Question about thermostat on incubator

My second clutch of eggs ever, first of this year was laid on monday. I put my really nice thermostat in the egg box, well the probe is in the egg box. I have it on the proportional heating, and I noticed a lot of vary in the temps, dropping down to 88, and than going back up to nearly 91. So I changed it over to on/off heating. Which is normally better? The pulsing or on/off heating? I made this incubator out of a cooler last year, and successfully hatched out my first clutch in it without any problems. So I just wanted some input. The thermostat is a Vivarium Electronics VE-300. Thanks

I think proportional is the preferred method. Personally I wouldn't put the thermostat probe in the egg box. I would put a temp probe in the box though. Also remember that the eggs start to warm up later in development so inside the egg tub temps will be different than the temps inside the incubator.

So put the probe outside of the egg box? I do have a thermo/hydro probe in the box as well. And it is normally pretty close to the same temp as the thermostat.

The Proportional option on that t-stat should give you a more consistent temperature inside of your incubator compared to the on/off style. Proportional is designed to use as little energy as possible to maintain the temperature while the on/off style will stay on until the desired temperature is reached then switch to off. The on/off style has a tendency to over shoot the desired temperature which is why you are getting the variance from 88 to 91. I always use proportional on all of my t-stats.

I place my t-stat probe in the top of my incubator, outside of the egg boxes. Once the whole incubator heats up the egg boxes along with the rest of the area inside the incubator should be fairly close to the desired temperature. It is a good idea to run your incubator ahead of time to work out any kinks you may come across, that way you aren't messing with it when the eggs are ready.

Hope that helps you out as much as possible! :gj:

Thanks, the variance was happening while the thermostat was on proportional, not the on/off. And I did run it for a few days, almost a week before the eggs were laid, and it ran fine, but then about 2 days before the eggs were laid I started to have this problem. And it got worse after I added the eggs.

your incubator is what controls your temps. your egg box is what controls your humidity. my probe is about center in my incubator. I use a herpstat nd. don't use the night drop feature, but this thermostat can be adjusted by 1/10 of a degree at a time. plus it has a high and low level alarms that you also set. and many other features. been using this one about 5 years and it works great.