Repairs; General; Changing The Impeller And Pump Unit - Homa H 500 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.

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 performance 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, consequently 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 sensitive 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.
A2/A4,
Hardeness class 80
DIN912/DIN933
11,8 Nm
28,7 Nm
58 Nm
100 Nm
245 Nm
494 Nm
45