Submittal Sheet

Functions
MAGNA3
4
24
Multipump modes
Multipump function
The multipump function enables control of single-head
pumps connected in parallel and twin-head pumps
without the use of external controllers. The pumps in a
multipump system communicate with each other via
the wireless GENIair connection.
Pump system:
• Twin-head pump.
• Two single-head pumps connected in parallel. The
pumps must be of equal size and type. Each pump
requires a non-return valve in series with the pump.
A multipump system is set via a selected pump, i.e. the
master pump (first selected pump). The multipump
functions are described in the following sections.
Alternating operation
Only one pump is operating at a time. The change from
one pump to the other depends on time or energy. If a
pump fails, the other pump will take over automatically.
Backup operation
One pump is operating continuously. The backup
pump is operated at intervals to prevent seizing up. If
the duty pump stops due to a fault, the backup pump
will start automatically.
Cascade operation
Cascade operation ensures that the pump
performance is automatically adapted to the
consumption by switching pumps on or off. The system
thus runs as energy-efficiently as possible with a
constant pressure and a limited number of pumps.
The slave pump starts when the master pump either
runs at 90 % of the maximum speed or runs on the
maximum curve.
The slave pump stops if one of the following conditions
are fulfilled:
• One of the two pumps runs on minimum curve.
• One of the two pumps runs below 50 % of the
maximum speed and at the same time runs below
50 % of the maximum power consumption.
Cascade operation is available in constant speed and
constant pressure. You can with advantage choose a
twin-head pump as the backup pump will start for a
short period in peak-load situations.
All pumps in operation will run at equal speed. Pump
changeover is automatic and depends on speed,
operating hours and faults.
Flow estimation accuracy
The calculated flow rate has a typical accuracy of ± 5
% of Qmax. The less flow through the pump, the less
accurate the reading will be. In worst case scenarios,
such as closed valve operation, the accuracy can be
up to 10 % of Qmax.
See also Heat energy monitor, page 25.
Example:
Fig. 32 Q
max
1. MAGNA3 65-60 has a Q
max
of 40 m
3
/h. A typical 5
% accuracy means 2 m
3
/h inaccuracy of Q
max
. ± 2
m
3
/h.
2. This accuracy is valid for the entire QH area. If the
pump indicates 10 m
3
/h, the measurement is 10 ± 2
m
3
/h.
3. The flow rate can be 8-12 m
3
/h.
Note: Use of a water/ethylene glycol mixture will
decrease the accuracy.
Low flow indication
The pump can experience low flow due to for example
valves being shut. In cases where the flow is below 10
% of the maximum flow, thus too low for the pump's
internal sensor to measure, it will be stated on the
MAGNA3 display. A speed measurement will tell you
that the pump is still running.
When the flow is high enough for the pump to
measure, the MAGNA3 display returns to normal.
TM05 2448 5111
H
Q
Max.
Min.
Q
max