1. |
Remove the actuator from the valve in the following steps |
a) |
Ensure plug face is not in contact with the seat - (apply air pressure to reverse action actuator) |
b) |
Remove the stem coupling. |
c) |
Unscrew the locking ring. |
d) |
Lift actuator off valve. |
|
|
2. |
Remove the spring cover plate. |
3. |
Relieve all spring compression by inserting a 1/4 "wide bar in the spring adjuster slots and rotating it counterclockwise. |
4. |
Remove the diaphragm case screws and nuts and separate the diaphragm cases. (In the reverse action arrangement care must be taken to lift the top diaphragm case assembly perfectly straight with a slight rotary movement until the slide is clear of the stem). |
5. |
Unlock the travel stop nuts and screw them off the actuator stem. |
6. |
Lift the diaphragm assembly and the actuator stem clear of the actuator taking care to withdraw the stem perfectly straight to avoid damaging the threads and the '0' rings in the reverse action arrangement. |
7. |
To replace the '0' rings, remove the yoke screws and separate the yoke from the diaphragm case or spring assembly. |
8. |
Remove the old '0' rings from the seal-box and replace with new ones. |
9. |
To replace diaphragm - unscrew and remove the diaphragm collar nut. |
10. |
Slide the diaphragm button and the old diaphragm off the actuator stem. |
11. |
Slide the new diaphragll' (dusted with French Chalk or Talc) over the actuator stem into position on the diaphragm collar. |
12. |
Replace the diapharagm button and lock the assembly together with the collar nut. |
13. |
To reassemble for Direct Action (Fig. 1) secure the spring tube assembly to the yoke by means of the yoke screws and place the spring in position on the spring carrier. To reassemble for ReverseAction (Fig. 2) secure the diaphragm case assembly to the yoke by means of the yoke screws, ensuring the air connection is facing in the right direction. |
14. |
Replace the travel tube in its correct position on the actuator stem (see Figs. 1 and 2). Slide the actuator stem into position taking care to keep it straight.
In the ReverseAction arrangement take care not to damage the '0' rings - a rotary action whilst sliding the stem into position is helpful - Place the spring over the stem on the diaphragm button. |
15. |
In the Direct Action version bolt the diaphragm case assembly to the spring tube assembly ensuring the air connection faces in the right direction.
In the Reverse Action version slide the stem guide in the spring tube assembly over the actuator stem and bolt the two diaphragm cases together. |
16. |
Replace the two travel stop nuts on the actuator stem with pointer disc between them. |
17. |
By rotating the spring adjuster clockwise - apply compression to the spring until the actuator stem starts to move at the required air pressure (i.e.. 3 or 6 psig). |
18. |
With the diaphragm assembly in its lowest position (apply air pressure for the Direct Action version) adjust the travel stop nuts so that the distance between the top nut and the base of the lower travel stop is the rated travel of the actuator or valve (see nameplate) + 1/32". Lock the nuts together. |
a) |
Pass the yoke base over the gland and bonnet to sit squarely on the bonnet shoulder. Rotate the yoke until the windows face in the required direction and then tighten the locking ring securely. |
b) |
With the plug face in contact with the seat and withthe actuator stem in its lowest position (apply air pressure to Direct Action actuator), press the half of the stem coupling which is threaded for the coupling screw against the actuator stem and valve plug stem so that :
i) The ends of the stems are equidistant from the tapped coupling screw hole, and
ii)The tapped coupling screw hole is on the same side of the actuator as the positioner or other accessories which may require attachment to the coupling screw. |
| Note: It may be necessary to move the plug off its seat by a slight amount in order to mesh the plug stem threads with the lower coupling threads. |
c) |
Apply the other half of the coupling carefully engaging the threads, then insert the coupling screw and tighten it by hand. |
d) |
With the actuator stem at its lowest position of the travel slacken of the coupling screw slightly and preventing the coupling from rotating. unscrew the valve stem from the coupling until the plug is firmly seated. |
e) |
Move the plug off the seat by changing the air pressure on the. diaphragm then unscrew the plug stem an additional turn out of the coupling to ensure positive seating. |
f) |
Tighten the coupling screw securely. |
g) |
Seat the valve plug firmly by means of the actuator (tJ) Adjust the travel indicator scale so that the shut mark
is opposite the travel indicator ring. |
i) |
Disconnect the air line used for assembly procedure then apply the check nut or attachments (if any) to the coupling screw. |
