Repairs; General; Changing The Impeller And Pump Unit; Shutdown - Homa MX F Serie Originalbetriebsanleitung

7. Repairs

7.1. General

The following repairs can be carried out on this machine:
•

Changing the impeller and pump unit

• Changing wear rings
When carrying out repair work, the following information
should always be noted:
• Round sealing rings as well as existing seals should
always be replaced.
• Screw fixings such as spring washers should always
be replaced.
• The correct torques must be observed.
In general, the following applies to repairs:
Switch off the machine, disconnect it from the mains
(have this done by an electrician), clean it and place
it on a solid base in a horizontal position. Secure it
from falling over and/or slipping.
If not otherwise stated, the torque values of the
below tables should be used. Values stated are for clean,
lubricated screws. Fixing torque [Nm] for screws A2/A4
(Coefficient of friction = 0,2)
A2/A4,
Hardeness class 70
DIN912/DIN933
M6 7 Nm
M8 17 Nm
M10 33 Nm
M12 57 Nm
M16 140 Nm
M20 273 Nm
7.2. Changing the impeller and pump unit
Changing the impeller and the pump unit.
• Loosen and remove the screws on the sealing
housing.
• Secure and remove the pump housing from the
sealing housing with suitable equipment, e.g.
hoisting gear. Place on a secure base.
• Fasten the impeller with suitable equipment, loosen
and remove the impeller fastening (cylindrical screw
with socket hex).
Pay attention to the locking screw!
• Remove the impeller from the shaft using a suitable
extractor.
• Cleaning the shaft
• Attach a new impeller to the shaft.
Make sure that the sliding surfaces do not become
damaged!
42 | ENGLISH
A2/A4,
Hardeness class 80
DIN912/DIN933
11,8 Nm
28,7 Nm
58 Nm
100 Nm
245 Nm
494 Nm
• Screw a new impeller fastener (cylinder screw with
socket hex and a new screw fixing) back into the
shaft. Fasten the impeller and tighten the fastening
screw.
• Place the pump unit on the sealing housing and
fasten it with screws.
• It must be possible to turn the impeller by hand.
Changing wear ring
The stationary and mobile wear ring determine the gap
between the impeller (mobile wear ring) and the intake
port (stationary wear ring). If this gap is too big, the per-
formance of the machine decreases, and/or it can lead to
entanglements.
Both rings are designed so that they can be replaced. This
minimizes wear on the intake port and and impeller, con-
sequently reducing expense for spare parts.
Changing sealing parts
Changing sealing parts on the liquid side such as the block
seal cartridge and the mechanical seal shaft requires a
certain amount of specialist knowledge about these sen-
sitive components. In addition to this, in order to carry out
the work, much of the machine must be dismantled.
Only original parts may be used for replacement!
Inspecting and replacing these parts is performed by the
manufacturer during the general overhaul or by specially
trained personnel.
For machines approved for work in areas subject to
explosion danger, please refer to the "EX-protection"
in the appendix.

8. Shutdown

8.1. Temporary shutdown

For this type of shutdown, the machine remains installed
and is not cut off from the electricity supply. For tempo-
rary shutdown, the machine must remain completely sub-
merged so that it is protected from frost and ice. Make
sure the operating room and the pumped fluid cannot be
covered by ice. This ensures that the machine is always
ready for operation. During longer shutdown periods, car-
ry out a regular (monthly to quarterly) function run for a
period of 5 minutes.
Caution!
Only carry out a function run under the proper con-
ditions of operation and use. Never run the machine
dry. This can result in irreparable damage!

8.2. Final shutdown / storage

Switch off the system, disconnect the machine from the
electricity supply and dismantle and store it.