Pump Systems and Installation
This domain tests how a pump installer selects, sets, and starts a pump so that it matches the well, the plumbing, and the customer's demand. Expect questions on submersible and jet pumps, drop pipe and fittings, pressure tanks, check valves, pitless adapters, well seals, and startup checks.
Core rules and concepts
- A pump's duty point is where its curve crosses the system-head curve. Total head includes lift, drawdown, discharge pressure, and friction loss.
- Set a submersible pump below the pumping water level with a margin for drawdown, seasonal decline, and safety. Never set it so close to the well bottom that sediment can enter.
- Use a check valve at the pump discharge; additional check valves may be needed on deep settings to limit water hammer and backflow, but each one adds loss.
- Size the drop pipe and pressure tank for the required flow and allowable pressure variation. A bladder tank's precharge is set below the pressure-switch cut-in, typically about 2 psi below it.
- Secure the pump with a torque arrestor where starting torque could damage the drop pipe or wiring. Seal the casing with a sanitary well seal.
- Follow the manufacturer's wiring, grounding, and cooling-flow requirements. A pump needs adequate flow past the motor to stay cool.
Worked example
A well has a static water level of 60 ft, a pumping water level of 90 ft, a seasonal decline of 10 ft, and a required safety margin of 10 ft. Set the pump at least 90 + 10 + 10 = 110 ft. The 30-ft difference between static and pumping level is drawdown and is already represented by the pumping level. Do not add drawdown a second time.
Traps
Adding drawdown twice, setting the pump at the well bottom, ignoring friction loss, using a tank precharge equal to cut-in pressure, and omitting the torque arrestor are common mark-losers.