Emerson Fisher OS2 Instruction Manual page 8

Type OS2
Type BMS2 (Figure 6)
Overpressure Shutoff Only
Adjusting the Overpressure Push Button:
1. Remove the tripping hook.
CAUTION
Be sure there is no pressure in the
manometric sensing device before doing the
following steps.
2. Turn in the adjusting screw until the distance between
the threaded stem and Pin D2 stops increasing.
3. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism.)
4. Adjust the push button to a distance of 1/16 in. / 1.6 mm
from Pin D2.
5. Tighten push button locknut.
Adjusting the Overpressure Trip Point:
Same procedure as adjusting the Type BMS1 for overpressure
shutoff only.
Underpressure Shutoff Only
Adjusting the Underpressure Tripping Hook:
1. Remove the overpressure push button or move it so that
it cannot contact Pin D2.
2. Turn out the adjusting screw.
3. Pressurize the Type BMS2 to the desired underpressure
trip pressure.
4. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism.)
5. Adjust the tripping hook to a distance of 1/16 in. /
1.6 mm from Pin D1.
6. Tighten tripping hook locknut.
Adjusting the Underpressure Trip Point:
Same procedure as adjusting the Type BMS1 for
underpressure shutoff only.
Overpressure and Underpressure Shutoff
Adjusting the Push Button:
1. Remove the tripping hook.
2. Turn out the adjusting screw.
3. Pressurize the Type BMS2 to the overpressure shutoff
trip pressure.
4. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism.)
5. Adjust the push button until it just touches Pin D2.
8
ADJUSTING
SCREW
TRIPPING
HOOK
ADJUSTING SCREW
LOCKNUT
LOCKNUT
E0607
Figure 6. Type BMS2 Construction
6. Manually trip the detection stage by moving Pin D2
(see Figure 5).
7. Unscrew the push button two turns which is a distance
of approximately of 1/16 in. / 1.6 mm.
8. Tighten push button locknut.
Adjusting the Overpressure Trip Point:
Same procedure as overpressure shutoff only.
Adjusting the Underpressure Trip Point:
1. Pressurize the Type BMS2 to a pressure between the
desired overpressure and underpressure trip points.
2. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism.)
3. Pressurize the Type BMS2 to the desired underpressure
trip pressure.
4. Turn in the tripping hook until the detection stage trips.
5. Tighten tripping hook locknut.
6. Verify that the trip pressure is equal to the desired
pressure setting by increasing pressure to the
Type BMS2, resetting the detection stage and then
reducing pressure to the Type BMS2 until the detection
stage trips. Adjust trip pressure setting if necessary.
Resetting the Trip Mechanism
Resetting of the Type OS2 slam-shut device is done
manually and, for NPS 8 and 10 / DN 200 and 250 body
sizes, with the bypass valve open. After the Type OS2 has
tripped, it must be manually reset before it can be placed
back in service. Before resetting the Type OS2, check for
and correct the reason for the overpressure/underpressure
condition. For the following procedures, see Figures 7 and 8.
To reset the detection stage, the pressure
in the manometric sensing device must
be below the overpressure trip point and/
or above the underpressure trip point.
Otherwise the detection stage cannot
be reset.
PUSH BUTTON LOCKNUT
PUSH BUTTON
PIN D2
THREADED
TRIPPING
STEM
PLATE
PIN D1
THREADED
STEM
LOCKNUT
TRIPPING
HOOK
Note