Grundfos MAGNA 2000 Serie Manuel D'instructions page 11

6. Start-up
Do not start the pump until the system has been filled
with liquid and vented. Furthermore, the required
minimum inlet pressure must be available at the
pump inlet, see section 11. Technical data.
The system cannot be vented through the pump.
The pump can be vented by slackening the
inspection screw.
Warning
If the inspection screw is to be
slackened, see fig. 8, care should be
taken to ensure that the escaping,
scalding hot liquid does not cause
personal injury or damage to
components.
Fig. 8 Venting the pump
Inspection screw
11