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 panel 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 YR
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 level is correct when the
measured evaporator approach and discharge
refrigerant gas superheat are within the values listed in
the table below.
The chiller must be at design operating
conditions and full load operation before the
correct refrigerant charge level can be
properly determined.
Liquid refrigerant will be visible in the evaporator sight
glass. The refrigerant level cannot be properly
determined by viewing the liquid refrigerant level in the
evaporator sight glass.
All YR Chillers shipped in Form 1 are charged with the
correct amount of refrigerant. Under some operating
conditions the chiller may appear to be overcharged or
undercharged with refrigerant. Consult with the YORK
Factory prior to removing or adding refrigerant. The
liquid line isolation valve may have to be partially
throttled to prevent overfeeding the evaporator in some
applications and under certain operating conditions.
Definitions:
Evaporator Approach = (S.E.T) - (L.E.L.T)
Discharge Superheat = (C.D.G.T) - (S.C.T)
Where:
S.E.T. = Saturated Evaporator Temperature
L.E.L.T. = Leaving Evaporator Liquid Temperature
C.D.G.T. = Compressor Discharge Gas Temperature
S.C.T. = Saturated Condensing Temperature
These values can be obtained from the OptiView control
panel. Refer to the Operating Instructions, 160.81-OI.
A visual check is sufficient to verify the oil level. Two sight
glasses are part of the oil separator and should be used
to determine the proper operating oil level.
The upper sight glass should have liquid oil visible in the
sight glass with the chiller off and the oil at 40 to 46°C.
When the chiller is in operation, the oil level may be
different from the standby condition, due to the
turbulence created by the discharge gas in the oil
separator.
160.81-ICOM-GB0 (01/02) 7-1
Evaporator Approach 0.6 to 2.8°C
Discharge Superheat 6.7 to 10.0°C
Evaporator Approach 2.2 to 4.4°C
Discharge Superheat 13.3 to 20.0°C
COMFORT COOLING APPLICATIONS
GLYCOL (ICE MAKING) APPLICATIONS