In my last post I mentioned that I might be getting some solar heating. I had checked my fan to make sure it was turning and found that it was stuck. A small push got it turning again. However my QC checks still showed signs of solar heating during the daytime. Then I started seeing elevated temperature readings at night as well. I suspected the fan bearing had seized causing the fan to get hot and be the source of the erroneous temperature readings. So I made some time to go outside, take the solar shield apart and see what was going on.
The first thing I did was listen for the fan running. No fan was heard. Then I put my hand up inside the solar shield to check the fan wiring to see if it had come loose. My hand brushed up against something that I didn’t recognize. I bent down and looked up inside the solar shield to find a small wasp next. Luckily it appeared it be deserted, otherwise I would most likely have been stung. I knocked down the nest and started taking the solar shield apart. A few wasps flew out and i jumped back. When the coast was clear I carefully started opening up the solar shield and peeked inside. I saw a larger wasp nest and several wasps flew out toward my face. I backed up as fast as I could move in preparation to run away. I ended up falling over backwards and slightly injuring myself. Luckily the wasps let me escape without stinging me. I got a can of bug spray put of the garage and that was the end of the wasp nest.
I was now able to complete my dis assembly and confirm that the fan had failed. I ordered a new fan, which took about a week to receive. Then I removed the old fan and wired in the replacement. The old fan was pretty hot when I pulled it out, so I feel pretty confident that ti was the source of my heating. The station appears to be working so I plan to let it run for a day or two and keep an eye on my QC checks. I also have a spare fan (I bought two) so I can make repairs faster when I have this problem again.