Operation; Shaft Seal Run-In; Control Functions; Overflow Alarm - Grundfos SCALA1 System Instructions Manual

4.3 Operation

4.3.1 Normal operation
When water is consumed in the water supply system,
the pump starts if the starting conditions of the pump
are fulfilled. This happens, for example, when a tap is
opened, making the pressure in the system drop.
The pump stops when the consumption stops, i.e.
when the tap is closed.
4.3.1.1 Starting and stopping conditions
To ensure optimal performance, the cut-in
pressure is set by Grundfos. It is therefore
not possible to adjust the cut-in pressure.
Starting conditions
The pump starts when at least one of the following
conditions is fulfilled:
• The flow is higher than Qmin (1.5 l/min).
• The pressure is lower than pstart.
Stopping conditions
The pump stops with a time delay of 10 seconds
when both of the following conditions are fulfilled:
• The flow is lower than Qmin (1.5 l/min).
• The pressure is higher than pstart.
The pstart values are shown in Technical data.

4.4 Shaft seal run-in

The shaft seal faces are lubricated by the pumped
liquid. A slight leakage from the shaft seal of up to 10
ml per day or 8 to 10 drops per hour may occur.
Under normal conditions, the leaking liquid will
evaporate. As a result, no leakage will be detected.
When the pump is started for the first time, or when
the shaft seal has been replaced, a certain run-in
period is required before the leakage is reduced to an
acceptable level. The time required for this depends
on the operating conditions, that is, every time the
operating conditions change, a new run-in period will
be started.
Leaking liquid will drain through the drain holes in the
motor flange.
Install the product in such a way that leakage cannot
cause undesirable collateral damage.

5. Control functions

5.1 Overflow alarm

If the refill valve starts to leak, causing loss of water
from the mains through the inner overflow drain, an
overflow alarm will be triggered. The pump is stopped
and two opposite yellow indicator lights will flash
simultaneously on Grundfos Eye. The alarm blocks
the system without any audible warning.
The alarm must be reset by switching the button on
the back of the pump from 1-Alarm D on to 0-Alarm
D off. See the figure below.
Related information
6.8 The pump is not running
13