Fischer Panda Panda 6000i PMS, Manual

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Maintenance Instructions
16.1.09 Panda_6000i_System_eng_s01835.book.R01 - Chapter E: Maintenance Instructions Page 65
E.7 The Raw water circuit
E.7.1 Clean raw water filter
Residue should be regularly removed
from the seawater filter. The seacock
must, in each case, be closed first. It often
suffices to merely hit the filter punnet.
If water should seep through the cover of
the raw water filter, this may never be sea-
led with adhesive or sealant. The cause
for the leakage must be sought. The
sealing ring between caps and filter hol-
ders must be exchanged in the simplest
cases.
Fig. E.7.1-1: Raw water filter
E.7.2 Reason for frequent impeller wear
1. Unreasonable operating conditions
The Cooling water pump Impeller must be regarded as a wearing part. The life expectancy of an
impeller can vary greatly and depends exclusively upon the operating conditions. The PANDA
Generator cooling pumps are so designed that the speed of the pump in comparison to other
generators is relatively low. This has a positive effect on the life expectancy of the pump.
2. Longer Suction Distance of Cooling Water
If the cooling water suction distance is long, or is blocked, this has a negative effect on the impel-
ler, so that an under-pressure occurs in the cooling water suction area. This can reduce the
efficiency of the impeller and place strain on the blades. This can greatly reduce the life expec-
tancy.
3. Operating in contaminated waters
The impeller is placed under great strain in waters with high contamination. The use of the impel-
ler in coral waters is also critical. There are known cases, whereby the impeller was so fatigued
after 100 hours use, that the lip seals were grinded away by the shaft. In these cases sharp cry-
stal parts from the coral press into the rubber seals and act as a grinding material on the stainless
steel shaft of the impeller pump.
4. Generator mounted above the water level
It is especially disadvantageous for the impeller pump, if the generator is mounted above the
water level. This means that a few seconds will pass before the impeller can suck in cooling
water. This short dry running period damages the impeller. The increased wear can also lead to a
breakdown. (See special instruction: "Effect on the impeller pump, if the generator is mounted
above the water line").