The fan works, the temperature on the thermometer reads steady, but can tell it is much cooler at the bottom rack than where the thermometer is at the top. I have the same problem with a homemade hatcher....again, even with the fan going. I am wondering if I should heat it up to much higher at the thermometer just to get the temperature correct where the eggs will be. Any advice? Oh, on the 1202, both center vents are open. On the home made - there is one vent hole near the top, and it is half open. Thanks!