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MES 40 - Troubleshoot cause of temp reading on display higher than actual temps

cman55

Smoke Blower
127
14
Joined Dec 24, 2012
Learned a hard lesson with the MES's temp anomalys. I just invested in a Maverick 732 and plan to use it in the future for accuracy and use the MES's readings just as a ballpark. Masterbuilt might want to look into this issue at some point down the road. 
 

hoity toit

Master of the Pit
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Same problem with mine.,,,,still under warrantee. Only 2 month old. Masterbuilt says if i cut the cord off, pop the nameplate and send proof of purchase they will begin the process of replacing the cabinet and controller...bummer. 2 month old unit have to take it apart and pay shipping to them. i think not.

I use the Mavs 2 of them. I wont be buying from Masterbilt again. Its great they are willing to replace the parts...but I dont understand why I have to disassemble the unit and go thru that hassel. They should issue a prepaid FEDEX call ticket and ship out a new unit. Just my opinion..

For now I'll live with it like all you other folks. :(

 

njfoses

Meat Mopper
212
13
Joined Oct 6, 2012
Same problem with mine.,,,,still under warrantee. Only 2 month old. Masterbuilt says if i cut the cord off, pop the nameplate and send proof of purchase they will begin the process of replacing the cabinet and controller...bummer. 2 month old unit have to take it apart and pay shipping to them. i think not.

I use the Mavs 2 of them. I wont be buying from Masterbilt again. Its great they are willing to replace the parts...but I dont understand why I have to disassemble the unit and go thru that hassel. They should issue a prepaid FEDEX call ticket and ship out a new unit. Just my opinion..

For now I'll live with it like all you other folks. :(

Probably not worth the hassle.  The replacement is likely to have the same exact issue.
 

ratboy5000

Newbie
13
11
Joined Feb 4, 2013
Ialso have the same mes40 i was also having heat trouble. I called masterbuilt and they are sending me new components to see if that will help. if not they Said they will replace the unit. i hope it doesn't so i get a new smoker and i'll have a cold smoker for free...
 

bigtexun

Newbie
28
11
Joined Oct 6, 2012
Sounds like the controller needs to be replaced with a PID, thermocouple and SSR.

Then you can set any temperature, and have a quality controller.  I know that is not what anyone wants to hear, but after reading through this thread, it seems like there is a basic quality problem with the system.

Those of you that have been asked to cut the cord and send in the nameplate for a replacement, should use the remains of the "bad" unit as an excuse for a project to replace the crappy controller with a nice PID based controller.

Of course it's not free...  The PID is around $25 to $35, the termocouple is $6 to $15, and the solid state relay is about $12.  I know you already paid Masterbuilt to do this for you in the first place...  But think of the pride you will have knowing that you did it right...

I'm getting ready to add a temperature controller to my charcoal grill, so I can get better control over the temperature.  My problem is I get the temp just right, then the wind kicks up and causes the temp to shoot up by 50 degrees while I'm sleeping.  I need something that can automatically adjust to changing ambient conditions... but it is nice to also know you have something that is accurate.

But yeah, you need good temperature control, and the full temp range you are supposed to have.

Just keep in mind that the PID will let you set any temperature, so there is a basic safety problem...  So you may want to add a limit switch, like perhaps a snap-disk switch calibrated for 275 degrees, or some other over-temperature control.  Some PID's may have a limit you can set, but a overtemp device would be a good safety measure.
 
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reinhard

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i have a Masterbuilt and i had what i thought was a faulty controler "brain box". up here in Minnesota it gets cold and i grill and smoke all year.  i did the break in for three hours and the next day fixed up about a 10 pound batch of venison summer sausage. to smoke the next day. well i was all excited the next day, stuffed the summer, and went out to get the smoker going.

plugged in the unit and no power on the control panel. no lights nothing. followed the troubleshooting guidelines and everything was fine with power going to the unit. well i unpluged the brain box and called Masterbuilt. told them what happened and they sent a new brain box on it's way. in the meantime i go to a butcher buddy of mine [i'm a former butcher and worked for 35 years].  he and another guy have the same Masterbuilt and had no problems with them for 3 years or so that they had them.

he asked me if i left the brain box outside [control pannel]. i said yes, didn't say anywhere in the book to take it off. he told me to take the brain box in the house because the gel in the digital area froze. thaw it out and put it back on and turn the unit on. i did that and sure enough it worked fine. so now i have two of them.

i'm only saying this incase there are some of you that do have cold climates at some time of the year. if you do have cold winters, make sure you take that brain box in the house with you when not in use. the cold doesn't bother the unit once it's on.  so far i have had no issues with my smoker and am happy with it. it does say in the manuel that temps may fluctuate 10 to 15 deg at times. i found this thread interesting and helpfull in case i run into problems of this sort. Reinhard
 

jarhead

Meat Mopper
243
17
Joined Nov 8, 2011
Well, I'm glad y'all had better luck with their SUPPOSED Customer Service than I have.

Mine is 3 weeks new and it was the last one that Sam's had.

Brought it home, seasoned it per directions, smoke coming out of the top of the glass. WTF?

Next day, I went to smoke a couple pork butts. Set the temp at 275 and checked the grate temps with the ET-732 after about an hour. 230 max on the hottest shelf.


Since then, I have sent their CS 2 emails and called twice. Nothing!!! It's been 3 weeks.

Sam's has a return policy, this is going back and I will never get another MB product again.

Maybe that's the reason Sam's discontinued carrying them. Too many returns for junk equipment.

JM2C and YMMV

Oh yeah, it shocked the he!! out of me too. Don't touch anything metal unless you like getting zapped.
 
 

linguica

Master of the Pit
1,170
27
Joined Sep 8, 2012
Well, I'm glad y'all had better luck with their SUPPOSED Customer Service than I have.

Mine is 3 weeks new and it was the last one that Sam's had.

Brought it home, seasoned it per directions, smoke coming out of the top of the glass. WTF?

Next day, I went to smoke a couple pork butts. Set the temp at 275 and checked the grate temps with the ET-732 after about an hour. 230 max on the hottest shelf.


Since then, I have sent their CS 2 emails and called twice. Nothing!!! It's been 3 weeks.

Sam's has a return policy, this is going back and I will never get another MB product again.

Maybe that's the reason Sam's discontinued carrying them. Too many returns for junk equipment.

JM2C and YMMV

Oh yeah, it shocked the he!! out of me too. Don't touch anything metal unless you like getting zapped.
 
It's hard to believe that CS would ignore a three week old unit that has become a shock hazard. That's solid grounds for a law suit.
 

indian george

Newbie
6
10
Joined Feb 6, 2013
I am a Custom Knife maker . I built  propane forges. That I use Pids to  control them I use K Type  thermo-couplings and wire. I  can use them on my smoker, toaster oven and etc.I run a solenoid with it too,it  controls the propane flow.Just be sure you use the correct wire , that is compatible with the coupling..
 

bigtexun

Newbie
28
11
Joined Oct 6, 2012
Yeah, turning things on and off based on temperature is pretty easy to do, from an engineering perspective.  From what I have seen, Masterbuilt has a assembly quality issue, as well as a technical problem with the accuracy of the probes.

Correcting probe inaccuracies should be easy, but not if your probe is reading high, and you want to cook at those high temps.

And regarding the correct wire...  Yeah, all a thermocouple is is a dissimilar metal junction, so a poor wire selection will cause inaccuracies.  The best thing is to get the thermocouple with a long enough lead that you don't feel compelled to add wire to make it longer.  You also want to select one designed for high temperatures so that the insulation can handle the heat.
 
 

bigtexun

Newbie
28
11
Joined Oct 6, 2012
Oh yeah, it shocked the he!! out of me too. Don't touch anything metal unless you like getting zapped.
Th3e shock hazard could be a wiring fault in the unit...  But it can also be a wiring fault at the outlet.  Don't these have a grounded 3-wire plug?  If it has a grounded plug, and the ground wire is connected to the chassis, then there is a problem with the outlet it is plugged into.  Check the ground wire resistance to the chassis, or check the connections inside the chassis.

As for poor customer service, you should talk to a couple of the people that got good service...  It may be that they have different contact info than you have.  Sometimes a Manufacturer will change contact info over time, or to certain retailers.  The worst is when they outsource...  But they will typically still maintain the old contact numbers, so if you can get an old number you may get better service.

Another problem with email, is that if their spam filter threw your email away for some reason, you will never hear back from them.
 

cman55

Smoke Blower
127
14
Joined Dec 24, 2012
Well, my MES40 Gen2's Controller finally gave up the ghost last night. Started to cold smoke some bacon today at around 0730. Outside temp was roughly 25F and dry but my controller read 310F. Ok, so I knew that was way off but I figured the unit must have gotten frozen over night or some moisture got inside the controller housing by some means so, I heated up the unit to 275F just to get the ice out and see if the internal temp sensor would come back online. Unfortunately, it is still waay off. I called Masterbuilt CS and talked with Becky. She very politely told me that the controllers are on back order and to check back in a week or two and they would be very happy to send out a replacement. She also assured me that the replacement work would be simple although I do have my doubts considering the controller is now part of the chassis and not sitting outside of the cabinet in the GEN2.  I must admit that I am disappointed with the quality of this unit as I purchased it for Christmas and babied this thing during several easy smoke sessions. I am hoping that the replacement Controller is indeed a fix and not simply a replacement. 

Keeping my fingers crossed..
 

briar

Newbie
2
11
Joined Jun 2, 2013
This is just an in general statement, but the more thermal mass the probe has (or is mounted to, its all a heat sink)... the more its going to read avg temps instead of highs and lows.

The built in probe should (under normal conditions) lag the maverick (in both directions) until temp is reached then the two should become closer.

To really check accuracy I would compare the avg temps of the two from readings taken over time.... deadband is another issue, close loop temp control circuits will have some deadband built into the circuit. The maverick doesn't need deadband.

I use to be a sears service man back in the day, and we would have complaints form little old ladies who would hang thermometers in their new oven and see a similar issue.

Once I showed them the math, they were usually happy and understood.

(not saying MES doesn't have an issue, just tossing my prior similar experience out there for what its worth)

B
 
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sigmo

Smoking Fanatic
★ Lifetime Premier ★
470
121
Joined Jun 4, 2012
That's a good point.  Most folks don't understand that the time constants of their temperature probes will have a great impact on what they see at any given moment, and they often expect one thermometer or sensor to read the same as another at all times.  Of course, that's impossible if the temperature is cycling up and down and the probes don't have the same thermal time constant.

One thing to remember, that was not obvious to me at first (but probably should have been) is that the thermal time constant of a probe is not entirely a matter of the thermal mass of the probe.  Instead, it's actually the ratio of thermal mass to surface area that's important.

I proved that to myself and some other very smart laboratory personnel where I used to work one time a number of years back.  We had a room that needed to be kept within some fairly tight temperature limits while an extraction (TCLP) was being performed.  I had initially installed a fairly small temperature probe to monitor that room, and we were annoyed to see the rather wide swings of temperature even though the average was holding what we wanted.

We all reasoned that the small probe was "seeing" much greater temperature extremes than the samples actually saw because the samples were fairly large (1 liter?) bottles full of (mostly) water.  Surely, a large bottle of water will experience a much slower change in temperature than a small temperature sensor probe, right?

I had this probe connected to a data acquisition system that monitored things constantly and allowed us to see things plotted on graphs.

So I got a 500mL (1/2 liter) glass bottle, filled it with water, and made a gland top for the bottle that allowed the same 3/8" stainless probe to be inserted so it was always held with the sensor at about the middle of that bottle of water.  I, and everyone else just assumed that the temperature graph would settle down and show a much smoother temperature curve, with far lower differences between the peaks and valleys of the temperature.

To everyone's astonishment, the chart looked virtually identical to what we were seeing with the probe "bare".  How could that possibly be?

But there it was, right in my face, and I'd made the changes myself.  So the experimental evidence showed that my "postulate" was incorrect.  Faced with that, I thought about it and realized that the thing that allows a probe to "see" a temperature change faster or slower is not the thermal mass.  It's actually the ratio of thermal mass to surface area.  The large glass bottle full of water, indeed, had a much much greater thermal mass.  Water has a high specific heat, and there was a half a liter of it there, that needed to be raised and lowered in temperature!  But the bottle's shape was not that dissimilar to the shape of the original probe!

So the surface area to "thermal mass" ratio was almost identical, as it turned out!

This also meant that the bottles used for the extractions were, indeed, (and unfortunately) also "seeing" these same extremes in temperature cycling.

I ended up building a temperature controller system for those systems that used a small air conditioner to cool as needed, and an electric heating device to heat when needed.  That keeps those extraction chambers well within the required limits now, but it turned out to be non-trivial, and I learned a valuable lesson about thermal time constants of sensors, bottles, and things in general!

Basically, big and massive doesn't equate to slow.  Again, it's the thermal mass to surface area ratio that's important in determining the thermal time constant of a sensor or a container.  So that gallon jug of milk DOES experience temperature changes pretty much at the same speed as a tiny bottle of jalapenos in my fridge.  And if I have two temperature probes, and they're made of the same stuff, and they're the same shape, it doesn't matter if one is a lot larger than the other.  The transfer of heat to and from the sensors to/from the surrounding air will be proportional to their sizes, so the thermal time constants will be the same for both probes.

I'm not sure why that wasn't obvious to me or the other (smart) folks where I used to work.  But it caught all of us off guard until we were forced to think about it by seeing the results of that "experiment" for ourselves.
 

Bearcarver

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For years, I've been keeping a GatorAde bottle, half full of water in my basement meat fridge. Then I have my Maverick Meat probe in that bottle, I also have the Smoker probe just hanging in the fridge. Then I have the Maverick receiver upstairs in my Dining Room. From there I am able to monitor the temp of the air in the fridge, and the water in the bottle. Once I get the fridge adjusted just right, the air in the fridge cycles from about 32* to 43*, and the temp of the water in the bottle never goes below 37*, and never higher than 38* (perfect curing temps). I do this to monitor the internal temperature of the meat I cure in that fridge, without having to put a probe in the meat. The water in the bottle is the same temp as the inside of the meat.

Bear
 

stovebolt

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  That's a fantastic idea. I will keep that in mind for future use. Thanks, Bearcarver.

Chuck
 
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Bearcarver

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  That's a fantastic idea. I will keep that in mind for future use. Thanks, Bearcarver.

Chuck
It works great !!!

And the batteries last for months, even leaving it on 24/7/365 !!

Bear
 

whitvt

Newbie
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10
Joined Sep 9, 2014
Well, I am experiencing the same issue. I have some cheap Hamilton Beach probes that seem to work using the boiling temp and freezer checks. But when comparing them to the meat probe and temperature sensor on the mes I don't know what ones are accurate as they all read different. The last 2 times I have smoked it seems like it has taken forerver to get the meat where I would like the temp to be at. So, now I guess I have to get some good temp probes  and do some checks/comparisons to the mes meat probe and smoker temps. What  pain in the ass. Can't someone just make a good quality product the you can rely on. I bet my smoker is at least 30 to 40 degrees colder than what the controller reads. Time will tell. I got my smoker last year in August.....
 

Bearcarver

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Well, I am experiencing the same issue. I have some cheap Hamilton Beach probes that seem to work using the boiling temp and freezer checks. But when comparing them to the meat probe and temperature sensor on the mes I don't know what ones are accurate as they all read different. The last 2 times I have smoked it seems like it has taken forerver to get the meat where I would like the temp to be at. So, now I guess I have to get some good temp probes  and do some checks/comparisons to the mes meat probe and smoker temps. What  pain in the ass. Can't someone just make a good quality product the you can rely on. I bet my smoker is at least 30 to 40 degrees colder than what the controller reads. Time will tell. I got my smoker last year in August.....
I think you'll find that on just about any smoker with a built in Temp Sensor.

I only trust my Mavericks, because it's easy to do a boil test for accuracy.

It's a shame my Mavericks don't have the distance that my MES Remote control has. My MES remote is usually the only one that works beside my Recliner.

Bear
 

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