English (GB)
30
Fig. 36
DN 32 valve, suction side and discharge side
10.6 Replacing the diaphragm and gear oil for dosing
head with single diaphragm (no diaphragm
leakage detection)
10.6.1 Drain gear oil
Fig. 37
Drain gear oil
1. Unscrew the locking screw (B) and collect the gear oil in a
container.
2. Screw the locking screw (B) and the new gasket (1b) back in
and tighten securely.
10.6.2 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).
10.6.3 Replacing a single diaphragm (no diaphragm leakage
detection)
• Remove the diaphragm and fit a new diaphragm (Q) on the
suction side. See fig.
Fig. 38
Replacing a single diaphragm
T
M
03
64
7
1
45
0
6
Caution
The O-rings must be correctly placed in the specified
groove.
Observe the flow direction (indicated by an arrow on
the valve)!
Only tighten plastic valves by hand.
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
Pump type
Version
Description
DMH 251
Single/double
1.3 l white oil
(Paraffin 55 DAB7)
DMH 252, 10 bar
Single/double
1.3 l white oil
(Paraffin 55 DAB7)
DMH 252, 16 bar
Single/double
1.3 l DHG 68
DMH 253
Single/double
1.3 l DHG 68
DMH 254
Single
3.5 l DHG 68
DMH 254
Double
4.5 l DHG 68
DMH 255
Single
3.5 l DHG 68
DMH 255
Double
4.5 l DHG 68
DMH 257
Single
5.5 l DHG 68
DMH 257
Double
7.5 l DHG 68
Note
Collect the gear oil in a container and dispose of it
correctly.
2)
1)
Discharge side
Suction side
TM
0
3
6
472
4
506
Pos.
Components
B Locking
screw
1b Gasket
F
Oil-filling screw with dipstick
L
Stroke-length adjustment knob
Caution
Risk of leaking oil and damage caused by oil loss!
For each oil change, a new flat gasket (1b) must be
fitted!
TM
03
6
473
45
06
Pos.
Components
1q
Dosing head screw
2q Intermediate
disk
2 Dosing
head
Q Diaphragm
1b
L
F
B
1q
Q
2
2q