another maverick probe question

Discussion in 'Meat Thermometers' started by soymateofeo, Jan 27, 2016.

  1. soymateofeo

    soymateofeo Newbie

    OK  I got myself the 732 and it seems awesome except for one thing.  I set the probes next to each other (meat and internal) and they are off by about 5 degrees from each other.  I did not put the meat probe in any meat but left it sitting in the chamber right next to the internal probe.  Is this a problem or is that to be expected since they are different probes and acting differently?  =)
  2. joe black

    joe black Master of the Pit OTBS Member

    One probe is made for the IT of the meat. The other probe should be placed close to the meat, but at the grate, about 1" above the grate. The probes are the same and inter-changable, but the difference is the feeds that they are plugged into at the reader.

    I hope someone else can give some more detailed information and perhaps confirm or add to my explanation. (or the attempt at an explanation, I'm not a techie)

    Thanks, Joe
  3. smokinal

    smokinal Smoking Guru Staff Member Moderator OTBS Member ★ Lifetime Premier ★

    I would check them both in boiling water. They should both read about 212. The food probe reacts to changes in temp slower than the pit probe, I think. Or is it the other way around. Either way they should both read 212 in boiling water & close to 32 in ice water.

  4. daricksta

    daricksta Master of the Pit OTBS Member

    Did you place both probes in boiling water to calibrate them? I did that when I received my ET-733. Both probes read the same. Did you try switching the probes so that the one that was connected to the #1 jack was now connected to #2 and vice versa? The probes themselves are interchangeable but perhaps the sensor in one was less sensitive than the other. Keep in mind that even a temp difference of 2-3° between the two probes or even the two jacks is within design specs.
  5. joe black

    joe black Master of the Pit OTBS Member

    Checking in boiling water should be done several times a year to stay right. However, 212* may not be the magic temp. Be sure to check your elevation as that will determine the exact boiling point of water. I'm in Greenville, SC at approximately 1100' above sea level and my BP is 210*.

    Good luck, Joe
  6. johnmeyer

    johnmeyer Smoking Fanatic

    Can the 732 be calibrated? I just looked at the manual and saw no mention of that. It would be really cool if I could add or subtract an offset.

    I too have observed, at room temperature, a 2-3 degree (F) difference between the two probes. The difference, at least with my unit, is entirely in the probe, so if you interchange the connections into the transmitter, the temperature readings also switch to the other side.

    I have checked the probes using boiling water and an ice water bath, and they usually read within 1-2 degrees of where they should be.

    BTW, if you are more than 1,000 feet above sea level, you need to read this chart (or any other chart) to adjust the boiling temperature reading you are looking for:

    If you want even more precision that offered by this graph, and are major-league geek like me, you can use the following calculator which will give you the precise boiling temperature, including not only altitude, but also barometric pressure (you pilots know all about this):

    Water Altitude Calculator

    When doing the ice water test, you need to stir the water and ice, and keep doing that for at least a minute. It works better if you have an ice crusher, but that isn't absolutely necessary. If you are really trying to be accurate, you should do both tests with distilled water, but this is probably only necessary for a true precision instrument, like the Thermapen. Various minerals can change the temperature reading considerably. For instance, for those of you who have made ice cream the old-fashioned way, adding salt to the water/ice mixture allows the water to get to a lower temperature without freezing. Therefore, if your water is a little brackish, as it is in many wells near the ocean, your ice water bath is probably going to give you a reading lower than 32 degrees.

    Sorry if this is too geeky, but forty years ago I worked at the test and measurement division of Hewlett-Packard and wrote papers on how various measurements could be traced back to the National Bureau of Standards, including all the accumulated errors along the way, so you could say: "this thermometer measures temperature in the range of 32 to 550 degrees, +/- 0.7 degrees, traceable to the NBS."

    BTW, when I do these tests on my Thermapen, it is dead-nuts on. 32.0 and 210.9 degrees (boiling temperature at my altitude). It is an amazing piece of equipment.

Share This Page