Emerson Fisher SS-264 Instruction Manual page 21

Instruction Manual
D103565X012
d. If the step decrease does not occur, repeat steps b and c until the step decrease is observed.
CAUTION
Do not fill the actuator cylinder too quickly as the fast stroking speed could alter the zero positioning of the valve.
Note
If the process is continued until the regulator pressure reaches 48 psig and the step change has still not been reached, contact your
Emerson sales office.
Travel Stop Adjustments
CAUTION
Ensure all the step of the previous section have been followed before adjusting the travel stops.
Once an acceptable leakage rate has been confirmed in the previous section, the closed travel stop in the Bettis needs
to be set. Refer to figures 12, 13, and 14.
1. With the supply air set to the recorded value from step 6.3 of the previous section, turn the Bettis "closed" travel
stop clock-wise (CW) until the stop is firmly seated against the internal scotch yoke of the actuator. Snug the stop
up against the yoke with a light turn of a wrench.
CAUTION
While torquing the travel stop lock nuts, take care not to move the travel stop screw which will change the position of the
ball/shaft assembly.
2. While holding the travel stop stationary, securely tighten the closed travel stop lock nut using a 1-13/16" wrench.
Torque to 136 N•m (100 ft•lbf).
3. Back out the Bettis "open" travel stop by turning the stop CCW approximately 5 turns.
4. Reduce pressure in the Bettis air cylinder until the ball/shaft assembly has rotated 90° ± 2° away from the zero
(closed) position per the encoder readout. Once reached, this is now considered the full open position.
5. Turn the Bettis "open" travel stop clock-wise (CW) until the stop is firmly seated against the internal scotch yoke of
the actuator. Snug the stop up against the yoke with a light turn of a wrench.
6. While holding the travel stop stationary, securely tighten the "open" travel stop lock nut using a 1-13/16" wrench.
Torque to 136 N•m (100 ft•lbf).
7. Set the supply regulator pressure to the specified pressure, typically 70 psig.
Note
The Ball/Shaft assembly requires about 45 psig to achieve the zero position; 70 psig ensures the ball is always driven to the closed
travel stop.
SS-264 Valve
September 2021
21