mechanical engineering

Critical systems should always be equipped with more than one pump. Choosing between the installation of one or more backup pumps depends on the costs of the installation and

• how critical the operation of the system is - a water supply system for a hospital is more critical than a chilled water cooling systems for homes.
• the delivery and installation time of a new pump.
  

If two or more pumps are used, the operation between the pumps should be systematically altered to achieve equal wear.
Alternatives for Alternating Pumps

Pumps can be systematically altered by

• manual alteration - where the operator selects the lead pump and the sequence of the lag pumps.
• duty alternation - where the lead pump change every time the pump or system is stopped.
• timed alternation - where the lead pump is switched by a timer or clock.
• equal run time - where the lead pump is switched to achieve the same operating time for each pump.
  

Note! Running an automatic system for equalizing the wear of the pumps

• has the advantage of extending the time before repair and reinvestments.
• has the disadvantage that all pumps may wear out on at the same time - reducing the operation safety for the whole system.