IMO 10/19
IMO-215 EN
9
4.5
Manual Override Gearbox (SRO)
The SRO is intended to move the valve upon failure of
the actuator, supply air, or electrical system. NOTE: The
following instructions reference a fail closed (clockwise to
close) installation, but a fail open installation is also possible.
The SRO can only be mounted to a QPX_/M male drive.
Installation
1. It is recommended to mount the handwheel on the
input shaft prior to assembling the gearbox to the valve.
2. Verify that the flanges on the gearbox and valve align.
Also verify that the valve stem and the bore of the
gearbox driveshaft match.
3. Make sure the valve is in the fully closed position.
4. Make sure that the gearbox is in the fully closed position
(as standard from the factory). This is achieved by
turning the handwheel clockwise.
5. Screw the stud bolts into the bottom flange of the gearbox
prior to mounting the gearbox on top of the valve.
6. NOTE: use of a gasket/sealant on the flanges between
the valve/ gearbox and between the gearbox/actuator
is recommended.
7. Insert the drive shaft of the valve into the bottom side
onto the gearbox.
8. Ensure the driveshaft can make a free quarter turn
clockwise (seen from the bottom side) from its end
position. The gearbox can then open the valve in case
of actuator or supply air failure.
9. Mount the gearbox perpendicular to the valve and
secure the fasteners.
10. Mount the actuator on top of the gearbox.
Figure 7.
Stop screw adjustment
1. Remove the air from the actuator and ensure the valve/
actuator/gear are in the fully closed position.
2. With the actuator and gear mounted, backout both
stop screws on the gear by 3-4 turns.
3. Using the actuator to cycle the valve, set the actuator
stops for both open and close (see section 2 of this IMO
for instructions).
4. Open Stop: Turn the gear handwheel counter clockwise
until it stops. Turn-in the gear open stop screw (Figure 8)
until it stops and then tighten the lock nut.
5. Close Stop: Turn the gear handwheel clockwise until it
stops. Turn-in the gear close stop screw (Figure 8) until
it stops and then tighten the lock nut.
6. For a fail open actuator, revere the above procedure.
Figure 8.
Operation
1. Vent the supply air from the pneumatic actuator.
2. The gearbox is operated by turning the handwheel.
Depending on the gearbox model, it can take between
8 and 13 turns to achieve full rotation.
3. The gearbox is self-braking so simply stop turning the
handle once the desired valve position is achieved.
4. When the cause of the malfunction is solved, turn the
handwheel back to the actuator failsafe position. The
actuator can now control the valve.
STOPSCREW-CLOSED STOPSCREW-OPEN
NUT
