YVAA Style A Air-Cooled Screw Liquid Chillers ... - Johnson Controls

FORM 201.28-NM1.1
ISSUE DATE: 8/29/2012
GENERAL REQUIREMENTS
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 maintenance
checks by the operator/customer, 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 a Johnson
Controls service organization to protect the operation
of the unit. If damage or a system failure occurs due
to improper maintenance during the warranty period,
Johnson Controls shall not be liable for costs incurred
to return the unit to satisfactory condition.
Weekly Maintenance
This “Maintenance” section applies to
the basic unit only and may, on individual
contracts, be supplemented by additional
requirements to cover any modifications
or ancillary equipment as applicable.
The “Safety” section of this manual
should be read carefully before attempting
any maintenance operations on the
unit.
The following maintenance checks should be carried
out on a weekly basis by the operator/customer. Please
note that the units are not generally user serviceable
and no attempt should be made to rectify faults or
problems found during daily checks unless competent
and equipped to do so. If in any doubt, contact your
local Johnson Controls Service Agent.
Unit Status
Press the ‘STATUS’ key on the keypad and ensure no
fault messages are displayed.
SECTION 9 - MAINTENANCE
Refrigerant Leaks
Visually check the heat exchangers, compressors and
pipework for damage and gas leaks.
Operating Conditions
Read the operating pressures and temperatures at the
control panel using the display keys and check that
these are within the operating limitations given in the
manual.
Compressor Oil Level
Compressor oil level will typically run below the bottom
of the sight glass. Oil levels will only be visible
in the sight glass after running for periods of 15 to 30
minutes at full compressor speed. Do not run with oil
levels above the sight glass. Be careful when viewing
the sight glass not to confuse a full sight glass with an
empty sight glass.
Refrigerant Charge
Assure there is a level of refrigerant in the evaporator
sight glass while running at “Full Load” for 15 to 30
minutes.
Adding Charge to a System
A sight glass is located in the evaporator. When optimally
charged after running full load, the refrigerant
level should be approximately in the center of the sight
glass. There should be little concern if the level is high
or low in the glass, it should not affect operation.
It is not necessary to weigh charge unless
the entire charge has been lost. The ease
of charging is possible since the microchannel
coils hold only a small amount
of refrigerant charge. A charging valve,
located between the fixed orifice and the
evaporator, may be used if charge adjustment
is required. Charge should be
added as liquid while circulating water
through the evaporator. If the complete
charge needs to be added, see Refrigerant
Removal, Evacuation and Charging a
YVAA Chiller on Page 130 in this section.
Use the valve on the liquid line for adding
the full charge and open the valves per
the procedure.
JOHNSON CONTROLS 129
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