Xylem O&M Mini F Series Variable Speed - Manual (Page 4)

Fig 2
4
Operation
The booster set is designed to boost the system pressure and maintain sufficient pressure to overcome the
static height and friction losses in the pipe work and provide each outlet with sufficient flow at the required
pressure.
When a demand is placed on the system, water will be supplied from any vessels that are fitted to the
system, once this supply is depleted the system pressure will start to fall, when the pressure falls to the
system set point the first pump will start and raise the pressure to maintain the set point, if demand
increases and the first pump is not able to cope the pressure will continue to fall to the second pump cut in
pressure (if fitted) The second pump will start and assist the first pump.
When demand decreases the last pump to be called in will be stopped, if demand continues to decrease
the next pump will be stopped. On two pump sets minimum run timers are fitted so once a pump has been
signalled to start it will run for a minimum of 90 seconds (default setting) even if the demand has cessed.
The next time the pressure falls the pumps will have been rotated so the opposite pump will be the first to
operate.
If a low level in the break tank occurs all pumps will be stopped until the water supply has been reinstated,
the pumps will then be automatically released to resume normal operation.
Because the pumps can run on through the timer circuit it is possible that the system pressure can sit at the
closed valve pressure of the pump.
Volt Free Contacts
Volt free contacts are not available on single pump units or on twin GXS sets.
Remote inhibit
Remote inhibit facilities are not available.
Alarm indicators
LEDs are provided to indicate:
Single pump sets. Pump run, pump tripped and low water level Fig 3
Twin pump sets. Pump run each pump, Power on and low water level Fig 1 & 2.
Panel
Fig 2. Gives details of indications and switches for the GXS20 twin pump control panel.
Fig 3
Single pump
Pump
running fault
LOWARA
Low
level
`Hand Auto Off
mini f booster set o and m instructions:Layout 1 09/05/2012 15:38 Page 4