I am in the Philippines. My water pressure tank is a Bestank 1/2 GP 21. It has a pump attached to the top of the tank. I am guessing the 1/2 is the horse power for the pump. I bought a Reverse Osmosis water system I would like to install. It requires a minimum of 40 psi. My pump cuts out at 30 psi. How can I tell what the max psi my tank will work at, and how do I increase the output psi? If my tank can be turned up, what psi should I set it at to run my water purification system? Thanks

You will have to adjust the pressure switch. I would raise it to about 60-70 psi. You will turn the screw on the larger spring clockwise until it comes on and ad a few more turns. See what the pressure is when it cuts off. Keep adjusting until it is at 70 psi. The small spring adjustment is the differential which is the gap between cut-in and cut-out. You want about a 10-15 psi differential so the pump does not short cycle. Run some water and the pump should come on after a drop in pressure and not cycle on and off when one tap is on. You want it to work smoothly so it comes on when needed and cuts off a while after taps are closed. Look here: http://www.ehow.com/how_5017272_adjust-pressure-switch-well-pump.html DrTom4444