Xylem HYDROVAR (HV2.1 - 3.45) - Manual (Page 8)

8
2 System Design
The following diagrams show typical single pump and multi-pump systems using the
HYDROVAR control unit. Connection can be made directly to a water supply. In such a case, a
pressure switch on the suction side should be used.
Single Pump Layout Multi Pump Layout
(1) pump with HYDROVAR
(2) diaphragm tank
(3) distribution panel
(4) gate valve
(5) non return valve
(6) low water control
(7) pressure gauge
(8) pressure transmitter
(9) drain tap
2.1 Pressure tank
A diaphragm pressure tank is used on the discharge side of the pump to maintain pressure in
the line when there is no demand. This will keep the pumps from continuing to run at zero
demand. With the HYDROVAR, it isn’t necessary to have a large tank for supply purposes.
The tank must be permitted and suitable for systems pressure. The tank should have a
capacity of min. 10% of the maximum system flow rate [l/min] of one pump (also valid for
multi-pump system).
Example:
Maximum flow rate of the pump = 250 litres per minute
Minimum volume of the tank = 250 x 0.10 = 25 litres
The pre-charge pressure of the tank can be determined in the following table:
NOTICE: To check and set the right pre-charge pressure, please make the tank
pressure less before.
required pressure (bar)
precharge pressure (bar)