Pump Selection Flashcards
What is Head Loss?
Resistance to flow measured in feet of head or sometimes PSI
How is a pump selected?
GPM and Head Loss of the system
What is BHP?
Brake Horse Power is a measurement of power consumption
What is a HP?
Horse Power is used to indicate a pump’s motor size.
RPM
Rotations per minute is the measure of motor speed
How does a pump work?
Pumps use suction or pressure to raise or move liquids
What are the two basic pump types?
Inline and End Suction
What is the rule of thumb for inline applications?
Lower flow applications (below 100 GPM) and 7.5 HP for the motor
When is an inline multistage pump used?
High head / low flow applications (e.g. a high-rise bldg. when you’re on a lower floor and need extra pressure)
What is the rule of thumb for end suction applications?
Normally flows between 100-2500 GPM
What is the difference between base mounted and closed coupled?
The impeller is mounted directly to the motor. Base-mounted pumps share a baseplate. Base mounted is preferred.
How many ways are there to configure your pumps in a hydronic application?
Single, parallel and series pumping
Explain single pump configuration
Used when there is no redundancy requirement
Explain parallel pumping configuration.
Used when one pump cannot handle flow requirement or pump redundancy is required
Explain series pumping
Used when one pump cannot handle head pressure requirement or pump redundancy is required
What is NPSH stand for?
Net Positive Suction Head
What is cavitation?
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
How can you make sure you have enough NPSH?
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.
What RPM should you select for your motor to limit noise issues?
1750 RPM
Common application for inline pumps
Recirculation applications (low flow applications)
Common application for multi-stage vertical pumps?
Booster pump applications (high head, low flow)
Common application for vertical centrifugal pumps?
Booster pump applications (limited space)
Common application for Diaphragm pumps?
Process applications (pumping slurries, solvents, and high-viscosity fluids)
What is a sump pump?
A pump used to remove water from a water-collecting sump basin
What is a sewage ejector pump?
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.
Why would you need to use a recirculating pump?
for maintaining temperature in DHW systems.
How does a VFD work?
A variable frequency drive controls the speed of an AC motor by varying the frequency supplied to the motor
