Replacing The Diaphragm - Grundfos DMX 227 Installation And Operating Instructions Manual

10.4 Replacing the diaphragm

If possible, rinse the dosing head, e.g. by supplying it
Note
with water.
10.4.1 Switching off the pump
1. Switch off the pump and disconnect it from the power supply.
2. Depressurise the system.
3. Take suitable steps to ensure that the returning dosing
medium is safely collected.
10.4.2 Replacing the diaphragm
1. Loosen the six dosing head screws.
2. Remove the dosing head.
3. Unscrew the diaphragm by manually turning it
counter-clockwise.
4. Refit the retaining ring (4), shim ring (5), lip seal (7) and
supporting ring (6). Replace faulty parts.
5. Screw in the new diaphragm completely.
6. Remove the motor fan cover, and turn the fan blades until the
diaphragm reaches the bottom dead centre.
7. Refit the dosing head carefully, and cross-tighten the screws.
Maximum torque: 70-80 Nm.
8. Deaerate and start the dosing pump.
2
3
6
Fig. 19 Replacing the diaphragm
Pos. Components
1 Diaphragm
2 Dosing head screws
3 Dosing head
4 Retaining ring
5 Shim ring
6 Supporting ring
7 Lip seal
After initial start-up and after each time the
diaphragm is changed, tighten the dosing head
screws.
Caution
After approximately 6-10 operating hours or two
days, cross-tighten the dosing head screws using a
torque wrench.
Maximum torque: 70-80 Nm.
18
7
5
1
4
Grundfos gear oil
Order no
98683958
98683959
Alternative special oil for DHG 68
Manufacturer
ARAL
BP
Chevron
ESSO
Fina
Mobil Oil
Texaco
Shell
elf
Description
5.0 l DHG 68
7.5 l DHG 68
Designation
Degol BMB 68
BP-Energol GR-XP 68
Chevron NL gear compound 68
Spartan BP 68
Fina Giran 68
Mobilgear 626
Texaco Meropa 68
Tellus 68
reductelf SP 68