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For dryers equipped with Adjustable Purge, the Outlet Check Valves sealing can be
verified by depressurizing the dryer and applying pressure to the outlet. The Outlet
Check Valves should seal and prevent air from pressurizing the towers. If a tower
begins to pressurize, the check valve on that side requires replacement. Note that
outlet check valves for dryers with Adjustable Purge do not have an orifice provided
in the valve seat.
8.6
Desiccant Changeout Procedure
When it becomes necessary to replace the desiccant in the towers, observe the
following procedure:
• The standard units are furnished with fill and drain ports on each desiccant tower.
Remove the caps on both ports.
• To assist in getting the desiccant to flow from the tower, insert a small rod in to the
drain port as necessary. This may be required as the desiccant is packed into the
towers which may interfere with the flow of the material from the towers.
• Retainer screens, located at the inlet and outlet piping connections of the tower,
are removable on all models. It is suggested that these screens be removed and
cleaned at the time of desiccant changeout. These screens can be accessed by
disconnecting the upper and lower manifolds from the dryer towers.
• After cleaning the retainer screens, replace screens and reattach the outlet port
plug.
• With the fill port plug removed, fill the dryer tower with the appropriate grade and
size desiccant.
• Once the towers have been filled, replace the fill port plug on each tower.
• Any connections disturbed in the desiccant changeout process should be leak
tested prior to re-commissioning the dryer.
To avoid injury, depressurize dryer before performing any service.
Be sure to wear respiratory protection during the draining and filling process to
minimize inhalation of desiccant, as desiccant will produce dust during this
procedure.
CAUTION
WARNING
