As all of these posts point out: Everyone figures their own ways to get the pellets to burn.
I live at about 5300 feet above sea level. So people recommend using a tube rather than the
AMNPS at this elevation.
But being a die hard, I've made the
AMNPS work well for me. Here's what I do:
Dry the pellets thoroughly. I have done it in the microwave oven, and when I do that, I put them in a microwave safe bowl and give 'em 30 seconds, then take them out and stir. You can see and feel the steam coming off of them! Then I put 'em back in and give them another 30 seconds. Then take out and stir. And so forth for about five or six cycles. If you let them run for more than 30 seconds, they WILL catch on fire. And that will smoke up your microwave oven for quite some time. :)
So lately, I've been drying them in our kitchen oven. It's a convection oven, so I run it in convection mode at about 250. I put the pellets in a foil steam-table tray (I LOVE those things!) in a thin layer. A half hour or sometimes longer gets them really dry!
A while back, I weighed a batch, then dried them, then weighed them again, and the percentage by weight of moisture they had was really quite astounding. And it's very dry around here. Still, they'd obviously absorbed a lot of moisture even though they'd been in their original bags from AMAZIN. Plastic bags do not stop water vapor. They may stop blatant water and drops, but they're actually quite porous. Put a sliced onion in a ziplock bag, and tell me you can't smell it through the plastic. ;)
So anyhow, I dry them thoroughly, and if I'm not going to use them immediately, I put them in a mason jar or other glass jar that really seals well. I put them in while they're still hot so they don't absorb moisture as they cool. And again, it's DRY here!
I pre-heat the smoker to at least the temperature I'm going to be smoking at. The smoker needs to be hot already in order to draft correctly.
I remove the pellet hopper/dropper thing COMPLETELY.
I took the whole chip burner and its little drawer out and threw that all away.
I use a chimney stuffed into the vent hole that is conveniently on the top of my gen 1 MES 40. It's about a foot of 3" stove-pipe and it jams perfectly into the vent and stays there even if it's windy. Perfect fit. Bear's point about condensation running down the chimney and then getting on your food is right on. But I always have a piece of foil pan on the right side of the top shelf to direct the airflow in the smoker all of the way to the left (opposite side as the vent is on) and then the smoke has to go over to the right to escape. That pan catches any drips so they cannot fall on your food. This wastes the whole top shelf of my smoker, but that's OK.
I fill the maze up HIGH. The deeper (taller) the pellets are, the more heat is generated at the "burn front" as the pellets work their way along. That higher heat helps drive moisture out of the adjacent unburned pellets so they're dry and ready to burn when the cherry reaches them. This goes especially for the corners! To make it burn around the corners, I've got the pellets high and deep. It doesn't matter if it "jumps across" at the corners, after all.
You have to make sure the pellets are not touching between rows everywhere else to keep it from short circuiting, but I get them piled high and then nudge them away from each other where they're too close.
Looking at your photo of your maze, that's not anywhere near as deep as I pile mine. Up well over the height of the separators, just not touching or too close. Gotta experiment a bit!
I light the pellets on the left end, farthest from the air inlet. That way, as they burn further, they get closer to the air source to help them burn later on in the run after they may have absorbed moisture again.
Also, as part of my modifications removing the original chip tray and drawer, I also installed a crude aluminum deflector that forces the air coming into the hole where the chip loader used to be over to the left and down, so it's blowing directly over my pellet maze. That also keeps drips from being able to fall on the heating element. Burning drips of grease and stuff off of the food will create nasty smelling smoke.
The maze is up on the wires at the left, bottom of the smoker so that it's up well off of the floor of the smoker to help with airflow beneath it.
I always have a drip tray above the pellet maze to prevent drips from being able fall into it. Not only does that help it burn properly, but drips getting directly onto the pellets will burn and create a bitter, nasty taste to the smoke.
I light the pellets with a Mapp Gas torch, and I've actually caused at least one of the spot welds on my maze to fail from getting that whole corner cherry red. I light the pellets an inch or two into them, not just the very edge.
I let it burn for ten minutes or so, and then I use a small computer fan, held in my hand, to blow on the burning end of the pellets. This will blow the flame out, but stoke the cherry massively to the point that when I take the fan away, it re-ignites into flames again! Once it'll re-ignite like that, I let it burn for a short while to actually cool down, and then I blow it out. Sometimes that's hard to do! Sometimes I have to close the door of the smoker and let it burn that way for a few minutes and then open the door and blow out the flames.
At that point, the pellets are ready to go. And I've had no troubles with them going out since I've followed that method.
You probably won't need to do all of those things because you're at a lower elevation. But you do have much higher humidity from the sounds of it. So maybe you will need to do a lot of those things.
I don't have access to my photos here now, but I can post some shots of the setup later if anyone wants to see the mess in my MES.