Wow, a smoked pork butt is an ambitious first smoke!
I second everything already said:
- no need for water;
- clean out the chip tray after each use (the remnants will only give you a few minutes of smoke);
- clean the trays and door gasket after each smoke;
- line the water tray and drip can with aluminum foil (put it on both the top AND the bottom of the drip tray).
Also, put some aluminum foil under the front door, going all the way under the front feet, to catch moisture and grease that drips out of the front door.
To know when to add chips, look at the smoke coming out of the vent. Always leave the vent open. You can close it while preheating to slightly speed up the process, but I can't think of any other reason to close it. Also, I store mine with the vent open and, before putting it away after use, I leave the door open for several hours to let as much moisture evaporate as possible. You have more humidity in San Diego than I have in Carmel, but either way, the inside of that thing, if left damp, can (and will) mildew.
Another way to figure out when to add chips is to use a flashlight to look into the chip loader opening. You can then easily see how many chips are left. In general, when doing a smoke at 225-250 (the range you should consider for your pulled pork) you will probably need to add chips every 30-45 minutes. If you get tired of this, you can purchase the A-Maze-N 5x5 AMNPS smoker, and put that in the bottom of the MES, on the rails to the left of the smoker tray. I bought one a month ago (I've had my MES for about three months), and it is really good for two things: low-temperature (160 degree and under) smokes, and really long smokes, like the 12-15 hours it will take you to finish your 8-pound pulled pork butt.
The other advantage of the AMNPS is that is provides continuous smoke whereas the MES, except at really high temperatures, tends to give you smoke only when the heating element is on. It cycles on and off in order to maintain the temperature you set, so you will find that you sometimes get 3-4 minutes where the smoke thins out. For 225 and up, this isn't a huge problems, because there is still some smoke inside, but with the AMNPS, the smoke is continuous. For lower temperatures, you definitely cannot get enough smoke without using it.
Oh yes, for the pulled pork, you absolutely need to read some of the posts on doing this. Start with Bearcarver's "bible" on the subject.
Boston Pulled Pork-step-by-step
The key thing to learn about is the "stall" where the temperature of your butt will suddenly stop increasing, usually in the 150-165 degree range. It will do this for hours. I keep notes on all my smokes, since smoking is more of an art than a science, and even with recipes, you still have to adapt, and here is what happened with my first pulled pork smoke. Note that from 1:00 until I finally "threw in the towel" and put the pork in foil, the temperature did not increase by more than two degrees.
Oh yes, you must use a thermometer.
Pulled Pork Butt
3:30 a.m. Out of the fridge
7:30 a.m. Preheat smoker to 245°
8:00 Start cook at 245° w/ hickory chips
2 cups of water in pan w/ ½ cup cider vinegar. Meat at 55°.
9:00 Meat at 77°. Adjusted MES down to get reading on Maverick to 245°.
9:35 Meat at 100°.
10:00 Meat at 115°. First mop with apple/rum spray
11:00 Meat at 135°. Mop.
12:00 Meat at 145°. Mop
1:00 Meat at 151°. Mop
2:00 Meat at 153°. Mop
3:00 Meat at 153°. Mop
4:00 Meat at 153°. Mop
5:00 Meat at 153°. Mop
5:30 Meat at 154°. Put meat in pan and covered with foil. No more chips
6:00 Meat at 158°. Increased smoker temp to 250°.
6:30 Increase smoker temp to 260°
7:00 Meat at 174°
8:00 Meat at 196°
8:15 Meat at 199° Took it out of the smoker, pulled enough for dinner, and let the remainder rest for 2 hours.
Total cooking time: 12:18
Next time: foil as soon as it starts to stall. In the above, that would be at 2:00 instead of 5:30.