Calibration

When parameter Shield H2O AutoBflush is On, the filter station monitors the difference between the shield water filter input and output pressure sensors. When this difference, adjusted by the Shield H2O Press Correction value, exceeds parameter Shield H2O Press-Diff Trip Point for a period of 5 seconds, then the filter station will begin the Shield Water Backflush sequence.

Parameters " Shield H2O AutoBflush” “Shield H2O Press-Diff Trip Point”

The Shield Water Backflush Sequence can also be triggered manually from the following display line by pressing the P-key.

S t a r t S h i e l d W a t e r

B a c k f l u s h S e q u e n c e ( P )

Shield Water Backflush Sequence

To backflush all of the filter elements, the backflush sequence must activate each shield water backflush solenoid for the time set by parameter Water Backflush Valve On Time. Note that this is the same Valve On Time parameter used for the shearer water backflush sequence described below.

Parameter "Water Backflush Valve On Time”

Solenoids are activated individually. The sequence fires all of the top solenoids, one after another, and then fires all of the bottom solenoids, one after another. In between solenoid activations, all solenoids are left deactivated for a time set by parameter Water Backflush Valve Off Time. Note that this is the same Valve Off Time parameter used for the shearer water backflush sequence described below.

Parameter "Water Backflush Valve Off Time”

Parameter Water AutoBackflush Time Interval is used to prevent the Shield Water Backflush Sequence from being triggered too often. This parameter is set to the minimum number of seconds required between automatically triggered Shield Water Backflush Sequences.

Parameter "Water AutoBackflush Time Interval”

For example, setting this to 3600, will limit the Shield Water Backflush Sequence to one automatic activation every hour at most. Note that this is the same parameter used to limit the triggering of the Shearer Water Backflush Sequence.