I85PREP
⌘ K
GA Well Driller study materials
GA Well Driller study resources

GA Well Driller: Pumps, Water Systems, and Pressure Equipment

GA Well Driller · Work through your exam, one topic at a time.

All guide sections

Pumps, Water Systems, and Pressure Equipment

Pumps, Water Systems, and Pressure Equipment

This domain tests pump selection, total dynamic head, tank and switch settings, and the mechanical details that keep a system from short-cycling or failing. Expect calculation items plus "what is wrong here" items.

Pump types and selection

  • Submersible - the default for deep wells; set above the well bottom and below the lowest expected pumping level, with a check valve, and with a torque arrestor and cable guards in high-flow settings.
  • Jet pumps - shallow-well (single pipe) and deep-well (two-pipe) versions, limited by lift and efficiency.
  • Turbine, reciprocating, and hand pumps - high-capacity or special applications.

Total dynamic head

TDH = vertical lift from the pumping water level to the discharge + pressure head + friction loss in pipe, fittings, and valves. Pressure head in feet = psi × 2.31. Select the pump so its curve delivers design flow at that head, not at zero head.

Controls

  • Pressure switch cut-in/cut-out (30/50 or 40/60 psi) defines the system pressure band.
  • Tank precharge should be about 2 psi below cut-in; a tank charged to cut-out pressure loses most of its drawdown and the pump short-cycles.
  • Include a check valve, a pressure relief valve where required, and backflow protection on any connection to a public supply or chemical injection system.

Worked example

Design flow 10 gpm; pumping water level 100 ft; pressure switch 40/60 psi; friction loss 12 ft. Size at cut-out pressure: 60 psi × 2.31 = 138.6 ft. TDH = 100 + 138.6 + 12 ≈ 251 ft. Choose a pump whose curve gives at least 10 gpm at 251 ft of head, verify it does not upthrust at low head or overload the motor at high flow, and set it well below the pumping level with the motor above the screen or open hole.

Traps

  • Sizing on static level instead of pumping level.
  • Forgetting that 2.31 ft equals 1 psi, or using cut-in pressure for sizing.
  • Precharging the tank to cut-out pressure.
  • Ignoring friction loss, then wondering why the top-floor shower is weak.