1. Torque application to tighten the lug
2. Avoid contact between the two nuts
3. Lug tightening nut
4. Flat lug
5. Counter-nut
6. Terminal tightening nut
7. Isolator
11.5 - Tightening torques for the main bolts and
screws
Screw type
Used for
Torque
value, N·m
M20 nut
Chassis
190
M20 nut
Heat exchanger side-side connection
240
M16 nut
Compressor fixing
190
H M16 screw
Heat exchanger water boxes,
structure
190
H M16 screw
Compressor suction flanges
190
H M20 screw
Compressor suction flanges TU & TV
240
M16 nut
Compressor discharge line TU
190
M20 nut
Compressor discharge line TV
240
H M8 screw
Drier cover
35
1/8 NPT
connection
Oil line
12
TE nut
Compressor oil line
24,5
7/8 ORFS nut
Oil line
130
5/8 ORFS nut
Oil line
65
3/8 ORFS nut
Oil line
26
H M6 screw
Stauff collar
10
Taptite screw M6
Oil line collar
7
Metric screw M6
Plate fixing, control box, terminal box
7
Taptite screw M10
Oil filter, control box fixing
30
ATTENTION: The tightening of the connections at the
compressor terminals requires special precautions. Please
refer to the chapter above.
11.6 - Evaporator and condenser maintenance
Check that:
• the insulating foam is intact and securely in place,
•
the sensors and flow switch are correctly operating and
correctly positioned in their support,
• the water-side connections are clean and show no sign of
leakage.
11.7 - Compressor maintenance
11.7.1 -
Oil filter change schedule
As system cleanliness is critical to reliable system operation, there
is a filter in the oil line at the oil separator outlet. The oil filter is
specified to provide a high level of filtration (5 µm) required for long
compressor life.
The filter should be checked after the first 500 hours of operation,
and every subsequent 2000 hours. The filter should be replaced at
any time when the pressure differential across the filter exceeds
2 bar.
The pressure drop across the filter can be determined by
measuring the pressure at the discharge port (at the oil separator)
and the oil pressure port (at the compressor). The difference in
these two pressures will be the pressure drop across the filter,
check valve, and solenoid valve. The pressure drop across the check
valve and solenoid valve is approximately 0.4 bar, which should be
subtracted from the two oil pressure measurements to give the oil
filter pressure drop.
11.7.2 - Compressor rotation control
Correct compressor rotation is one of the most critical appli-cation
considerations. Reverse rotation, even for a very short duration,
damages the compressor and can even destroy it.
The reverse rotation protection scheme must be capable of
determining the direction of rotation and stopping the compressor
within one second. Reverse rotation is most likely to occur
whenever the wiring at the compressor terminals has been
modified.
To minimise the opportunity for reverse rotation, the follow-ing
procedure must be applied. Rewire the power cables to the
compressor terminals and/or the downstream variator connection
decks as originally wired.
For replacement of the compressor, a low pressure switch is
included with the compressor. This low pressure switch should be
temporarily installed as a hard safety on the high pressure part of
the compressor. The purpose of this switch is to protect the
compressor against any wiring errors at the compressor terminal
pin. The electrical contact of the switch would be wired in series
with the high pressure switch. The switch will remain in place until
the compressor has been started and direction of rotation has
been verified; at this point, the switch will be removed.
The switch that has been selected for detecting reverse rotation
is Carrier part number HK01CB001. This switch opens the contacts
when the pressure falls below 7 kPa. The switch is a manual reset
type that can be reset after the pressure has once again risen
above 70 kPa. It is critical that the switch be a manual reset type
to preclude the compressor from short cycling in the reverse
direction.
11 - STANDARD MAINTENANCE
29