If a pump fails to meet the demand (due
to malfunction, intake blockage etc.),
then it is stopped and another pump shall
take over. Each pump has its own
setpoints, (P*213, 223, 233, 243, 253,
263 & P*214, 224, 234, 244, 254, 264)
but each time all pumps have stopped,
then the setpoints are sequentially
rotated between the pumps to ensure
equal pump use.
5= Duty backup and assist
First pump comes on, if it cannot cope,
it goes off and next pump comes on
(duty backup). This continues until the
last pump comes on and if it cannot cope
the first pump comes back on to assist
the last pump (duty assist) if the level
continues to rise all other pumps will
come on (assist) in turn until the level
decreases to the pump off points. Each
pump has its own setpoints, (P*213,
223, 233, 243, 253, 263 & P*214, 224,
234, 244, 254, 264).
6= Service ratio duty assist
All pumps are used to assist each other
(run at the same time) and each pump
has its own setpoints (P*213, 223, 233,
243, 253, 263 & P*214, 224, 234, 244,
254, 264). And a service ratio setting.
The third setpoint (P*215, 225, 235,
245, 255, 265) is used to set the service
ratio. Each time a pump is required to
start then the pump with the least
running hours (with respect to the
service ratio) is started (i.e. the setpoints
are re-assigned accordingly).
For example, if two pumps A and B
have the service ratio set to 2 and 1
respectively, then pump A will operate
for twice as many hours as pump B.
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