Jotul F 500 firebox seal and overfire problem

[DaveA]

I have an 11 yr old Jotul 500 that has always been difficult to control from over-fire. I installed a flue damper last year (some say not supposed to do that), and that helped a lot. This year when cleaning the chimney I noticed that the cement between the baffle plate and the back of the fire box was brittle and breaking off. Now when I have a hot fire, I occasionally get a whiff of smoke.
1. Could this breaking off cement be part of that problem?
2. What recommendations do others have regarding the brand of cement to use to seal that up?
3. Any recommendations to stop the over-fire problem?

 

[bholler]

I have an 11 yr old Jotul 500 that has always been difficult to control from over-fire. I installed a flue damper last year (some say not supposed to do that), and that helped a lot. This year when cleaning the chimney I noticed that the cement between the baffle plate and the back of the fire box was brittle and breaking off. Now when I have a hot fire, I occasionally get a whiff of smoke.
1. Could this breaking off cement be part of that problem?
2. What recommendations do others have regarding the brand of cement to use to seal that up?
3. Any recommendations to stop the over-fire problem?

Some pics would help. How tall is the chimney? Has anyone ever measured the draft?

 

[xman23]

Have you looked at the ash door gasket? I had to go to the next size diameter gasket to seal it well. As well as all the other gasket condition. You've been opening the dog house and keeping the slide lubed and closing properly?

So from new it's been touchy about controlling. I don't see anyone here having that problem. Mine almost gets that way at 700 degrees, I have to close the air all the way to get it slowed down.

 

[Simonkenton]

I have that same stove and I love it! As bholler said, how high is the pipe? Are there any bends in the pipe?

 

[DaveA]

The stove is in the basement, the chimney is interior until it goes through the roof of our bungalow. The chimney is straight with no bends. No I have not measured the draft, although it seems to have more than enough, as the only way to slow down the burn is to close off the chimney damper (I incorrectly called it a flue damper in my original message.) I think that the ash pan door has a good seal. Not sure what to use to lube the intake slide, I just cleaned it last year, and it slides back and forth without any issues and it looked closed when I operated it while open for cleaning.

 

[DaveA]

Some pics would help. How tall is the chimney? Has anyone ever measured the draft?

What do you want to see in the pics?

 

[bholler]

What do you want to see in the pics?

The area you are asking about. The whole setup. Anything that could give us info to help you.

 

[bholler]

The stove is in the basement, the chimney is interior until it goes through the roof of our bungalow. The chimney is straight with no bends. No I have not measured the draft, although it seems to have more than enough, as the only way to slow down the burn is to close off the chimney damper (I incorrectly called it a flue damper in my original message.) I think that the ash pan door has a good seal. Not sure what to use to lube the intake slide, I just cleaned it last year, and it slides back and forth without any issues and it looked closed when I operated it while open for cleaning.

Yes of course you have enough draft. You probably have too much draft which is why it is hard to control. What temperatures are you typically seeing on the pipe and stove? What temp do you start shutting back at?

 

[Simonkenton]

bholler and I are asking, how many feet high is the pipe? A very important question. Get a tape measure and find the answer bitte schon.

 

[RSNovi]

I owned a F500 V1 at my old house. The stove was in the basement with >32' of chimney. It was very easy to over fire if I left unattended with the air wide open.

At my new house with a F500 V2, I have about 20' of chimney. The stove seems not want to over fire like my old one. I think it still could, but not so quickly.

Chris

 

[DaveA]

The area you are asking about. The whole setup. Anything that could give us info to help you.

bholler and I are asking, how many feet high is the pipe? A very important question. Get a tape measure and find the answer bitte schon.

21 feet of chimney (including 5' stove pipe). Straight run.

The area you are asking about. The whole setup. Anything that could give us info to help you.

 

[DaveA]

Yes of course you have enough draft. You probably have to much draft which is why it is hard to control. What temperatures are you typically seeing on the pipe and stove? What temp do you start shutting back at?

I don't have a stove pipe thermometer. Stove top holds at 500 plus with the air intake closed completely. To bring under 500 I need to close the stove pipe damper. I typically start to close the air intake at about 300-400 so it doesn't get away on me.

 

[bholler]

View attachment 265285View attachment 265287

21 feet of chimney (including 5' stove pipe). Straight run.

Just some furnace cement in that area will take care of it. 21' is not really excessive. I am sure you are a bit over draft spec but it shouldn't be to bad.

 

[bholler]

I don't have a stove pipe thermometer. Stove top holds at 500 plus with the air intake closed completely. To bring under 500 I need to close the stove pipe damper. I typically start to close the air intake at about 300-400 so it doesn't get away on me.

500 is not an over fire at all. But get a pipe thermometer. It will respond faster than the cast top will giving you better control

 

[begreen]

Clean off the area and get some stove and furnace cement in the gap. With the next fire, try closing down the air sooner. The mass of the cast iron is slow to react. Try closing down the air 50% soon after the wood is fully aflame, regardless of stovetop temp. Take the air down until the flames become less vigorous and lazier, but not out. Wait ~5 min for the fire to regain strength and close it down again, maybe all the way this time or until the flames get lazier. Secondary combustion should be kicking in at this point. The stovetop temp may only be 200-250º at this point. That's ok, it will continue to climb.

 

[DaveA]

500 is not an over fire at all. But get a pipe thermometer. It will respond faster than the cast top will giving you better control

The stove pipe is double walled, so I'm not sure how accurate the pipe thermometer will be. I know that 500 is not too hot, but at this time of year, 500 cooks me out of the house. Thanks for all your help.

 

[bholler]

The stove pipe is double walled, so I'm not sure how accurate the pipe thermometer will be. I know that 500 is not too hot, but at this time of year, 500 cooks me out of the house. Thanks for all your help.

A probe thermometer designed for double wall pipe will be pretty accurate. I was assuming by the fact you said it was hard to keep from over firing that you thought 500 which you can maintain was to hot

 

[begreen]

The stove pipe is double walled, so I'm not sure how accurate the pipe thermometer will be. I know that 500 is not too hot, but at this time of year, 500 cooks me out of the house. Thanks for all your help.

A probe thermometer is used on double-wall stove pipe. See my starting a stove thread in the sticky section at the top of the forum.

 

[old greybeard]

I have a heavy draft and run a damper on my double wall pipe as well. The combination of the probe in the pipe and the stovetop works great. I usually close my damper early, pipe temps really take off other otherwise. When the pipe starts into the run zone the stove top is still very cool. I close the damper 1/2. Then close the damper fully when the stovetop starts into the nice run zone. Usually end up both thermometers balanced pretty even with damper shut, air closed or almost closed. Then keep the damper closed as you open air to increase burn or reduce coals.

 

[DaveA]

Thankyou everyone for the valuable advice. Been burning wood on/off for 30 years, and still learning.

 

[firefighterjake]

View attachment 265285View attachment 265287

21 feet of chimney (including 5' stove pipe). Straight run.



View attachment 265288

Is that where the baffle board meets up with the stove? It is a bit hard for me to see when blown up . . . if so I believe I once read that Jotul ships the baffle board cemented to the back of the stove to keep the board from shifting/moving/breaking during shipment and it may not be all that critical. That said, I have found some furnace cement easy enough and cheap enough to apply to keep things looking as they did originally.