Grundfos MFV - Deaerating the Pump; Draining the Discharge Line; Setting the Opening Pressure

English (GB)
6
Fig. 3 Setting the relief pressure
5.2 Setting the opening pressure
The opening pressure of the pressure loading valve is factory-set
to 3 to 4 bar, and should not be adjusted unless absolutely
necessary.
For DDI pumps with flow monitor or DDA FC/FCM pumps,
a counterpressure of 3 to 4 bar on the pressure loading valve is
required.
If the factory-set pressure of 3 to 4 bar is to be changed,
proceed as follows (see fig. 4).
1. Remove the protective cap from the black knob
(pressure loading side).
2. Press the safety bolts against each other with a pair of
needle-nosed pliers.
3. Remove the knob.
4. To reduce the opening pressure, use a pair of needle-nosed
pliers to turn the threaded thrust part counterclockwise out of
the housing, until the required counterpressure is reached,
e.g. 1 to 2 bar.
5. Refit the knob. Both safety bolts must engage.
6. Refit the protective cap.
Fig. 4 Setting the opening pressure
5.3 Deaerating the pump
Before starting up the pump, it can be depressurised and
deaerated using the multi-function valve (see fig. 5).
• To deaerate the pump, turn the green deaeration knob (1)
clockwise (direction of arrow on protective cap) as far as it will
go.
• As long as the deaeration knob (1) is turned as far as it will go,
the dosing medium can flow through the relief line (7) to the
tank.
• When released, the deaeration knob automatically returns to
its original position.
5.4 Draining the discharge line
Proceed as follows (see fig. 5).
• Simultaneously turn the green deaeration knob (1) and the
black knob (4) clockwise (direction of arrow on protective cap)
as far as they will go. The dosing medium flows through the
relief line (7) back to the supply container.
• The two knobs must be held in this position until all the
medium has flown into the container.
• When released, both knobs automatically return to their
original positions.
Fig. 5 Multi-function valve components
TM04 1221 1211
Pos. Description
1 Adjusting mark
2 Adjusting slot for relief pressure
Approx. relief pressure [bar]
Slot upper edge (A) 7 + 2
Slot centre (B) 10 + 2
Slot lower edge (C) 16 + 2
Caution
Do not bend or break the small pin on the inside of
the protective cap. A broken pin will make the
corresponding function (deaeration/draining)
impossible.
TM04 1222 1211
Approx. opening pressure [bar]
Slot centre (B) 1 to 2
Slot lower edge (C) 3 to 4
7 + 2 bar
10 + 2 bar
16 + 2 bar
1 to 2 bar
3 to 4 bar
Warning
A non-return valve must be fitted to the injection
point, otherwise the entire content of the system can
flow back.
TM04 1223 1211
Pos. Description
1 Green deaeration knob (pressure relief side)
2 Relief outlet
3 Discharge side outlet
4 Black knob (pressure loading side)
5 Flow direction of dosing medium
6 Valve inlet
7 Relief line