Perma Pure GASS-2040 - Manual (Page 17)

17 GASS-2040 User Manual | Original Instructions
When the sample gas is under positive pressure, it allows condensate to be directly expelled
through a solenoid valve (See Figure 9). When the drain timer in the PLC times out, a
solenoid valve energizes and allows the pressure in the filter to push the condensate out of the
filter.
The filter drain event can be triggered externally via the Manual Filter Drain input to the PLC.
Refer to the I/O Wiring section for connection details on page 11.
4.6 Automatic Probe and Filter Blowback Operation (Optional)
Figure 9
Adjust the Blowback Time as described in the Operator interface section on page 14.
Dust in the probe filter needs to be removed periodically to extend the life of the element. This is
accomplished by passing compressed air backwards through the filter (See Figure 10). The
blowback system consists of an accumulator tank and solenoid valve to accomplish this task.
When the blowback timer in the PLC expires, a solenoid valve is energized for two seconds. This
allows compressed air to flow from the accumulator tank directly into the probe filter causing
collected dust on the filter element to be forced back into the stack through the probe pipe. The
timer then resets to the user selected cycle time and begins counting down to the next blowback.
The cycle repeats indefinitely unless the timer is turned off. When calibration gas flow is de-
tected, the blowback timer is temporarily paused. This prevents the blowback valve from activat-
ing while a system calibration cycle is in process.
Figure 10
The filter blowback event can be triggered externally via the Manual Filter Blowback input to the
PLC.
Refer to the I/O Wiring section for connection details on page 11 and the electrical wiring
diagram in the appendix.