I just changed the pressure switch on our Pentair Shallow Well pump. We've had it for about 2 years. We've been having well problems for a while. Before the original switch shorted, our water worked fine, but then that switch shorted because of a leak in the main water shut off switch nearby where the well is in our crawl space/basement. I replaced the water shut off valve, and then replaced the pressure switch. I had heard that using a low pressure 30/50 switch may help, but our water was constantly dying and would lose pressure really fast. I've now installed a 40/60 switch that was originally included with the pump, along with a new pressure gauge. The pump will turn on. I have primed it with water first, and when I run it I can open up the valve on the top of the pump and it is still full of water, and the pump builds up 0 pressure whatsoever. I did forget to drain the tank and check the PSI with a tire pressure gauge first. I am going to be doing that today to see if that works, but if it doesn't, where should I start diagnosing next? It's a 100 year old house, shallow well in a swampy/marshy bog area. the well was apparently hand dug and does not appear to have casing around it, but there is concrete floor around it. The pipes are all galvanized steel, and one of the check valves has cracked before and had to be replaced.
At any rate, since it's winter, it is not ideal to do that right now, and I'm also curious if there might be something I can do in the meantime to get it to draw pump water again. I've tried to be thorough here. I'm not precisely sure which Pentair model it is. There's just the one pipe coming from the well up to the pump, and the output pipes, and tubes from the pressure tank. It's not a huge pressure tank, maybe like 3 ft across. This was all here when we moved into the house, except the pump which replaced an old Red Lion pump. We had a well guy come out to do that, and he said he thought that there might be a crack somewhere in the drop pipe and that he wouldn't be able to do anything about that. The more I have learned about wells, the more suspect that statement that seems. We have had a second opinion, and they said that our well might be going dry...in a swamp. A third opinion said that notion is ridiculous.
Could it be the impeller? That I forgot to drain the tank, and it's not calibrating correctly? Or crack in the drop pipe or foot valve issue? Could what is most likely be discerned based on this info? Thanks to the kind soul who reads and perhaps responds.