Repairs; General; Changing Various Parts Of The Pump - Homa MX-ET Serie Originalbetriebsanleitung

7. Repairs

7.1. General

The following repair work may be done on this machine:
• Exchange of blade wheel and pump chamber
• Exchange of split ring
In general, the following should always be heeded when
doing this work:
• O-ring seals and existing seals must always be re-
placed.
• Screw locking devices such as spring washers must
always be exchanged.
• Torque values must be complied with.
The following applies in general to repair work:
Switch the machine off, disconnect it from the grid, clean
it and lay it in a horizontal position on a firm supporting
surface. Secure it against falling over and/or slipping away!
Unless stated otherwise, the torque values in the Tables
should be used. Values for clean, lubricated screws.
Tightening torque [Nm] for A2/A4 screws (friction coeffi-
cient = 0.2)
A2/A4,
strength 70
DIN912/DIN933
M6 7 Nm
M8 17 Nm
M10 33 Nm
M12 57 Nm
M16 140 Nm
M20 273 Nm

7.2. Changing various parts of the pump

Exchanging impeller and pump housing
• Loosen and unscrew the cylinder head screw on the
sealing casing with a hexagon socket.
• Secure the pump housing with a suitable device, e.g.
an auxiliary hoisting gear, and withdraw it from the
sealing casing. Lay it on a secure surface.
• Fix the blade wheel firmly with a suitable device,
loosen and unscrew the blade wheel mounting (cylin-
der head screw) with a hexagon socket.
Pay attention to the screw locking device!
• Withdraw the blade wheel from the shaft with a suit-
able extractor.
• Clean the shaft
• Mount the new blade wheel on the shaft.
40 | ENGLISH
A2/A4,
strength 80
DIN912/DIN933
11.8 Nm
28.7 Nm
58 Nm
100 Nm
245 Nm
494 Nm
Make sure that the mating surfaces are not damaged!
• Insert a new blade wheel mounting (cylinder head
screw with a hexagon socket and a new screw lock-
ing device) into the shaft. Fix the blade wheel firmly
and tighten cylinder head screw firmly.
• Place the pump part on the sealing casing and secure
it with the hexagonal nuts.
• It must be possible to rotate the blade wheel by hand.
Exchanging the split ring
Split rings determine the clearance between the blade
wheel and the suction inlet. If this clearance becomes
too large, the handling capacity of the pump falls and/or
clogging may occur. The ring is designed so that it can be
exchanged. This reduces signs of wear at the suction inlet
and blade wheel and minimizes the cost of replacement
parts.
Exchanging the slide ring seal
Exchanging the slide ring seal requires basic knowledge
and some specialist knowledge of these sensitive com-
ponents. Furthermore, the machine must to a large extent
be dismantled for this work.
Only original parts may be used as replacements!
Checking and exchanging these parts is done by the man-
ufacturer during a general overhaul or by specially trained
personnel.
In the case of Ex approved machines, please also note
the "Explosion protection" or FM approved machines
in the "FM protection" section in the Appendix.