Typically the hardest part of the job is topic selection so it will be fresh, educational and interesting.
Pumps are really designed to operate at only one point. That hydraulic condition of one point of head and flow is the best efficiency point (BEP), also known as the best operating point. Anywhere else on the published set of curves is simply a commercial compromise. It would be too expensive for most end users to have a pump designed and built for their unique set of hydraulic conditions.
Pay attention to the published pump curves. Manufacturers’ pump performance curves are based on clear water at approximately 65 F, unless stated otherwise. They will not be corrected for fluid viscosity. The horsepower stated may or may not be corrected for specific gravity or viscosity.
The maximum realistic suction lift is about 26 feet. See the previous section where pumps do not suck. If you are at sea level the atmospheric pressure will be 14.7 pound per square inch absolute (psia), which translates (multiply by 2.31) into about 33.9 feet of absolute head. So, in a perfect world, if there was no fluid friction or vapor pressure working against the system you might be able to lift cold water 33 feet.
In reality, fluid friction and the negative consequences of vapor pressure will work against you and preclude fluid lifts of much more than 26 feet. Always calculate the net positive suction head available (NPSHa) and compare to the pump’s net positive suction head required (NPSHr) value. The higher the margin, the better.
Industrial pumps do not come from the factory ready to “plug and play.” There are exceptions to this comment, but never assume. The pump will require oil to be added to the bearing housings. The impeller clearance must be ascertained and set for the fluid (temperature) to be pumped. The driver will need to be aligned to the pump. Yes, the alignment may have been performed in the factory, but the second the unit was moved for transport the alignment was lost.
You will need to check alignment again after the piping is installed, and again when the base is grouted in. The direction of rotation should be ascertained and matched to the phase rotation on the motor driver.
The mechanical seal will need to be set after these other steps are completed. Most manufacturers do not install the coupling at the factory because it will just need to be removed for all of these aforementioned reasons.
Understand cavitation. Cavitation is the formation of vapor bubbles in the fluid stream due to a drop below the vapor pressure of the fluid. The formation of the bubbles typically occurs just in front of the impeller eye since this is typically the lowest pressure in the system. The bubbles subsequently collapse downstream as they enter a region of higher pressure. The bubble collapse is what causes the damage to the pump impeller.