Jotul F45 Greenville Experiences

[bigealta]

Oh yeah you removed the rear shield.
Interesting test.

 

[Todd]

1.5 hours in, turned down to low.

View attachment 323021 View attachment 323022 View attachment 323023

Here’s a similar load from last night comparing the temps from before and after the pea gravel. There seems to be quite a dip in flue temps compared to before.

 

[Todd]

34 lbs of Red Oak for this evening’s fire!

 

[Todd]

An hour in cruising at med low air.

 

[bigealta]

So sounds like the removal of the rear heat shield sheds more heat from the f45's exhaust than the added pea gravel's affect of raising firebox temp.

Actually that does not make a much sense though?

What do you think is going on there?

 

[Todd]

So sounds like the removal of the rear heat shield sheds more heat from the f45's exhaust than the added pea gravel's affect of raising firebox temp.

Actually that does not make a much sense though?

What do you think is going on there?

I had the rear heat shield and bottom heat shield off since last year. The only difference is the pea gravel in the side shields this year.

Flue temps were about 100-150 degrees higher last year. Maybe the sides are sucking more heat away from the firebox somehow? I don’t know, you’d think with no pea gravel the convection between the shields would whisk away more heat?

Stove top temps are also higher. All I’ve done this year so far is cold starts and the stove top temps are coming up faster than the flue temps now. I’ve seen 500 in 15 minutes ! It’s not the flue probe, I have three of them and they all do the same.

 

[Todd]

Here’s my first full load burn at lowest air setting. These flue temps are getting down to Blaze King territory lol.

This is an hour in. Shut her down all the way after 30 min. Plenty of secondary action going on.

 

[bigealta]

Hmmm. Hard to comprehend that higher stovetop temps co exist with colder flue temps.
I'm perplexed.

 

[Jebb]

From a unmodified F45v2 user, hitting STT of 500 from a cold start in 15 minutes is damned impressive

 

[Todd]

Hmmm. Hard to comprehend that higher stovetop temps co exist with colder flue temps.
I'm perplexed.

Well I think that’s the way it’s supposed to be? My previous wood stoves ( Keystone, Fireview and BK Princess) all were like that.

I’m just surprised my flue temps dropped this much from last year because of this mod. It must of made the heat transfer efficiency better somehow? I’ll take it, more radiant heat is better for my open floor plan and high ceilings.

 

[bigealta]

Well I think that’s the way it’s supposed to be? My previous wood stoves ( Keystone, Fireview and BK Princess) all were like that.

I’m just surprised my flue temps dropped this much from last year because of this mod. It must of made the heat transfer efficiency better somehow? I’ll take it, more radiant heat is better for my open floor plan and high ceilings.

ok so with higher stove top temps and assuming higher internal temps , the f45 is probably drawing more air thru the stove which could account for the flue temps being cooler. The fire and secondaries flames and coal heat has direct paths to the stovetop and sides.

I guess this could be a reason Why the actual exhaust is cooler?

 

[bigealta]

And / or the sides and back are running cooler than last year as they are shedding more heat at a faster rate.

So the top runs hotter while the rest of the stove runs "cooler" with a faster heat transfer.

 

[Todd]

Actually the sides are running a bit hotter and stay warmer for longer. I never really took temps off the back though.

 

[EbS-P]

Conduction moves more heat than convection.

 

[Jfior1983]

I’m about to have my f45 installed in anchorage Alaska. House is Well insulated, Triple pane windows, chalet style home with about 1600 sf. Hoping I didn’t make a mistake not getting the f55. My question is…what is “normal” operating temp? Should I have a thermometer on the stove top, or on the pipe? Pretty excited about this, since I wanted a non-cat stove and this seemed to be the best option I could find. Anyone offering tips for operation? I’m going to burn well seasoned white birch.

 

[Todd]

I’m about to have my f45 installed in anchorage Alaska. House is Well insulated, Triple pane windows, chalet style home with about 1600 sf. Hoping I didn’t make a mistake not getting the f55. My question is…what is “normal” operating temp? Should I have a thermometer on the stove top, or on the pipe? Pretty excited about this, since I wanted a non-cat stove and this seemed to be the best option I could find. Anyone offering tips for operation? I’m going to burn well seasoned white birch.

Both stove top and flue temps are good guides to what’s going on with your stove. I mostly monitor flue temps after reloading since they usually react faster than stove temps. Once I see flue temps get up to the 400 -500 range I’ll start backing down the air in stages and keep watching the temps and fire til I get the output I want. I like to keep the stove temp below 700 and mostly cruise in the 500-650 range and my internal flue temps are usually around 400-600 depending on the air setting and weather conditions affecting draft.

 

[Woody Stover]

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.

Do you think the lower flue temps are due to removing the rear shield, allowing faster heat transfer from the firebox? If that's the case, removing the side shields should remove heat even faster, and drop flue temp even more, no?

 

[Todd]

Do you think the lower flue temps are due to removing the rear shield, allowing faster heat transfer from the firebox? If that's the case, removing the side shields should remove heat even faster, and drop flue temp even more, no?

No I had the rear and bottom heat shield off last year. The only difference this year is the pea gravel in the side shields. I thought about removing the side shields for testing but I wouldn’t like the look and I like the extra thermal mass.

 

[bigealta]

Todd, Besides the temp differences, what differences are you noticing with the pea gravel vs without.

 

[Todd]

Todd, Besides the temp differences, what differences are you noticing with the pea gravel vs without.

A little more radiant heat from the stove and the blocks.

 

[Woody Stover]

It was getting late when I posted last night, and somehow I missed a bunch of posts by you and bigealta which covered the shields being on or off. But now I'm more confused than before about the physics of what is going on with the pea gravel. About the time I think I'm starting to understand how these stoves work, then you throw me a curve ball like this! 😆

 

[Todd]

Ha, tell me about it, I can’t figure it out either. I was just trying to eliminate the convection heat for more radiant heat thinking it would be better for my high ceilings and great room. So far it works and if I get better efficiency I’ll take it.

I was actually thinking of selling this stove for another Woodstock but thought I’d try this first. I don’t think I could justify $3k for a new stove but I always have my eyes open for a good deal.

 

[Woody Stover]

I was actually thinking of selling this stove for another Woodstock but thought I’d try this first. I don’t think I could justify $3k for a new stove but I always have my eyes open for a good deal.

It's the Fall Foliage Special! Don't miss out!!
The straight cats are on sale (if that's what you like and if it'll do what you want,) plus the tax rebate, adds up to substantial savings. 🤗
But yeah, I know, if you don't spend any money, you save even more. 😏
I can't really justify it either, but I might grab an F 35 to try out. I'm old, I might as well spend my money. 💸 Plus who knows, an asteroid could fall on me any day now. 😆 I could sell my Dutchwest (maybe refurb it, too) to recoup some cash, and still have a backup stove just in case.

 

[Todd]

Just bought a new John Deere with a snow blower so a new stove is out for now. Awhile back I went to a local dealer when the new Jotul F445 came out and the owner said he’d give me $2k for my F45 if I traded it in for the F445! That’s what I paid for it back in 2020! These stove prices have gone insane the last couple years. I wouldn’t mind finding a used Keystone though if I could do an even swap or come ahead. 😁

 

[Crab]

Just bought a new John Deere with a snow blower so a new stove is out for now. Awhile back I went to a local dealer when the new Jotul F445 came out and the owner said he’d give me $2k for my F45 if I traded it in for the F445! That’s what I paid for it back in 2020! These stove prices have gone insane the last couple years. I wouldn’t mind finding a used Keystone though if I could do an even swap or come ahead. 😁

If you find 2 Keystones let me know ...I paid far less than 2k for my V1 F45....No burning yet but finally this weekend the 45' towable lift was available to clean the flue and pressure wash the upper levels of our house. Got 2 Red Solo cups(16oz apiece) of black/gray powder. There was already some soot in the bottom of the tee before soot-eating. So , I'm thinkn' 1 and a half Solo cups. Will be burning tomorrow. Quite honestly the temps have been higher than normal, maybe could have burned 2 times but ut would have been small fires....