Compressed Air System Shutdown Procedure

There are certain steps required in the case of a shutdown exceeding one week.

There are also required procedures for bringing a compressed air system back on line.

System Shutdown Procedure

Run the compressor to full operating pressure then close the service valve on the downstream side of the receiver.
Shut the compressor down
Close the service valve between the receiver and the compressor if one is in place
Go to the farthermost drip leg. Drain it until all water is purged. Close the valve to preserve line pressure. Work your way back to the first filter you encounter, draining each drip leg as you go.
Drain all in-line filters manually. If the filter has a solenoid drain, remove the power to the solenoid.
Drain the trap on a refrigerated dryer. Close the inlet and outlet valves on a dual tower desiccant dryer. (NOTE: If your refrigerated dryer has a horizontal heat exchanger it is likely it will be impossible to remove all the moisture. If the heat exchanger is vertical all you have to do is drain the trap).
Deenergize the dryer.
Drain the receiver.
After all drains and drip legs have been drained, depressurize the system.
Deenergize the compressor.
Drain the after-cooler trap
Allow the compressor to cool completely to ambient temperature. This may take as long as an hour for larger compressors.
Once the unit has cooled completely assure the oil is completely foam free.
Drain any condensed water from the sump. Open the drain valve until only oil is draining.
If the shutdown is anticipated to last longer than a month it is wise to suspend moisture absorbing media in the sump tank. This will keep internal oxidation to a minimum.

In the case of a refrigerated dryer, restore power to the dryer at least 4 hours prior to pressurization.
In the case of a desiccant dryer the system must be fully operational for at least 24 hours if the dew point is -40 F. If the dew point is below that the system may take as long as a week to get to the required dew point.
Remove any absorbent material that may have been suspended in the oil reservoir
Check the oil level in the compressor
Open the valve between the compressor and the receiver
Check voltage to the compressor to assure correct voltage is available
Start the compressor
Pressurize the receiver and allow the compressor to come up to temperature.
Check the compressor for oil and air leaks. Be sure to repair any leaks before proceeding. Seals may dry out and leak. Gaskets and O-rings may harden and leak as well
Once the compressor is up to minimum operating temperature slowly open the service valve between the receiver and the system.
Pressurize the system
Check for open valves and leaks. Check correct operation of manual drains.
If a desiccant dryer is installed check for correct alternation of towers. Assure correct dew-point has been achieved prior to placing the system in service.
Reenergize all solenoid drain valves. Test for proper operation
Return the system to service