Gardner Denver Air Dryer DGH115

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?

Loss of pilot pressure will eventually prevent purge/repressurization valves from opening. Remaining pressure can be vented to atmosphere through the manual vent on the pilot air filter.

Is the system fully depressurized before removing the bowl?

Remove the filter bowl by turning counterclockwise and then pulling straight down.

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.

Process and pilot valves checked for leaks and proper operation

Purge pressure adjustment valve checked for proper adjustment

Air control valves are operating and sequencing correctly

Inlet/Outlet switching valves are functioning correctly

High Pressure Models 40 through 450 ONLY. Inlet switching valves are normally open

Purge/repressurization valves are normally closed

12 volt DC, normally-closed, 3-way pilot solenoid valves are wired to the controller

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

Warning: This procedure requires trained personnel with PPE!

Purge mufflers checked regularly?

Muffler disseminator elements changed annually?

Enter the back pressure in the muffler cartridges

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

Muffler cores replaced after 5 complete cycles following the completion of the Start-Up Procedures?

Sign off on the mufflers replacement