an automatic blowdown valve for releasing air pressure when the engine is stopped,

a valve for draining moisture that accumulates in the receiver tank,

a drain cock at the bottom of the piping at the bottom of the oil storage tank,

an air filter service indicator to show when the filter needs servicing, and

a demister, or special filter, that separates lubricating oil from compressed air.

Remember a good maintenance program is the key to a long machine life. So it is up to both the operator and the mechanic to ensure that the maintenance is performed on time every time.

Air Cleaner Servicing
The air cleaner contains a primary and secondary dry filter element (fig. 3-54). An air filter restriction indicator is located at the rear of the air filter housing to alert the operator of the need to service the filters. When a red band appears in the air filter restriction indicator, secure the compressor and service the filters.

The primary element is cleanable by using compressed air. When the element is cleaned, never let the air pressure exceed 30 psi. The secondary filter is not cleanable and should be replaced when necessary.
Reverse flush the primary element by directing compressed air up from the inside out. Continue reverse flushing until all dust is removed. Should any oil or greasy dirt remain on the filter surface, the element should be replaced. When the element is satisfactorily cleaned, inspect it thoroughly before installation. Inspection procedures are as follows:

Place a bright light inside the element to inspect it for damage. Concentrated light will shine through the element and disclose any holes. A damaged element is to be replaced.

Inspect all gaskets and gasket contact surfaces of the housing. Should faulty gaskets be evident. replace them immediately.

After the element has been installed, inspect and tighten all air inlet connections before resuming operation.

CAUTION

Do not strike the element against any hard surface to dislodge dust. This will damage the sealing surfaces and possibly rupture the element.

Main Oil Filter Servicing
The main oil filter is a replaceable cartridge. The servicing of the filter is required as indicated by the maintenance indicator on the filter or each time the compressor oil is changed. Under normal operating conditions. the oil is changed at approximately 500 operating hours. Under severe conditions. more frequent servicing is required.

Figure 3-54.- Air filter.

Demister or Separator Element
The demister, or separator element, is located inside the receiver tank (fig. 3-55). Replacement of the demister is indicated by the maintenance indicator (usually mounted on the receiver tank but also can be remote-mounted) or any sign of oil in the air at the service valves. You can reach the demister after removing the plate on the end of the receiver tank.