7. After 5 minutes of operation, close the service valve and attach the hose or service line of the tool or device to be operated.

8. Open the service valves fully and start the work. After start-up, the unit automatically provides compressed air at the discharge service valves. Only periodic checking of the gauges on the instrument panel is then required.

9. When the engine is started during the day, after the first daily start-up, the above warm-up steps maybe eliminated,

STOPPING THE UNIT. - When stopping the unit at the end of the day, you should take the following steps:

1. Close the service valves and permit the engine to run at idle for 5 minutes. This will allow the engine coolant temperature to level off and the entire unit to cool down.

2. Turn the ignition switch to the OFF position.

COLD-WEATHER START-UP. - The following steps should be completed during cold-weather Start-up:

1. Start the engine using the heater switch and priming pump according to the engine manual.

2. Warm the engine until the engine coolant temperature reaches 120°F. Leaving the side curtains closed for a few minutes helps the engine to warm up.

3. Turn the ignition switch to OFF.

4. When the engine has stopped, start the engine again with the service valves partly open. Be sure the side curtains are open.

5. When the compressor has run for several minutes and the gauges indicate normal operating conditions, connect up the tools and go to work.

LUBRICATING THE UNIT. - The lubrication chart in the operator's manual for the particular make and model of compressor you are operating will show you where the unit should be lubricated, how often to lubricate, and what lubricant to use. The frequency will vary depending upon operating conditions and usage. Operating under abnormal conditions requires more frequent service.

CAUTION

Before servicing the compressor air system or compressor oil system, open the service valves to the atmosphere to relieve all pressure in the systems.

SERVICING THE AIR CLEANER. - A two-stage, dry type of air cleaner, installed inside the engine enclosure at the right rear, falters the intake air (fig. 12-31). Air is drawn into a first-stage element that causes nearly all the dust in the air to drop into a bin. Air then enters the second-stage element, a paper cartridge, where more dust is trapped and collected.

The dustbin should be removed by hand and emptied daily. Some models have a self-emptying dustbin that is piped into an aspirator in the exhaust pipeline, just beyond the muffler. When the aspirator is used, no alterations are allowed to be made to the engine muffler or exhaust pipe.

A service indicator is mounted on the side of the air cleaner housing. As the paper cartridge clogs with dust, a red indicator flag gradually rises in the window. When the cartridge is completely loaded, the window will show all red, and the flag will be locked in place. It is time to replace the paper cartridge, Discard the old cartridge and reset the red flag so that the window shows clear. Cleaning used paper cartridges is not recommended.

Figure 12-31. - Air cleaner.