Maintenance time today. Trying to do things fairly quickly so I can fire it back up and keep refractory temps up. Cleaned the chimney cap and then pulled the plug on bottom and cleaned that out. Then let the boiler cool down a little bit. Cleaned the boiler and then pulled the old center bricks, or the nozzle out. They were getting "opened up" from wear and tear. Slots were getting to big. So time for some new ones. And now we are fired back up. And now it's break time. Let's see. What will be for lunch?
The boiler is now heating up faster and seems to be running less often. I believe everything is getting hotter quicker and it is holding its heat a little longer. The combination of the cleaning and the new nozzle is making a nice difference. GOODER time of year for that!
I just ordered a new set of nozzle bricks for the Wood Gun. I see it has been almost one year since I put the last ones in. This year I ordered a newer product they have called the Cap Center Brick. This spans the over to the two side bricks so that if your “shelf” is eroding, like mine is, you can get more life out of your side bricks. I talked with the wife about putting the firewood in when I’m not here. The firewood can be heavy for her, especially the hardwood. So I had to ask her to not drop or throw the wood in there. She acknowledged it is hard for her sometimes. I figured it was because this nozzle seemed to go sooner. Each time a drop or throw risk cracking the nozzle bricks or shelf underneath and then it’s downhill from there. So I will try splitting next year’s firewood a little smaller for her. Smaller split size does help to maintain a good coal bed and therefore gasification anyway. I will take some pictures of the job when they come in. Should be shipped out today.
Getting the next nozzle replacement done this morning. Alternate Heating Systems was quick getting my order out, I think I ordered it Tuesday morning, and the big brown truck showed yesterday afternoon! That is quick! So here goes..... Out with the old: As you can see here there is only a little bit of the “shelf” that holds the nozzle bricks in place left. It is worse than I thought. The side bricks will need to be replaced sooner than later. But, for now: These bricks may make the Wood Gun function a little different. These Cap Center Bricks leave a lip that may prevent the firewood splits from sliding down to the nozzle all the way like they normally do. This may cause a loss of gasification more frequently. Maybe this area I can let fill in with ashes though. We will see. But for now we are fired back up! Maybe I can get through the rest of this and next season with these. We will see how it performs now.
Extreme heat ignites them when they pass through the coals before the lower chamber. Once you have a good bed of coals, and all that air is sucked through them by the fan, the coals become red/orange hot. Then everything has to pass through them to get out. Ignition!
When you compress any gas it heats up. The nozzle compresses the gas enough that when it exists the combustion chamber it ignites. When the nozzle wears out you won't get complete combustion. Even if there were no coals below the nozzle it would still burn off the smoke. The smoke just has to be hot enough that the compression created by the nozzle is enough to ignite it.
Through my experience with this gasser: The nozzle holes are fairly large. I don’t think it has to do with compression. It has to do with the forced air getting the coals so hot that gas ignites from the temperature. You do not get gasification if you don’t have a good bed of hot coals. Gases pass through the nozzle and do not ignite if hot coals are not there.
Every model is different. My inlaws have one and it will burn off smoke with 0 coals once up to temperature.
Correct. Most goes right through to be collected in ash tray at bottom of ash cyclone. Inside this round “tube” is a cone that is large at the top and goes down to about an inch at the bottom where ash falls into tray.
So these particular nozzle bricks are kinda "repair" bricks, made to extend the life of the rest of the firebricks? What did the OEM nozzle/bricks look like?
If you go to the top of this thread and work down you will see the OEM bricks that started this thread about this time last year when I replaced them.
Would placing a flexible 'grate' over the nozzle bricks -> up high on the side bricks help? Even something thin, like consistency of a metal 'shopping cart' ?