I said I would report back after a few weeks, but that didn’t happen. It is now the middle of the winter, and the snow is falling all around. No mosquitos. But the earlier log post speaking of action in the next few weeks still remained, like an itch that needs scratching. So here it is.
The valve core, solenoid, and connector change definitely fixed the problem. The trap continued to work flawlessly for the remainder of the season, and the trap is still in use to measure the outside temperature, although it is in the “off” state and the propane disconnected. The controller module continues to run and upload the temperatures inside the case.
I did not experiment further to determine whether it was the valve contacts or the electromagnet that was failing at high temperatures because I convinced myself that the most likely problem was the contacts, that is, the connection between the controller board and the solenoid connector. Without thorough cleaning and some anti-oxidation treatment, it is only too tempting to believe that this connection could become intermittent at elevated temperatures.
To some extent, I regret not having resolved this issue during the season as I said I would, but, really, there were and are more pressing concerns in life than theoretical anti-mosquito research. Nonetheless, I plan to replace the original magnet and valve mechanism after a thorough cleaning and inspection, and see what happens this coming June, when the mosquitos will start to stir. We will just have to wait to see what happens to either the trap or these plans in the next three months.