Electrical Connections; Electric Servomotor (Optional); Electronic Preselection Counter (Optional); Electrically Heated Dosing Head (Optional) - Grundfos DMH 251 Installation And Operating Instructions Manual

Connection of DN 20 pipe lines
• Depending on the pipe material and connection, glue the pipe
(PVC), weld it (PP, PVDF or stainless steel) or press it in
(stainless steel).
• Fit the gasket.
• Screw the pipe on the valve using the union nut.
Fig. 20 Connection of DN 20 pipe lines
Connection of DN 32 pipe lines
• Depending on the pipe material, fit the pipe to the welding
neck flange and weld it (stainless steel) or insert it into the
headed bush and weld it (PP, PVDF).
Fig. 21 Connection of DN 32 pipe lines
9.8.1 Connecting a liquid-heated dosing head (optional)
As an option, liquid-heated dosing heads are available in
stainless steel.
2f
2f1
40
Fig. 22 Liquid-heated dosing head
Pos. Components
2f Dosing head, liquid-heated
2f1 Hose nipple, DN 10 connection
Required characteristics of heating liquid:
• The heating liquid must not chemically attack stainless steel.
• Maximum permissible pressure: p
• Maximum permissible temperature: t
= 3 bar.
max.
= 100 °C.
max.

10. Electrical connections

Make sure that the pump is suitable for the electricity supply on
which it will be used.
Warning
Electrical connections must only be carried out
by qualified personnel!
Disconnect the power supply before connecting
the power supply cable and the relay contacts!
Observe the local safety regulations!
The pump housing must only be opened by
personnel authorised by Grundfos Alldos!
Protect the cable connections and plugs against
corrosion and humidity.
Only remove the protective caps from the
sockets that are being used.

10.1 Electric servomotor (optional)

To connect the servomotor to the power supply, see the
installation and operating instructions for the servomotor.

10.2 Electronic preselection counter (optional)

To connect the preselection counter to the power supply, see
the installation and operating instructions for the counter.

10.3 Electrically heated dosing head (optional)

2e
Fig. 23 Electrically heated dosing head
Pos. Component
2e Dosing head, electrically heated
• To connect the temperature controller to the power supply,
see the installation and operating instructions for the electric
temperature controller.
2e1
2e2
2e3
Fig. 24 Temperature controller
Pos. Connections
2e1 Sensor
2e2 Heating
2e3 Power supply
23