English (GB)
31
10.6.4 Fitting the dosing head
• Fit the dosing head and cross-tighten the dosing head screws
(1q with 2q) using a torque wrench.
10.6.5 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 %.
10.6.6 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
10.7 Replacing the diaphragm for dosing head with
double diaphragm
10.7.1 Removing the dosing head
1. Close the suction and discharge lines and loosen the suction
and discharge valve connections.
2. Loosen the six dosing head screws (1q with 2q).
3. Remove the dosing head (2).
10.7.2 Replacing a double diaphragm
1. Clean the intermediate disk (3q), sealing rings (4q) and
covering rings (5q). After a diaphragm breakage, replace the
parts by new ones.
2. Remove both clamping sleeves (6q) slightly using pliers. After
a diaphragm breakage, replace the parts by new ones.
3. Measure the outer wall thickness of both new diaphragms (Q1
and Q2): s1
(Q1)
< s2
(Q2)
.
Fig. 39
Installation of diaphragm
1) The shape of the diaphragm varies depending on pump type.
4. Fit both new diaphragms (Q1 and Q2) and the parts (3q - 5q)
in the correct order, as is shown in the diagrams (the clamping
sleeves (6q) are used for centring purposes).
Fig. 40
Diaphragm on dosing-head side
Note
See section
for subsequent
start-up!
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
Warning
Wear protective clothing (gloves and goggles) when
working on the dosing head, connections or lines!
The dosing diaphragm should be replaced with each
gear oil change.
Before removing the dosing head, valves and lines,
empty any remaining medium in the dosing head into
a drip tray by carefully unscrewing the suction valve.
Note
Only use original Grundfos gear oil!
For product numbers, see "Service kit catalogue" on
www.grundfos.com
TM
0
3
6
474
4
5
06
Pos.
Components
1q
Dosing head screw
2q Intermediate
disk
2 Dosing
head
Q1/Q2
See fig.
3q - 5q
Caution
Observe correct installation of diaphragms (Q1 and
Q2)! See fig.
Fit the thinner diaphragm (Q1) on the dosing side
and the thicker diaphragm (Q2) on the oil side/pump
side!
TM
03
64
75
45
06
Pos.
Components
S
Contact pressure gauge (installation position)
Q1
Diaphragm on dosing-head side
Q2
Diaphragm on oil side/pump side
3q
Intermediate disk
4q
Sealing rings
5q
Covering rings
6q
Clamping sleeves
1q
2
2q
3q - 5q Q2
Q1
1)
s
1
< s
2
2
5q
4q
3q
4q
5q
Q2
Q1
6q
3q
S
