Epitman2, I'd leave the incubator alone. Mama Hens have been known to disapear for most of a day and the babies still hatch. Just resist the urge to turn up the setting until about a day has passed. This will help you avoid temperature spikes which will kill the embroyos (sp?). Even with a "professional" Mama Hen there will be cold nights and she won't be able to maintain exactly 100 degrees...
See what I'm saying?
The perfect settings we try to maintain just mimic average conditions that broody hens deal with. An average is just that. Heat can kill. Many of the things we humans do or forget to do (did I turn those eggs every 8 hours?) may lower our hatch rate, but rarely outright slay everyone.
My first hatch was 5 of 24. The incubator temperature was too cold thanks to the cheap thermometer that came with it. Now I use at least two thermometers. The five survivors hatched on Day 24. Then I hatched 11 of 12, followed by 13 of 18. Then I joined BYC and found out what all I was doing wrong. (Mostly "helping" too much, I'm ashamed to say...) On Christmas Day I hatched 5 of 7. The rest of that hatch were not fertile. One chick didn't even pip. One blue egg didn't get beyond peeping. The other five are raising heck on my back porch right now, waiting for me to finish their pen and coop outside.
Great luck on the rest of your incubatation time!