Lubrication (Not For Len); Servicing And Adjustment Procedures; Unloader Or Check Valve; Valves - Atlas Copco LE5 Instruction Book

Industrial Air Division

4.2 Lubrication (not for LEN)

It is strongly recommended to use the Atlas Copco approved P.A.O.
(polyalphaolefine) compressor oil to keep the compressor in
excellent operating condition.
If this oil is not available:
- at normal operating conditions, a good-quality, mineral motor oil
(not multigrade) with a viscosity grade of SAE 10 W 20 can be
used. The oil must meet the requirements of the API
(American Petroleum Institute) classification code SE-CC, SE-
CD or better. If mineral oil is used, the oil must be changed
more frequently (see section 4.1). Mineral oil can be mixed

5 Servicing and adjustment procedures

Warning: Release the pressure from the compressor before
starting repair or maintenance works. Isolate the compressor from
the mains.

5.1 Unloader or check valve

Dirt, condensate, coke formation and oxidation influence the proper
operation of the valve. Depending on the working conditions
(ambient temperature, working pressure, load cycle, oil type), it is
recommended to replace the unloader or check valve assembly
after 3000 to 4000 running hours. Replacement instructions are
included in the maintenance kits (4 and 3-Fig. 4).

5.2 Valves

A faulty valve must be replaced immediately. A faulty valve can
be discovered as stated in section 6, points 1 and 4. It is highly
recommended to replace the valves and gaskets each time the
cylinder heads are disassembled, because a new position of old
valves results in accelerated wear.
Replacement of valve disks (Figs. 5)
LE5-9 LE11
LE/LT12
LT5-11 LP LT5-11 HP Operation sequence
LE7N LE9N
• •
Remove the fan guard, unscrew cap (1-
Figs. 1) and remove the cover, air filter
and cover of the air intake silencer.
•
Disconnect cylinder head cover (11)
from the inlet and outlet pipe flanges.
Remove cover (11).
•
Remove cylinder head cover (11).
Disconnect outlet and inlet caps (15 and
14) from the flanges and/or pipe
coupling. Remove the caps.
• •
Remove spring (10), outlet valve guard
(9) and outlet valve disk (8).
• •
Lift off valve seat (7) and remove inlet
valve disk (6). Do not remove guide
pins (2).
10
with P.A.O. oil, but the excellent P.A.O. lubrication properties
are reduced.
- at extreme operating conditions (high ambient temperature,
high loading factor, high pressure), a special diester synthetic
lubricant should be used. Consult Atlas Copco for the
specifications and change interval.
Note
The crankcase is connected to the air intake silencer or suction
line through a breather valve. Faulty operation of this valve or
clogging of the calibrated hole will result in too high a
crankcase pressure and promote oil consumption.
LE5-9 LE11
LE/LT12
LT5-11 LP LT5-11 HP Operation sequence
LE7N LE9N
• •
Remove and discard all O-rings and
rubber joints.
• •
If necessary, remove the carbon
deposits from the inlet valve guard at
the cylinder top. Take care that no dirt
drops into the cylinder.
• •
Clean and inspect all parts.
• •
Fit a new joint (3). Do not stretch the
rubber while inserting it in its groove;
the ends should meet. Some vaseline
facilitates assembling.
• •
Put a new inlet valve disk (6) into place
and install valve seat (7).
• •
Fit a new O-ring (5) and joint (1).
• •
Install a new outlet valve disk (8), guard
(9) and spring (10).
•
Install cylinder head cover (11). Use
new flange gaskets, if necessary. Fit
the flange and cylinder head bolts and
tighten them alternately.
•
Fit a new O-ring (13) and joint (12).
Reinstall inlet and outlet caps (14 and
15) and cover (11). Clamp the cylinder
head assembly securely into place.
Secure the flanges and/or reconnect the
pipe coupling.
• •
Reinstall the fan guard, cover of the air
intake silencer, air filter, cover and cap
(1-Figs. 1).
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