I have 4 different thermometers in a still air incubator. The digital reads 98. The one that came with the incubator reads 102. One, an aquarium thermometer reads 100. The other one, a regular thermometer reads 104. They are in 4 different areas of incubator. Which one do I go by? Last night, I did have 2 reading the same. I have not put eggs in yet, just trying to get temp right.
Too many variables. Too many thermometers and too many locations in the box. Eliminate the too many thermometers variable. First, choose the thermometer of highest quality, one of the glass tube type, but not the one that came with your still air which has the degree index on a slip of paper. No. A good old fashioned, glass tube thermometer. Then, bring your incubator up to temp. Have a couple of water drinking bottles filled with tepid water, approx body temperature, your body temperature. Place a couple of those in the incubator as heat sinks to simulate the bio mass of eggs. Wait. Wait Wait. Wait at least 4 hours for the temperature to stabilize and begin taking a reading. The thing is that you're going to have to find the "mean" or average temperature in three or four places in your box. Back corner, front corner, middle, etc. You'll likely find a 2 or 3 degree swing between those areas. That natural without a fan moving the air about. You'll want to "average" about 101 on a still air unit and have no spots above 102. 103 will begin to kill eggs. And good luck. Have patience. Don't rush the egg deployment until you feel it is safe to put them in.
Another way to get an idea of accuracy is to use a bulb thermometer in ice water. Get a glass of ice and put some cold water in it. Wait 2-3 minutes let the water come up to ice temp. Then put your bulb thermometer in the glass of water. It should read 32 degreesF. Once you know that thrmometer is accurate (or how far off that thermometer is) you can put that thermometer with the others all together in the bator, (side by side) and let them all come up to temp. Then you can compare to the checked thermometer and have an idea of what ones are right.
Just remember, that you get huge differences in where you place the thermometer in the incubator. Still airs are like that. Have no place above 102 and try to hit an average of four different places that you can live with.
I've found even in my forced air, I have hot/cool spots, so I can imagine the difference in the stills.
Hot air rises so in a still air the elevation you put the thermometer in is extremely important. A normal recommendation is 101.5 F at the top of the eggs. If you measure it some place other than the top of the eggs, then you need a different reading. There are two different issues with thermometers. One big one is that due to manufacturing tolerances, many just don’t read right. Next time you are in a place that sells outside thermometers look at the ones on the shelf. It’s pretty normal for me to find 5 to 9 degrees different in the high to low. That’s with them on the same shelf in a climate controlled building. Especially don’t trust the one that comes with the incubator, regardless of make or model. They are often way off and preset temperatures are often not that accurate. Check them out before you trust them. The other issue is repeatability. Some thermometers, like most of the ones you hang on your porch, are made to be repeatable to 1 or 2 degrees. That means if it reads 99 one time, the next time it might read 101 although the temperature is the same. What you need to do is get a thermometer that is accurate to within 0.1 degree. That means its repeatability is really good, close enough for out purposes. Then you need to calibrate it. I’ll give you a couple of links for that and throw in a hygrometer calibration method just because I have it. Good luck. Calibrate a Thermometer http://www.allfoodbusiness.com/calibrating_thermometers.php Rebel’s Thermometer Calibration http://cmfarm.us/ThermometerCalibration.html Rebel’s Hygrometer Calibration http://cmfarm.us/HygrometerCalibration.html
At the ALBC conference Don Schrider said if you use two thermometers to take the average of the two and go with that. 99.5 is the so called ideal temp but I've never seen a hen using a thermometer so how do they know? I've read a temp of 100 - 101 isn't bad. Mine runs 99.7- 100. and I've got to live with that. So what to do. Use a digital and if you use two average those. Pull two of yours or you'll just drive yourself crazy and that's my job. Keep in mind placement of your incu is also important. A room average temp 70-80* and little occupancy. You don't want breezes or drafts. Put one of those thermometers on an outside wall. I wish you well.
