Gardner Denver Air Dryer DGH60

WARNING! The pilot air filter housing is a pressure-containing device, de-pressurize before servicing.

Is the pilot air pressure in the range of 60 - 120 psig (4.1 - 8.3 barg)?

Slowly open manual drain valve on bottom of filter bowl by turning clockwise to verify that the housing is de-pressurized before removing bowl.

Is the dryer isolated from air supply?

Is the dryer de-pressurized by running dryer and allowing system pressure to purge to atmosphere?

Is the remaining pressure vented to atmosphere through the manual vent on the pilot air filter?

Is the system fully depressurized before removing the bowl?

Is the filter bowl removed by turning counterclockwise and then pulling straight down?

• Process and pilot valves should be checked frequently for leaks and proper operation.

• Purge pressure adjustment valve should be checked frequently for proper adjustment.

- Determine if air control valves are operating and sequencing correctly. Refer to Section 3.3 for a general description of operating sequence. Refer to Tables 7-3 and 7-4 for time sequences for Standard Controllers. Refer to Tables 8-3 and 8-4 for time sequences for Energy Savings Controllers.

• Inlet/Outlet switching valves are non-lubricated shuttle valves. Pressure differences between the online and offline desiccant towers cause the shuttle valve to shift.

• High Pressure Models 40 through 450 ONLY. Inlet switching valves are normally open, pneumatically piston-actuated, Y-angle poppet valves. A yellow indicator can be seen through a clear window at the top of the actuator when the valve is in the open position.

• Purge/repressurization valves are normally closed, pneumatically piston-actuated, Y-angle poppet valves. A yellow indicator can be seen through a clear window at the top of the actuator housing when the valve is in the open position.

• 12 volt DC, normally-closed, 3-way pilot solenoid valves are wired to the controller and are used to direct pilot air to the actuators of the purge/repressurization valves.

• Purge pressure and subsequent flow is adjusted by means of a quarter-turn ball valve located in the bypass line of the upper piping.

• Models 40 through 3000 are equipped with a single safety relief valve that has been sized at a minimum to provide overpressure protection due to a fire for both desiccant towers.;

NOTE: The use of the correct replacement desiccant is necessary for proper dryer operation. Never use hygroscopic salts of the type commonly used in “deliquescent ” type dryers.

1. Frequency Of Desiccant Replacement

Desiccant should be replaced whenever the required dew point cannot be maintained while the dryer is being operated within its design conditions and there are no mechanical malfunctions. Refer to Section 11.0 for troubleshooting hints.

NOTE: Desiccant life is determined by the quality of the inlet air. Proper filtering of the inlet air will extend the life of the desiccant. Typically desiccant life is 3 to 5 years.

2. Procedure for Desiccant Charge Replacement

• De-pressurize and de-energize the dryer.

• Remove the fill and drain plugs from desiccant tower and drain the spent desiccant. Place a container at the base of the vessel to collect the desiccant. If necessary tap the sides of the vessels with a rubber mallet to loosen desiccant.

NOTE: Use extreme care when inserting rods or other tools through the desiccant fill or drain ports to loosen packed desiccant. Internal flow diffusers at the ends of the desiccant beds can be damaged or punctured by sharp instruments. These diffusers are necessary to distribute the airflow and keep the desiccant beads within the tower. Desiccant beads in exhaust mufflers, afterfilters, or the piping connected to the desiccant towers may indicate a perforation of a diffuser.

• Replace the drain plug using Teflon tape or another pipe thread sealant suitable for compressed air service.

Warning: This procedure requires trained personnel with PPE!

Check if muffler disseminator elements are clogged with desiccant dust

If the tower pressure gauge of the off-stream tower rises above 5 psig (3.5 barg), the muffler elements should be replaced.

Check if the tower pressure gauge of the off-stream tower rises above 5 psig (3.5 barg)

IMPORTANT: Replace muffler cores provided with unit after 5 complete cycles following the completion of the Start-Up Procedures.

Check if muffler cores have been replaced after 5 complete cycles following the completion of the Start-Up Procedures

Sign off on the mufflers replacement