-12 F here this morning.... Stove can't keep up, time to put on a sweater. Glass is clean after 24 hours of burning hard.... Thermostats still off.
2022/23 VC Owner thread
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-11 here. Had my heat on yesterday too. Went snowboarding and couldn't feed the stove to run it hot.
Made pizza when I got home as an excuse to crank the oven to 500. Thinking today is a French onion soup kind of day
bert670
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I have wondered.... but the answer seems to be an easy one..... it comes out the back of the stove. Some of it goes up the chimney, as I do see a rise in flue gas temps when I get the cat that hot.
I will admit it is kind of amazing that something can be that hot and then just a few feet later is only 400-500 deg or less.... here is how I rationalize it:
- Temperature is not energy, it is temperature. Energy is mass * temperature, sort of. Point is that something can be really hot and there could be very little energy if the mass is small.
- Take the mass of the exhaust gasses and intuitively compare it to the mass of the cast iron in the back of the stove. A big difference! When I think about it this way it feels much more believable.
- Those who are thinking hard on this will realize this argument only makes sense under transient conditions, (stove is heating up). If the stove is already hot we need to look at the heat flux through the cast iron.
- Ultimately the heat goes to room air flowing up the back of the stove. I suspect this air flow is much much greater then the flow of air through the stove.
- In addition to the mass think about the surface area (heat flux). At the cat exit there is a relatively small cross sectional area of gas, say 13 x 2.5 = 32.5 in^2. Compare that to the surface area of the back of the stove... ~ 29x22 = 638 in^2 or 19.6x the area of the cat exit.
- So we take that really hot gas and spread that heat across a cast iron heat exchanger that is almost 20 times the area..... Now it seems to be much more plausible, at least to me it does....
- The other thing to consider is the velocities of the gas. The velocity of the gas will be much slower than the velocity exiting the cat. So the hot gas has lots of time to sit there and transfer heat to the cast iron.
- And another thing..... The airflow through these stoves is pretty low, that's how we get the high efficiencies and long burn times. I think many of us would be shocked if they could "feel" how low the airflow through the stove actually is.... It really is just a whisper. Just for fun take a candle or lighter and put it near your flapper inlet. I would bet it bends the flame but does not blow it out (somebody will do it and prove me wrong.... I am sure. But you get the point)
Good answer but...If air flow was that slow draft would make the gas flow faster and cool things.
Not sure where you are going with that..... Draft sets the flow so I am struggling to understand the point, no offense.
More draft = more airflow (all else being equal) and hence faster combustion rates, higher heat flux and hence higher temps.
Did such a good job of running my stove last night that a pipe froze and burst on the other side of the house. Still waiting on the plumber to get here. Already shut off that zone and drained the line.
It doesn't get as cold here but when it gets to zero or single digits I turn the thermostat up as high as it will go, the stove is close to the thermostat. It will run the heat and keep the pipes from freezing and warm the outer rooms.
In theory the air control sets the flow, these things are supposed to be "air tight".
This is what I do. Or else my thermostat would never click on and the outer rooms would freeze
I think the low Friday night was something like -15 or something wild like that. Plumbers found at least 2 bursts in the pipe. They capped off both ends and said that they had to wait for it to thaw before they were able to fix it. For the next couple days I’m down a heat zone so the stove it is.
My big issue is that the stove is in the same room as the thermostat. The stove room might be 75 but the outer rooms are obviously much colder. Also this happed in a bay window that doesn’t have basement below it so there wasn’t that protection of a 60 degree basement to keep the pipe warm.
My home is on a crawlspace that has vents, the vents close when it's cold but it still gets cold under there. I have forced hot air with ducts down there so even with the stove in the room with the thermostat I can turn the heat to 80* and the furnace puts some heat under there. It won't run long as it doesn't take much to raise the room with the thermostat and stove but it's enough to keep everything warm enough.
Data from the cold snap, (Friday - Sunday)
Stove burned really well went it got cold, notice peaks all <1300 during the cold streak. Before and after the cold snap I was seeing my usual peaks at 1600.
Key damper was full open for the entire time.
What was different?
Stove burned really well went it got cold, notice peaks all <1300 during the cold streak. Before and after the cold snap I was seeing my usual peaks at 1600.
Key damper was full open for the entire time.
What was different?
- I ran with a bit more air, 50%- 75% when it was cold. Stove temps were 450 - 600. Hotter than I have been running.
- Maybe my stove like to run with more primary air and hotter STT?
- I also did some hot reloads where I added a few spilts when the cat was >800
- Obviously it was cold and thus more draft
- Is it even possible my cure is more draft? Not less as I have been pursuing? Seems hard to believe.
I would agree about the draft. With lower draft the hot gasses linger in the cat chamber and run hot. We are adding two more feet to test this theory. Seems like a draft needy stove.
Shelves finally came in. Only 6 months of waiting. Definitely helps fill the space more
Those look good, how much do they cost? Does the finish match the stove well?
Spot on match. 10 minute install. They weren't cheap. I'd have to check the invoice but I think they were about 300 per shelf
Thanks $300ea is comical but would be nice for a steamer so you can still load from the top.
First full load with metal cat. Key damper full open, air at 50%.
Real nice looking burn, except for the temps >1400 for almost 3 hours.....
Cat lit off real fast! Below are pics after the first burn. It looks very good, no real change in one burn.
Real nice looking burn, except for the temps >1400 for almost 3 hours.....
Cat lit off real fast! Below are pics after the first burn. It looks very good, no real change in one burn.
After I closed the bypassed damper air was at 100%
At 20:10 I closed it down to 50% where it stayed for the rest of the burn.
Do not know why it bumped up at 4 am..... I was sleeping. I can only assume some of the coals crumbled and exposed more fuel.
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