ARI Armaturen STEVI 426 EN - Manual (Page 9)

Rev. 0040314001 0410 Page 9
Operating and installation instructions
Straight through control valves - STEVI
®
425 / 426
6.0 Putting the valve into operation
7.0 Care and maintenance
Maintenance and maintenance intervals have to be defined by the operator according to
the service conditions.
7.1 Replacement of stem sealings
7.1.1 EPDM-ring stem sealing design
Stem sealing consisting of:
1 scraper (pos. 27)
2 gaskets (pos. 24)
1 O-ring (pos. 25)
This sealing can be used for water and steam up to 130 °C operating temperature. Because
of the elastomer material the sealing rings are maintenance free.
If the stem starts leaking, the ring pack is worn out and must be replaced.
Replacement of EPDM-stem sealings:
- Remove actuator.
(Refer to operating instructions for actuator!)
- When replacing the sealings (pos. 24, 25),
make sure that the parts are installed in the
correct order and positions (refer to Fig. 7).
Damaged stems must also be replaced (refer
to item 7.2 for instructions) since a new
sealing will soon start leaking again if the
stem is damaged.
ATTENTION !
- Before putting the valve into operation, check material, pressure, temperature
and direction of flow.
- Regional safety instructions must be adhered to.
- Residues in piping and valves (dirt, weld beads, etc.) inevitably lead to leakage.
- Touching the valve when it is operating at high (> 50 °C) or low (< 0 °C) media
temperatures can cause injury.
Affix warning notice or protective insulation as appropriate!
Before putting a new plant into operation or restarting a plant after repairs or
modification, always make sure that:
- All works has been completed!
- The valve is in the correct position for its function.
- Safety devices have been attached.
ATTENTION !
Refer to item 10.0 and 11.0 before
dismantling the valve.
Fig. 7