Ok, so I bought a Herpstat II. It is used but they Seller said it was fine. I have been trying to test the incubator we built as we are expecting a clurch here in a couple weeks.

The problem is the last two days it has held steady at 90 all day. Then when I check in the morning it is down around 86. The first time I thought maybe I forgot to turn off the Nitedrop. But the second time I know I had it off and when I checked it after noticing the temp down, it still showed it was off. I am quite sure I am using the correct probe and output.

Any idea what I am missing? Is there some kind of reset or overide?