Fisher insert

[Young burner]

Hello all ,

I moved into a house last year with a fisher insert not sure the year. I used the wood stove last year and had trouble keeping the stove regulated temperature wise . The stove top temps would run around 400 to 800. I had a couple times it went up to 900 with the air intake completely shut. The stove has a 8 inch chimney liner connected to it. I can’t put anymore than a piece of wood or two max without it getting to hot . Is this normal for these stoves ? Any info would be greatly appreciated.

Here are pictures of the stove that I have if that helps at all.



I was also wondering if a smoke baffle plate would help my situation especially with burning so much wood !

 

[coaly]

Does the Insert have the factory damper at outlet? There should be a lever or chain control through slot at right of Insert through fireplace faceplate, I can’t see it in pics.

Yes, a baffle moderates temperature spikes and is the best and easiest modification you can do.

Everything points to an air leak into firebox. You should be able to control the fire closing air intakes down to a glow with little to no flame depriving fire of oxygen. (Not a good burning practice)

Wire wheel the back side of doors at sealing area. This is the raised area and grooves along side of it. (You can remove doors easily to wire wheel with drill outside to prevent dust in the home) Also scrape and wire wheel the door seal clean. This is the channel iron welded to stove front. This will make a 3 point seal all the way around door. The raised area on doors will contact the center web of channel iron, and the edges of channel iron need to make contact on back of door.

Light stove, and using a match shaken out to create smoke, or incense stick, go around the door seal area to see if the smoke rushes into the door seal. If so, flat gasket material made for installation of glass can be cemented flat in the door seal channel. You can test fit for gasket using a strip of cardboard in door seal first to make sure you have clearance between door and seal for gasket to allow doors to latch properly. Worn hinges plates, door hinge pins, or improperly welded hinge plates all contribute to air leaking around door seal. The latching handle angle looks correct, so it’s not door latch adjustment.

 

[Young burner]

Thank you. I used a lighter and it sucks the flame in around the doors. I can hear air sucking in through the doors slightly when it’s really quiet. I wire wheeled the doors and channel last year with no luck. The stove does have the factory damper installed with a chain on the side . I can control it pretty well when I close it down pretty good. It’s a very temperamental stove but I do not want to go through the hassle of a new stove. I’m used to outdoor wood boilers so I like to burn whatever I want with out epa stuff stopping me. And the stove puts out tremendous amounts of heat. I just want to get It Safer for the house and family. I was also wondering if I install a baffle plate should I let it drop the whole way in the back against the channel for the fire brick or keep it raised up Some ? And how long can I make it or just stop somewhere a little past the exhaust outlet ? Thank you in advance for any answers or advice.

 

[coaly]

Flat gasket in the seal channel will make it perform like a different stove.

The depth of baffle plate depends on chimney.

It is safe to make it half the depth, or longer getting close to the front with higher chimneys. You can keep it flat, or tilted upward at front. Just make sure the path the smoke goes through is at least the same square inch opening as flue square inch diameter. 8 inch is 50.24 square inches. Newer stoves have baffles that come up a couple inches from the door. This makes the firebox design an S flow instead of original which is a diagonal flow.

 

[Young burner]

Good afternoon everyone ,
I’m burning my fisher insert and I installed the baffle plate . I also installed a thin gasket on my doors to seal them up better and it does work like a new stove. My only problem is the doors on the inside seem to get build up with thick tar creosote. I’m having to choke the stove down on the air intakes to 1/2 turn or less during burn cycle because I am getting stove top temps over 600 degrees at times. Is this normal ? I’m also closing the flu damper to about half close to 3/4 closed .

 

[Young burner]

To add to my last post . The wood I’m burning is ash. The trees have been dead on my property for a long time and I cut them down and stacked it over 8 months ago . I checked some of the wood by resplitting it and most of it is 16 to 20 percent. I’m sure some of it is over because I have some that water drained out ends when I put it in stove .

 

[coaly]

Everything sounds normal except the deposits on doors and that much water in Ash.

How large is the baffle plate? From rear, how far forward does it extend? Is it flat? How far from stove top, or what is the opening height above it?

Ash is a naturally dryer wood. Standing dead is ready after splitting and stacking within months, tops are dryer and ready anytime. So it must be getting wet to see any sign of moisture coming out the ends??

That is a normal stove top temperature. The front gets hotter with baffle which is good. The surface temperature will be about 1/2 the inner temp which is right for a clean burn. Do you have a blower extracting heat from the rear of it?

 

[Young burner]

Everything sounds normal except the deposits on doors and that much water in Ash.

How large is the baffle plate? From rear, how far forward does it extend? Is it flat? How far from stove top, or what is the opening height above it?

Ash is a naturally dryer wood. Standing dead is ready after splitting and stacking within months, tops are dryer and ready anytime. So it must be getting wet to see any sign of moisture coming out the ends??

That is a normal stove top temperature. The front gets hotter with baffle which is good. The surface temperature will be about 1/2 the inner temp which is right for a clean burn. Do you have a blower extracting heat from the rear of it?

I keep my wood stacked off the ground and the top covered with a tarp but I did notice more moisture content than normal for ash . A lot of it is really punky. My baffle that I installed is 19 inches long and I angled it up to about a 3 inch opening from top of stove . I can shut my flu damper and still open the doors and no smoke in my house at all. Is it still ok to close the flu damper with the baffle plate installed . I noticed I have a very strong draft with my chimney it’s 35 feet high and straight up . The liner is also insulated.

 

[Young burner]

I don’t have a blower I use a small fan aimed at the bottom port of the stove and shield the air so it doesn’t blow into the air intakes. I’m still in the process of fabricating a blower design for it like I’ve seen in some of your posts coaly.

 

[coaly]

Yeah, Ash will be so dry at the top of standing dead, it is already dry. The bottom needs drying, and the longer it stands dead, the softer the bottom gets which gets punky absorbing water like a sponge. I bring those in and stack near stove for final drying until they are extremely light and dry.

Can’t explain the deposits on doors, other than cooling them below condensing point, but I would raise the front of baffle to the minimum outlet square inch opening to match chimney square inch diameter.

Deposits are from water vapor condensing on a cooler surface. This allows smoke particles to stick. The water vapor is from burning the hydrogen in the fuel, not necessarily from the moisture content in the wood. Oven dry wood contains 6% hydrogen. The molecular ratio of hydrogen to water is 9. So burning the hydrogen creates .54 pounds of water for every pound of fuel burned. 25% moisture content adds another 1/4 pound of water to every pound of fuel. The condensing point is 250°F, so below that critical temperature, water vapor condenses allowing smoke particles to stick.

Smoke particles and water forms pyroligneous acid. Primarily wood alcohol and acetic acid. In liquid form this is harmless. When allowed to bake on the surface, this becomes the various stages of creosote. If the fan is blowing cool air on the doors this could reduce the temperature below the condensing point causing the formation. Blowing into the bottom slot under the firebox will remove the hot air from around the back, moving it forward out of the upper slot. This also removes the heat from the hottest area of the stove around the outlet. The baffle is designed to reduce that hot area at the exhaust, moving it forward to the stove top.

 

[Young burner]

Yeah, Ash will be so dry at the top of standing dead, it is already dry. The bottom needs drying, and the longer it stands dead, the softer the bottom gets which gets punky absorbing water like a sponge. I bring those in and stack near stove for final drying until they are extremely light and dry.

Can’t explain the deposits on doors, other than cooling them below condensing point, but I would raise the front of baffle to the minimum outlet square inch opening to match chimney square inch diameter.

Deposits are from water vapor condensing on a cooler surface. This allows smoke particles to stick. The water vapor is from burning the hydrogen in the fuel, not necessarily from the moisture content in the wood. Oven dry wood contains 6% hydrogen. The molecular ratio of hydrogen to water is 9. So burning the hydrogen creates .54 pounds of water for every pound of fuel burned. 25% moisture content adds another 1/4 pound of water to every pound of fuel. The condensing point is 250°F, so below that critical temperature, water vapor condenses allowing smoke particles to stick.

Smoke particles and water forms pyroligenious acid. Primarily wood alcohol and acetic acid. In liquid form this is harmless. When allowed to bake on the surface, this becomes the various stages of creosote. If the fan is blowing cool air on the doors this could reduce the temperature below the condensing point causing the formation. Blowing into the bottom slot under the firebox will remove the hot air from around the back, moving it forward out of the upper slot. This also removes the heat from the hottest area of the stove around the outlet. The baffle is designed to reduce that hot area at the exhaust, moving it forward to the stove top.

Next time I have the stove going I need to take my ir temp gun and see what the temp of the doors are . I’m just afraid of getting the stove too hot . If I don’t pay attention to it it will get up to 700 degrees very easily . I can control it but anymore than 1/2 turn on each air intake and it will go well above 700 during the burn cycle. So you saying I should adjust the baffle so the front is about 1.5 inch to 2.5 inch from stove top ? I noticed the stove smoking a lot yesterday while burning I’m not sure why. Stove top was about 500 all day. I’m just trying to figure this stove out especially just installing the baffle . So any advice is greatly appreciated.

 

[Young burner]

Here are some pictures . The deposits are as bad I did a hot burn at the end of the night and cleared some of it up .

 

[Young burner]

It gets really thick on the bottom door frame on the stove while burning

 

[coaly]

Yes, I would raise the plate at front. Start with the minimum opening matching the chimney flue square inch. I think your Insert is 21 wide outside, so 20.5 inside would be about 2 1/2 opening. Not much difference, but you’re doing it to change the angle to allow faster flow rising upward in the firebox, possibly scavenging the smoke away from doors more. Every venting system is different, so you can only try, keeping track of the burn characteristics with changes. The areas you see any formation is where there is stagnation, or little movement or turbulence of the flow, usually in corners.

How far from the doors are the log ends? I would try a few things and not be too concerned about it. As a coating of soot can build up, keep it scraped off occasionally since it has a high insulating value.

Surface temperature will be about 1/2 the internal temperature. 1100f is considered the lowest for a clean burn, so 6-700 is normal, 800 is getting hot, but nothing to worry about. Burning all Ash will be a faster and hotter burn too. Try a mix, if you have it, and run with air just cracked to 1 fin open.

Running a blower that pushes air out the vent across top will cool the top as well.

There are lots of variables like fuel, outdoor temperature, atmospheric pressure…. So some cold days with high pressure it will burn much better than a warmer day, or when a low pressure area moves over slowing it down considerably.

 

[vt-new-fp]

Flat gasket in the seal channel will make it perform like a different stove.

The depth of baffle plate depends on chimney.

It is safe to make it half the depth, or longer getting close to the front with higher chimneys. You can keep it flat, or tilted upward at front. Just make sure the path the smoke goes through is at least the same square inch opening as flue square inch diameter. 8 inch is 50.24 square inches. Newer stoves have baffles that come up a couple inches from the door. This makes the firebox design an S flow instead of original which is a diagonal flow.

Coaly, could you give more info on the flat gasket. I have the same stove and the same issues. I've been looking at Tractor Supply and on Amazon for gaskets and there are a million different types to choose from - fiberglass, metal mesh, etc, etc - what kind and size would work here? Thanks!

 

[Young burner]

Coaly, could you give more info on the flat gasket. I have the same stove and the same issues. I've been looking at Tractor Supply and on Amazon for gaskets and there are a million different types to choose from - fiberglass, metal mesh, etc, etc - what kind and size would work here? Thanks!

Flat Gasket Tape for Stoves and Fireplaces, Self Adhesive Flat Gasket, 5/8"x1/8" Length 72" Wood Stove Flat Gasket Tape https://a.co/d/9fLj5Ov

This is the link on Amazon that I got mine from and it work really well . One roll did the trick but I ordered 2 for a replacement .

 

[vt-new-fp]

Awesome, thank you!

 

[Young burner]

Good afternoon,

I’m back this year again with some question that I hope coaly can help with. My stove seems to be burning great. I get the stove top temp up to 700 to 750 on the hottest part of the stove which is where the baffle ends inside. The farther toward the front you get it drops to around 650. My question is I seem to be going through a lot of wood. I close the flu damper to about 3/4 closed and it seems to burn a lot longer. My main concern is flu temps. With this inserts it’s almost impossible to check the temps even if you take the top surround off. It looks to be an insulated flu liner. I just cleaned the flu after burning about a total of 2 weeks burning off and on. And I got a decent amount of power/ creosote toward the top which somewhat normal. Am I burning the stove hot enough I close the air intake down to a little over a half turn and it seems to stay around 700 to 750 and when it start to drop and only coals I open the air intakes to almost 1 turn then when the stove drops to around 500 or so I load it back up. And I doing something wrong or is this normal operation ? . Any feedback would be greatly appreciated

 

[Young burner]

I’m afraid to get it to hot and I’m afraid to run it to cold. What are normal temps especially on the stove top. I read your previous comments to me about temps but it seems like it needs to burn hotter with the flu having stuff in it. I checked my wood and it’s mostly all ash and alittle bit of cherry all reading 15 to 16 percent moisture. Once I close the stove down to keep temps at 700 to 750 the stove smokes a lot of white out the chimney but I don’t wanna get the stove hotter and my wood is dry. Is it normal for all these older stoves to smoke decent ?

 

[bholler]

Good afternoon,

I’m back this year again with some question that I hope coaly can help with. My stove seems to be burning great. I get the stove top temp up to 700 to 750 on the hottest part of the stove which is where the baffle ends inside. The farther toward the front you get it drops to around 650. My question is I seem to be going through a lot of wood. I close the flu damper to about 3/4 closed and it seems to burn a lot longer. My main concern is flu temps. With this inserts it’s almost impossible to check the temps even if you take the top surround off. It looks to be an insulated flu liner. I just cleaned the flu after burning about a total of 2 weeks burning off and on. And I got a decent amount of power/ creosote toward the top which somewhat normal. Am I burning the stove hot enough I close the air intake down to a little over a half turn and it seems to stay around 700 to 750 and when it start to drop and only coals I open the air intakes to almost 1 turn then when the stove drops to around 500 or so I load it back up. And I doing something wrong or is this normal operation ? . Any feedback would be greatly appreciated

They do go through allot of wood. Even with a good baffle they are really inefficient

 

[Young burner]

They do go through allot of wood. Even with a good baffle they are really inefficient

I see this. It puts out so much heat and my wood is free but I just wanna burn the stove correctly. Like I said I’m afraid of burning to cold and or to hot. What are normal temps to keep the stove at ? These inserts are impossible to check flu temps all the time.

 

[bholler]

I see this. It puts out so much heat and my wood is free but I just wanna burn the stove correctly. Like I said I’m afraid of burning to cold and or to hot. What are normal temps to keep the stove at ? These inserts are impossible to check flu temps all the time.

Get an auber remote flue thermometer if you want to know flue temps. But if your getting black crusty stuff at the top you can't really go much lower at all. Is the liner insulated?

 

[Young burner]

From looking at the liner when I remove the surround it has insulation around it. I’m checking stove temps at the point of where the baffle ends in the stove which will be the hottest part. Should I not go by that temp because it seems the stove is 100 more degrees lower everywhere else.

 

[Young burner]

My chimney liner is around 30 feet or more high. The stove is in the basement if that helps at all