Homemade Incubator Temp Swing Advice

Discussion in 'Incubating & Hatching Eggs' started by timbowsr, Mar 16, 2015.

  1. timbowsr

    timbowsr Chillin' With My Peeps

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    I have built an incubator and hopefully will be running a test batch in a couple weeks ... after some temperature settings and practice!! I have a question and hope someone can give me some advice about my thermostat settings. I have the STC-1000 digital thermostat installed and it allows me to set a control temperature and a swing value ... but it doesn't let me set any decimal values. I thought what I would try was a setting of 100 with a swing value of 1. This would kick off my heat source at 100 and allow it to fall to 99 and then resume heating. What I have found is that the temp actually has to go below 99 for the thermostat to kick the heat source back on, and this results in the overall temp dipping to around 98.8 to 98.7 and it takes about 10 to 15 secs for it to climb back to 100. Is this ok? Or should I set to 101 and let it drop down to 100? I just don't know and hope someone with more knowledge and experience could help. BTW, I do have dual fans circulating the air, and redundant thermometers and the temp seems to be consistent throughout the incubator.
     
  2. AmyLynn2374

    AmyLynn2374 Humidity Queen

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    More experienced and knowledgeable hatchers can correct me if I am wrong, but I would say no. Forced air needs to average 99.5. The eggs are not going to cool down to 98.8 as quick as the air, so they are never theoretically going to dip below that 99 mark and if it only takes 10-15 minutes to bring it back up I would say you are well within safe limits.
    Now, with that being said I'll be surprised if one of our tech savy DIYers don't swing in with some techy garble to make it even better and more precise...lol
     
  3. WalnutHill

    WalnutHill Overrun With Chickens Premium Member

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    I have the STC-1000 on my incubator and it is the best thing since automatic egg turners.

    I set F1 at 38.1 (set)
    I set F2 at 0.3 (swing below set when heating, or above set when cooling)
    I set F3 at 1 (compressor delay, not used for heating)
    I set F4 at -2.0, which is the calibration point for my controller.

    When calibrating, it's essential to use a calibrated thermometer, like a digital medical thermometer, and place the sensor for the STC-1000 in the same place as the calibrated thermometer. Let the incubator warm up for several hours before trying to calibrate the STC-1000.

    Adjust the STC-1000 F4 setting until it matches the known good thermometer as closely as possible. It will likely take several attempts to get it zeroed in. Once set, it should not need to be recalibrated unless you reset it.

    While the air temperature at the sensor ranges from 37.7 to 38.3 in my incubator, it's the average temperature, which affects the embryo development over time, that is critical. So with my controller set at 38.1, it turns on at 37.7 (once it passes 0.3 less than 38.1) and turns off at 38.1. Temperature on three thermometers reads a rock solid 38C/100.4. It's almost boring. And it's not just when I look, as I have a 24 hour memory thermometer and the 'bator is 6 feet from my desk where I spend way too much of my time. [​IMG]

    And I have the heat off in my office, temperatures swing from upper 50s to mid 60s over the day and night. The incubator doesn't care.

    There are many opinions on what is the best incubation temperature. The best incubation temperature is the one that reliably develops the most properly developed chicks in the expected timeframe with the fewest issues and best vigor. I prefer 100.4, others swear by 99.5. You could shoot for 100 and split the difference.

    These temps are for a circulated air incubator.
     
    Last edited: Mar 16, 2015
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  4. AmyLynn2374

    AmyLynn2374 Humidity Queen

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    See, I told you.... [​IMG] techy garble...lmao
     
  5. WalnutHill

    WalnutHill Overrun With Chickens Premium Member

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    Yep but I did misstate one thing. At 38.1 it turns off the heat, at 38.4 it switches to cooling mode. I just watched it cycle. I don't have anything hooked up to cooling so it just rides along until it cools down. I wired the function to a receptacle, with the intention of wiring up a fan that would either pull cool air or exhaust hot air, but didn't need it.

    I have a ceramic heat emitter, not a light bulb, so heat is still emitted after the controller switches it off, unlike a light bulb. I doubt it makes a difference, but I like the emitter. No light, and long life.
     
    Last edited: Mar 16, 2015
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  6. timbowsr

    timbowsr Chillin' With My Peeps

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    Ok, so a little more detail on the temp swing ...

    We were having a hard time getting this incubator up to temperature, so we ended up lining it with 3/4 styrofoam insulation. This did the trick! Last night we ran it up to temp and let it kick off/on a couple times and I guess I was excited and didn't post accurate times/temps. I ran it this morning with cooler outside temperatures to make sure it would still come up to temp ... which it did and this is what I found out. The incubator reaches 100, it shuts off the heat source and the temp begins dropping to 99 and then the heat source kicks back on. It takes about 20 seconds for the temp to drop enough to trigger the heat source and after that the temp continues to drop from 99 to 98.6 ( dropped to this temp every cycle that I tested ). It then begins to climb again and over a period of about three minutes comes back up to 100 and rinse and repeat. During the climb i noticed that it sort of plateaus at 99.5 in about a minute and then takes the remaining couple of minutes to get back to 100 ... sorry for the long windedness.

    Now the only thing that is currently in the incubator is a glass pie plate with about a 1/4 inch of water, two light bulb receptacles, the light bulbs ( heat source ), and two fans ( one blowing up by the bulbs and the other blowing down from the top and opposite side of the incubator ), and a secondary thermometer. So there is really not a lot to absorb/radiate heat back into the incubator, so that swing time/drop may improve as I get my turners and trays in. BTW, the incubator is big enough to have 3 Little Giant egg turners on separate "shelves" ... roughly 18"x18"x24"

    So if we are averaging temperatures and taking into account what AmyLynn said about the eggs not dropping temp as quick as the air temp I think this might work. Please give me your opinion guys. This incubator was a blast to build and I'll be posting some pics and details eventually.

    Thanks for the help!!
     
  7. WalnutHill

    WalnutHill Overrun With Chickens Premium Member

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    Put a cup of moist sand in the incubator and leave it 6 hours or more. Put a thermometer in the sand and read the temp there. It will provide average temps.

    Of course, while short term temp swings +/-1 or +/-2 of the target will do no harm (the broody hen walks away sometimes), extremes for over an hour can do great harm, especially high temps.
     

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