After start-up
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.
Torques
Pump model
Torque
[Nm]
DMH 254
50-54
DMH 255
50-54
DMH 257
50-54
Related information
6.1 General information on installation
8.4 Setting the pressure relief valve
The pressure relief valve is set to the pressure given by the
customer, or to the rated pressure (maximum counter-pressure).
The opening pressure can be set to a lower value by the customer.
Opening pressure of the pressure relief valve
Rated pressure of the pump
[bar]
Opening pressure of the pres-
sure relief valve
[bar]
4
5
10
13
16
18
25
28
Setting the opening pressure
•
To set the operating pressure, a pressure gauge must be
installed in the discharge line and an isolating valve must be
installed after the pressure gauge.
•
To set the pressure relief valve, use a screwdriver.
TM036464
Setting the opening pressure
Set the pressure relief valve as follows:
1. Close the isolating valve after the pressure gauge.
2. Remove the cover (1 m) from the pressure relief valve.
3. Start the pump.
4. Using a screwdriver, slowly turn the adjusting screw (2 m) of the
pressure relief valve counter-clockwise until the desired opening
pressure is obtained.
2m
1m
TM036465
Setting the pressure relief valve
Caution
Risk of damage to the pump or system!
When blocked, the pressure relief valve does not work
properly and can produce pressures of several hun-
dred bar in the pump or system.
Do not block the pressure relief valve during adjust-
ments!
5. Replace the cover of the pressure relief valve.
6. Open the isolating valve after the pressure gauge.
8.5 Zero point adjustments
8.5.1 Adjusting the zero point for system pressures up to 100
bar
The zero point of the dosing pump is factory-set to a slightly lower
counter-pressure than the rated pressure of the pump. If the
operating counter-pressure deviates considerably from this value,
an adjustment of the zero point will ensure more precise values.
Counter-pressure at the factory-set zero point of the pump
Rated pressure of the pump
[bar]
Counter-pressure at the facto-
ry-set zero point
[bar]
10
3
16
3
25
10
8.5.2 Adjusting the zero point
3l
2l
1l
4l
3l
L
TM036466
Adjusting the zero point
Pos.
Components
L
Stroke-length adjustment knob
1l
Cover
2l
Locking screw
3l
Screw
4l
Scale ring
32
English (GB)
Summary of Contents for DMH 25X
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