Starting Up The Product; Before Startup; Venting The Pump; Venting Of Heating Systems - Grundfos ALPHA2 L Series Installation And Operating Instructions Manual

5. Starting up the product

5.1 Before startup

Do not start the pump until the system has been filled with liquid
and vented. The required minimum inlet pressure must be
available at the pump inlet. See section
installation dimensions.

5.2 Venting the pump

Venting the pump
Fig. 5
The pump is self-venting. It does not need to be vented before
startup.
Air in the pump may cause noise. This noise will cease after a few
minutes running.
Quick venting of the pump can be obtained by setting the pump to
speed III for a short period, depending on system size and
design.
When the pump has been vented, that is when the noise has
ceased, set the pump according to the recommendations. See
section
10. Setting the pump.
The pump must not run dry.
The system cannot be vented through the pump. See section
12. Pump settings and pump performance.
14. Technical data and

5.3 Venting of heating systems

Venting of heating systems
Fig. 6
The heating system can be vented via an air escape valve
installed above the pump. When the heating system has been
filled with liquid, follow this procedure:
1. Open the air escape valve.
2. Set the pump to speed III.
3. Let the pump run for a short period, depending on system size
and design.
4. When the system has been vented, that is when the possible
noise has ceased, set the pump according to the
recommendations. See section
Repeat the procedure, if necessary.
The pump must not run dry.
10. Setting the pump.
7