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3. Special maintenance instructions
• Measuring units
Trip the SAV before you remove it from the body. SAV valves provided with underpressure release (standard version)
will close automatically.
ATTENTION
Prior to dismantling the tripping mechanism, the valve plate and the valve stem (40, 53, 59, 156, 207) of a measuring
unit released by underpressure should be moved back to reach at least its re-engagement position.
In view of the necessity of a new zero-adjustment by means of the shim (138, 234) an exchange of the measuring units
K5 for K4 or K4 for K5 or K6 cannot be made at site.
• Valve stem (40, 53, 59, 156, 207)
It is important that the valve stem can be moved easily and smoothly. Should any faults or damages of material (e.g.
ridges or flaws) be detected at the valve stem shoulder, the valve stem has to be replaced by a new one.
When fitting an new (two-piece) valve stem into the measuring units K4, K5, K6 of the series produced up to 1989,
make sure that a new guide sleeve (139, 243) and a new closing spring (119, 242) are mounted together with the
valve stem. The new version does not provide for a pressure relief ball mechanism.
Before inserting the valve stem (156, 207) into the guide sleeve (139, 242) pull the pressure relief balls (former
version) apart by applying the special assembly bolt W4 from above.
• Spring retainer (24, 103, 204)
The contact surfaces between spring retainer and diaphragm plate (26) and between switch bush (8), spring retainer
and guide sleeve (104, 206) should be kept free from grease.
• Relieving springs
For maintenance of measuring units K4, K5, K6 delivered before July 1986 make sure to fit new relieving springs
stock no. 10 008 640.
• Valve plate (155, 222)
For inserting the O-ring (124, 220) into the groove of the valve plate proceed as follows:
- grease the O-ring and put it on the groove; apply an equal pressure by hand on several points around its circum-
ference for even insertion.
- press the O-ring fully into the groove.
• Shim (138, 234)
The shim serves to adjust the tripping device to its exact zero position. After any replacement of the diaphragm, the
shim must be re-integrated unchanged.
720.20 S.05
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