Jotul F45 Greenville Experiences

[Todd]

1.5 hours in, turned down to low.

 

[Todd]

It’s been a very mild Winter for us this year and I’m not complaining after the previous record snowfall Winter we had last year. I’ve only had to plow snow once so far and only burned two cords of wood!

Most days have been a 12 hour reload schedule, only a few times have I had to go with an 8 hour schedule. The last two days was one of those rare times. Seems I hit a wall once temps dip into the teens and below so this cabin needs more heat than a 12 hour schedule can provide.

I’ve been getting by fine Burning mostly Aspen all season but I have a small stash of super dry Oak I needed to burn up so the last couple days I’ve been digging into that. I can see why Jotul states firewood over two years seasoned can be too dry! This stuff can really take off fast and burns very hot! A full load has been giving me flue temps and stove top temps in the 600-700 range and I need to shut the stove down much sooner than my typical load of Aspen. Burn times are surprisingly shorter as well.

Overall the stove has been working great. I’ve kept the secondary air blocked by about 25% and that seems to be the sweet spot for the majority of burns. The extra thermal mass I added to the hearth seems to even out the heat some and deflect the radiant heat out into the great room more than before.

Looking forward to seeing some reviews once the new catalytic F45 comes out. I’ve heard they also have a thermostatic controlled secondary air, should be interesting.

 

[Upnort]

Looking forward to seeing some reviews once the new catalytic F45 comes out. I’ve heard they also have a thermostatic controlled secondary air, should be interesting.

Wait, are you serious? Is such a stove coming out?

 

[Todd]

Wait, are you serious? Is such a stove coming out?

Yup!

HPBA update

Just got back from the trade show in Nashville. There wasn’t a whole lot of surprises or new products. Most notable was jotul. They have replaced the castine with a smaller version of the Oslo. Same castings only smaller. The new cats are being made in Texas and have an innovative SS can design...

www.hearth.com

 

[Todd]

Swept chimney today, got about a pint of fine soot after burning just under 3 cords. I was a little worried that I’d have more since I was playing around with blocking the secondary air but all seems well.

I think I’ll change out the door gasket before next season, starting to get a little buildup in a lower corner.

 

[Todd]

After three seasons burning the firebox and baffle look great. No warpage, sagging or cracks.

 

[begreen]

Looks good, as it should be.

 

[Crab]

Looks good, as it should be.

Yep look great. I won't sweep until early fall when I rent a lift to pressure wash the house. Last year I had 2 cups of fine stuff. When I plugged the smoke pipe 2 months ago all looked well in it and at the tee. I had a great year burning after learning to reload at a lower temp and burn/expect at higher temps in the flue with my oak and hickory at 14/15%....One day I'll take time to write up my trials and tribulations. We had a very mild winter again.

 

[Todd]

Here’s something that’s been bugging me about this stove and other Jotul’s that I can’t find an answer to. The top of the stove isn’t just a solid cast iron top. There is an inner square piece that is gasketed and has retainer clips inside holding it down. Why is this? Could you just leave that cover unhinged and use it for access to the top of the baffle? Easier maintenance? Not sure if this cover is heavy enough to keep the seal and not affect the draft? Anyone know?

 

[begreen]

Yes, likely for easier maintenance and servicing. I believe a removable top is a requirement for UK sales. I was told that's why that Jotul tops are gasketed. They are bolted down for shipping, but the bolts are not required for daily use.

 

[Todd]

That’s kind a what I thought. Since my stove is rear vented I might be able to go through there with a soot eater and not have to disconnect the pipe.

 

[Todd]

I ended up popping the whole top off. I’ll just leave it unbolted since there’s a gasket around it and it’s got to be about 30-40 lbs. This should make maintenance easier a I could probably sweep straight up through there instead of disconnecting the pipe. There’s no way I can sweep down from the top with my steep pitch metal roof. There was lots of ash behind the turbulators plugging those holes as well as other nooks and crannies I just couldn’t reach with my vacuum.

 

[EbS-P]

I think all hearth installs should remove the bolts when installed. It would make cleaning so much easier. I’m thinking about taking my bolts out the the top of my F400. Then the baffle doesn’t have to come out to clean. But I’m worried I’d chip the enamel so they will stay in.

 

[begreen]

I think all hearth installs should remove the bolts when installed. It would make cleaning so much easier. I’m thinking about taking my bolts out the the top of my F400. Then the baffle doesn’t have to come out to clean. But I’m worried I’d chip the enamel so they will stay in.

I pulled the bolts on our F400 at the first cleaning. They didn't go back in until I sold the stove.

 

[bigealta]

I've been running my f400 with Bolts Removed since day 1. No problems at all. Those bolts are long gone.

 

[Jebb]

After three seasons burning the firebox and baffle look great. No warpage, sagging or cracks.

View attachment 327666

I was happy to find this picture. I noticed I also have some tarry creosote build up in the back of my firebox in the little space between and above the rear bricks, and was concerned something might be wrong, but mine looks very similar to yours in the back. Must be an area that just doesn't get direct flames to burn it off.

 

[Todd]

I was happy to find this picture. I noticed I also have some tarry creosote build up in the back of my firebox in the little space between and above the rear bricks, and was concerned something might be wrong, but mine looks very similar to yours in the back. Must be an area that just doesn't get direct flames to burn it off.

Yeah I think because of the relatively cooler air coming up through that secondary air tube it makes a little creosote back there. Probably wouldn’t hurt to have a hot fire once in awhile and at the end of the season to remove that. Could eventually cause some corrosion.

 

[Todd]

18 lb load of Aspen last night. Probably didn’t need the fire but it felt good and still testing some mods for a little better radiant heat.

 

[Crab]

Nice fire....Looked at ur 3 day wx history, wow some large temp swings. Looks like ur 7 day forecast/guess shows the same swings. No need to burn here yet.

 

[Todd]

Yeah weird weather, 75 yesterday and this morning it’s 38.! Currently in a moderate drought, haven’t seen rain in weeks!

Looking forward to burning this year, I have a lot of Oak to burn. Should be quite a treat after burning mostly Aspen the last two years.

 

[Jebb]

First fire if the season last night. Ran stove with windows open downstairs as I was thinking temps were marginal for draft. A little over half full of ash splits. Got distracted and left air control too far open and came back to a fireball and STT of almost 900..... Oops. The 3 feet I added to my outdoor stack combined with appropriately dry (16%) wood means I'm going to have to relearn the stove a little this fall.

 

[Todd]

So with the new shoulder season here I’m going to try something a little different. Usually I’ll just burn low and slow or a small hot take the chill off fire. This year I want to see if I can take advantage of the extra thermal mass and if it will hold and release some heat burning hotter fires.

I removed the rear heat shield and filled the side shields with pea gravel to make the stove more radiant. So far testing has shown the stove top temps come up much quicker and tend to be about 150 degrees or more higher than my internal flue temps. Without the mods those temps are cooler.

The sides take a little longer to heat up but they get a bit hotter than without the gravel and stay warmer longer.

With the 1500 lb of 4” thick concrete pavers surrounding the stove I’m hoping the extra radiant heat from the stove will soak in better and last longer?

 

[bigealta]

So with the new shoulder season here I’m going to try something a little different. Usually I’ll just burn low and slow or a small hot take the chill off fire. This year I want to see if I can take advantage of the extra thermal mass and if it will hold and release some heat burning hotter fires.

I removed the rear heat shield and filled the side shields with pea gravel to make the stove more radiant. So far testing has shown the stove top temps come up much quicker and tend to be about 150 degrees or more higher than my internal flue temps. Without the mods those temps are cooler.

The sides take a little longer to heat up but they get a bit hotter than without the gravel and stay warmer longer.

With the 1500 lb of 4” thick concrete pavers surrounding the stove I’m hoping the extra radiant heat from the stove will soak in better and last longer?

Interesting.....

So i guess the question would be does the pea gravel and hotter stovetop temps mean higher flue temps where exhaust temps are higher. And if so, are you loosing heat from those higher exhaust temps.
And With higher stovetop temps and higher firebox temps are you consuming wood faster? I'd say most likely.

The ultimate goal is getting the most heat from the wood into the house while still burning cleanly.

My guess would be At a certain stove top temp the fire is too hot and loses to much heat up the stack.

Perhaps the next test would be to remove the pea gravel and place a heat absorbing material/heat sink very close to the stove walls but not touching. This would be to prevent the firebox from getting too hot but still absorb some heat in the material.

And you could move it closer or farther from the stove for testing different placements.

I've found by IR Gun readings that the fireplace walls across from my f400 have a pretty narrow focus on the location of the hot spots. Straight across from the high part of the stove sides show the highest temps.

I've also found that too much thermal mass is a waste. The outer bricks on my interior fireplace never get hot. They don't even get much, if any warmer than the room temps.

Direct and straight line of site to the face of the thermal mass yields the hottest temps.

Touching the stove, of course, yields by far the greatest heat transfer.

You may also be able to restrict the air even more when burning with the pea gravel to lower the stovetop temps to where you normally run the stove to keep a similar burn to pre pea gravel.
But if i remember correctly you are already running it with most of the air shut down already?

 

[Todd]

So far I have found the flue temps are lower than before. The other night the internal flue temps were running at 450 while the stove top temps were at 650. My thinking is without the shielding I’m getting more heat transfer through the stove and less up the chimney. Kind a like the difference between single and double wall stove pipe. More heat goes up the double wall.

 

[Todd]

Yeah most of the time I burn at the lowest setting or just a smidge above. Last couple fires I was burning at medium low and the flue temps were staying under 500. I have yet to burn a full load with the pea gravel, maybe this weekend, it may not even hit 50 this Sunday.