tiffany, I have the large flush lopi wood insert and really love it. We purchased it about 4 years ago, if I remember correctly, and I can say that I finally really know my stove. I remember all the advice I got at the time, from many of the same people that have helped you out, and it helped so much as it was our first experience with one. We have used it virtually exclusively, to heat our house and it does a great job! We're in upstate NY so we burn 24/7 all winter. Like the guys emphasize, good wood is key. We have 13 acres, 7-8 is forest and we cut and split our own. Someone also mentioned that it takes time to really get familiar with everything, and it's true! It's a continual learning experience, even if you seem to have figured a lot out already! Good luck!

 

[KBCraig]

Lopi used to have some good videos on starting and running your stove, but I don't see those on the website now.

From a completely cold stove, I plan on an hour to get the fire started and then settled into burn mode. From a warm stove, 30-45 minutes. When reloading a hot stove, I allow 30 minutes.

I let the blower be my guide. This is my technique with a 25' flue on my Lopi Freedom insert (cooking surface, not flush-mount).

With primary and bypass both open, I load up and start a top/front fire and leave the door cracked about three inches. When it's burning well (probably 10-15 minutes), I push the door in to about a 1" gap.

Another 10-15 minutes to let more wood start burning, then close and latch the door.

Only after the stove gets fully involved and the top surface is hot, do I push in the bypass. How hot the fire is at that point determines how long the next wait is; it can be another 30 minutes, easily.

When the blower kicks on, I pull out the primary all the way, then push it in about a half inch (basically flush with the blower knob). When reburn starts, I pull it out completely, or maybe in 1/8" or so.

Then I ignore it. If it gets too warm in the room (very likely), I turn down the blower speed. After the fire dies down about 80%, I'll open the primary all the way to heat it up for the next load of fuel.