Product Manual

CU331SP variable frequency drive
SQ, SQE, CU 331, and SP
10
40
Operating conditions for the stop
function
It is only possible to use the stop function if the system
incorporates a pressure sensor, a non-return valve and
a diaphragm tank.
The non-return valve must always be installed before
the pressure sensor.
Fig. 26 Position of the pressure sensor and diaphragm
tank
Diaphragm tank
The stop function requires a diaphragm tank of a
certain minimum size. The tank must be installed as
close as possible after the pump and the precharge
pressure must be 0.7 x actual setpoint.
Recommended diaphragm tank size:
If a diaphragm tank of the above size is installed in the
system, the factory setting of ΔH is the correct setting.
If the tank installed is too small, the pump will start and
stop too often.
Setting the direction of rotation
The start-up guide is started the first time the
CU331SP is connected to supply voltage. Then while
going through the start-up guide, the CU331SP tests
and sets the correct direction of rotation without
changing the cable connections to the motor.
The correct direction of rotation can be set in these
ways:
• automatic setting.
• manual setting when the direction of rotation is not
visible.
Automatic setting
The CU331SP automatically tests and sets the correct
direction of rotation without changing the cable
connections.
Automatic setting requires a sensor.
This test is not suitable for all pump types and will in
certain cases not be able to determine for certainty the
correct direction of rotation. In these cases, the
CU331SP changes over to manual setting where the
direction of rotation is determined on the basis of the
installer's observations.
Manual setting when the direction of rotation is not
visible
The correct direction of rotation is set manually without
changing the cable connections. This requires that it is
possible to observe the head or flow rate.
Status functions
The CU331SP shows the following data:
• power consumption
• operating hours
• measured value
• speed
• input power
• motor current.
The status information can be shown in the display.
Power consumption
The value of the power consumption is an
accumulated value calculated from the pump's startup
date and cannot be reset. No additional sensor is
required.
TM05 5804 4012
Rated flow of pump
[gpm (m
3
/h)]
Typical diaphragm tank size
[gal (l)]
0-26 (0-6) 2 (7.5)
27-105 (7-24) 4 (15.1)
Pump with non return valve
Diaphragm tank
Pressure sensor