Installation; Earthing; Overflow Valve; Suction Line - Grundfos DMH 25X Montage- Und Betriebsanleitung

5. Installation

The operator is responsible for setting up the system
in accordance with the requirements of Directive
99/92/EC, taking into account the appropriate
standards for its application.
The motor and accessories for the pumps, e.g. the
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actuator, frequency converter and metrology-based
monitoring, must at minimum meet the requirements
of Directive 2014/34/EU as applicable to pumps.
Accessories for the system and pipeline must at
minimum meet the requirements of Directive
2014/34/EU as applicable to pumps.
An intrinsically safe installation must only be made
and checked by someone who is "appropriately
qualified".
Make sure you read the installation and operating
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instructions supplied with the individual electrical
components.
Make sure you adhere to applicable national
regulations when installing the system.

5.1 Earthing

All pumps and accessories for the installation must
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be earthed.
The plastic version of the diaphragm leakage detection does not
have a conductive connection to the pump and must be earthed
by the customer.

5.2 Overflow valve

DMX 226: An overflow valve must be installed in the
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discharge line to prevent impermissibly high
pressure on the discharge side of the pump.
DMH 25X and DMH 28X: If the DMH 25X or DMH 28X is the only
pressure source in the system, it is not necessary to install an
overflow valve in the discharge line.

5.3 Suction line

Impurities in the dosing medium may damage the
diaphragm or block the discharge side of the dosing
head.
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Install a filter (aperture size 1.5 mm) in the suction
line to prevent the pressure increasing in the event of
a fault due to a blockage on the discharge side and
damage to the diaphragm.

5.4 Dosing of combustible media

For dosing combustible media, see section
dosing media.
5.4.1 Installation for feed mode
Warning
The pump must not run dry, even during
commissioning/recommissioning.
The pump should be installed so that the discharge line can be
deaerated during start-up of the pump to enable the dosing
medium to flow into the dosing head.
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5.4.2 Draining off the dosing medium
Lines for draining off media safely should be connected to the
safety valves (such as the overflow valve in the discharge line on
the discharge side of the pump) or vent valves via which the
combustible media are drained off.
5.4.3 Protection against running dry / flow indicator
5.4.4 Diaphragm leakage detection
The evaluation of the diaphragm leakage signal (electrically
isolated reed contact) of the diaphragm leakage detection must
be used to stop the pump immediately.

6. Commissioning

For dosing combustible media, see section
dosing
4.2.2 Permissible
The media must be drained off safely in order not to
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pose a risk to persons or property.
Warning
An explosive mixture of vapours may form in tanks
which are partially empty. The pumps must not run
dry in order to prevent explosive atmospheres in
storage tanks being transferred to other areas.
The customer should install level indicators in tanks
or flow indicators on the discharge side of the pumps
to prevent them from running dry.
The intake of air must be prevented.
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Check suction lines regularly to make sure they are
tight.
During operation, pumps must not become a source
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for impermissible medium leaks (this is particularly
important where combustible media are dosed).
media.
Warning
Risk of explosion due to overheating of the pumps.
The pumps must not run against closed valves and
fittings.
Warning
The first time the pump is started up or when it is
restarted after the dosing head has been emptied,
explosive vapour mixtures may form.
The pump must run with a completely full dosing
head during start-up and when restarted:
• Fill the dosing head and suction line with the
dosing medium, or,
• with flooded suction, deaerate the discharge line
to enable the dosing medium to flow into the
dosing head.
4.2.2 Permissible