Repairs; Disassembling Of The Pump; Assembling Of The Pump - Mast Pumpen NP 4 Betriebsanleitung

7.3

Disassembling of the pump

Repairs must be accomplished by authorized persons only.
Warranty claims expire with unauthorized repairs or arbitrary
modifications. Any liability for consequential damages such as
personal damages, property and material damages caused by
inproper repairs is excluded.
For pumps with electric motor only: The power supply must be
disconnected for all services always.
Note: Following, the first stated pos. in brackets is valid for range NP 4 and NP 8,
the second stated pos. for range NP 12, e.g. (Pos. 4 / Pos. 10).
7.3.1 Dewater the pump by unscrewing the lock screw at the bottom of the pump
(pos. 13 / pos. 16).
7.3.2 Dismantle the casing (pos. 11 / pos. 14) by unbolt the screws (pos. 15 M6 /
pos. 26 ring nut).
7.3.3 Pull out the diffuser (pos. 8 / pos. 11).
7.3.4 Position the pump horizontally for replacing the shaft seal. For pumps with
electric motor only: dismantle fan casing and fan impeller to allow a blocking of
the shaft for demounting the impeller later.
7.3.5 Demount impeller (pos. 6 / pos. 10) and seal ring (pos. 5 / pos. 9) (right-hand
thread, wrench size 17 or 19), and take-off the seal ring from the impeller.
7.3.6 Push out the counter ring (pos. 4 / pos. 8) and the o-ring (pos. 3 / pos. 7) from
the back casing.
7.4

Assembling of the pump

7.4.1 The assembling of the pump is the reverse order of the disassembling explained
above.
7.4.2 When mounting the counter ring (pos. 4 / pos. 8) grease the outer side of the
thereunder mounted o-ring (pos. 3 / pos. 7) (Caution: the sliding surface of
the shaft seal must not be greased!). After that, push the seal ring on the
shaft of the impeller and mount it on the engine/motor shaft.
7.4.3 When installing, keep the sliding surfaces of the counter ring (pos. 4 / pos. 8)
and the shaft seal (pos. 5 / pos. 8) dust-free and greaseless.
7.4.4 Adjust the air gap between impeller and diffuser as shown in 7.5 next page.
7.4.5 Run a performance check of the complete unit.
Multi-purpose pump NP 4, NP 8, NP 12
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