1. The stroke lengths is set to the minimum value while the dosing pump is running. Consequently, the
diaphragm is at the greatest possible distance from the housing and can be easily grasped.
IMPORTANT!
Before you continue, disconnect the power supply to the pump or switch off the pump.
2. Use a suitable tool (WAF 10 open-ended spanner for DE/DX 20 and WAF 13 for DE/DX 40...100) to
remove the dosing head
①
(see Fig. 1). Slightly loosen the diaphragm by turning in counterclockwise
direction.
3. Diaphragm flange
⑤
is removed complete with diaphragm
②
, support plate
③
(only on DE/DX 20),
deflector plate
④
, diaphragm rod
⑥
and compression spring
⑦
using a suitable tool (WAF 5 wrench for
hexagon socket head cap screws) (see Fig. 2)
4. Grasp the edge of the diaphragm
②
and remove by turning in counterclockwise direction. On the DE/DX
20, the support plate
③
behind the diaphragm is removed at the same time. If diaphragm
②
can not be
removed because the diaphragm rod
⑥
is also turning, clamp the end of the diaphragm rod to secure it in
position. Diaphragm
②
can now be removed (see Fig. 3)
NOTE!
Before fitting a new diaphragm, the support plate
③
(only on DE/DX 20) must be cleaned to remove any
chemicals, otherwise they may corrode the back of the diaphragm.
5. Check that the deflector plate
④
is in perfect condition and replaced if necessary.
6. Grease diaphragm rod
⑤
with Molykote Longterm W2 at the contact point with the housing and along
the diaphragm thread. Also grease the area around compression spring
⑦
.
7. Push the support plate
③
(only on DE/DX 20) on to the threaded connector of the new diaphragm
②
with the concave side facing towards the diaphragm (see Fig. 4)
8. Turn the new diaphragm
②
together with support plate
③
(only on DE/DX 20) in clockwise direction until
it rests securely in diaphragm rod
⑥
. The smooth side of the support plate presses against the end of the
diaphragm rod
NOTE!
Make sure deflector plate 4 is positioned correctly. It must sit on the spigot of the diaphragm rod and must
not be trapped between the diaphragm rod and the support plate.
9. Diaphragm flange
⑤
is reinstalled complete with diaphragm
②
, support plate
③
(only on DE/DX 20),
deflector plate
④
, compression spring
⑦
and diaphragm rod
⑥
. Tighten screws crosswise (see Fig. 5)
10. Attach dosing head
①
. Tighten screws crosswise, e.g. top left – bottom right – top right – bottom left.
The tightening torque for the dosing head screws is 2 Nm on the MAGDOS DE/DX 20 and 6 Nm on the
MAGDOS DE/DX 40…100 (see Fig. 6).
IMPORTANT!
The diaphragm will not provide a tight seal if the tightening torque is too low. The dosing head may be dam-
aged if the tightening torque is too high.
11. After connecting the dosing lines, the dosing pump is started as described in "Start-up" (Section 9). If
the diaphragm wears down frequently, refer to "Troubleshooting" (Section 13) for a description of possible
causes.
Maintenance | Operation & Maintenance Instructions |
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