Grundfos DMH 25 Series - Page 33

33
13.7.5 Filling with gear oil
1. Check that the locking screw (B) is tightened.
2. Slacken and remove the oil-filling screw (F).
3. Set the stroke-length adjustment knob (L) to "0".
4. Slowly add the hydraulic oil through the oil-filling opening (F)
until the oil reaches the mark on the oil dipstick.
5. Wait 30 minutes.
6. Let the pump run for approx. 5 minutes with a stroke-length
setting of 0 %.
7. Let the pump run for approx. 10 minutes with a stroke-length
setting of 40 %.
13.7.6 Checking the oil level
1. Switch off the pump, check the oil level and add oil,
if necessary.
2. Refit the oil-filling screw (F).
Torques
13.7.7 Cleaning the ball non-return valve
Fig. 42
Contact pressure gauge
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.
Cleaning the ball non-return valve
Fig. 43
Ball non-return valve
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.
Caution
Risk of leaking oil and damage caused by oil
loss!
For each oil change, a new flat gasket (1b) must
be fitted!
Caution
After initial start-up and after each time the
diaphragm is changed, tighten the dosing head
screws.
After approximately 6-10 operating hours or
two days, cross-tighten the dosing head screws
using a torque wrench.
Pump type
Torque
[Nm]
DMH 251, 10 bar 8-10
DMH 251, 16 bar 10-12
DMH 251, 25 bar 13-15
DMH 252 8-10
DMH 253 10-12
DMH 254 50-54
DMH 255 50-54
DMH 257 50-54
Note
Only clean the ball non-return valve after
a diaphragm breakage!
TM03 6453 4506
T
5u
4u
3u
2)
U
5s
3u
2u
S
6s
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)
TM03 6476 4506
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
Caution
Tighten the ball non-return valve and connection
piece by hand only.
t7
t6
t5
t4
t3
t1
t2
t1