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DigiQ 2 vs Tel-Tru vs BGE thermo

Carolina Q
Carolina Q Posts: 14,831
edited November -1 in EggHead Forum
Ok. My new Digi Q arrived today. Recently got a new Tel-Tru 200-1000 as well.

Checked the boiling water calibration on the Tel-Tru and it was spot on. Did the same with the BGE thermo. Perfect.

Installed the Guru, set to hold 400°

Lit the lump, clipped the Guru's pit probe to the Tel-Tru, opened the small holes on the DFMT about half way.

Sat back with a beer to see what would happen.

Temps aren't even close. Opened the petals on the DFMT til fully open. TT managed to get to 400°, but the Guru said 430°!!

Removed the TT and replaced with BGE thermo. Same story.

After nearly an hour, I now show 360 on the dome gauge vs 400 Guru - which is clipped TO the dome gauge! In other words, temps are all over the place and the current 40° difference seems rather a lot! Am I doing something wrong?

I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

Michael 
Central Connecticut 

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Comments

  • ResQue
    ResQue Posts: 1,045
    Not sure but if you are doing something wrong then so am I. I have the same problem with my stoker. I need to check my stoker's pit probe in boiling water.
  • 2Fategghead
    2Fategghead Posts: 9,624
    Michael, I have everything you got except I got the CyberQ II. I don't know if the pit probe are different at this time but in the past I did check all my probes in boiling water and all was close except my Maverick and I kept that in mind. Keep in mind the notch on the Tel-Tru is where the probe needs to be in the water not the very tip. :unsure:
  • 2Fategghead
    2Fategghead Posts: 9,624
    You have a thermopen you can check them with.
  • Carolina Q
    Carolina Q Posts: 14,831
    Yeah I figured so that's where I put it. Guess I'll follow their calibration instructions if I ever finish this cook. It's real exotic - baking a potato now, just about to add a chicken breast. Should eat by 11-ish! :angry:

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • Carolina Q
    Carolina Q Posts: 14,831
    good point, except mine is weird when I use it to check air temps. Takes forever to settle on a temp. Not sure I believe what I see.

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • Carolina Q
    Carolina Q Posts: 14,831
    It shouldn't be this difficult, should it?! It's JUST a GRILL!! :laugh:

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • Michael:

    Over the years I've seen a temperature disparity between the dome thermometer and the temperature at the grid discussed on the forum as being a natural 25° or so difference.

    I have the old grandfather generation Guru and I have always clipped the alligator to the grid, not to the Tru-Tel dome thermometer, and observed the above is pretty well always true.

    My very basic and simple Guru directions said to clip it to the grid near the meat, so I just did as I was told. My hair got gray from worrying about other things.

    Judy in San Diego
    Judy in San Diego
  • If you look at those Stoker videos again, all the thermometers are in synch. :P :evil:
  • Carolina Q
    Carolina Q Posts: 14,831
    Thanks, Judy. Maybe I should set it for a target of 375° next time and clip it to the grid. In fact, I think I'll go do that now and see what happens. I'm just use to using dome temp!

    My hair got gray because of my parents. :P

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • Carolina Q
    Carolina Q Posts: 14,831
    Never knew THAT was coming! :laugh: AND, I could be looking at it on my Mac!! For the same price too! Hahaha...

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • 2Fategghead
    2Fategghead Posts: 9,624
    Not to be a smart a$$ but, recently I called ThermoWorks about what you just said. Here is what they told me nicely over the phone.

    http://www.thermoworks.com/blog/2010/11/temperatures-dont-lock/
  • I think this is a case of RTM. You have to calibrate this too, although some products are made better and come calibrated out of the box--Stoker.

    Your answer is page 12 & 13 of this.
  • Carolina Q
    Carolina Q Posts: 14,831
    Maybe I didn't say it well. When I stick it in a roast, it's fine. When I use it to check AIR temp, it takes forever. Therefore, I just wondered if it's really not intended for air temps. Eventually it gets there, but it's certainly not instant - mine isn't anyway.

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • ResQue
    ResQue Posts: 1,045
    But I thought you had the red one? :whistle::lol:

    The green one is much faster for checking air temps ;)
  • FlaPoolman
    FlaPoolman Posts: 11,676
    I told you you should have bought the hearing aid :whistle: :laugh: :laugh:
  • Carolina Q
    Carolina Q Posts: 14,831
    Thermapen is actually YELLOW. It's better at meat temps. It's the Guru that's red - and so far, it ain't even CLOSE. Or else both dome gauges are off. :laugh:

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • Carolina Q
    Carolina Q Posts: 14,831
    Thanks for the help...Mr. Fassel. :laugh:

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • Carolina Q
    Carolina Q Posts: 14,831
    Yeah, that doc comes with the unit. Thanks though. Shouldn't HAVE to calibrate a brand new $300 device!! :angry:

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut 

  • You one of those guys that blame everything on your parents? Sheesh! Man up!

    Judy
    Judy in San Diego
  • Grandpas Grub
    Grandpas Grub Posts: 14,226
     
    Oh Pat that was just junk yard dog mean. :laugh: :laugh:

    Kent
  • Grandpas Grub
    Grandpas Grub Posts: 14,226
     
    Some observations on my stuff. Maverick is about 20 to 40 degrees off anything.

    My digiq is within a few degrees of the stoker. Both the stoker and q2 are within 10° of the bge dome thermometer.

    When clipping to the dome thermometer and q2 or stoker if the clip is closer to the ceramics than the tip of the dome thermometer. I try to clip just above the 'indent' on the dome thermometer when I am clipping to the dome.

    At the grid the q2 & stoker are within 10° when clipped at the same place. Meat probes are within 10° when placed in the same spot in the meat.

    I have gotten to a point where I don't stress too much over it. 10 to 30 degrees doesn't make a lot of difference until I get to the end of the food cook.

    Kent
  • Grandpas Grub
    Grandpas Grub Posts: 14,226
     
    "it ain't even CLOSE. Or else both dome gauges are off"

    That's because those are silver.

     
  • srq2625
    srq2625 Posts: 262
    A thought .... I've read that putting a probe in direct contact with anything metel in the cooker is a sure way to get erroneous readings. Don't know if it's true or not, but I don't do that any more.

    By doing the calibration, you know that these two instruments are reading correctly (at least at 212°F :)). I'm wondering if clipping your DigiQ probe to the Tel-Tru might be causing the Tel-Tru to be operating in an environment for which it was not designed.
  • SmokeyPitt
    SmokeyPitt Posts: 10,490
    Have you checked the pit probe from the guru in boiling water? You might also go ahead and check in a cup of ice water to see if it is close to 32F. If it is off, I suppose the next step would be to recalibrate as you mentioned. It is odd that it didn't come calibrated from the factory. The calibration instructions in the manual look straightforward enough.


    Which came first the chicken or the egg?  I egged the chicken and then I ate his leg. 

  • Let us know how far off the DigiQ is when you calibrate it. I'll bet it isn't off by more than a couple of degrees.
    The Naked Whiz
  • You need to understand how the unit works. There is a micro-thermocouple inside the SS probe. It is sensing the temperature of the probe, not the meat or the air. So, getting an accurate reading is entirely dependant on the temperature of the metal probe moving to the temperature of what you are measuring. Since air doesn't hold much heat, it takes a lot longer for the probe to change temperature and get to the temperature of the air around it than it does if you place the probe in something that holds a lot of heat like water or meat. Try boiling water in an oven vs. on the stove. The air in the oven contains very little heat to be transferred to the water, so it takes a long time. The heating element on your stove holds tremendous heat and the water heats up much faster.

    Thermoworks makes a probe which is more suiting for measuring air temperature. It has holes in the end of the probe so that the thermocouple is in contact with the air directly and can thus measure the temperature of the air rather than waiting for the air to heat up the metal of the probe first.
    The Naked Whiz
  • Regarding the comments that a $300 device should be calibrated at the factory, they are actually. All the units are calibrated to a traceable standard before they leave the factory. FWIW, the worst probe error I have seen with all my units and probes was about 7-8 degrees on one unit. All the other units have been within 2 degrees. I calibrated the unit with larger error and it was then spot on.

    In interest of fair and balanced reporting, I should say that the probes I tested with The Stoker were slightly less accurate, but only by a small amount, nothing worth talking about. The Stoker probes are also calibrated at the factory and can be adjusted by the user.
    The Naked Whiz
  • rooster
    rooster Posts: 252
    read The boiling point calculator under the cookbook heading. That makes a small difference.
  • Hatch
    Hatch Posts: 149
    The DigiQ is calibrated here at the factory to the standards set by the NIST.
    If you have any concerns please ffel free to give us a call.

    Kenny
  • Carolina Q
    Carolina Q Posts: 14,831
    Thanks, Kenny. You were very helpful and it was great talking with you this afternoon. At your suggestion, when I cook the butt this weekend, I will clip the pit probe to the grid and set the Guru target temp to about 225°. In theory, that should give me 250° dome, which is what I'm used to.

    As I mentioned, I had calibrated both the Tel-Tru and the OEM Egg thermo just before last night's cook. Today, I checked the pit and meat ports on the Guru. I did not recalibrate, just checked readings. They both read 210-211° in boiling water so everything reads the same. Still not quite sure why they don't when clipped together, but as long as I know they are all accurate, I can manage. Wonder if it has anything to do with the clip that's on the Guru's pit probe? Don't see why it would.

    Another option we discussed was simply replacing the dome thermo with the Guru's pit probe. As I understood you, that should be fine as long as the tip of the probe is at least an inch inside the dome. I doubt I'll do that, but it might be interesting to try, just to see the results.

    I had the 10CFM blower damper open about halfway for last night's 400° cook. Will close it to about 1/4 for the butt.

    Thanks again for your advice. I appreciate it!!

    I hate it when I go to the kitchen for food and all I find are ingredients!                                                                                                                                                                                                                           

    Michael 
    Central Connecticut