Manual Pressure Control Packs
Vacuum Mode (Negative Gauge) Operation
7
3.
For subsequent pressure changes:
a.
Pull to open the Equalize valve.
b.
Carefully open the Pressure Supply valve (to increase pressure) or the Test Port
Vent valve (to decrease pressure).
c.
Close the Pressure Supply or Test Port Vent valve once the pressure is close to
the target value or the piston begins to float.
d.
Push to close the Equalize knob and rotate the Pressure Adjuster knob to adjust
the final pressure and float position.
4.
If the Pressure Adjuster must be turned too many rotations to establish a floating
pressure:
a.
Pull to open the Equalize valve.
b.
Open the Pressure Supply or Test Port Vent valve to bring the pressure closer to
the target value.
c.
Push to close the Equalize knob and rotate the Pressure Adjuster knob to adjust
the final pressure and float position.
5.
If the Pressure Adjuster knob will not rotate, it is probably at the end of its stroke. In
this case:
a.
Pull to open the Equalize valve and rotate the Pressure Adjuster knob in the
opposite direction about 10 to 20 turns.
b.
Push to close the Equalize valve and rotate the Pressure Adjuster knob to adjust
the final pressure and float position.
Vacuum Mode (Negative Gauge) Operation
Please refer to Figures 1, 2, or 3, as appropriate.
1.
Verify that the mode valve is set to Vacuum (Negative Gauge).
2.
Verify that the bell jar is mounted on the deadweight gauge.
3.
Close the Test Port Vent valve and carefully open the Vacuum Supply valve to
decrease pressure in the test port and in the DWG bell jar.
a.
Adjust the Vacuum Supply valve to achieve the desired rate of change in
pressure.
b.
Close the Vacuum Supply valve once the pressure is close to the target value or
the piston begins to float.
c.
Close the Reference Vent valve.
d.
Push to close the Equalize valve and rotate the Pressure Adjuster knob to adjust
the final pressure and float position.
4.
If the Pressure Adjuster must be turned too many rotations to establish a floating
pressure:
a.
Pull to open the Equalize valve.
b.
Open the Reference Vent valve, then use the Vacuum Supply or Test Port Vent
valve to bring the pressure closer to the target value.
c.
Close the Reference Vent valve, push to close the Equalize knob and rotate the
Pressure Adjuster knob to adjust the final pressure and float position.
