Emerson Fisher OS2 Instruction Manual page 7

Type BMS1 (Figure 5)
Overpressure Shutoff Only
Adjusting the Threaded Stem:
1. Remove the tripping hook or rotate so it cannot contact
Pin D2.
2. Turn in the adjusting screw until the distance between
the threaded stem and Pin D1 stops increasing.
3. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism.)
4. Adjust the threaded stem to a distance of 1/16 in. /
1.6 mm from Pin D1 (detection stage set).
5. Tighten threaded stem locknut.
Adjusting the Overpressure Trip Point:
1. Pressurize the Type BMS1 to the desired trip pressure.
2. Turn in the adjusting screw until the detection stage can
be reset.
3. Turn out the adjusting screw until the detection
stage trips.
4. Verify that the trip pressure is equal to the desired
pressure setting by reducing pressure to the
Type BMS1, resetting the detection stage and then
increasing pressure to the Type BMS1 until the detection
stage trips. Adjust trip pressure setting if necessary.
5. Tighten adjusting screw locknut.
Underpressure Shutoff Only
Adjusting the Threaded Stem and Tripping Hook:
1. Rotate the tripping hook so that it cannot contact Pin D2.
2. Turn out the adjusting screw.
3. Pressurize the Type BMS1 to the desired trip pressure.
4. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism)
5. Adjust the threaded stem to a distance of
1/16 in. / 1.6 mm from Pin D1 (detection stage set).
6. Tighten threaded stem locknut.
7. Rotate the tripping hook into position and adjust the
tripping hook locknuts until the hook is at a distance of
1/16 in. / 1.6 mm from Pin D2.
8. Tighten tripping hook locknuts.
Adjusting the Underpressure Trip Point:
1. Maintain the desired trip pressure in Type BMS1.
2. Turn in the adjusting screw until the detection stage
is tripped.
3. Verify that the trip pressure is equal to the desired
pressure setting by increasing pressure to the
Type BMS1, resetting the detection stage and then
TRIPPING HOOK
PIN D2
THREADED
STEM
TRIPPING
PLATE
PIN D1
TRIPPING HOOK
LOCKNUTS
THREADED STEM
LOCKNUT
E0606
Figure 5. Type BMS1 Construction
reducing pressure to the Type BMS1 until the detection
stage trips. Adjust trip pressure setting if necessary.
4. Tighten adjusting screw locknut.
Overpressure and Underpressure Shutoff
Adjusting the Threaded Stem:
1. Rotate the tripping hook so that it cannot contact Pin D2.
2. Turn out the adjusting screw.
3. Pressurize the Type BMS1 to the desired overpressure
trip pressure.
4. Reset the detection stage only. (See Figure 7 and the
section on Resetting the Trip Mechanism.)
5. Adjust the threaded stem until it just touches Pin D1.
6. Manually trip the detection stage by moving Pin D1.
7. Unscrew the threaded stem two turns which is a
distance of approximately 1/16 in. / 1.6 mm.
8. Tighten threaded stem locknut.
Adjusting the Overpressure Trip Point:
Same procedure as overpressure shutoff only.
Adjusting the Underpressure Trip Point:
1. Pressurize the Type BMS1 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 BMS1 to the desired underpressure
trip pressure.
4. Adjust the hook by progressively moving the tripping
hook locknuts until the detection stage trips.
5. Tighten tripping hook locknuts.
6. Verify that the trip pressure is equal to the desired
pressure setting by increasing pressure to the
Type BMS1, resetting the detection stage and then
reducing pressure to the Type BMS1 until the detection
stage trips. Adjust trip pressure setting if necessary.
Type OS2
ADJUSTING SCREW
LOCKNUT
ADJUSTING
SCREW
7