I just re-read the part where you mention the pressure switch is atop the well. Is that one of those goofy setups where it's a standard, homeowner-grade pressure switch sitting right atop the cap? I didn't know anyone did that anymore. There was a drilling company around here that did that back in the day (guessing the 1980's/90's). Everyone around here hated theirs as they always gave trouble after a while. It was a pretty stupid idea: The driller just used standard switches that were meant for indoor applications - not IP65 (or anything close to it), so moisture/humidity would get inside the switch and foul up the contacts and make the pivoting contact arm stiff/dry. Most folks put a section of well tile and a cap or sealed section of culvert over top of theirs to protect from rain, but that still doesn't stop humidity & condensation from getting in. If yours is like this and the switch hasn't been replaced, I'd take some emery to the contacts and a bit of lube to the arm in the switch.
I'd think you'd be far better to keep things conventional and mount the tank & switch inside. I'm guessing that there must be a reason they aren't? No basement, or nowhere to put them? In theory, you want the pressure switch sensing line right close to the bladder tank to avoid the pressure surges you get if it's too far away from the tank. But even though it's not proper practice, I'd be tempted to try a quick and cheap retrofit and put a standard pressure switch inside the house on the main line and see how it does with the tank still buried. It'd be pretty easy/cheap to do.
I don't have a pic of one of the local wells that was run like that. But here's a picture of one run in the same style that I took from a thread on this site years ago (might even be yours?). If yours is setup like this, I'd look for a different installer. A standard switch like this should not be in an external environment. You need something water/moisture-proof (IP65 or better).
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