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7500 Series Manual
Warning!
If K1 is used to energize power to the enclosure, K1 will remain energized if pressure is below P1 during
system operation. An alarm is required and must be located such that an operator will be notified of the
alarm.
6.5.2 Program 2
Program 2 is used in hazardous gas atmospheres.
Pre-Purge
The purge valve (SV) is energized when enclosure pressure is greater than P1.
If enclosure pressure goes above P4 during purging, the SV shuts off but will energize when below P4.
Oscillation of SV may be noticed.
Setting the pressurization valve on the manifold has to be done after purging, or the power to SV will
have to be interrupted to set this pressure. The solenoid valve is energized once enclosure pressure
is above P1. Adjusting the pressurization valve before the solenoid valve is energized will allow the
enclosure pressure to be above P1 when purging is completed. Fine adjustment of P1 can be achieved
after purging when the solenoid valve is off.
The purge timer begins counting down when enclosure pressure is greater than P3 and must remain
greater than P3 to purge successfully. If the pressure drops below P3 at any time, or for any length of
time during purging, the purge timer is reset and will not begin counting down until pressure is greater
than P3.
Operation Mode
After the purge timer counts down, the SV shuts off and K1 is energized.
If enclosure pressure drops below P2, the SV is energized and will stay energized for the value of HYST
(%, leakage compensation). If HYST is set to 0, leakage compensation is turned off.
If enclosure pressure drops below P1, K1 remains on, and an alarm shall be implemented. K2 can be set
to P- or Alarm to indicate below safe or operating pressure.
If enclosure pressure goes above P4, K1 remains. If K2 is setup as Alarm, K2 will energize.
Warning!
If enclosure pressure is below P1 when K1 is used to provide power to the enclosure during operation, K1
will remain energized. An alarm is required and must be located such that an operator will be notified of the
alarm.
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