Pulsafeeder Pulsar Shadow - Manual (Page 43)

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11.6 Leak Detection System Maintenance
Although the PULSAlarm leak detection system requires minimal maintenance, vacuum must be
maintained to prevent false alarms and diaphragm damage.
11.6.1 Vacuum Setpoint Adjustment
If the optional switch is purchased, it is factory preset at the specified vacuum setpoint, 150 mm Hg (6
in. Hg), at which loss of vacuum causes the vacuum switch to actuate. The standard pressure switch is
set to actuate at 5 psig.
Use the following procedure to perform a Vacuum setpoint adjustment:
1. Disconnect the alarm circuit from the vacuum switch.
2. Remove the switch enclosure cover and loosen the knurled locking ring on the switch.
3. Rotate the hex adjusting ring counterclockwise to increase or clockwise to decrease the setpoint.
4. Verify the new setpoint (refer to the next section).
5. Repeat steps (3) and (4) above until the required setpoint as attained.
6. Tighten the switch locking ring and replace the switch enclosure cover.
7. Reconnect the alarm circuit to the vacuum switch.
Use the following procedure to perform a setpoint adjustment test
1. Evacuate the system to approximately 650 mm Hg (26 in. Hg) OR properly prime and prepare the
pressure system.
2. Remove the switch cover and connect ohmmeter leads across the common terminal and the other
terminal used in operation (NO or NC).
3. Record the status of the switch (open or closed).
4. a. Vacuum: Break the vacuum system at any point external to the pump to permit gradual loss of
vacuum.
b. Pressure
5. Observe the ohmmeter to detect actuation.
: remove the pressure gauge, and install a hand pump or other means of producing a small
amount of pressure in the system.
The setpoint can be observed by reading the vacuum/pressure
gauge upon actuation.