Older Jotul 400

[axle27]

I purchased an older 1600 sq. ft. cabin that has a Jotul P400, the older, non-catalytic one. It seems to run fine. I swept the chimney before the season started but did not do a tear down. The pipe was relatively clean. I have a temp sensor (magnetic kind) set on the pipe about a foot above the stove outlet and one on the top of the stove. When I start it and get it rolling (which usually does not take much effort), I see the pipe temp run hotter than the stove, then it will flip where the stove is running 50-75 hotter than the pipe. From what I have read, this is how it should be. I run between 350 and 400 most of the time when the house is populated but draw it down at night for a longer burn. I burn oak almost exclusively (2.5 cords were given to me and is seasoned over 2.5 years). Like many others, I'm finding that I cannot get this unit to run more than 4 hours between loads even with it banked almost completely down.

I've read lots of stuff in this forum and it sounds as if I should aluminum foil some of the air inlet on the rear?

 

[EbS-P]

How tall is the flue? That is the stove top temp when you reload?

 

[axle27]

the stack exits vertically, 18" to a 45, about 30" to another 45 then 20+ ft straight to the roof. If I get up in the middle of the night for a reload (usually 3.5 hours after I load it then go to bed), it is round 250 on the stove.

 

[EbS-P]

the stack exits vertically, 18" to a 45, about 30" to another 45 then 20+ ft straight to the roof. If I get up in the middle of the night for a reload (usually 3.5 hours after I load it then go to bed), it is round 250 on the stove.

That’s sounds about like mine. It’s not a big fire box. Check the door and ashpan gaskets for good seals. Do you have an IR thermometer to verify your magnetic one?

I found a small leak in My ashpan door seal. I run 400-500 stove top temps load at 10 pm then at 5 it’s below 150. I have 15’ of insulated liner. And I burn with the air 15% open most of the time. If I needed to tame an overdraft I would add a damper before covering the intake. I’m not saying you have one just how I would address it.

 

[axle27]

That’s sounds about like mine. It’s not a big fire box. Check the door and ashpan gaskets for good seals. Do you have an IR thermometer to verify your magnetic one?

I found a small leak in My ashpan door seal. I run 400-500 stove top temps load at 10 pm then at 5 it’s below 150. I have 15’ of insulated liner. And I burn with the air 15% open most of the time. If I needed to tame an overdraft I would add a damper before covering the intake. I’m not saying you have one just how I would address it.

My stack is uninsulated. I've run it to 400 or 425 but nothing higher. When we first started (about a month ago...yeah, we are that new to this place), it went nuts on me to like 700 or so. I'm learning its ways but getting more than 4 hours is a tough climb for a smaller stove like this. Been learning to get up at 1 or so and reload, then again later when I get up for the day. Not a long term solution, but one that works now. My home footprint may not be the most conducive to this particular stove as 1600 sq ft is right on the edge of what the OEM notes for this unit.
You mean a damper on the outlet pipe? I've considered but have read that this could make things worse.

 

[EbS-P]

I can heat 2000 sq ft as long as the temps are above 28f down here but it’s 5 loads a day?

Have you checked your woods moisture content with a meter? Room temp on a fresh split face?

 

[axle27]

It's been between 28 and 35 nightly here but it fluxuates. Being within 200 feet of a river likely does not help.

I have not checked the moisture content but it is on my agenda. I assume you mean letting the splits acclimate to room temp before loading? Yes.

 

[EbS-P]

It's been between 28 and 35 nightly here but it fluxuates. Being within 200 feet of a river likely does not help.

I have not checked the moisture content but it is on my agenda. I assume you mean letting the splits acclimate to room temp before loading? Yes.

Yes bring inside then split right before testing.

 

[begreen]

Our F400 got an average 8 hr burn in shoulder season, 6 hrs with outdoor temps around freezing, and 4hr burns when it dropped to 20º. This is mostly because the heat loss of our house is high at cold temps and the stove had to be pushed much harder to keep up with it in very cold weather.

 

[axle27]

I've been doing some research on this site and I think I need to run this thing to a higher temp before banking back for the night. Lately, I've been seeing temps right around 225 after a 4 hour burn and a good coal bed. I've been choosing the good, solid splits for the overnight burns.

The last few nights, I've gotten smoke out of the door when I open it. I've read where this is somewhat common but I believe that this is at lower temps and loading. I did a chimney sweep back in October when I started burning, but have not sense. The forecast is for warmer weather, so I want to burn in or around 400 during the day, then bank back for the night. That is what we did when I was a kid, but that was a completely different stove (and man, do I wish I could find one now).

 

[begreen]

The F400 firebox is wide but shallow. In milder outdoor temperatures (>45º) there could be some smoke rollout during a reload if done too early while the wood is still flaming and outgassing. If the flue system is on the short side or the stove was rear-vented, this could be worse. Stoves with deeper fireboxes loaded N/S and top-vented can do a bit better under these conditions.