Stratasys J850 Manual page 104

Filters are installed in the lines that supply Model material to the print heads.
To ensure that the heads remain in optimum condition, the filters are
replaced by your service provider, as part of the scheduled maintenance
routine. However, filters used for certain materials need to be replaced more
often. A counter keeps track of the amount of material passing through the
filters, and the Maintenance Required indicator appears in the printer
interface when it is time to replace a filter. The counter for RGD515 material,
for example, is set to notify you after 20 hours of use. This is enough, on
average, for about a year of printing.
To check the material-filter counters, open the Maintenance Counters screen
(see "Maintenance Counters" on page 4-29) and scroll down to the Filters
section.
The figure above shows that 21 hours of filter time have passed since the left
filter was installed, and that it needs to be replaced.
1. Prepare the following tools and materials:
❒ 8-mm hex (Allen) key
❒ protective gloves
❒ cleaning cloths or paper towels
❒ replacement 10-micron filters (supplied in the Start-up Kit)
2. Close the printer application.