Enabling The Dip Switch Settings; Checking The Dip Switch Settings; Start-Up; Operation - Grundfos PM 2 Installation And Operating Instructions

5.2 Enabling the DIP switch settings

When the desired DIP switch settings
have been made, they must be enabled,
Note
otherwise the PM 2 cannot detect the
settings.
To enable the DIP switch settings, press [Reset] or
disconnect and reconnect the power supply to the
unit.

5.3 Checking the DIP switch settings

When [Reset] is kept pressed for at least 3 seconds,
the light fields for the DIP switches set to "ON" will
illuminate in the pressure scale.
The light fields illuminate from right to left. This
means that if the light field to the far right is on, DIP
switch 8 has been set to "ON", etc. See the table
below.
Light field [bar] 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
DIP switch no. 1 2

6. Start-up

1. Open a tap in the system.
2. Switch on the power supply.
3. Check that the "Pump on" and "Alarm" indicator
lights as well as all the green light fields in the
pressure scale illuminate briefly.
– The pump is running, and a pressure will be
built up in the system. The pressure is indicated
by the light fields in the pressure scale.
4. Close the tap.
5. Check that the pump stops after a few seconds
and that the "Pump on" indicator light goes out.
The system is now ready for operation.
If a pressure is not built up in the
system within 5 minutes after start-up,
the dry-running protection will be
activated, and the pump is stopped.
Check the priming conditions of the
pump before attempting to restart the
Note
pump.
The pump is restarted automatically if
DIP switch 6 (AUTO RESET) has been
set to "ON", otherwise the pump can be
restarted manually by pressing [Reset].
3 4 5 6 7 8

7. Operation

The PM 2 automatically starts and stops the pump.
This can be achieved in two different ways:
• On delivery, the unit has a default setting which
can be used in systems with or without a pressure
tank. See section 7.1 Start/stop according to
water consumption.
• In systems with a pressure tank, it is possible to
use the setting described in section 7.2 Start/stop
with 1 bar differential pressure. This setting will
reduce the pump operating time.
7.1 Start/stop according to water
consumption
As default, the PM 2 is set to this operating mode,
i.e. DIP switch 5 set to "OFF".
With the default setting the pump will
not stop until it reaches its maximum
Caution
pressure.
7.1.1 Starting and stopping conditions
Starting conditions
The unit starts the pump when at least one of the
following conditions is fulfilled:
• The flow is higher than Q
• The pressure is lower than p
The default start pressure is 1.5 bar and can be
increased in steps of 0.5 bar. See section 5.1 DIP
switches.
Stopping conditions
The unit stops the pump with a time delay of
10 seconds when the following conditions are both
fulfilled:
• The flow is lower than Q
• The pressure is higher than p
The p and Q values are shown in section
start min.
11. Technical data.
7.2 Start/stop with 1 bar differential
pressure
This operating mode can be used in systems with
a pressure tank of a sufficient size.
In this operating mode, the pump is started and
stopped at a 1 bar differential pressure, which
reduces the pump operating time. If the pressure
tank is of an insufficient size, it will cause cycling of
the pump.
To enable this operating mode, set DIP switch 5 to
"ON". See section 5.1 DIP switches.
.
min.
.
start
.
min.
.
start
11