Pressure switch troubleshooting

I have a rainwater collection system, located in an outbuilding, that provides the water for my home. The plumbing is similar to a well water system. The water tanks feed a pump and a captive air tank, then go through a 3-stage filtration, and then to the house. The water pressure at the house has been weak lately. I checked the pump and air tank and found that the air tank had such low pressure that it wouldn't register on my tire gauge and the pump had a leak at the pressure switch. When I tried to add air to the air tank, it caused my slow leak at the pressure switch to shoot a strong stream of water out. I assumed that the leak was causing the tank to lose pressure, so I replaced switch. I then pumped 40psi into the tank using a compressor, opened the supply valve from the water tanks, and turned power on to the pump. The system filled pipes with water and the leak at the pressure switch was gone. Everything seemed great but I still didn't have normal water pressure at the house. So I adjusted the pressure switch. This switch only has one adjustment screw for both in and out (furnas brand). I had to crank it up considerably in order to get good pressure at the house. This caused excessive pressure in the pipes and I burst the pvc pipe between the pump and the captive air tank. I have repaired the pipes and am allowing the pvc compound to dry overnight before pressurizing the system again. In order to avoid a repeat of today's disaster, what should I do differently? Was it a bad idea to pump air into the tank? Is the tank bad (maybe a damaged bladder)? Did I get a bad switch? This goes far beyond my basic knowledge of plumbing and any help would be appreciated.

You need 5 PSI less air in the tank than the start pressure of the pressure switch. If you have 40 PSI air in the tank, the pressure switch needs to be 45/65.

It sounds like your filters are clogged and no matter how much pressure the pump can build, pressure can't get to the house.

Thanks for the quick response. I pulled the filters out and replaced the sediment filter. It was dirty, but not too terrible. I then charged the captive air water tank with about 20psi. I started to hear air and water moving through the pipes. A bunch of air built up at the filters. They have relief valves on them, so I relieved all of the air pressure from them and then checked the pressure in the captive air tank. It went down considerably. This sounds to me like I have a busted bladder. Otherwise the air shouldn't make it into the pipes, right? Or can it make it in there when the water is drained completely out of the captive air tank? If so, should I fill the pipes with water and then try to pump air pressure into the tank? If I need to replace the tank, do you have any recommendations for the best size/brand/model of tank for a 12,000 gallon storage capacity system that supplies a 1800 square foot house with a family of 3 living in it?

Thanks in advance for any help on this.

Yes the bladder is busted. The air should not go on down the pipe line. Cycling on and off is what breaks bladders the same way a wire can be broken by bending it back and forth multiple times.

The larger the tank the fewer times the pump will cycle. But if you use a Cycle Stop Valve to stop the cycling, you can safely use a much smaller tank and it will make the pump and everything last much longer.

I would replace that tank with a CSV and a 4.5 gallon size tank like this.

It sounds to me like your tank is bad. Otherwise there wouldn't be air in the filters.

Thanks for all of the help. I really do appreciate you sharing your knowledge. I'm replacing the tank. Hopefully it goes smoothly and fixes all of my problems. If not, I may be bugging you again.