Oil Specifications; Atlas Copco Roto-Injectfluid; Mineral Oil; Oil And Oil Filter Change - Atlas Copco GA55 Instruction Book

Decrease the shut-down warning level and shut-down level for the compressor element outlet temperature to the minimum
settings. Run the compressor: when reaching the setting, the unit must shut down. Afterwards, reset the warning and shut-
down levels to their original values.
9. Damaged flexibles or flexible joints must be replaced.
10. Any leakage should be attended to immediately.

4.3 Oil specifications

Attention
Never mix oils of different brands or types. Use only non-
toxic oils.

4.3.1 Atlas Copco Roto-injectfluid

It is strongly recommended to use Atlas Copco Roto-injectfluid.
This is special oil for screw compressors which keeps the
compressor in excellent condition.
See also section 4.6.

4.3.2 Mineral oil

Although Roto-injectfluid is recommended, mineral oil can be
used after taking following precautions:
- the previously used oil should first be drained and the system
flushed
- the oil filters should be replaced
- the oil must meet the requirements as specified below
High-quality, mineral oil with oxidation inhibitors and anti-foam
and anti-wear properties. The viscosity grade must correspond
to the ambient temperature and ISO 3448, as follows:
Ambient temperature
Consistently above 25 degrees
celsius . . . . . . . . . . . . . . . . . . . . . ISO VG 68 Minimum 95
Between 25 and 0 degrees celsius ISO VG 46 Minimum 95

4.4 Oil and oil filter change

(Figs. 3.5 and 3.6)
1. Run the compressor unloaded for 3 minutes.
2. Stop the compressor. Switch off the voltage. Unscrew oil
filler plug (FC) only one turn to permit any pressure in the
system to escape.
28
Viscosity Viscosity
grade index
3. Remove vent plug (VP-Fig. 1.3), wait 5 minutes, remove
drain plug (DP2) and catch the oil in a receptacle.
4. Remove the oil filters (OF).
5. Clean the filter seats on the manifold. Oil the gaskets of the
new elements. Screw the elements into place until the
gaskets contact their seats, then tighten by hand (approx.
half a turn).
6. Drain the oil by removing drain plugs (DP1 and DP3).
Collect the oil in a collector and deliver it to the local oil
collection service.
7. Reinstall plugs (DP1 up to DP3) and fill the air receiver
with oil until the level reaches the filler plug opening.
Reinstall plugs (FC and VP) and tighten.
8. Run the compressor for a few minutes. Stop the compressor
and wait a few minutes to allow the oil to settle.
Depressurize the system. Fill the air receiver with oil until
the level reaches the filler plug opening. Tighten filler plug
(FC).
9. Reset the oil and oil filter service warnings 4).

4.5 Storage after installation

Run the compressor twice a week until warm. Load and unload
the compressor a few times. If the compressor is stored without
running from time to time, protective measures must be taken.
Consult Atlas Copco.

4.6 Service kits

Service kits are available offering the benefits of genuine Atlas
Copco parts while keeping the maintenance budget low. The
kits comprise all parts needed for servicing.
Service kit for oil filters
and air filter
For GA55-GA55 W
For GA75-GA75 W-GA90C
For GA90C-GA90C W
Instruction book
Ordering number
2901 0416 00
2901 0431 00
2901 0431 00
2920 1381 02