VAG Operation and Maintenance Instructions • 14
7.3.2 Recommendations for the replacement
of parts
Profile seals and O-rings must be replaced whenever necessary.
The replacement intervals depend on the operating conditions.
7.3.3 Cleaning and lubrication
When being replaced, the profile seal and the O-rings should al-
ways be lightly greased. Use lubricants with approval for applica-
tion with foodstuffs or drinking water.
Recommended lubricants:
• For the profile seal and the O-rings: KLÜBERSYNTH VR 69-252
(NFS61-approved)
Manufacturer: Klüber Lubrication München AG, Germany.
7.3.4 Replacement of the profile seal
Due to the double-offset bearing, the profile seal can be replaced
without disassembly of the disk. Valves of up to valve size 36“
must either be completely dismantled from the pipeline or at least
disconnected from the pipeline on one side to replace the profile
seal. In the same way as for the installation of the disk, all safety
precautions need to be taken.
Disassembly of the sealing ring:
• Open the disk (2) until the profile seal (3) emerges from the body
• Unfasten the retaining ring screws (5.1)
• Remove body (1) and sealing ring (3)
• Clean the disk (2) in the sealing zone
• Check the seat ring in the body for damage or deposits
• Insert the new sealing ring into the groove of the disk and slight-
ly grease it with KLÜBERSYNTH VR 69-252 (NFS61-approved)
• Insert the hexagonal screws (5.1) and fasten them.
7.3.5 Replacement of the O-rings in the
bearing
For this kind of maintenance work, the valve must be depressu-
rised.
• Turn the butterfly valve (2) into closed position
• Unfasten the hexagonal nuts at the gear flange and pull the gear
off the shaft (7)
• Loosen the threaded pin and pull off the coupling. Pull the ad-
justment spring (20) off the shaft
• In the depressurised pipeline, the hexagonal screws (14) are
Picture 12: Replacement of O-ring - Step 1
unfastened and the bearing flange (10) as well as the bearing
cover (11) are pulled off. Slightly grease the O-rings (17 / 16)
with KLÜBERSYNTH VR 69-252 before installation.
Picture 13: Replacement of O-ring - Step 2
• Reassembly is done in reverse order
• Tighten the hexagonal screws (14) only slightly to prevent ten-
sioning the bearing bush (12) on the disk (2). Secure the flange
position using the threaded pins (15).
Picture 14: eplacement of O-ring - Step 3
• Assemble the adjustment spring (20) and the coupling
• Before mounting the gear, check whether the disk position and
the gear position match
Picture 15: Replacement of O-ring - Step 4
