Grundfos MQ Operating instructions

GRUNDFOS
ILLUSTRATED SERVICE INSTRUCTIONS
MQ
50/60 Hz

2
Contents
Fitting the non-return valve in the suction port .................................................................... 2
Dismantling the pump.......................................................................................................... 3
Assembling the pump........................................................................................................ 10
Replacing the capacitor..................................................................................................... 18
Replacing the flow sensor ................................................................................................. 20
Replacing the pressure switch........................................................................................... 24
Replacing the non-return valve of the outlet...................................................................... 27

3
Fitting the non-return valve
in the suction port
Remove the suction port.
1
Fit the non-return valve into the suction port.
2
Fit and tighten the suction port.
3

4
Dismantling the pump
Remove the screw of the clamp.
1
Remove the clamp.
2
Remove the screws of the pump sleeve.
3
Loosen the pump sleeve using a screwdriver.
4

5
Remove the pump sleeve.
5
Pull out the self-priming part.
6
Remove the inlet part.
7
Remove the O-ring from the self-priming part.
8
Pull the valve seat out of the self-priming part.
9
Remove the O-ring from the valve seat.
10

6
Remove the O-ring from the inlet part.
11
Remove the plug in the middle of the motor cover.
12
Hold the shaft with a screwdriver.
13
Slacken the impeller nut while holding the shaft.
14
Remove the washers.
15
Remove the impellers and chambers.
16

7
Remove the washers.
17
Pull off the rotating shaft seal part using two screw-
drivers.
18
Remove the stationary shaft seal part if the motor is
not to be pulled out.
19
Insert a screwdriver between the pump housing and
the rubber ring, and prise out the stationary shaft seal
part.
20
Pull the rubber ring out of the pump housing using a
screwdriver, and remove both rings.
21
Remove the four screws of the terminal box cover.
22

8
Take off the cover.
23
Remove the screws of the control unit.
24
Remove the retaining clip of the capacitor.
25
Disconnect the red and white motor conductors from
the capacitor.
26
Disconnect the blue motor conductor from the terminal
block.
27
Slacken the screw which fixes the earth conductor of
the motor.
28

9
Loosen the cover of the pressure tank with a light
blow.
29
Unscrew the pressure tank.
30
The pressure tank.
31
Remove the screws of the end cover.
32
Remove the four screws in the hole for pressure tank.
33
Disengage the end cover from the pump using a
screwdriver.
34

10
Pull out the motor conductors.
35
Push out the motor.
36
Remove the O-ring from the motor.
37
Remove the O-ring on the shaft using a screwdriver.
38
Remove the stationary shaft seal part if it has not been
removed (picture 19).
39
Remove the rubber ring.
40