Xylem IM167 R8 Aquavar CPC (Centrifugal Pump Control) - Manual (Page 89)

89
MultiPump – Constant Pressure Control
Pump Sizing
It is recommend to use the same size pump for a multi-pump configuration. This is to
ensure even distribution of flow rates especially when small flow demands are put on the
system. If the operator requires a flow range of 10 – 500 GPM for the system, it would be
recommended to select a TRIPLEX system, with each pump capable of a maximum of 167
GPM at the required TDH. (167 GPM x 3 pumps = 501 GPM ) A smaller sized pump is more
capable of providing the low flow rates, rather than a larger pump that may oscillate more
at the low flows. One of the immediate benefits is to have all the same pumps for parts and
spares. No smaller jockey pumps. Each pump is evenly distributing the required flow and
pressure. Remember to allow system friction losses at maximum flow!
Tank Sizing
Similar to the single pump constant pressure system, the multi-pump system should have
a diaphragm or bladder type tank for system cushion. The tank should be rated for the
maximum system pressure, and be sized for 10-25% of the single pump capacity. This is total
tank volume, not drawdown. If you have a triplex system of 167 GPM per pump capacity,
then your tank size should be a minimum of 17 Gallon capacity. Go to the next higher
tank volume if you have a suction lift or flooded suction. The tank provides small
drawdown capacities on drive start up and provides a “cushion” for the entire system at
normal operation and will provide compressibility at shut-down. The tank pressure will greatly
improve system operation. A larger tank is acceptable and sometimes required, just do not
exceed 50% volume of the flow for one pump, this may cause system problems.
Programming
The following steps are for multi-pump, constant pressure systems, with up to four (4) Aquavar
CPC. Each Aquavar CPC will have to be programmed according to this parameter guide. The
parameters will not transfer over to each unit. There are two options for downloading the
parameters into each Aquavar:
A) Manually entering each parameter into the Aquava
control panel/display with the following steps.
B) Using the first Aquavar control panel, you can
download the software to each additional Aquavar
via the control panel. Take the programmed control
panel from Aquavar #1, then insert and replace each
additional control panel for Aquavar #2, #3, #4. This will
automatically download saved parameters into the other
Aquavar units. See diagram to the left.
PROGRAMMING