I too just tried to install a 3.5/3.5" computer fan that was wired for 110v, so I could just plug it into the socket. I put it in after I stabilized my bator to 100. The next day my bator was at 106!!!! I tried to adjust the temp, but couldn't get it down.
I later pulled the fan out and found that is the problem. The fan itself was running at 115 degrees, so it was acting like a constant heat source. 6 hours after removing the fan, the bator was down below 99 and I had to raise the temp and by the night I got it stabilized again at 100.
The problem could be I used a 110v fan, which I would assume would run hotter and faster than a 12v. Or maybe it is because I used an oversized fan. The one that comes with LG is a little over an inch and half.
So I am back to still air.
I have had more problem with getting ready for this hatch. First the fan adventure, then I got that fixed. Then my turner stopped turning, couldn't figure that out so it is turn by hand. Then the batteries on my thermo/hygrometer went dead and I had to drive 25 miles into town to get a new little button battery. Lucklily my eggs just got here yesterday, so they are sitting getting climitized and I think all my problems that can go wrong are worked out. I'm set for setting tomorrow.
Cory