Uneven heating with the 40" MES Gen 1

Discussion in 'Electric Smokers' started by dr k, Oct 31, 2015.

  1. dr k

    dr k Master of the Pit

    Those that have a  40" Gen 1 know how easily the AMNPS works in it but It's not easy to get even heat across the grates. Since I got this smoker in May I've been running four temp probes on the four corners of the second grate from the top.  The right rear corner was always way hotter than all the other corners and the left corners were significantly cooler.  All the corners were out of balance.  I could smoke two 1lb. chubs of ground beef for chili in the center third of the second grate and the finished IT would be ten degrees different from the other.

    I made a deflector shown in past posts which was better than no deflector then saw Bear's simple design to get heat to the left side of the smoker as well as away from the smoker temp sensor.  Then the heat would come back to the right side out the top vent.  That was the best heat deflection so far but still big corner temp differences.  So I used his idea with a few of mine.  The pic below is what I'm doing for even heating.

    The water pan sits closer to the door than the back wall because the grate holders aren't centered on the side walls, directing heat up the back wall.  If you move the water pan up an inch to the flat grate holder or any other position other than the one intended to hold the water pan, it can be centered in the smoker.  Just put a grate over the water pan and have the two parallel wires on the grate straddle the pointed ends of the water pan then lift off the grate put it at the level you want. 

    Cardboard burns at 451*F and many food companies use cardboard containers that can be heated in the oven as long as it's seven inches away from the heating element.  I have 8.5"X11" standard paper sized pieces of cardboard that come one in a package of my business order forms.  I put a grate on the bottom Ievel with the beveled edge towards the door so the grate is flat at the right rear corner.  I wrapped the piece of cardboard in aluminum foil (shown not foiled for contrast) and butt an 11" side up against the back wall and as far as it could go to the right wall (there's a small crack between the cardboard and right wall where the cardboard butts up to the grate holder.)  The cardboard blocks heat from going up the back wall/right rear corner past the MES temp sensor straight to the vent.  The foil wrapped cardboard isn't phased from the heat.  It's the right size, disposable and available to me.  I can always look for something more durable like Bear has.

    Moving the water pan to the second from the bottom level allows heat to not be trapped.  It seems to make the heat work it's way around the smoker since the water pan is elevated and centered in the smoker.  Drippings that fall into the water pan don't vaporize as much, being farther from the heating element.  All top three grates can be used. 

    This set up gets me heating cycles that coast up and down within 10*F.  Setting the MES temp at 235*F gets me an actual 235*F average on the four corner probes.  The smoker above is a new spare I'll use as an outdoor warming oven for up coming holidays etc.  The $273.00 one from Amazon arrived so dented in the back MB sent me a new one.  Both operate flawlessly.  I did mock ups in my house.  The one outside is black and seasoned.  I'm still on the fence with selling this tested but unused smoker.

    redheelerdog likes this.
  2. bearcarver

    bearcarver Smoking Guru OTBS Member

    Looks Good, Kurt !!

    I had my Deflector above my water pan----Maybe that's why I had to elevate the left side of the deflector to push the heat to the left, and your cardboard is just laying flat.

    Now that I'm using my Gen #2.5 instead of my Gen #1, none of this is needed. The changes made fixed these problems, like I was hoping they would.

    Last edited: Oct 31, 2015
  3. bill1

    bill1 Smoke Blower

    temperature measurements of air taken close to a wall probably are just an indication of how well or how poorly the wall is insulated at that spot.  How do temperatures vary in a volume corresponding to where your meat will be placed?  As long as that is fairly uniform, I think you're good.  
  4. bearcarver

    bearcarver Smoking Guru OTBS Member

    I don't know about Kurt, but I always keep my Maverick Probes at least 3" from any wall. I imagine Kurt does too.

  5. redheelerdog

    redheelerdog Master of the Pit SMF Premier Member

    Thanks for the info Kurt. I have a 12"x12", .25" steel plate positioned in the back right corner of my MES 30, it helps allot with getting the heat to flow more up towards the middle.

    Sounds like you really got that baby dialed in.

    Have fun!
    Last edited: Nov 1, 2015
  6. bill1

    bill1 Smoke Blower

    I agree that if the sensing element is at least 3" from a wall, the effect I mentioned is minimal.  
  7. dr k

    dr k Master of the Pit

    Yup. Four inches from the corners or so which is about three inches from the walls.
  8. brickguy221

    brickguy221 Smoking Fanatic

    On my BT Smoker, temperatures taken close to the walls read close to same as controller reads. Temperatures 3" from the walls are 15* or so less that what the controller reads, so if I want shelf temp of 235*, I set controller at 250* and it works out good.
  9. bill1

    bill1 Smoke Blower

    I'm coming to the conclusion that all these smokers would benefit from a convection oven-style fan that just moves and mixes hot smoke around inside the smoker.  You'll still have the same basic thermal properties that cause draft and overall flow from inlet to exhaust but I think we need to "mix it up" more inside.  The speed of the smoke past the meet should help increase flavor too.  

    High temperature integrated motor/fan units that would mount completely inside a smoker would be expensive.  But I think we can rig up a cheap motor that sits outside the hot smoker and just a shaft through a teflon bushing feeds into the smoker where metal fan blades rotate.  For those that believe in water pans, putting the fan close by should help with evaporation and smoke "humidity" as well.    

    Anyway, it's on my list of mods to try.  
    dr k likes this.
  10. dr k

    dr k Master of the Pit

    Wow!  That's a big piece for a Mes 30.

  11. dr k

    dr k Master of the Pit

    It crossed my mind.  Your idea of having the motor on the outside kind of like the induction motors on a furnace seems to be a good idea.  It doesn't even need to spin fast or it could be a fast tiny propeller.  I was thinking about the inside corners of the smoker being rounded like a 1/4 pipe in each corner or strips of metal to make two 45* angles in each smoker corner instead of the one 90*.  The motor could be opposite the corner of the heating element at the bottom blowing to a corner next to it to start a circular convection at the bottom and the heat take it up.  Just moving the water pan from the bottom level to the second from the bottom keeps heat  moving more evenly in these MES tall ovens.


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