Grundfos DMH 25 Serie Montage- Und Betriebsanleitung Seite 35

10.7.7 Cleaning the ball non-return valve
Only clean the ball non-return valve after a
Note
diaphragm breakage!
S
5s
4u
U
5u
T
Fig. 42 Contact pressure gauge
Pos. Components
S Contact pressure gauge
5s Union nut
6s Contact output
T Ball non-return valve
U Connection piece
2u Deaeration screw
3u O-rings
4u Connection for earth cable
5u Union nut
* 2) or locking unit (instead of contact pressure gauge
and its connection)
Removing the ball non-return valve and contact pressure
gauge
1. For pumps and pressure gauges in explosion-proof version,
unscrew the earth cable (4u).
2. Hold the connection piece (U) with a screwdriver and unscrew
the union nut (5u).
3. Unscrew the ball non-return valve (T) from the dosing head.
6s
3u
2)
2u
3u
Cleaning the ball non-return valve
t7
t6
t5
t4
t3
t1
t2
t1
Fig. 43 Ball non-return valve
Pos. Components
t1 O-ring
t2 Ball non-return valve body
t3 Ball
t4 Spring sheath
t5 Pressure spring
t6 Screw part
t7 O-ring
1. Unscrew the screw part (t6) using round pliers.
2. Clean all parts. Replace faulty parts by new ones.
3. Re-assemble the ball non-return valve.
4. Refit the ball non-return valve (T).
5. Screw the contact pressure gauge (S) and connection piece
(U) back on.
6. For pumps and pressure gauges in explosion-proof version,
screw the earth cable (4u) back on.
Tighten the ball non-return valve and connection
Caution
piece by hand only.
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