If it's a bladder tank, use two pounds less than the cut in pressure.
Check the spec tag on your water tank. It should be 10 PSI lower than the factory settings. Normally around, 28 PSI for a 30 gallon tank. the air pressure is to be set at 2 to 3 psi lower than the pump turn on pressure.
The recommended amount of air pressure in a bladder tank is typically around 2 psi below the cut-in pressure of the water pump.
The air pressure should be 2-3 psi LESS than the pressure switch cut on. If you have a good 30/50 switch, then 27-28 psi air is good. (this is measured when tank is almost empty of water.)Total pressure with this switch should never be more than about 58 psi
Check the pressure switch at the bottom of the tank by removing the gray cover and looking at the sticker on the underside. The right pressure is 2 lbs under the cut in pressure which is the lower of the two. For example, if the sticker says 30/50 then the right psi would be 28. If it says 40/60 then the right pressure would be 38. you need to first empty the tank completely of water before checking air pressure in the tank. then fill the tank to the right psi and then turn the water on to the tank.
The recommended pressure tank settings for optimal performance typically range between 20-40 psi for the cut-in pressure and 60-80 psi for the cut-out pressure. These settings may vary depending on the specific system and manufacturer's guidelines. It is important to consult the manufacturer's instructions for the most accurate settings for your pressure tank.
House pressure, 75 PSI maximum.
The pressure in the tank will vary from your cutin pressure to your cutout pressure. If you increased the pressure in the system, your air-charge will now be wrong. A good rule of thumb is cutin - 2 psi.
Cut out pressure is between 115 and 130 psi... cut in pressure is no more than 25 psi below the cut out pressure.
About 40-70 psi.
The water pressure depends on the residual air pressure in the tank. Normally it should be between 30 -50-psi. Tank air pressure is important, it should be about 27-29 when water is nearly empty.
The size of tank is immaterial. ALL domestic well water pressure tanks should have 28 or 38 psi when nearly empty. The difference is whether it has a 30/50 or a 40/60 pressure switch on it.
A hot water heating systems water pressure should be 12-25 psi , the air in the expansion tank should be set around 10 psi but can only be accurately tested with no water pressure against it. Usually u can tell if the tank is bad when the relief valve on the boiler starts releasing water