AEC WD 350 through WD3000 Dehumidifying Dryers - Manual (Page 38)

350-2100 cfm Dryers Chapter 6: Maintenance 37 of 58
service. Satisfactory filtration should be obtained through the second or third washing , however the dirt
holding capacity of the filter decreases after each washing.
After Each Cleaning:
• Inspect the filter element – hold a light bulb behind the element to find fatigued paper or residual
dirt.
• Inspect the end plates – damage here could allow air to bypass the filter.
• Look for rust on the end plates and metal core – rust particles could flake off and contaminate the
dryer and resin.
• Check the gasket for damage – a damaged gasket will allow contaminants into the process. Replace
if needed.
6-4 Servicing the Regeneration Filter
WARNING:
Operating the dryer without the regeneration air filters installed will void the warranty.
Filter Cleaning is an important part of dryer maintenance.
These dryers are equipped with a filter in the regeneration air loop. Regular filter cleaning will keep
your dryer operating at peak efficiency.
To Clean the Regeneration Filter:
• Turn off and/or lock out electrical power to the dryer.
• Slide the panel filter out of its housing.
• Vacuum or carefully blow out the filter with compressed air. If the filter is worn or can't be
cleaned, replace it.
• Slide the filter back into its housing.
6-5 Dirty Filter Alarm Calibration
Dryer models 350-2100 may be equipped with an optional Dirty Filter Indicator. When this indicator
lights, it is time to clean or change the filter. The Dirty Filter indicator is tested and calibrated at the
factory, but it can be adjusted in the field.
1. Be sure that your filter is clean, and use the following procedure.
2. Remove the process air return filter element from its housing.
3. Block off approximately 50% of the filter's surface area to simulate a dirty filter.
4. Reinstall the cartridge and secure the cover.
5. While the process blower is operating, adjust the trim screw on the differential pressure switch until
the alarm light just comes on.
6. Remove the restricted filter cartridge from the housing again. The alarm light should stay off when
the process blower operates if the switch is adjusted correctly.
7. Re-install the obstructed cartridge filter. The alarm light should go on again if the switch is adjusted
correctly.
8. Fine tune the switch setting so it consistently warns of a blocked filter and does not falsely indicate
a blockage of a clean filter.