Xylem IM043 AQUAVAR Variable Speed Pump Control - Manual (Page 33)

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Circulator applications
On circulator pumps, the system curve can be automatically tracked through the use of a differential
pressure transducer. This pressure transducer reads the outgoing discharge pressure and the incom-
ing return pressure and compensates for differences in pressure as demand and speed increase.
Programming is the same as just covered for the single transducer version. Data on the differential
pressure transducer can be found in Appendix A.
Iv. Single Pump Constant Flow
A single pump AQUAVAR controller system can also be set to maintain a constant flow by changing
motor speed to create more or less pressure when demand changes. The pump should be selected
so that the flow rate required is approximately in the middle of the pump curve and the maximum
pressure is within the performance of the pump at maximum speed. In general, pumps are not
designed to be piped in series (discharge to suction) due to maximum working pressure limitations.
Select a single pump which meets system requirements through either higher staging or larger
impeller diameters.
An orifice plate with differential transducer or a flow transducer can be used for constant flow appli-
cations. Follow the instructions provided with the orifice/transducer or flow transducer assembly for
installation procedures and electrical connections.
Instructions
In flow applications, you will want to change the
sensor curve from linear or to quadratic and the
units from PSI to %, when using to orifice/transducer
assembly. To do this, hold down the
key at the main menu until screen:
1. Enter the number 66.
2. Briefly press the key to scroll through
the displays until screen:
3. Use the to change to Quadratic. Note: If
you are using a flow sensor rather than an
orifice plate, leave the sensor curve at linear.
4. Briefly press the key to scroll through
the displays until screen:
Programming
PASSWORD 0000
0066
Screen
SENSOR CURVE
QUADRATiC
t
DiMENSiON UNiT PSi
*
*
*