Jotul F3 CB (USA) burning too hot

[Gatesway]

Our F3 is not burning way too hot lately. So, I replaced the gaskets (door, glass & ash pan). All went well. There seems to be an air leak somewhere else (I've tried the $1 bill test, BTW).

The manual states that there is a gasket around or behind the "main air throttle" on the upper right above the door hinges. Not sure how to get to it or change it. The dealer said he never has sold one in 40 years.

Other ideas?

Thanks!

John

 

[jetsam]

Door and ash pan are the big two.

Try running a source of smoke (incense, candle, burning twig) around the door and ash pan to see if the smoke gets sucked into places other than the air intakes.

How long is your flue? Yesterday was real windy on the east coast. Maybe you are a candidate for a key damper.

 

[Gatesway]

Jetsam,

Will do, thanks. I just changed them, but will verify if they are leaking. Have you ever heard of a Air Manifold gasket on the F3? I'll take a pic of the air manifold they are referring to (it is the main air vent control).

Thanks for your help!

 

[Gatesway]

I did as you suggested with incense. The main draw of air as the fire was (is) ramping up was in the back of the stove. I took off the wall protector and behind it was a cover with one screw. I loosened the screw enough to see behind it - and it was the intake that is 75% plugged from the Jotul factory. I've seen this picture before. Air is pouring in there...but not around either the main or ash door.

So, any other ideas?

 

[EbS-P]

If you don’t see any unusual flames in the fire box it could be that. From the parts diagram it looks like that gasket seals between the air distribution plate and the front plate. If this has been a gradually increasing problem it could be that gasket but if it started all at once I’d be looking for other explanations. The dealer not needing one in 40 years I think says something. It did get cold and windy the past two days. Could it just be the extra draft?

Wish I was more helpful.
Evan

 

[begreen]

Is the startup air control fully closed?

 

[Gatesway]

How would you suggest I gain access to that gasket? I'll get the 3/16" LD X 16" required by the owners manual. Do you have any idea what LD means? All of the gasket material for my stove (in the owners manual) is LD.

Thanks for any and all help!

JG

 

[Gatesway]

Yes, Begreen, the startup air is fully closed.

thanks!

 

[begreen]

How would you suggest I gain access to that gasket? I'll get the 3/16" LD X 16" required by the owners manual. Do you have any idea what LD means? All of the gasket material for my stove (in the owners manual) is LD.

Thanks for any and all help!

JG

LD is a low-density gasket. Pull out the ash pan and with a bright flashlight, look to see if there is ash impacted at the back of the ash pan holder. Dig back there with a poker to check. If there is, get it all out. Ash buildup back there can move the pan forward and prevent the ashpan door from sealing tightly.

 

[Gatesway]

Begreen, yes, I’ve learned that years ago. Great catch. But sadly, no, that is not the issue.

Just now, I came back in the LR and the stove is 700 and running like a freight train. I noticed soot/creosote/char in the lower left corner of the glass door (Photo #1) That corner is chipped - but when I‘ve changed the gasket, I felt there was enough glass covering the gasket to be OK. Maybe not!

New glass is on order.

This afternoon when the stove was running away, I used incense to look for air channels getting in the stove. The only one I found was the secondary burn intake in the back. Tonight I took out the “USA Plug” and used gasket sealant to stop any air infiltration around it (leaving the hole next to it open). That made no difference.

My main air control does only go 3/4 of the way closed. So, what about grinding the lever shorter like I‘ve read? I don;t like that much. What about the flue damper idea?

Other thoughts?

Help!

 

[begreen]

The glass does look blackened a bit on the right side bottom too. I wouldn't expect that when burning hot. Maybe the gasket is not sealing well there. If you are ordering new glass, get a new glass gasket too.

A flue damper may make a good difference, how tall is the flue system on the stove?

Has anything changed in the house this year that would affect draft? Has the top been off the stove?

The fire looks good with nice blue flames. Is the wood species different?

 

[Gatesway]

New door glass gasket (3 days) so don’t suspect that too much. Inside is single wall 6” and then transitions at 8’ level to double wall insulated pipe thru the roof (another 8’ or so,.

Nothing else has changed. Top has not been off stove. Fire does look good...but will burn up the wood in an hour. Wood is 3 year old white oak.

Flue damper...I’m hesitant. WOndering what has changed...what is leaking? Also, cleaned chimney this fall. F3’s are a bugger to clean after you’ve swept the chimney. A friend has a Fisher. Now that is a slick clean up!

Thanks! Keep the questions coming!

Oh, what about the gasket behind main air manifold damper?

 

[begreen]

Our stove liked to cruise at 650º+ and that was on NW softwood. 3yr oak is bound to burn hotter. We had a key damper on the stovepipe. This was leftover from the F602 installation prior to the F3CB. I used it at times.

The only thing odd is the blackened glass at the bottom. I'd reexamine how well the glass gasket is placed and sealing at the bottom of the glass. If perfectly placed, it might need a tad more tension on the lower glass clips. If adding tension, do it in small steps, like an 1/8th turn.

 

[Gatesway]

@begreen OK, I have an update!

The air manifold is super loose or feels like metal on metal. I loaded up the stove with wood and sure enough, it took off again with all the dampers closed. I started to mess with the manifold and tried to push it in (it is that sloppy) and the fire continued to roar. Then I took plyers (it was HOT!) and pulled straight out on the manifold selector knob and it sealed the air leak and the fire has died down!

So, I found the leak. It seems I need 16" of 3/16" gasket for around the manifold (per the manual). But, how do I replace the gasket? I have searched and searched for instructions on changing the air manifold gasket and have found nothing.

Ideas?

 

[EbS-P]

Is this the gasket on the air defector?

best pictures I have found are here

Jotul F3CB Air Deflector

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[Gatesway]

Yes, I believe it is on the air deflector (See link below for exploded diagram on page 20.

https://jotul-static-content.s3.amazonaws.com/usa/Current_Manuals/Wood/F3%20CB/139676_R07_Manual_F_3_CB_NA_EPA.pdf