For what it's worth, I started out thinking that I needed water in the MES because I was used to using a charcoal smoker, and that's just how I'd always done it.
But I was having trouble keeping the
AMNPS burning. Todd said to not use any water in the pan and be sure to pre-dry the pellets and make sure to have plenty of airflow so the pellets get enough combustion oxygen.
Doing all of that has worked fantastic. And from turkeys to pork butts to ribs and pork loins, everything has come out nice and moist. So I don't think the water is necessary in the MESs. I think the airflow, even when we try to enhance it, is far less than what one gets with the kind of charcoal smoker I was using before.
So things tend to stay plenty moist without the water pan.
I am running a first gen 40. It seems to me that the idea of putting an extra vent pipe on the 2nd gen units is a good one. The way I see it, if you come out of the side and run the elbow up, and maybe even add a bit more of a vertical stack, you will increase the draft.
Vertical stacks induce draw because the hot air is lower in density than the cooler air outside of the cooker. So that cool, dense air wants to push into the bottom vent and displace the warm, moist low density air.
But you may need the extra stack height to get enough draft in the gen 2s. The side vent is better for getting better air flow pattern inside the cooker. But it seems to have also reduced the draft. The extra flue pipe should overcome this.
A taller flue stack creates more pressure differential (head). So it sucks harder on the smoker.
Even though it's dry here, and I run without water, I have not seen any meat come out anything but nice and moist.
Part of the fun of all of this is tinkering. At least it is for me.
I think with an
AMNPS and an auxiliary taller stack, the gen 2 units may end up working fine. You may even need to throttle the aiflow a bit. But I'd throttle it at the inlet. You want a negative pressure in the smoker so you are not driving moisture and smoke out into the space between the inner walls and the outer walls. Positive pressure driving smoke and moisture into the insulation space is a bad thing!
That's where the black liquid dripping out comes from. Imagine that conductive smoke-laced condensation running on your electrical and electronic parts! This may be what's killing the controllers.
Get good draw with a taller stack, then adjust the airflow at the inlet, throttling it down there so you have a slight vacuum inside the smoker. That way, any air that enters the space between the walls is cool, clean, dry, outside air.
Phoned in.