©2018 Mahoning Valley Water Inc.  How to Adjust Well Pressure Tanks Adjusting Pressures General      Tank pressures are controlled by an electrical pressure switch which opens and closes the pump electrical circuit at various pressures registered at the diaphragm of the switch. Design      Two sets of poles are located in each switch, one for source power and the second for use power (i.e. submersible pump). Switch Settings      Switches are normally pre-set at the factory for turn on/turn off pressures.  Residentially, the differentials are 20 psi.  Each switch box is marked with its' pre-setting i.e.  20/40,  30/50,  40/60. Tank Settings      The tanks are pre-charged with air at the factory.  The empty tank pressure should always be 2 psi below the cut-on pressure of the switch used.  When adjusting switch pressure, tank pressures must also be adjusted.  To adjust tank pressures, the tank must be empty. Adjusting Switch Pressures      The tank switch will have two spring-loaded adjustment nuts, a large and a small. Small - Differential Adjustments.  Will adjust cut-off pressure only. Large - Range adjustments.  Adjusts both cut-on and cut-off pressures by     the same amount i.e. maintains differential pressure between the two settings.      Adjusting the nuts clockwise (i.e. turning the nut downward) will raise pressures; adjusting the nut counter-clockwise (i.e. turning the nut upward) will lower pressures. Other      Always check settings with the installed pressure gauge when resetting pressures.  Remember, higher pressures will decrease the volume of draw down water available.  This is due to the fact that a larger volume of air in the tank will displace storage capacity available for water.  See tank manufacturers charts to determine available water volume at various pressures. MAHONING VALLEY WATER