Technical data

7 MAINTENANCE
The Safety Section of this manual should
be read carefully before attempting any
maintenance operations on the unit. This
section should be read in conjunction with
the control centre Operation Instruction.
The units have been designed to operate continuously
provided they are regularly maintained and operated
within the limitations given in this manual. Each unit
should be included in a routine schedule of daily
inspection checks by the operator/ customer (see
Section 6), backed up by regular service inspection and
maintenance visits by a suitably qualified Service
Engineer.
It is entirely the responsibility of the owner to provide for
these regular maintenance requirements and/or enter
into a maintenance agreement with York International to
protect the operation of the unit. If damage or a system
failure occurs due to improper maintenance during the
warranty period, York shall not be liable for costs
incurred to return the unit to satisfactory condition.
This maintenance section applies only to the basic YS
unit and may, on individual contracts, be supplemented
by additional requirements to cover any modifications or
ancillary equipment as applicable.
7.1 Scheduled Maintenance
The table on the following page lists the regular
maintenance operations which should be carried out by
a suitably qualified Service Engineer.
The interval necessary between each 'minor' and 'major'
service can vary depending on, for example,
application, site conditions and expected operating
schedule. Normally a 'minor' service should be carried
out every three to six months and a 'major' service at
least once a year. It is recommended, however, that
York Service is contacted for recommendations for
individual sites.
7.1.1 Check the oil and refrigerant levels - Weekly
The refrigerant charge must be checked with the unit
shut down and all pressures and temperatures
equalised between the evaporator and condenser. The
level should be half way up the evaporator sight glass.
The oil charge should be checked after operation on full
load for around half an hour. The level should be visible
in the first stage sight glass. Add or drain oil as
necessary to achieve this level. No oil level should be
visible in the second stage sight glass.
7.2 Special Maintenance Requirements
In addition to the regular maintenance schedule, there
are some further special requirements for maintenance
of the unit based on the number of operating hours from
initial start-up:
At 200 hours of operation:
n
Check operating temperatures / pressures
n
Check chemical condition of oil
n
Change oil filter elements
n
Change oil return strainers
n
Check drive coupling
n
Check compressor / motor alignment
n
Check vibration levels
At 1000 hours of operation:
n
Check operating temperatures / pressures
At 5000 hours of operation:
n
Check operating temperatures / pressures
n Check chemical condition of oil
n
Change oil filter elements
n
Change oil return strainers
n
Change oil
n
Check drive coupling
n
Check compressor / motor alignment
At 30,000 hours of operation:
n
Replace compressor shaft seal
At 50,000 hours of operation:
n
Compressor internal inspection
For practical reasons it is not necessary to carry out
these maintenance operations at the exact operating
hours specified. The work should, however, be carried
out slightly before rather than after the specified hours.
The calendar time taken to reach the number of
operating hours specified above will vary significantly
depending on operating schedule. If a maintenance
operation given above closely coincides with, or has
been recently been completed as, part of the regular
scheduled maintenance then the operation need not be
repeated.
035L02381-GB0 7-1