Calibration question


8 Years
Sep 1, 2014
Hi everyone! Following from a horrible hatch failure last week, many of you suggested calibrating my incubator. I got a nifty thermometer/hygrometer from Amazon and I am testing it on various positions within the incubator.

This new gadget has a deviation on temp of +/- 1 degree Celsius. It's deviation on humidity is +/- .5 degree.

Now, my incubator is set at 38.5c because clearly it wasn't warm enough last time around. The new gadget is reading a fairly stable 36.6 along the sides of the bator and 35.1 in the centre of the bator.

Here's the question- should I go ahead and set the temperature higher by a degree to compensate for the potential variance in the new gadget? Or should I think that it's actually on target (around the sides because the centre is way too low) and its reading it a degree lower?

Oddly enough the humidity seems to be fairly on target between the bator and the gadget. It's off by a little but not enough to make me concerned. What are your thoughts?
I think you need to calibrate that nifty thermometer/hygrometer against a medical grade thermometer at 100 degrees. Based on my bator deviations, I try to keep real temp of 99.5 at the low spots, and am ok with it getting up to 101 in the high spots. Then, I rotate the eggs around so they hit the highs and lows. My hatches have been spot on, with internal pips day 20, hatches day 21 with several stragglers going into day 22. Are you saying that your meter shows that much deviation within your bator, or that is it's accuracy range?
Yes, the variation is the temps within the incubator- with the lows in the centre reading around 35c and the sides 36.5c. That's a huge gap I thought.

I will get a medical thermometer too to check the accuracy of the digital one I bought. Thanks for the advice!
I forget Londonchix, do you have a fan or is it a still air incubator?

And yes on using an oral thermometer from your medicine cabinet. I've a digital one I use to fine tune the incubator. Using a fan incubator I measure through the vent hole and let it find the high, then turn off and on until I find the low. The lowest temp will be about 20 seconds after the heater kicks on. It takes time to warm up so the air temp is still going down. Then I take the average and say that's my incubating temp. With a fan unit I make a shape of doughnut with the eggs. Leave some out of center and keep corners clear. This provides excellent air circulation so I don't really have hot and cold spots.
Hiya egghead, yes it's a forced air. It's that Janoel knock off. I was thinking how I could possibly hold the digital thermometer while keeping the lid on so going through the vent hole make lots of sense! You are always full of good ideas
Just remember that going through the vent hole will most likely place the sensor above the level of the eggs, so it will give a false high. What you're looking for is to get a comparison of the temp registered by the medical thermometer at the same exact location as the other thermometer you're using. This year, I made a couple of holes through the side of my bator to put a mercury medical thermometer closer to egg position. I left that one in place until lock down. It was good b/c with it's slow read, it would give me my "over time" max out temp at that location.
Well, I went out and got a regular medical digital pen thermometer-the kind you would get at a walgreens (don't have walgreens here but anyway!) and it's not picking up a reading most times. I have tried going through the vent hole and got ridiculously low readings, then I tried turning it on the quickly dropping it in next to the new gadget, replacing the lid and wait until it "beeps" but still the reading is not good enough and just says "lo". I tried it on myself but it only seems to work properly under the tongue (did that several times to make sure-I don't have a fever :) . If I checked the temp under the arm, it's about 2 degrees lower (although it is meant to be used that way too per instructions). So, it looks that that's a bust. I will replace the battery but its not looking like that will help much.

The only other medical thermometer I have is a forehead tester and really I am not keen on the idea of keeping buying thermometers that won't work on the incubator.

But the handy gadget from amazon is still going strong but I have nothing to test it against. Suggestions?

I have a crazy thought-perhaps I boil a pot of water, we know the temp of point of boil-then I could place a thin pan of the top, put the new gadget on top of that to see if I am close to the temp of boil? Would that work?
So I stuck in an unfertilised egg to test the temp with my forehead thermometer. Thought this would be the only way to get the proper temp of the surface of the egg. So far, the forehead thermometer is reading a stable temp on the egg. I think I solved my problem, perhaps?

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