New Lopi F/P Insert--Problems with carbon monoxide and running cool

[caaron]

I purchased a new Lopi Declaration wood-burning fireplace insert and had it installed by a competent company. I have a 28' chimney with a 6" SS liner that is insulated and connected directly to the stove by screws and also insulated and sealed.

The first problem I have is that the stove rarely goes over 200-250 degrees, even with very dry wood. I've been burning oak and osage orange with a moisture content between 6 & 12% as measured by a moisture meter. I have good draft and no problem sustaining a fire but it just levels out at 200 degrees even with the fan off. I've tried it with the window open and closed (I have a pretty tight house but there seems to be adequate draft with the windows closed and the bypass damper closed).

The second problem I have is that when it is hot enough to close the draft control down to encourage secondary burning the carbon monoxide detector goes off. This only happens when the air control is pulled out to reduce the amount of air going into the unit. I can see the secondary combustion flames (which I want) but then I get the CO alarm so I can't use it this way.

I've had the installation reinspected and there are no obvious problems. The chimney flue is clean and clear, the connection to the stove is tight and clear. I'm wondering how the CO can get from the stove into the room with the doors shut and the unit sealed, and it seems as if it is coming through the vent with the hot air being blown into the room.

Any ideas or suggestions?

 

[UNCLEBEEF]

caaron, you say this is a new install, did you get the insert hot enough to cure the paint? i am the proud new owner of a lopi endeavor and i know when i had my first five or six fires the stove was giving off pretty heavy paint fumes. i started curing the paint on a warm day so i could leave the windows open. does your insert have a cold air intake? if not i would be concerned that you may pull exhaust from either a water heater or standing pilot furnace vent stack and cause a negative pressure in your home. this is very dangerousif this happens.

 

[daveswoodhauler]

Take us through your start up typically....and include when you start shutting the air down.
With my stove, it makes a huge difference to make sure you start with decent kindling....i.e kindling/newspaper...then very "small" splits....get it burning good, and then throw on bigger splits.
If you are using a super cedar, or something similar, you still need to use kindling and small splits.....i.e. dont stick a firestarter in the stove along with 4 6" splits and expect it to take off.
Maybe post a pic of what you are starting the fire with.....we'll get you on the right track.

Edit, its also odd that you are seeing secondaries with only a 200 stove temp.

 

[flyingpig]

Welcome to the forum

We don't have that many Declaration owners here so I'm glad you join the gang. I've got mine installed about a year ago and it's been working wonderfully. I have pretty much the same set up as your, 28 ft. external chimney with uninsulated SS liner, relatively mild mid-Atlantic weather (or a tad warmer..), and half way dry oak. From my trial & error in the past year, I need to leave the door crack open (with the bypass open) for about 10~15 min in order to generate enough draft. The thermometer right in the middle of the door will start to climb up over 150F at that time when I shut the door & bypass. Then it will normally climb up to around 450F if I use only 2-3 large logs, or it can go over 600F if I have more logs in there. I'll need at least 4 medium logs at start in order to generate enough heat. Otherwise it won't take off. Once it hits 500 or 550, I can pull out the primary air control almost all the way out in one step ... may be a little adjustment in a range of 3/4 inch to sustain the secondary burn.

I have couple of video clips on Youtube. Go search for the Lopi Declaration and you can see how strong is the fire when it gets going.

Let us know a bit more about your situation. Where do you measure the temp? How tight is your home insulation? Will you have a good fire if you continue to crack the door open? What is the position of the two rods when you start? Also, do you have the chimney blocking plate installed?



Cheers......Som

 

[caaron]

Thank you for all of the responses.

I did run the insert hot enough to burn off the paint smell when I first got it--windows open and it got up to 400 degrees that time with the bypass open.

I typically start a fire with newspaper and dry fire starters and 3 or 4 small dry logs that I've split down to about 3x2" by 16" and I start with the bypass open (upper control pulled out all the way) and air control closed (bottom control pushed all the way in). I'll leave the door cracked open for about 3-5 minutes and usually get a very hot fire very quickly and can then add 2 or 3 larger logs (about 6"x4"x16") and close the door and the fire will be strong. After another 5 minutes I can close the bypass (upper control pushed all the way in) and the fire will sustain itself and burn very well with no problems. It usually will continue to burn fine and I'll add logs as needed and the fan usually kicks on at about 175 degrees.

The insert does not have a blocking plate since it is connected directly to the SS flue liner with screws and 'flue goo' (high temperature sealant used by chimney sweeps). The liner is also insulated.

I don't have a cold air intake, and I assume that the fresh air that fuels the stove comes in from the room into the upper part of the face plate (where the hot air also comes out from the blower).

As far as negative pressure is concerned, it is a possibility since my house is very tight. But where the furnace and water heater are (in the basement) there is a fresh air intake with a damper that opens to let fresh air into that area if there is any pressure draw (like from our whole-house attic fan in spring, summer and fall). The room where the insert is is about 15x20' with two windows and a door. It also has a return vent to the furnace so that heat produced can be recirculated. The only time I get a CO alarm is when I pull out the lower control after the fire is hot to get secondary combustion while I'm running the blower on the insert. The CO detector is about 6-7' away from the insert. When I pull out the lower control to induce secondary combustion I can see the reduction in the flames from the logs and blue and yellow flames coming out of the tubes at the top of the insert, but the temperature seems to remain constant--from 200-250 degrees. That is usually when the alarm will go off. I can burn fires with the damper closed and the air control off as long as I want without kicking off the CO alarm, but again I only get about 200 degrees and have no secondary combustion.

I check the temperature with a magnetic thermometer on the face of the stove near the upper vents. I also have a laser thermometer and they are both consistently the same temperature so I'm pretty sure they're both accurate.

I can take pictures of the fire and attach them if you think they'd be helpful...

 

[daveswoodhauler]

Well, I'm stumped...was going to suggest that you might have a bad thermo, but if you have IR too and it reads the same.
Question, what is the max your IR gun will go to? (Thinking to open the firebox and take a reading when you have secondaries)
Hopefully someone else with the same stove will chime in.

 

[caaron]

The thermometer goes up to 600 degrees...

 

[flyingpig]

I believe the temp at the air outlet is lower. I bet you'll get higher reading if you move the thermometer to be on the door itself (I use middle bar). My fan doesn't kick in until at least 350F so I guess it's just the location of the thermo rather than burning issue.

The blocking plate will help create an air insulation layer around the flu. It also helps prevent cold air from outside to drop down on the stove and get into the house (and heat loss from the room going up). So the insert may create enough draft with the insulated SS liner, but you'll probably get your room warmer with blocking plate.

I still can't figure out the CO detector problem. Thinking of the flu as a tube sucking air out from the room, when you close down the primary air, the secondary air will need to suck the air from the room more into the stove because that's the only air inlet available at that time. Your room may have a bit less negative pressure since the secondary air inlet is very restricted. But that shouldn't cause the room to draw more CO from outside.....

Somehow I feel that it's the combusted air from the flu flows back down the chimney and get into the room b/c we don't have blocking plate. But I don't have any theory to support this. Try crack open windows and see if it still happens, or move the CO detector to other location with the same distance...

Cheers.....Som

 

[Shari]

Regarding the CO issue:

Do you have a separate heating appliance like a forced air system (gas or oil)? If yes, is there a roof exit chimney for that appliance? If yes, is your appliance flue and wood insert flue the same height? If yes, could it be you are experiencing a back-draft down your appliance chimney when running your insert?

 

[caaron]

[quote author="flyingpig" date="1296189027"]I believe the temp at the air outlet is lower. I bet you'll get higher reading if you move the thermometer to be on the door itself (I use middle bar). My fan doesn't kick in until at least 350F so I guess it's just the location of the thermo rather than burning issue.

I checked tonight and the blower kicks on at 135 degrees. If I put the thermometer on the door I get a reading that is about 25 degrees hotter.

The blocking plate will help create an air insulation layer around the flu. It also helps prevent cold air from outside to drop down on the stove and get into the house (and heat loss from the room going up). So the insert may create enough draft with the insulated SS liner, but you'll probably get your room warmer with blocking plate.

The flue is insulated around the liner and there doesn't seem to be any heat loss from the room--it is usually too hot even though I'm only burning at 200 degrees so most often the blower is on very low speed...

 

[caaron]

Regarding the CO issue:

Do you have a separate heating appliance like a forced air system (gas or oil)? If yes, is there a roof exit chimney for that appliance? If yes, is your appliance flue and wood insert flue the same height? If yes, could it be you are experiencing a back-draft down your appliance chimney when running your insert?

We do have a gas furnace and hot water heater and they have a separate chimney next to the one for the fireplace but are at the same height. But my CO reading only happens when I close the air damper down to get secondary combustion and not when I have a fire going with or without the bypass closed. It seems to me that if it were a backdraft down the chimney from the gas appliances it would happen anytime I had a fire going. And I have a CO detector next to the furnace and hot water heater and it never goes off...

 

[Shari]

We do have a gas furnace and hot water heater and they have a separate chimney next to the one for the fireplace but are at the same height. But my CO reading only happens when I close the air damper down to get secondary combustion and not when I have a fire going with or without the bypass closed. It seems to me that if it were a backdraft down the chimney from the gas appliances it would happen anytime I had a fire going. And I have a CO detector next to the furnace and hot water heater and it never goes off...

Okay.... scratch that idea then......

 

[caaron]

I'm still stumped as to why I can't get a hotter stove. The fire burns well and there are lots of red hot coals but I rarely get it to go over 225 degrees. It still kicks plenty of heat into the room, even without secondary combustion but it seems odd I can't get it to burn hotter...

 

[rdust]

I've been burning oak and osage orange with a moisture content between 6 & 12% as measured by a moisture meter.

Tell us more about the wood. When was the wood cut/split/stacked?

I find it hard to believe you have wood that is in the 6-12% range. Was this checked on a fresh face after splitting it? Wood dried in a kiln is usually 10% and will rise once it sits in a normal environment again. Last year I had some elm from a tree my old man cut over 20 years ago, the wood was stacked in his elevated/covered wood rack for that time. When I check a piece it was 14%, that's about the best any wood dried naturally in this climate is going to do, wood will find it's EMC.(equilibrium moisture content)

 

[ronski]

i also have a lopi declaration.for some reason after an overnite burn my co detector goes off.i leave it stocked and let it max burn.in the morning the alarm goes off and i move coals around add wood and it starts back up and the alarm stops.after talking to my installer he says its a cold flu but when i restart up the fire i dont need any paper i seem to disagree.i am also having trouble with excessive wood coals in fireplace wich he attributes to green wood,it seems like my firebox can fill up with all this unburnt coals.i am new to wood inserts and not sure if i am doing something wrong or if there could be a error in installation.my stove is using about a 15' 6" flu in an existing chimney.the installer also used a 45` to make stove fit right.any suggestions wood be greatly appreciated.

 

[rdust]

i also have a lopi declaration.for some reason after an overnite burn my co detector goes off.i leave it stocked and let it max burn.in the morning the alarm goes off and i move coals around add wood and it starts back up and the alarm stops.after talking to my installer he says its a cold flu but when i restart up the fire i dont need any paper i seem to disagree.i am also having trouble with excessive wood coals in fireplace wich he attributes to green wood,it seems like my firebox can fill up with all this unburnt coals.i am new to wood inserts and not sure if i am doing something wrong or if there could be a error in installation.my stove is using about a 15' 6" flu in an existing chimney.the installer also used a 45` to make stove fit right.any suggestions wood be greatly appreciated.

You may want to start a thread of your own so it gets more notice. With that said 15' straight up is about bare minimum with these new stoves so that could be contributing along with less than perfect wood.

 

[caaron]

I'm a woodworker and woodturner so I know about wet and dry wood and use a moisture meter a lot. Most of my wood was split and down for 1-2 years. A lot of it is gray but solid and when I check with the moisture meter probes most of it comes out between 12% and 14%. I hand picked the most dry wood, which was between 8% & 12% along with some very dry scraps from woodturning, which were completely dry at 6% (stored indoors for 2 years). Most of it was oak, cherry, and osage orange, which all burn well.

I've been burning oak and osage orange with a moisture content between 6 & 12% as measured by a moisture meter.

Tell us more about the wood. When was the wood cut/split/stacked?

I find it hard to believe you have wood that is in the 6-12% range. Was this checked on a fresh face after splitting it? Wood dried in a kiln is usually 10% and will rise once it sits in a normal environment again. Last year I had some elm from a tree my old man cut over 20 years ago, the wood was stacked in his elevated/covered wood rack for that time. When I check a piece it was 14%, that's about the best any wood dried naturally in this climate is going to do, wood will find it's EMC.(equilibrium moisture content)

 

[begreen]

What is this flue goo stuff? If it's high-temp silicone, that might be what is setting off the detectors. Furnace cement is ok on a flue pipe, silicone is not.

When you are checking moisture, are you re-splitting the wood and checking on the freshly exposed surface of the wood or is it just be checked on the ends?

 

[caaron]

The flue goo stuff is a high temperature compound that the chimney sweep uses--I think it is mortar-based.

I'm checking the moisture at several places on the log (not on the ends) but on the sides where they were split.

 

[begreen]

Try resplitting a few pieces and retesting. You are burning excellent firewood, but they are particularly dense woods that dry slowly in the core.

 

[caaron]

Good suggestion. When I rechecked some of the larger oak logs 10-12" wide by 18" long they read 8-12%, but after I split them on the bandsaw they read 14-18% at the very center. Still dry enough to burn but not as dry in the core as they were near the surface. Now I also have some 'manufactured" wood bricks which are wood shavings that are highly compressed without any glue, binders or additives. They burn pretty hot and are very dry but still the insert won't get higher than 250 degrees...

I'm still stumped...

Try resplitting a few pieces and retesting. You are burning excellent firewood, but they are particularly dense woods that dry slowly in the core.