ARI Armaturen STEVI 423 DN300 EN - Manual (Page 9)

Rev. 0040318001 0410 Page 9
Operating and installation instructions
3-way control valves - STEVI
®
423 (DN300)
7.2 Replacement of internal parts
7.2.1 Replacement of plug and stem
- Remove the actuator. (Refer to operating
instructions for actuator!)
- Slacken nuts (pos. 22) by about 2-3 turns.
Series 423
- Loose nuts (pos. 7).
- Detach bottom flange (pos. 3).
- Remove plug (pos. 8) with stem (pos. 10).
- Drive pin (pos. 9) out with a drift.
- Unscrew plug (pos. 8).
- Bolt new parts together, drill and pin them.
- Replace gasket (pos. 36).
- Assemble in reverse order.
- Secure with nuts (pos. 35) and tighten them
crosswise.
(For tightening torques refer to point 7.3.1)
7.2.2 Replacement of the seat ring
- Remove actuator. (Refer to operating instructions for actuator!)
- Remove plug as described in item 7.2.1.
- Unscrew seat rings (pos. 2 top and bottom) with a special wrench (can be obtained from
the manufacturer).
- Clean thread and sealing taper in body (pos. 1) respectively bottom flange (pos. 3) and
apply with suitable lubricant.
- Replace respectively recondition seat rings (pos. 2 top and bottom).
- Install seat rings (pos. 2 top and bottom). (For tightening torques refer to item 7.3.2.)
- Replace gasket (pos. 36).
- Assemble in reverse order.
- Secure with nuts (pos. 35) and tighten them crosswise.
(For tightening torques refer to item 7.3.1.)
ATTENION !
Refer to item 10.0 and 11.0
before dismantling the valve.
ATTENTION !
Refer to item 10.0 and 11.0 before dismantling the valve.
Fig. 8: Series 423