RED VALVE INSTRUCTION MANUAL
MODEL GS700 REVERSE-ACTING ACTUATOR
3.0 MAINTENANCE
3.1 GENERAL
Actuator parts are subject to normal wear and must be inspected and replaced when necessary. The frequency of inspection
and part replacement depends on the severity of the service conditions. Normally, only the rubber parts such as the
diaphragm, stem seal, gasket, and rings will require replacement.
3.2 PRECAUTIONS
Be aware that large pressure and spring forces are required to actuate a valve. Sudden release of these forces or of valve or
actuator pressure has the potential to cause personal injury or damage to property.
Before starting to disassemble the actuator, proceed as follows:
A. Isolate the valve from the line pressure.
B. Release fluid pressure from the valve.
C. Release air pressure from the diaphragm chamber of the actuator.
D. Remove all actuator spring preload. Note that if the actuator travel has been set up to be less than nominal, it may not be
possible to remove all preload with the spring adjuster nut alone. In this case, it will be necessary to disassemble the stem
connector to remove remaining spring preload.
3.3 REVERSE-ACTING ACTUATOR (Refer to Figure I and the Actuator Assembly Drawing)
3.3.1 Disassembly
A. Bypass or isolate the valve and reduce the diaphragm pressure to atmospheric.
B. Rotate the spring adjuster nut (Item 29) downward on the actuator stem until all spring preload is removed.
C. If necessary, remove the stem connector by removing the four cap screws (Item 23). Loosen the setscrew in the stem
clamp (Item 26) and remove the stem clamp from the actuator stem.
D. If necessary, remove the actuator from the valve by unthreading the hold-down nut or studs and nuts, as applicable.
E. Remove the spring adjuster nut (Item 29) from the actuator stem.
F. Remove the cap screws (Item 4) and hex nuts (Item 5) and remove the base (Item 3).
G. If the diaphragm is not being replaced, remove the stem and diaphragm plate assembly (items 11, 12, 13, 14, and 16). If the
diaphragm is being replaced, block the lower end of the actuator stem, then unscrew the flat head screw (item 11) and remove the
diaphragm plate (item 13), the diaphragm (item 14) and the diaphragm stop (item 12).
H. If necessary, remove the actuator stem (Item 16) from the bushing (Item 30).
1. If necessary, remove the cover (Item 2) and the yoke plate and bushing assembly (Items 31 and 30) by removing the hex nuts and
lockwashers (Items 9 and 10).
J. Remove the bushing from the yoke plate by removing one of the retaining rings (Item 34).
