8
Installation
5.2
Installing the operating fluid return line
ONF 16/25 M
Turn off the vacuum pump, vent to atmospheric pressure and allow to cool, if neces-
sary.
Unscrew operating fluid drain screw 33.
Drain off operating fluid.
Separate the operating fluid from the condensate.
– If the drained operating fluid is free of contamination, it can be fed back to the rotary
vane pump.
Screw in hose piece 221 in place of the operating fluid drain screw; take care with O-
ring 145.
Remove gas ballast valve 42 from the pump and absorb the operating fluid under-
neath.
Re-fit the gas ballast valve 42 with intermediate flange 45 and screw tight with longer
screws ; take care with O-ring 148.
Screw fitting/hose nipple 220 into intermediate flange 45; pay attention to O-ring 138.
Fit operating fluid return hose 222 at both sides.
Fasten hose clips 223.
Fig. 3:
DUO Rotary vane pump with ONF and operating fluid return line
ONF 25 XL
Unscrew operating fluid drain screw 33.
Drain off operating fluid.
Separate the operating fluid from the condensate.
– If the drained operating fluid is free of contamination, it can be fed back to the rotary
vane pump.
NOTICE
Make sure that the return for the operating fluid works.
Operating fluid is only sucked in and returned starting from a minimum quantity of oper-
ating fluid in the ONF.
Top up with operating fluid in order to ensure the return of operating fluid at the start
of the evacuation phase.
33
Operating fluid drain screw
42
Gas ballast valve
45
Intermediate flange
138 O-ring
145 O-ring
148 O-ring
198 Operating fluid filler screw
rotary vane pump
220 Hose nipple
221 Hose piece
222 Operating fluid return
line
223 Hose clip
223
222
220, 223, (138)
45 (148)
ONF
198
42
33 (221/145)
