Which “should” give faster-higher temp burns, but shorter burn cycles ? What I’m hearing from y’all’s is the fuel has to season for three years etc. yes it absolutely does if you want to load thick long hardwoods.
My Jotul is weak
- Thread starter Angelo C
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Two shots of a fire as normally loaded early on in cycle full vent. BTW the idiot that designed to vent control “knob” needs to have his fingers burned in an open fire as punishment for not even having used his own design.
What I’m seeing is a middle section of Cat/ tube is not firing or not heating up as a result . I’m not sure how the “tube” cat relationship or timing works but I have noticed the cats will hear up and glow before good tube airflow ? Do I have that timing correct ?
2 years old white oak, 300* temps at the cornerstone of unit.
OAT about 25*
What I’m seeing is a middle section of Cat/ tube is not firing or not heating up as a result . I’m not sure how the “tube” cat relationship or timing works but I have noticed the cats will hear up and glow before good tube airflow ? Do I have that timing correct ?
2 years old white oak, 300* temps at the cornerstone of unit.
OAT about 25*
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Twenty minutes later :
Blower fan on 3/4 speed. (Speed control button broke off- so it’s a one speed unit now. Three calls to installer have yielded ZERO options as to replacement)
Temp up to 400*
Room temp 67*
Blower fan on 3/4 speed. (Speed control button broke off- so it’s a one speed unit now. Three calls to installer have yielded ZERO options as to replacement)
Temp up to 400*
Room temp 67*
Yes and no. The fire is hotter and burning quicker, but when the air control is wide open or near to it, there is not enough vacuum in the firebox to pull sufficient air through the secondary manifold. This leads to incomplete combustion with most of the heat going up the flue and a cooler firebox. If there was a thermometer reading the flue gas temps, this would be self-evident.
When the air is closed down enough, the vacuum in the firebox pulls air through the secondaries leading to much more complete and hotter combustion, in the firebox, leading to a hotter stove body and cooler flue temps. This thread illustrates the process, showing how stove and flue temps respond to closing down the air.
So allowing LESS air increases temps by inducing more vacuum ?Yes and no. The fire is hotter and burning quicker, but when the air control is wide open or near to it, there is not enough vacuum in the firebox to pull sufficient air through the secondary manifold. This leads to incomplete combustion with most of the heat going up the flue and a cooler firebox. If there was a thermometer reading the flue gas temps, this would be self-evident.
When the air is closed down enough, the vacuum in the firebox pulls air through the secondaries leading to much more complete and hotter combustion, in the firebox, leading to a hotter stove body and cooler flue temps. This thread illustrates the process, showing how stove and flue temps respond to closing down the air.
Well that’s counter to everything I’ve ever seen.
I have the surround off now as I have added some insulation to the firebox in hopes of containing some losses. The flue is the hottest section of the unit until the fuel is completely burning, then it actually lowers temps and the flame/face of box becomes hottest around 600*. Interestingly the sides were hotter than the top of the box. The room did see higher temps BUT it was closer to 40* today. So I’ll post back later today on temps after this reload is fully firing.
This is what the Jotul F500 secondary combustion looks like with the air almost all the way closed. The firebox is around 1200º in this case, with a stove top probably around 600º.
I think this (what begreen said) could be the cause, or at least the way to go for the biggest improvement that is possible with this stove.
@Angelo C I'd carefully and completely try what he says. (Also because there is a long record of having provided many solutions to stumped owners even those who have been burning a long time).
@Angelo C I'd carefully and completely try what he says. (Also because there is a long record of having provided many solutions to stumped owners even those who have been burning a long time).
Tring to wrap my head around the "open window" test. If the stove vent is set to "low" then the stove is letting less outside air through the box ? How would letting less outside air give an indication of "tight" compared to having the vents "fully open" ?
Wouldn't the box need more outside air when vent is fully opened as opposed to partially ?
Nothing seems intuitive with this operation.
I get much more "airflow" heat and flame action when vents are fully opened. When vents are partially or fully closed it seems like it's starting for air.
Wouldn't the box need more outside air when vent is fully opened as opposed to partially ?
Nothing seems intuitive with this operation.
I get much more "airflow" heat and flame action when vents are fully opened. When vents are partially or fully closed it seems like it's starting for air.
No, the stove is using less "primary air" and more secondary air. Both are still outside air. However, the secondary air is unrestricted and not linked to the air control. As the vacuum in the firebox increases due to closing off the primary air, the draft pulls the air from the path of least resistance - the holes you see in the secondary manifold. The fire needs to be warmed up for this to happen so that the fire is not completely squelched by the primary air reduction.
The same amount of room air is entering the firebox but being routed to a different internal vents ?( vent control dependand )
If that’s the case what would opening a window or door be indicative of when the “vent” is closed vs open fully ?
If that’s the case what would opening a window or door be indicative of when the “vent” is closed vs open fully ?
I think you're mixing up two things here.
1. The air going into the firebox has 2 routes. One is the primary air you control. The second is secondary air thru the tubes in the top of the firebox. You can't close that. The quantity is determined by the draft (i.e. flue temps; more for a hot fire than for a colder one). The best stove operation for this type of stove is to (once the load is going well) close the primary air, have the wood create gases that the secondary air will burn. That creates most heat and the longest burn.
2. The door/window has to do with the following. Your stove takes air from the room (either primary and/or secondary). That air has to be replenished - otherwise your stove would create a vacuum in your home. If your *home* is too tight, not enough air leaks in for what's sucked out of your home by the stove. If that is the case, stoves don't burn well. That is easily checked by opening a (home-). window or door a crack as that allows for enough air to get in if the rest of the home is too tight.
1. The air going into the firebox has 2 routes. One is the primary air you control. The second is secondary air thru the tubes in the top of the firebox. You can't close that. The quantity is determined by the draft (i.e. flue temps; more for a hot fire than for a colder one). The best stove operation for this type of stove is to (once the load is going well) close the primary air, have the wood create gases that the secondary air will burn. That creates most heat and the longest burn.
2. The door/window has to do with the following. Your stove takes air from the room (either primary and/or secondary). That air has to be replenished - otherwise your stove would create a vacuum in your home. If your *home* is too tight, not enough air leaks in for what's sucked out of your home by the stove. If that is the case, stoves don't burn well. That is easily checked by opening a (home-). window or door a crack as that allows for enough air to get in if the rest of the home is too tight.
So, the “vent” control is not an outside air volume control but a direction control?
And the tight house theory is resolved by allowing more air into the house.
No it is in a 2 story great room with fans running the wrong direction. Fireplace on an outside wall.
Then I am not understanding what a leaky basement door has to do with completing the simple fresh air test by the insert, as directed several pages ago at post #52..
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