Xylem IM167 R8 Aquavar CPC (Centrifugal Pump Control) - Manual (Page 95)

95
MultiPump – Slave Pump Control
Overview
The Aquavar CPC has the ability to use up to three “dry” relay contacts for constant speed
“SLAVE” or lag pump control. This is useful if the operator requires a wide range of flow rates
in certain situations (i.e. emergency flow), and does not require all variable speed controlled
pumps. When the required demand increases beyond capacity of the variable speed
controlled lead pump, then the FULL SPEED lag pump will turn on. Each relay will be wired
to your constant speed pump starter, sized for the appropriate horsepower and voltage. The
relay outputs located on the terminal control board X1 (SEE DIAGRAM FROM PREVIOUS
PAGE) will actuate when programmed according to the operators desired output. The lag
pumps will turn on when the Aquavar controlled pump cannot keep up to the required
demand. The lag pumps will be operated by across the line starters, and signaled to start
via the Aquavar relays located on terminal’s 19 through 27 of the X1 terminal block. The lag
pumps are referred to as “SLAVE” pumps, because they operate with commands from the
Aquavar controlled “LEAD” pump. The Aquavar controller will actuate the relays, and provide
a time delay for ON/ OFF on each relay.
The figure shows Pump 1 when it cannot maintain the system pressure (value decrease). Next,
Pump 1 + lag pump 2 will operate as a lead and lag system. If Pump 1 + 2 cannot maintain
system flow, then lag # 2 pump will turn on, then you will have all three pumps ( 1 + 2 + 3 )
operating in the system. You can operate up to 3 slave pumps, with 1 Aquavar controlled
pump.
NOTE: Each lag pump is controlled by the speed of the lead Aquavar pump, system
pressure drop (value decrease), and a delay time in seconds. Do not set the pressure drop
too close to operating system pressure, or pump cycling will occur!
Lag Pump
Starts Lag Pump
Starts
Value Decrease
Pump 1 Pump
1+2
Pump
1+2+3
Capacity (GPM)
Head
PROGRAMMING