Mechanical Installation; Installation Of Pump; Pipework; Pipe Connection - Grundfos AC Series Installation And Operating Instructions Manual

5. Mechanical installation

Before installing the pump, check that the pump type
and parts are as ordered.

5.1 Installation of pump

The pump should be installed in a horizontal position
with the suction pipe as short as possible and the
suction lift as small as possible.
The pump should be installed in a well-ventilated and
frost-free location.
The pump may be installed outdoors, but it should be
protected from the elements by means of a suitable
cover.

5.2 Pipework

It is advisable to fit isolating valves on either side of
the pump. It is thus not necessary to drain the
system if the pump needs service.
The pump must not be stressed by the pipework.
The pipework must be correctly sized taking due
account of the pump inlet pressure.
If the pump is installed at the lowest point of the
system, impurities and sludge may accumulate in the
pump.
Install the pipes so that air locks are avoided,
especially on the suction side of the pump.
See fig. 1.
Pipework
Fig. 1

5.3 Pipe connection

5.3.1 Suction pipe
If the pump is installed above the liquid level, a foot
or non-return valve must be fitted in the suction pipe
below the liquid level.
Connect the suction pipe to the pump suction port.
See fig. 2.
Every joint of the suction pipe must be completely
tight.
If a hose is used as a suction pipe, it must be non-
collapsible. A strainer is recommended in cases
where solids could enter the suction pipe and block
the pump.
5.3.2 Discharge pipe
Connect the discharge pipe to the pump discharge
port. See fig. 2.
The discharge pipe should be at least the same
diameter as the discharge port of the pump to
minimise pressure drop, high flow velocities and
noise.
Discharge port
Suction port
Suction and discharge ports
Fig. 2
5.3.3 Bypass connection
If there is any risk of the pump running against a
closed discharge valve, a minimum liquid flow
through the pump should be ensured with a bypass.
The required minimum flow rate is shown in the table
below.
Required minimum flow rate*
Pump type
AC 15
AC 20
AC 25
AC 30
* The required minimum flow rate applies to liquid
temperatures from -10 °C to +55 °C.
3
[m /h]
2.4
3.0
3.6
4.2
7