Dismantling The Diaphragm And Valves; Reassembling The Diaphragm And Valves - Grundfos DDE series Montage- Und Betriebsanleitung

7.3.2 Dismantling the diaphragm and valves

Warning
Danger of explosion, if dosing liquid has
entered the pump housing!
If the diaphragm is possibly damaged,
don't connect the pump to the power
supply! Proceed as described in section
7.4 Diaphragm
This section refers to fig. 10.
1. Make system pressureless.
2. Empty the dosing head before maintenance and
flush it, if necessary.
3. Set adjustment knob to 0 %.
4. Switch off mains supply.
5. Take suitable steps to ensure that the returning
liquid is safely collected.
6. Dismantle suction, pressure and deaeration
hoses.
7. Dismantle valves on suction and discharge
side (5, 6).
8. Remove the cover (9).
9. Loosen screws (8) on the dosing head (7) and
remove the screws and discs.
10. Remove the dosing head (7).
11. Unscrew diaphragm (4) counter-clockwise and
remove with flange (2).
12. Make sure the drain opening (11) is not blocked
or soiled. Clean if necessary.
13. Check the safety diaphragm (1) for wear and
damage. Replace if necessary.
If nothing indicates that dosing liquid has entered the
pump housing, go on as described in section
7.3.3 Reassembling the diaphragm and
Otherwise proceed as described in section
7.4.2 Dosing liquid in the pump
20
breakage!
valves.
housing.

7.3.3 Reassembling the diaphragm and valves

The pump must only be reassembled, if nothing
indicates that dosing liquid has entered the pump
housing. Otherwise proceed as described in section
7.4.2 Dosing liquid in the pump
This section refers to fig. 10.
1. Attach flange (2) correctly and screw on new
diaphragm (4) clockwise.
– Make sure that the O-ring (3) is seated
correctly!
2. Connect/switch on mains supply.
3. Turn the adjustment knob slowly to bring the
diaphragm into its service position "inside"
(end of suction phase, diaphragm retracted).
Set adjustment knob back to 0 %.
4. Switch off mains supply again.
5. Attach the dosing head (7).
6. Install screws with discs (8) and cross-tighten
with a torque wrench.
– Torque: 4 Nm.
7. Attach the cover (9).
8. Install new valves (5, 6).
– Do not interchange valves and pay attention to
direction of arrow.
9. Connect suction, pressure and deaeration hoses
(see section 4.2 Hydraulic
Tighten the dosing head screws with a
torque wrench once before commissioning
Caution
and again after 2-5 operating hours at 4
Nm.
10. Deaerate dosing pump (see section
deaerate the pump).
11. Please observe the notes on commissioning in
section 5. Startup!
housing.
connection).
5.3 Start and