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

4
Operation
The booster set is designed to maintain a constant system pressure with varying flows.
Each inverter head has its own 4-20ma transducer which monitors the system pressure at all times.
If one inverter or transducer fails the next inverter will continue to function independently. All inverters
talk to each other through a RS485 serial coms link. Each inverter head is fitted with an adjusting screw
to adjust the set point. See figure 1 below
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 Teknospeed pump will start to ramp up to maintain the set point, if demand
increases and the first Teknospeed reaches maximum speed and again the system pressure continues to
fall the second Teknospeed (When fitted) will be called in to ramp up and assist the first pump.
When demand reduces the last Teknospeed to be called in will start to ramp down and eventually stop, if
demand continues to decrease the next Teknospeed will start to ramp down and stop. 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.
The remote inhibit if fitted will operate in the same way and stop all pumps if inhibited.
Volt Free Contacts
Volt free N/O (Closes for fault) alarm contact is available from each Teknospeed head. See electrical
drawing for connection details.
Remote inhibit
A remote inhibit can be achieved by utilising the low water terminals, a N/C external Stop/Start circuit can
be connected in series with the low water terminals. (open to inhibit) See electrical drawing for connection
details.
Alarm indicators
LEDs are provided to indicate:
Power-Run-Alarm2
The number of times a Red LED flashes indicates
The type of alarm (see Figure 2)
An attempt is made to reset the alarm every 20
seconds after 3 unsuccessful attempts the inverter stops
f at least 10 minutes elapse after an alarm without any
further faults occurring the reset attempts counter is reset.
LED No OF
FLASHES
TYPE OF ALARM
2 Converter overcurrent
3 Converter overtemperature
4 Motor overtemperature
5 No water (LOW1/LOW2)
6 No signal from pressure transmitter
7 Undervoltage
8 Serial interrupted (timeout)
Fig 1.
Fig 2.
mini V booster set o and m instructions:Layout 1 11/05/2012 15:20 Page 4