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.