Originally Posted by beetandsteet
Originally Posted by PCalvin
I am just finishing up a hatch with a little giant 10200 (forced air, manual temp adjust) with so so results. I think i have traced the problem to the manual "thermostat" not being a thermostat at all, but merely a timer circuit.
Most people remedy this by keeping the room temp stable, therefore the heating rates stable. I stole the temperature control off of my kegerator for the late hatchers, it's the same one as in this link:http://www.backyardchickenelearning.com/improving-little-giant-still-air-incubator/
Once they are out i will open up the cover and check the circuit for an actual temp sensor to confirm.
You are right; I have observed the same thing. That's why keeping the room's temperature stable is so critical to getting a good hatch.
It is in fact a thermistor based thermostat control circuit but a very poorly and very cheaply designed one...
There are something thing you can do to sorta help it out but you can't turn a Pinto into a Ferrari, without exceeding the cost of replacing the Pinto with the Ferrari...
One thing that can help that is a cheap and free patch, is to unscrew the thermostat module and remove it, then take a bigger drill or knife and enlarge the hole that the variable resistor (aka adjustment knob) goes through so it no longer rubs, then reassemble... As designed (might vary by year) the foam rubs up against the resistor shaft so every time you handle the lid there is the possibility that the foam rubbing up against the shaft ever so slightly turns the shaft just that little bit, and due to the design this small turn of the shaft can have a big impact on temp stability... The same can happen due to changes in humidity and temp in the room that will cause the foam to expand and contract just that little bit and turn the knob... It might sound far fetched that this would happen but it can and does happen...
FYI I'm a freelance electronics engineer by trade