Pump Selection

Question 1

What is Head Loss?

Answer 1

Resistance to flow measured in feet of head or sometimes PSI

Question 2

How is a pump selected?

Answer 2

GPM and Head Loss of the system

Question 3

What is BHP?

Answer 3

Brake Horse Power is a measurement of power consumption

Question 4

What is a HP?

Answer 4

Horse Power is used to indicate a pump’s motor size.

Question 5

RPM

Answer 5

Rotations per minute is the measure of motor speed

Question 6

How does a pump work?

Answer 6

Pumps use suction or pressure to raise or move liquids

Question 7

What are the two basic pump types?

Answer 7

Inline and End Suction

Question 8

What is the rule of thumb for inline applications?

Answer 8

Lower flow applications (below 100 GPM) and 7.5 HP for the motor

Question 9

When is an inline multistage pump used?

Answer 9

High head / low flow applications (e.g. a high-rise bldg. when you’re on a lower floor and need extra pressure)

Question 10

What is the rule of thumb for end suction applications?

Answer 10

Normally flows between 100-2500 GPM

Question 11

What is the difference between base mounted and closed coupled?

Answer 11

The impeller is mounted directly to the motor. Base-mounted pumps share a baseplate. Base mounted is preferred.

Question 12

How many ways are there to configure your pumps in a hydronic application?

Answer 12

Single, parallel and series pumping

Question 13

Explain single pump configuration

Answer 13

Used when there is no redundancy requirement

Question 14

Explain parallel pumping configuration.

Answer 14

Used when one pump cannot handle flow requirement or pump redundancy is required

Question 15

Explain series pumping

Answer 15

Used when one pump cannot handle head pressure requirement or pump redundancy is required

Question 16

What is NPSH stand for?

Answer 16

Net Positive Suction Head

Question 17

What is cavitation?

Answer 17

The liquid in the pump turns to vapor because there isn’t sufficient NPSH at the suction end of the pump. Can’t meet system curve

Question 18

How can you make sure you have enough NPSH?

Answer 18

By making sure that each pump is capable of crossing the system curve and selecting non-overloading motors that won’t be overloaded at any point on the pump curve.

Question 19

What RPM should you select for your motor to limit noise issues?

Answer 19

1750 RPM

Question 20

Common application for inline pumps

Answer 20

Recirculation applications (low flow applications)

Question 21

Common application for multi-stage vertical pumps?

Answer 21

Booster pump applications (high head, low flow)

Question 22

Common application for vertical centrifugal pumps?

Answer 22

Booster pump applications (limited space)

Question 23

Common application for Diaphragm pumps?

Answer 23

Process applications (pumping slurries, solvents, and high-viscosity fluids)

Question 24

What is a sump pump?

Answer 24

A pump used to remove water from a water-collecting sump basin

Question 25

What is a sewage ejector pump?

Answer 25

A pump is designed to pump sewage uphill in order to reach the sewer main, is necessary when a plumbing fixture is installed below the main sewer or septic line.

Question 26

Why would you need to use a recirculating pump?

Answer 26

for maintaining temperature in DHW systems.

Question 27

How does a VFD work?

Answer 27

A variable frequency drive controls the speed of an AC motor by varying the frequency supplied to the motor