LEAKS---HELP--JOTUL MODEL SERIES 8

[MikeS]

jotul model series 8 leaks and smells like smoke.

I have "strong light" tested
re-cemented the top corners (remove old, pack in new)
replaced gaskets for flue outlet, both of them--the flat and the round ones.
High Temp RTV around pipe adapter (it was already a tight fit)
new top gasket
new top gasket for the round hole in top (from previous models that could have top-flue--mine has a plate)

the only way to detect leaks for me is nose--the top-back-center smells slightly smokey.

Is there a better way to find leaks?

is there a secret to gasketing? this stove has many very thin rope and flat gaskets. I have used thicker ones but they compress down fine. I was very careful about getting them perfect and not stretched at all. every one I have replaced is exactly centered with an equal amount of gasket showing all around and tightly butted.

One time, I pulled the lid and there was trace soot on the stove behind the top. I figured the gasket leaked there where it butted together. so I cut a couple inches out and put in a new piece with tighter butt joints and it WAS BETTER. thinking I had found the leak, I replace the whole top gasket. but now it seems to smell again. I played a similar game with the big hole in the top--now it has a new fat gasket with lots of compression. the lid just sits on these stoves, the holes for the screws were never drilled and tapped. I am tempted to tap them M-6 and add a couple screws but I am not sure it will make much difference. inspection of top gasket shows the corner cement making a smooth indent--i dressed up some casting roughness so the whole top should mate perfectly with the new gasket.

I think I need a leak detector or something...

The only gaskets left are on catalyst cover, ash pan, glass and door. so far, my thinking was that ash pan is too low and door/glass has no smell so I think it is OK. inspection of cat cover gasket did not show any sign of leak (no trace of soot or discoloration, etc).

ANY EXPERTS OF LEAK FINDING OUT THERE?
I AM READY TO SELL IT AND BUY A NEWER ONE (NO CAT) THAT IS SIMPLER AND HAS FEWER GASKETS (THIS JOTUL HAS 8 THAT I KNOW OF. AND THEY ARE STRANGE SIZES/CONFIGURATIONS. PLUS, THERE IS THE STUPID HOLE IN THE FRONT FOR THE BYPASS ROD(I AM WILLING TO ACCEPT THAT LEAK)

i have the minimum reasonable chimney length and am at 5000 ft msl so i have precious little draft to spare. Perhaps any leaks that would be trivial (door, glass, ash pan, etc) are too much for my limited draft install and allows the inside pressure to get high enough to leak somewhere that normally would not be a concern?

any ideas would be appreciated...

ms

 

[begreen]

Is it possible you are smelling the RTV curing? Normally this is not used for wood stove piping. The pipe temperatures can exceed the rating for the RTV.

 

[MikeS]

no, I smell smoke, not RTV or burning rubber. It is leaking. Somewhere.

I realized the RTV was at the limit of its application for this location.

after much deliberation and out of desperation, I tried just a teeny bit, perfectly applied with the excess wiped off.

I used metal-fortified type good for 600F, I think. the place i put it probably won't get that hot due to convection cooling in this area. long, high firing will cook it, but so far it is OK.

I have been making small fires because I am tired of waiting for them to burn out so I can resume the goose-chase.

BUT--this brings up another issue: the instructions for some stoves (not necessarily either of the two (that I am aware of after much searching) different and incomplete manuals Jotul has provided for their "Model Series 8") suggest installing the pipe adapter into the flue adapter so far that the "bulge" is tight against the stove's flue adapter. I will never be able to do this without removing the flue adapter and pressing the pipe adapter into it with a press (the log splitter? LOL). I tapped it in with a block of wood and a hammer and it is straight and tight. I carefully worked the insert part of this adapter so it was perfectly round. I pressed it in as far as I thought reasonable. then I put the RTV in there. I am not sure I could screw it back onto the other half of the flue adapter once the pipe adapter was pressed in as described.

I have a telescoping black pipe adapter to the 6" class A. but i think the smell is coming from the stove down near the top or back.

I am just wondering if anyone else has played the perpetually leaking stove game and what tricks they may have.

Thanks for any info

ms

 

[webbie]

Keep in mind that, given a decent chimney, all leaks should pull air in - NOT SMOKE OUT.

So, as I used to tell customers, I should be able to drill a 1/2" hole easily in the side of your stove and not get any smoke out!

There is no such thing as an "airtight" stove, and if you have done the basics that is probably good enough. Tell us about the chimney and stove pipe situation.

 

[jtp10181]

I have heard of this but never tried it.... dunno if it would even be possible on the stoves you cant shut the air off. Also don't know if it would hurt the CAT at all.

Anyway.... you close off everything you can and then put a shopvac in reverse onto the outside air hookup. See where air leaks out, maybe even add some smoke?

 

[MikeS]

i considered visible, but not too noxious indicator smoke. it may come to that.

it has 13.5 or 14 feet of 6" class A metal fab. it is near the edge of the house, so I have 6 or 7 feet sticking up outside just to get this length. I may someday stick another 2 feet on there. but local (Boulder, CO) contacts with dealers from these forums suggested i would be OK with this minimum recommended chimney (even at 5000 feet which also has a performance impact). it is straight up. the inside connector is black dual wall telescope (stainless inside, I think). stove has a cat that "looks" OK.

I think it is barely enough because when I engage the cat, I have to be careful that the fire doesn't go out, leaving hot, off-gassing wood and a stove full of smoke. eventually, it will "delayed ignition" and puff smoke out. I have to be pretty careful operating (another reason for considering a modern, no-cat stove). manual suggests waiting a few minutes before closing the door, then more delay before engaging cat, etc. for me, those times are double--on the order of 15-min to half hour. Also, waiting too long is another issue, because then there will be too much active flame and the reduced draft after cat engagement will do the same thing. I have to build fires carefully, monitor the startup carefully, and hit the sweet spot to get the thing catalyzing.

I will likely replace the cat with a metal-substrate unit from sud-chemie because it will have less head loss. i bought the stove used and figured a new cat wouldn't be unreasonable once I get the install perfected. but I won't do it until I am sure I have a long-term heating solution. if not, I will just sell this and get another, modern, simpler unit.

as a side note, I am not being too demanding, I don't think. I expect and can tolerate some smoke when adding wood, etc. I can carefully open the door and let the box get drafting well, open more and add wood (but only at certain times during the burn--like when there are coals, but not when there are flames). if a little smoke spills when fueling, fine. but last season (this is the second season) i operated this stove with less issues. if smoke spilled, I could open windows, fan room, etc and within a few minutes, all better. this can still happen.....

the issue I am chasing now is different. after getting operation perfect and closing stove for a long time, I will enter the room and it will smell smokey even though the stove has not been touched and it appears to be operating perfectly. smelling above the back center suggests something is leaking there. and all the gaskets there are new. And it is every burn, not occasionally. of the last 15 fires, 14 have done this to me and only 1 has not (when I thought my new gaskets had fixed the thing.

That is why I am wondering about the ash pan, door, glass gaskets. if they allow extra air in, the pressure in the stove will be a bit higher. I realize it is a stretch, but maybe someone with better draft would not have any issues....

I agree with the 1/2" hole theory. when I crack the door, the stove drafts IN properly. if I violently pulled the door open quickly, I could get some smoke to come out. but making a normal hole in the box just adds air and all seems OK.

Also, opening the ash pan door just adds air. it is like a blacksmith's forge or a "blast furnace" so i wouldn't do it carelessly--it could aggressively run away and over fire QUICKLY.

 

[MikeS]

I could pressurize the stove with shop vac as a reader suggested. I would expect that would float the lid. if it weighs 40 pounds but has 2 square feet of area, it would only take about 4 inches of water column pressure to lift it. the shop vac may be capable of this performance. and it may leak around the gasket long before fully floating on the air cushion. Still, it could possibly show other leaks, or show where the lid STARTS TO FIRST LEAK as it is being lifted by the pressure.

Here is an even better idea:

small pot of water and toss in some dry ice. place in stove and close it up. look for "smoke" coming out. I should be able to pressurize the stove (as the DI is rapidly gasified) enough to have the "smoke" coming out the chimney.

if I get some time, I will do it tomorrow. the local super market has dry ice. maybe I could steal a neighbor's halloween fog machine

if anyone gets rich from my "smoke" idea, please PM me for my address so you can send me some royalty checks!

 

[MikeS]

FYI--current status---fire is about 2 hours old. no flame, just hot embers. room smells fine, no smoke! if I put my head right over the top center and a little back, there is a definite smoke smell. at the top corners of the stove, just hot air smell. behind the back, around the back of the stove pipe, same--no smell. but center back top smells!

I need some special gasket like they use on jet engines or something. accordion folded stainless or titanium or something.

this is silly.

 

[MikeS]

Also, my house is not tight enough to have any fan/dryer, etc lower the pressure. (of course, I need to measure that).

the room is large, my windows are cheap, etc. I don't think I have tight-house issues.

ms

 

[begreen]

Describe the complete flue system that this stove is connected to. What type pipe, how high, interior or exterior?

What condition is the cat in? Is the honeycomb clean? Do you smell smoke before the cat is engaged?

 

[MikeS]

flue/chimney described above. figure 13.5 total feet of system with 5.5 of it being double-wall inside black and 8 feet of Metal-Fab temp-guard through the building. only about 16 to 18" in the attic, about 6.5 or 7 feet stick up outside.

the inside telescope is a Warnock Hersey (Metal Fab) part, too. listed double-wall connector pipe.

three sheet metal screws at the ceiling support box.

Cat looks good. I have had it out for inspection. I never thought it looked like it needed washing or cleaning with a pipe cleaner or anything.

Usually, there is some odor before engaging cat. I figure this could be from starting the fire. I am convinced that there is a chronic, long term, ongoing issue with a small leak. sometimes a smoke spill during loading, etc can pollute the room, but after airing out the room it can go away and come back on its own. but i can always smell a bit of smoke right above the top of the stove.

We never put much stock in our opinions while we are in the room with the stove. Only after entering the room from outside or another, smoke free room do we really say to ourselves "this is smokey." That is, we are aware that we can become accustomed to the smell while being in the room, so we weight our opinions more on our impressions upon entering from somewhere else.

However, sometimes even while in the room, we will notice it.

Only one time has this chimney been flowing the wrong way when we lit a fire (and it wasn't really that cold outside). every other time, we light a fire and there is very little if any spillage while the fire starts.

 

[jpl1nh]

I'm by no means an expert, but it sounds like your draft is just a bit sluggish to me. With a good strong draft you would hardly ever have smoke spillage while loading and Web makes an ecellent point about a well functioning chimney always pulling smoke in. I have somewhat similar issues with my soapstone cat stove, especially when it's not that cold out. I can get the gas burnoff back puffing situation if I'm not careful to turn the draft down too much. Once my stove is really warm, with that thermal mass, I have no issues. I too can typically smell a bit of smoke leakage at times, but again its with a cold stove. My chimney is 6x10 tile lined center of the house masonary, through the roof peak, about 16' with a 90 from the stove and the 90 that the wall thimble creates. Woodstock had suggested that the settings I found to work best for me suggested that the draft could be a bit weak. If that is your issue, the extra 2' of pipe you mentioned wouldn't hurt.

 

[hookspacken]

I get a very faint smoke smell at times after the catalyst is engaged. I account it to the catalyst temp gauge that extends down int othe refractory package.

 

[MikeS]

OK, more info:

I have learned that draft is directly proportional to height of stack, ignoring frictional losses and assuming constant temperature within. adding 2ft will make my chimney 15% better than before (13.5 to 15.5 feet). I will probably put on a 3' stick if i come across one--a theoretical 22% increase in available draft. after that, it will be getting silly (sillier?) with more than 10' sticking up out of my roof.


I did the dry ice in water. couldn't really fill the whole stove with white "smoke" but I did find some leakage around the bottom, from near all the tin that covers the ash pan and its connection to the stove bottom. if I can find and fix this, that will help. with so little draft, keeping the air ONLY entering at the intake is important.

so, I will "drop her oil pan" and see how that connects to the stove.

 

[MikeS]

Also, it worked last season. the only difference is that I moved it forward, put tile on the cement board it was sitting on, an moved it back. so I lost about 5/8" height of stack by adding the tile.

i bought it used and it had a very rough move before last season, but it was OK.

to tile, I did a very gentle move of 4 feet and put it back, now it smells like smoke.

 

[begreen]

Is this stove connected with top exhaust or rear exhaust? Has the flue cap been checked for any plugging?

 

[MikeS]

When the "8" got catalyzed in (i suspect) the mid nineties, the only option is "rear" exhaust. the top exhaust gets covered with a casting. the "rear exhaust" flue adapter is adjustable: straight up or straight back. mine is set up to exhaust straight up.

the flue cap (chimney cap?) is fine. i can see it through a skylight. it has big, maybe 1/2" holes stamped in it. it is not a "fine" screen, but stamped from stainless steel with big, square holes.

I will post up more info on the bottom leaks once i get time to look into it.

 

[swestall]

Last year I had a Defiant CAT stove. Some of my cement had loosened over time and I would get smoke puffing out the weak spots when I got a secondary ignition off the CAT during a very slow burn with the draft control almost closed. The pressure created by the ignition would find the leaks in the stove easier than it would go up the flu: path of least resistance. You can create the same effect and see what happens. Hope this helps.

 

[MikeS]

i opened, cleaned and inspected under the grate. there are 5 holes in the bottom casting. any jotul pros know what their purpose is?

there are 4 across the front, to at each side. there is one in the back center. diameter is 0.392"

I tapped them 7/16 NC to leave me the option of plugging them easy from the outside and reassembled.

there was sheet metal around the ash pan that has special "wings" that covered these holes in case embers fell through.

Still, I don't think I can afford any extra holes. I stuck bolts in there for now and left the sheet metal off.

Will post as to how much it helps.

i will get short bolts to use as plugs and then replace the sheet metal if it works out.

Perhaps these holes cool the grate?

Perhaps they are to let any explosive gases that may accumulate in the stove to dissipate out the bottom?

I have two manuals for this stove. each lists only three gaskets--door, glass, bypass. there are also flue outlet, flue outlet adapter, lid, lid center hole, ash pan door, ash pan-to bottom.

I am kind of disappointed that the Norwegians didn't specify them all. the lid top center casting and the ash pan to bottom are thin fiber gaskets. not sure how to get that material. the 3/16 and 1/4 rounds seem a bit weird too--not at the typical hardware stores around here--the smallest easy to buy stuff is 5/16.

Do you Jotul guys have better docs? perhaps a service manual or something with parts, like the special gaskets, listed somehow by number?

 

[MikeS]

I used 3/8 rope on the lid because it looked similar. when I inspect it, some places are more compressed than others.

I wonder if I should switch to 1/2 inch rope?

anyone know what is good for Jotul model series 8 lid? the door is specified at 3/8, but no spec for lid in the books.

Thanks

 

[begreen]

Mike, I'm not sure, but those bottom holes sound like they may be for a bottom heatshield? Was there one installed on this stove at some point? Do these holes go clear through from outside to inside the firebox? I can't see how they would cool the grate. More likely they would put too much air under it and heat it up.

 

[MikeS]

not sure. they sure look factory. they were drilled, I believe--I didn't have to clean them up to run the tap through them. i don't think they were cast in. but they didn't appear "fresh" either.

the factory heat shield attaches to the sides of the ash pan. it covered the holes, but not to seal them--it is about 1/4" away.

these holes were open to the room. i plugged them with 7/16" NC bolts, but it didn't help. i am still smokey.

I am now looking at the top gasket again, considering trying some 1/2 instead of the 3/8. I put a heavy pot of water on top to weight it down. but really, this pot of water is probably only 10 pounds added to a 40 pound lid. I may add some bricks or something to see if compressing the lid gasket helps. I am also looking at bulk gasket on the McMaster-Carr website. it is very inexpensive for the small sizes (and they have the small ones, too) and they offer a tightly-woven type that may be better. or worse...


I also keep thinking something changed when I moved it--but there is nothing obvious.

now that the holes are plugged, I may repeat the dry ice test--the "smoke" won't all pour out the holes and I may be able to get if more full of the smoke.

thanks again...

 

[begreen]

Just a note. If the top gasket is not sealing perfectly all the way around the rim, the stove will burn wrong. When you have the top off next, look for black soot. If the stove is burning well, there should only be a fine grey ash. Black soot trails often point to an air leak.

Also, check the rear exit pipe and elbow with a level. If it is even slightly going downhill, it will affect draft. Make sure it is still pitched uphill towards the flue.