18
Maintenance
7.2 Changing the operating fluid
The changing interval for the operating fluid depends on the pump applications, but
should be carried out once a year.
The level of deterioration of operating fluid P3 can be determined for clean processes
with the colour scale (in accordance with DIN 51578); supplementary sheet PK 0219
BN on request or download it from the Internet.
Suck off operating fluid from the pump through the operating fluid filler opening.
Fill the specimen in a test tube or some similar vessel and test by holding against the
light.
Where discolouration is red brown (equivalent to 5 on the scale) change operating flu-
id.
Switch off the pump.
Unscrew operating fluid filler screw 87.
Unscrew operating fluid drain screw 86.
Fig. 10: Draining the operating fluid
Screw in operating fluid drain screw 86; pay attention to O-ring.
Screw in operating fluid filler screw 87.
Allow pump to run for a maximum of 5 seconds with the vacuum flange open.
Depending on the applications, Pfeiffer Vacuum recommends determining the ex-
act service life of the operating fluid during the first year of operation.
The replacement interval may vary from the guide value specified by Pfeiffer Vacuum
depending on the thermal and chemical loads, and the accumulation of suspended par-
ticles and condensation in the operating fluid.
86
87
WARNING
Hot operating fluid!
Danger of burns when draining due to contact with skin.
Wear suitable protective clothing.
Use a suitable collecting vessel.
WARNING
Operating fluid may contain toxic substances from the pumped media!
Danger of poisoning from the emission of harmful substances from the operating fluid.
Wear suitable protective clothing and respirators.
Dispose of operating fluid according to the local regulations
