Starting; During Operation - Atlas Copco GA55 Instruction Book

Instruction book
Example:
If operating at a pressure of 10 bar(e) in an ambient temperature of 20 degrees celsius and at a relative air humidity of 100 %, the
minimum temperature to prevent condensate from forming is 68 degrees celsius. Regulate the cooling water flow during loaded
operation to obtain a temperature between 70 and approx. 75 degrees celsius at the outlet of the compressor element.
4. Open the cooling water inlet valve (customer's installation).
5. Open the water flow regulating valve (customer's
installation). This step can be overlooked if, after previous
operation, the setting of this valve has not been disturbed.
3.3 Starting (Fig. 1.9)
Important
For GA Full-feature, switch on the voltage 4 hours before
starting to energize the crankcase heater of the refrigerant
compressor.
1. Switch on the voltage. Check that voltage on LED (2) lights
up. The message <<compressor off>> appears.
2. Open the air outlet valve (AV-Fig. 1.1).
3. Close the condensate drain valve (Dma-Fig. 1.5).
4. Press start button I (8). The compressor starts running and
automatic operation LED (1) lights up. Ten seconds 3) after
starting, the drive motor switches over from star to delta.
At the same time 3) the compressor starts running loaded.
The message on display (4) changes from <<Auto
unloaded>> to <<Auto loaded>>.
2920 1381 02
Fig. 3.4 Minimum compressor element temperature for water-cooled units
On water-cooled compressors also:
5. If necessary, regulate the cooling water flow during loaded
running to obtain the most suitable temperature at the outlet
of the compressor element, i.e. between 2 and 7 degrees
celsius above the relevant temperature in Fig. 3.4. For
optimum operation, the cooling water outlet temperature
4) must never exceed the value specified in section 7.5.
Consult Atlas Copco if condensate should be formed during
frequent unloading periods.

3.4 During operation

1. Check the oil level during loaded operation: the pointer
of the level gauge (Gl-Fig. 3.5) must register in the green
range.
If the level is in the LOW range, press button O (9-Fig.
1.9), wait until the compressor has stopped and switch off
the voltage. Depressurize the oil system by unscrewing the
oil filler plug (FC-Fig. 3.5) one turn, wait a few minutes
and add oil until the level reaches the filler plug. Tighten
the plug.
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