IOS has developped a new test for monitoring stability of the FW#3 positioning in MKIV Brewers. This test, called FC.RTN, records the SL intensity and the R5/R6 values at a range of FW#3 step numbers around the nominal value for o3 mode. This allows the Brewer user to assess the state of the UV combo filter for damage, to determine the most optimal step number for o3 mode and to monitor the repeatablility of the FW#3 positioning by doing this test periodically and comparing the results.

The test is part of our Brewer operating software version 3.79.