CC 145
18
4
Maintenance Activities
4.1
General
An air-conditioning system is - just as all the other parts of a vehicle -
subjected to constant mechanical strain and stress. To ensure a trouble-free
operation of the system and to avoid any damage to its parts, it is important
to perform all required service activities on the air-conditioning system by
trained and qualified personnel who are knowledgeable in the field of
refrigeration.
The proper handling of the system including proof of the service activities
record (completed maintenance and service schedule) is a prerequisite for
acceptance any warranty claims in the event of damage to parts subject to
maintenance.
Regardless of the maintenance intervals specified in the maintenance and
service schedule, all attachments of the unit and the connections of the
refrigerant lines must be checked for tightness within the first four weeks
following the initial start-up of the air-conditioning system or the vehicle.
Even if the air-conditioning system is not in operation, wear caused by normal
ageing or the strain and stress occurring during the driving operation of the
bus may occur on individual components. All checks listed in the
maintenance and service schedule have therefore to be performed
independently of the operation hours of the system.
Loss of refrigerant is possible even if the refrigerant connections are tight.
Due to the structure of the material of the refrigerant lines, these show a
diffusion rate the extent of which varies depending on the ambient
temperatures. In the event of a relatively high refrigerant loss within short
intervals, leaks in the system can be assumed.
During long term non-use the air-conditioning system should be operated for
about 15 minutes at least once a month in order to prevent the shaft seals of
the refrigerant compressor from hardening. A requirement for this is a
minimum outside temperature of > 8 °C.
The drive pulley of the electromagnetic clutch is continuously rotating when
the vehicle engine is in operation. Bearing wear or possible damage to the
clutch therefore occurs practically independently of the operating time of the
air-conditioning system. It is therefore imperative that the clutch must be
checked for correct lubrication, belt tension etc., in accordance with the
maintenance instructions.
CAUTION
- The refrigerant receiver is subject to the Pressure Equipment Directive.
Check the refrigerant receiver every 6 months for cracks, corrosion and
other damage.
- The receiver must be replaced in the event of cracks, mechanical damage
or corrosion.
- The maintenance intervals indicated in the maintenance and service
schedule are based on operation hours of the vehicle, with the exception of
the compressor assembly, which are based on the air-conditioning unit's
hours of operation.
- These time intervals are empirical values that may vary widely depending
on the type of system and type of bus concerned.
