York YVAA, Installation, Operation & Maintenance Instructions Manual, Page: 161 / 178

JOHNSON CONTROLS
161
FORM 201.28-NM1.1
ISSUE DATE: 1/31/2018
9
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 main-
tenance 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 pro-
vide 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.
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 attempt-
ing any maintenance operations on the
unit.
Weekly Maintenance
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 lo-
cal Johnson Controls Service Agent.
Unit Status
Press the ‘STATUS’ key on the keypad and ensure no
fault messages are displayed.
Refrigerant Leaks
Visually check the heat exchangers, compressors and
pipework for damage and gas leaks.
SECTION 9 - MAINTENANCE
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 bot-
tom 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 opti-
mally 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 micro-
channel 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 adjust-
ment is required. Charge should be added
as liquid while circulating water through
the evaporator. If the complete charge
needs to be added, see Refrigerant Re-
moval, Evacuation and Charging a YVAA
Chiller on Page 162 in this section. Use
the valve on the liquid line for adding the
full charge and open the valves per the
procedure.