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8.2
Prefilters and Afterfilters
•
Prefilters
- The prefilter element must be changed as often as required to prevent
contamination of the dryer's desiccant bed.
The prefilter and automatic drain must be checked daily. To prolong filter element
life, it is recommended that a mechanical air/moisture separator be placed immedi-
ately before the prefilter.
•
Afterfilters
- The purpose of the afterfilter is to remove residual desiccant dust.
Depending upon equipment application and usage, frequency of filter element
change will vary. It is recommended that the filter element be changed every six
months at a minimum.
8.3
Solenoid Valves
If improper solenoid operation is suspected, clean all solenoid valves. Disconnect
power to the solenoid coil, depressurize unit and remove the solenoid’s coils and
plunger stems to clean. If the solenoid valves fail to operate, check the following:
• Solenoid valve leaking - Disassemble, clean and repack or replace.
• Control Circuit - Check to verify that the solenoid is receiving electric current at
appropriate times in the cycle.
• Burned out solenoid coil.
• High/low voltage - Voltage should be + 10% of nameplate readings.
8.4
Muffler Changeout Procedure
• Depressurize the dryer and turn control power off.
• Replace muffler.
• Follow Start-up procedure described in Section 7.6.
• Turn control power back on.
8.5
Outlet Check Valves
The integrity of the Outlet Check Valves are verified by visual inspection. After
depressurizing the dryer, remove the hexagonal cap located on the valve body.
Remove and inspect the seat. Replace seat as required. Note that on dryers
manufacatured without the Adjustable Purge option, the check valve seat is
provided with a specific orifice drilled into the seat. Be sure replacement seat or
complete valve is provided with the same sized orifice in the seat as the original.
Should the drying system be overloaded and/or malfunctioning, causing high
pressure drop, afterfilters will prematurely plug. This problem can be avoided by
frequent inspection and proactive replacement of elements.
To avoid injury, depressurize dryer before performing any service.
WARNING
NOTICE
