Hovabator failures?

I got a Hovabator with automatic turner last year, and I've used it 3 times. I got excellent hatches last year, the best being 31 chicks out of 36 eggs. I just set it up for a test run, and had it running steady for 2 days at 100*. I then put 18 of my mutt eggs in, and didn't change anything else. By that night, it had shot up to 113 for what could have been up to 6 hours :-( That was 3 days ago, and I candled some of the lightest brown eggs, they were all clear. I just don't understand why this happened and what is up with my incubator!? Anyone else's Hovabator ever done something like that? I'm starting to think I could do a much better job with a homemade incubator!

 

I candled some of the darker brown and green eggs that are now at day 5, and saw veins in all except 2! Apparently the two light brown eggs I was candling were laid by the same hen and weren't fertile. But the rest are still growing! So thankfully, the temp spike didn't completely ruin the hatch. And I realized that I did add the PC fan right before I put the eggs in, is it possible that it put off enough heat to cause the spike? Because since I turned the knob back down and got the temperature right again, it is holding steady at around 100.4 and 100.6 and has been just fine the past few days. Hopefully thats all it was and not anything wrong with the incubator! I definately don't want another episode of that! Sorry to hear about your chicks tgrlily Just keep trying, you'll get it right eventually! It took me 4 or 5 tries with my first incubator (a Little Giant) before they finally started hatching well.