Looking for a bit of advice. I read through the FAQ section and didn't see an answer. I bought a house last year that is on well water. This is my first experience owning a home with a well. There is very little information on the system. The previous owner didn't do a good job maintaining it, and told me he didn't have much information. My old Diamond pressure tank (35 gallon I think) started leaking the other night. I purchased a new 34 gallon Amtrol tank (well-x-trol) and Boshart pressure switch. Both the pressure switch was set to 30-50psi, and the tank was precharged to 40 psi. Before purchasing, I figured that our current system had a low pressure cut on of 20psi and cut off at 40psi. When I mentioned this to the wholesaler, he said I'd have to adjust the switch down from 30 to 20, and bleed air off the tank.

THe plumber that came by to change everything out didn't have an accurate gauge to measure the tank pressure. So we left everything as is, and the system is running 30 to 50psi.

WHat I know about my system: Our well is 185ft deep, and the pump is at 175ft. Water form the pump goes to the pressure tank. Downstream of the pressure tank is a chlorine injection point. The water then flows into what I think is a retention tank. It's quite a bit bigger than a hot water tank, and is a fiberglass wound tank. After the retention tank is a pair of upright fiberglass tanks that are shaped like acetylene cylinders. I think these are some sort of carbon filter. They have valves on the top and about every 36 to 48 hours they go through a backflush operation.

My question is should I worry about the additional 10 psi of pressure? Will this have a negative impact on the well pump? I am a little worried about the house plumbing as I have Poly-B piping. I'm a little concerned about the impact of running additional pressure in these pipes. However, I'm not sure if I need to be concerned about the impact on my well pump. How does one chose the pressure set points of the switch? In other words, why would someone pick 20/40 over 30/50.

Well pump is a franklin electric 3/4hp 10 GPM pump. It's about 3 years old.