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9.3.2 Reassembling the pump/motor
Have all parts cleaned and be free of burrs. Have new gaskets, oil and if required oil seals available.
1. If the electric motor was removed or replaced, inspect the surface of the bushing (27) for
scratches. If the surface is damaged, the VAF Instruments motor and bushing will need to be
replaced completely, as these items are critical for the gas tight seal.
2. If the oil seals (26) were removed, install these now, together with lantern ring (25). Take
care not to damage the oil seals. If the oil seals (26) are still in place, make sure these are
not damaged during reinstallation. Ensure the lubricating oil channel is clean. Smear a small
amount of oil over the seals. Install the electric motor (32). The terminal box should
preferably be located at the top.
3. Smear some oil on the face of the pump house (2). Mount the pump house (2) on the pump
face (22) with the 3 hex socket head cap screws (16). Use water and soap on the
mechanical seal (9) and press this into the pump house over the slightly prominent motor
drive shaft.
4. Insert the woodruff key (11) into the coupling (14) with Loctite Retainer 542. Mount the
coupling (14) with attention to the mechanical seal onto the motor shaft. (The sleeve should
slip easily onto the shaft). Care is to be taken to ensure the keyway in the coupling mates
with the drive pin (31) in the motor shaft.
5. Install the impeller (10) onto the shaft, taking care to line the keyway up with the woodruff
key (11). The impeller should fit readily onto the shaft. There is no difference between
frontside or backside. However, when refitting the same impeller it is preferable to adhere to
the original position.
6. Place the casing cover (5) on the pump casing (2), with a new O-ring gasket (8). Re-use all
of the shims (4). If a shim gets damaged it must be replaced with a new one of exact the
same thickness, otherwise pump performance will be affected or the pump may even jam.
Gently tighten all cover nuts (7).
7. Check that the pump rotates freely by hand. This can be done at the cooling fan of the
electric motor.
8. Check the oil level in the reservoir (38), if required refill.
CAUTION:
UNDER NO CIRCUMSTANCES SHOULD THE PUMP RUN WITHOUT LIQUID.
THE PUMP HOUSING MUST FIRST BE FILLED WITH LIQUID, OTHERWISE THE
PUMP WILL SEIZE AND DAMAGE WILL OCCUR.
9. Reconnect the suction and discharge piping to the pump casing. Reinstall the drain and vent
plugs after filling the pump casing and suction line with water.
10. Reconnect the pump motor to the mains supply. Make sure that all piping is installed, and
the pump is filled with water. Make sure any discharge valve is opened before starting,
enabling air to be released.
11. Check the direction of rotation by switching on the pump motor for a short moment only!
Look at the motor fan and notice the direction in which the fan spins. This must be
CLOCKWISE when looking from the back cover of the motor. An arrow also indicates correct
direction of rotation. If direction of rotation is wrong, interchange any of two line wires of the
power cable in the terminal box.
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