Manual Control; Stopping; Taking Out Of Operation At End Of Compressor Service Life - Atlas Copco GA55 Instruction Book

Instruction book
4. Regularly press the key <<More>> (5-Fig. 1.9) 6) to call
up information about the actual compressor condition:
- the status of controlling the compressor (automatic or
manual, local or remote)
- the status of the compressor start/stop timer (on or off)
5)
- the maximum allowable unloading pressure
- the outlet pressure
- the pressure difference over the oil separator
- the compressor element outlet temperature
- the actual cooling water outlet temperature 7)
- the status of the overload protection of both the drive
motor and fan motor 8) (normal or not)
- the total running and loading hours
- the dewpoint temperature (on Full-feature compressors)
3.5 Manual control (Fig. 1.9) 9)
Normally, the compressor runs in automatic operation, i.e. the
electronic regulator loads, unloads, stops and restarts the
compressor automatically. LED (1) is then alight.
Co
F104
AF
AF Air filter
AR Air receiver
Ca Air cooler
Co Oil cooler
WI Water inlet
WO Water outlet
Fig. 3.7 View on coolers (GA55/75 W)
2920 1381 02
Ca
AR
If required, the compressor can be unloaded manually. In this
case, the compressor is switched out of automatic operation,
i.e. the compressor remains running unloaded unless it is loaded
again manually.
Manually unloading
Press the key <<Unld>> (unload) (5). LED (1) goes out. The
message <<Manual Unloaded>> appears on the display.
Manually loading
Press the key <<Load>> (5). LED (1) lights up. The command
<<Load>> does not force the compressor in loaded condition,
but it will switch the compressor to automatic operation again,
i.e. the compressor will be loaded if the air net pressure drops
below the programmed level.
Manually starting
In automatic operation, the regulator limits the number of motor
starts. If the compressor is stopped manually, it must not be
restarted manually within 6 minutes after the last stop.

3.6 Stopping

1. Press stop button O (9-Fig. 1.9). LED (1) goes out. The
message <<Programmed stop>> appears. The compressor
runs unloaded for 30 seconds and then stops.
2. To stop the compressor in case of emergency, press button
(S3-Fig. 1.9). Alarm LED (3) blinks. After remedying the
fault, unlock the button by pulling it out (on earlier
production units by turning it to the left) and press key
<<Rset>> (5) before restarting. The message <<All
WI
conditions are OK>> appears. Press keys <<Menu>> and
<<Main>>.
WO
3. Close air outlet valve (AV-Fig. 1.1) and switch off the
voltage.
4. Open condensate drain valve (Dma-Fig. 1.5).
On water-cooled compressors only
5. Close the cooling water inlet valve.
6. If freezing temperatures may be expected, drain the
cooling system completely.
3.7 Taking out of operation at end of
compressor service life
At the end of the service life of the compressor, proceed as
follows:
1. Stop the compressor and close the air outlet valve.
2. Switch off the voltage and disconnect the compressor from
the mains.
3. Depressurize the compressor.
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