A true plug and play system that provides the highest efficiency for its operation, our YORK® YLAA Air-Cooled Scroll Chiller allows you to reduce your energy costs while being friendlier to the environment. Whether your cooling needs are industrial or commercial, we can help you put together a complete air-cooled chiller system.

With advanced technology, air-cooled water chiller systems featuring our YLAA Chillers offer remarkable real-world performance. Brazed evaporators and microchannel condensers enable more efficient heat transfer, providing lower life-cycle costs.

• Reduce your energy costs as much as 40% – get the best efficiency at all operating conditions and lower your annual energy consumption.
• Be friendlier to the environment – become a leader in environmental design with zero-ODP HFC-410A refrigerant and up to 50% less refrigerant charge.
• Operate your own way – choose from a variety of energy, sound, and mechanical configurations to suit your many application needs.
• Lower your cost of ownership – minimize your installation cost, maximize your usable space, lower your electric bills and reduce your service expenses by choosing a lighter, smaller, more efficient, low maintenance chiller.

INTRODUCTION
YORK YLAA chillers are manufactured to the highest
design and construction standards to ensure high performance,
reliability and adaptability to all types of air
conditioning installations.
Rigging and lifting should only be done by a professional
rigger in accordance with a written rigging and
lifting plan. The most appropriate rigging and lifting
method will depend on job specific factors, such as the
rigging equipment available and site needs. Therefore
a professional rigger must determine the rigging and
lifting method to be used, and it is beyond the scope of
the manual to specify rigging and lifting details.
This manual contains all the information required for
correct installation and commissioning of the unit, together
with operating and maintenance instructions.
The manuals should be read thoroughly before attempting
to operate or service the unit.
All procedures detailed in the manuals, including installation,
commissioning and maintenance tasks must
only be performed by suitably trained and qualified
personnel.
The manufacturer will not be liable for any injury or
damage caused by incorrect installation, commissioning,
operation or maintenance resulting from a failure
to follow the procedures and instructions detailed in
the manuals.
WARRANTY
Johnson Controls warrants all equipment and materials
against defects in workmanship and materials for a
period of eighteen months from date of shipment, or 12
months from date of start-up, whichever occurs first,
unless labor or extended warranty has been purchased
as part of the contract.
The warranty is limited to parts only replacement and
shipping of any faulty part, or sub-assembly, which has
failed due to poor quality or manufacturing errors. All
claims must be supported by evidence that the failure
has occurred within the warranty period, and that the
unit has been operated within the designed parameters
specified.
All warranty claims must specify the unit model, serial
number, order number and run hours/starts. Model and
serial number information is printed on the unit identification
plate.
The unit warranty will be void if any modification to
the unit is carried out without prior written approval
from Johnson Controls.
For warranty purposes, the following conditions must
be satisfied:
• The initial start of the unit must be carried out by
trained personnel from an Authorized Johnson
Controls Service Center (see SECTION 6 – COMMISSIONING).
• Only genuine YORK approved spare parts, oils,
coolants, and refrigerants must be used.
• All the scheduled maintenance operations detailed
in this manual must be performed at the specified
times by suitably trained and qualified personnel
(see SECTION 10 – MAINTENANCE).
• Failure to satisfy any of these conditions will automatically
void the warranty (see Warranty on page
11).
HANDLING
These units are shipped as completely assembled units
containing full operating charge, and care should be
taken to avoid damage due to rough handling.
SAFETY AND QUALITY
Standards for Safety and Quality
YLAA chillers are designed and built within an ISO
9002 accredited design and manufacturing organization.
The chillers comply with the applicable sections
of the following Standards and Codes:
• ANSI/ASHRAE Standard 15 - Safety Code for
Mechanical Refrigeration.
• ANSI/NFPA Standard 70 - National Electrical
Code (N.E.C.).
• ASME Boiler and Pressure Vessel Code - Section
VIII Division 1.
• ARI Standard 550/590 - Positive Displacement
Compressors and Air Cooled Rotary Screw Water
Chilling Packages.

ASHRAE 90.1 - Energy Efficiency compliance.
• Conform to Intertek Testing Services, formerly
ETL, for construction of chillers and provide
ETL/cETL listing label.
• Manufactured in facility registered to ISO 9002.
• OSHA – Occupational Safety and Health Act.
In addition, the chillers conform to Underwriters Laboratories
(U.L.) for construction of chillers and provide
U.L./cU.L. Listing Label.
Responsibility for Safety
Every care has been taken in the design and manufacture
of the unit to ensure compliance with the safety
requirements listed above. However, the individual
rigging, lifting, maintaining, operating or working on
any machinery is primarily responsible for:
• Personal safety, safety of other personnel, and the
machinery.
• Correct utilization of the machinery in accordance
with the procedures detailed in the manuals.
ABOUT THIS MANUAL
The following terms are used in this document to alert
the reader to areas of potential hazard.
A WARNING is given in this document
to identify a hazard, which could lead to
personal injury. Usually an instruction
will be given, together with a brief explanation
and the possible result of ignoring
the instruction.
A CAUTION identifies a hazard which
could lead to damage to the machine,
damage to other equipment and/or environmental
pollution. Usually an instruction
will be given, together with a brief
explanation and the possible result of
ignoring the instruction.
A NOTE is used to highlight additional
information, which may be helpful to
you but where there are no special safety
implications.
The contents of this manual include suggested best
working practices and procedures. These are issued for
guidance only, and they do not take precedence over
the above stated individual responsibility and/or local
safety regulations.
This manual and any other document supplied with
the unit are the property of Johnson Controls which reserves
all rights. They may not be reproduced, in whole
or in part, without prior written authorization from an
authorized Johnson Controls representative.
MISUSE OF EQUIPMENT
Suitability for Application
The unit is intended for cooling water or glycol solutions
and is not suitable for purposes other than those
specified in these instructions. Any use of the equipment
other than its intended use, or operation of the equipment
contrary to the relevant procedures may result in
injury to the operator, or damage to the equipment.
The unit must not be operated outside the design parameters
specified in this manual.
Structural Support
Structural support of the unit must be provided as indicated
in these instructions. Failure to provide proper
support may result in injury to the operator, or damage
to the equipment and/or building.
Mechanical Strength
The unit is not designed to withstand loads or stresses
from adjacent equipment, pipework or structures. Additional
components must not be mounted on the unit.
Any such extraneous loads may cause structural failure
and may result in injury to the operator, or damage to
the equipment.
General Access
There are a number of areas and features, which may
be a hazard and potentially cause injury when working
on the unit unless suitable safety precautions are taken.
It is important to ensure access to the unit is restricted
to suitably qualified persons who are familiar with the
potential hazards and precautions necessary for safe
operation and maintenance of equipment containing
high temperatures, pressures and voltages

Pressure Systems
The unit contains refrigerant vapor and liquid under
pressure, release of which can be a danger and cause
injury. The user should ensure that care is taken during
installation, operation and maintenance to avoid damage
to the pressure system. No attempt should be made
to gain access to the component parts of the pressure
system other than by suitably trained and qualified personnel.
Electrical
The unit must be grounded. No installation or maintenance
work should be attempted on the electrical
equipment without first switching power OFF, isolating
and locking-off the power supply. Servicing and
maintenance on live equipment must only be performed
by suitably trained and qualified personnel. No
attempt should be made to gain access to the control
panel or electrical enclosures during normal operation
of the unit.
Rotating Parts
Fan guards must be fitted at all times and not removed
unless the power supply has been isolated. If ductwork
is to be fitted, requiring the wire fan guards to be removed,
alternative safety measures must be taken to
protect against the risk of injury from rotating fans.
Sharp Edges
The fins on the air-cooled condenser coils have sharp
metal edges. Reasonable care should be taken when
working in contact with the coils to avoid the risk of
minor abrasions and lacerations. The use of gloves is
recommended.
Frame rails, brakes, and other components may also
have sharp edges. Reasonable care should be taken
when working in contact with any components to avoid
risk of minor abrasions and lacerations.
Refrigerants and Oils
Refrigerants and oils used in the unit are generally nontoxic,
non-flammable and non-corrosive, and pose no
special safety hazards. Use of gloves and safety glasses
is, however, recommended when working on the unit.
The build up of refrigerant vapor, from a leak for example,
does pose a risk of asphyxiation in confined or
enclosed spaces and attention should be given to good
ventilation.
High Temperature and Pressure Cleaning
High temperature and pressure cleaning methods
(e.g. steam cleaning) should not be used on any part
of the pressure system as this may cause operation of
the pressure relief device(s). Detergents and solvents,
which may cause corrosion, should also be avoided.
Emergency Shutdown
In case of emergency, the control panel is fitted with
a Unit Switch to stop the unit in an emergency. When
operated, it removes the low voltage 120VAC electrical
supply from the unit controller, thus shutting down
the unit.

INTRODUCTION
YORK YLAA Air-Cooled Scroll Chillers provide
chilled water for all air conditioning applications using
central station air handling or terminal units. They
are completely self-contained and are designed for outdoor
(roof or ground level) installation. Each complete
packaged unit includes hermetic scroll compressors, a
liquid cooler, air cooled condenser, a charge of Zero
Ozone Depletion Potential Refrigerant R-410A and
a weather resistant microprocessor control center, all
mounted on a rugged steel base.
The units are completely assembled with all interconnecting
refrigerant piping and internal wiring, ready
for field installation.
Prior to delivery, the packaged unit is pressure-tested,
evacuated, and fully charged with Refrigerant R-410A
and oil. After assembly, a complete operational test is
performed with water flowing through the cooler to assure
that the refrigeration circuit operates correctly.
The unit structure is heavy-gauge, galvanized steel.
This galvanized steel is coated with baked-on powder
paint, which, when subjected to ASTM B117 1000
hour, salt spray testing, yields a minimum ASTM 1654
rating of “6”. Units are designed in accordance with
NFPA 70 (National Electric Code), ASHRAE/ANSI 15
Safety code for mechanical refrigeration, ASME, and
rated in accordance with ARI Standard 550/590.
GENERAL SYSTEM DESCRIPTION
Compressors
The chiller has suction-gas cooled, hermetic, scroll
compressors. The YLAA compressors incorporate a
compliant scroll design in both the axial and radial
direction. All rotating parts are statically and dynamically
balanced. A large internal volume and oil reservoir
provides greater liquid tolerance. Compressor
crankcase heaters are also included for extra protection
against liquid migration.
Brazed Plate Evaporator
The compact, high efficiency Brazed Plate Heat Exchanger
(BPHE) is constructed with 316L stainless
steel corrugated channel plates with a filler material
between each plate. It offers excellent heat transfer
performance with a compact size and low weight, reducing
structural steel requirements on the job site.
The heat exchanger is manufactured in a precisely controlled
vacuum-brazing process that allows the filler
material to form a brazed joint at every contact point
between the plates, creating complex channels. The arrangement
is similar to older plate and frame technology,
but without gaskets and frame parts.
Water inlet and outlet connections are grooved for
compatibility with field supplied ANSI/AWWA C-606
couplings.

The evaporator is equipped with a thermostat-controlled
heater. The heater provides freeze protection
for the evaporator down to -20°F (-29°C) ambient. The
evaporator is covered with 3/4” flexible, closed-cell,
foam insulation (K=0.25).
A 1/16” (1.6mm) mesh wye-strainer is provided as
standard for installation upstream of the heat exchanger
to prevent clogging from water system debris.
Condenser
Microchannel Condenser (MCHX)
MCHX Condensers are made of a single material to
avoid galvanic corrosion due to dissimilar metals.
MCHX and headers are brazed as one piece. Integral
sub cooling is included. The design working pressure
of the MCHX is 650 PSIG (45 bar). MCHX Condenser
is easily washable with clear water.
Fans
The condenser fans are composed of corrosion resistant
aluminum hub and glass-fiber reinforced polypropylene
composite blades molded into a low noise
airfoil section. They are designed for maximum efficiency
and are statically and dynamically balanced for
vibration free operation. They are directly driven by
independent motors, and positioned for vertical air discharge.
The fan guards are constructed of heavy gauge,
rust resistant, coated steel. All blades are statically and
dynamically balanced for vibration free operation.
Motors
The fan motors are Totally Enclosed Air-Over, and are
current protected. They feature ball bearings that are
double sealed and permanently lubricated.
Control Center
All controls are contained in a NEMA 3R/12 cabinet
with hinged outer door and includes a Liquid Crystal
Display with Light Emitting Diode backlighting for
outdoor viewing:
• Two display lines
• Twenty characters per line
Display/Print Keys
• Color coded 12-button non-tactile keypad with sections
for display and print of typical information:
• Chilled liquid temperatures
• Ambient temperature
• System pressures (each circuit)
• Operating hours and starts (each compressor)
• Print calls up to the liquid crystal display
• Operating data for the systems
• History of fault shutdown data for up to the last
six fault shutdown conditions.
• An RS-232 port, in conjunction with this press-toprint
button, is provided to permit the capability
of hard copy print-outs via a separate printer (by
others).
Entry Keys
This section is used to enter setpoints or modify system
values.
Setpoints Keys
Updating can be performed to:
• Chilled liquid temperature setpoint and range
• Remote reset temperature range
• Set daily schedule/holiday for start/stop
• Manual override for servicing
• Low and high ambient cutouts
• Number of compressors
• Low liquid temperature cutout
• Low suction pressure cutout
• High discharge pressure cutout
• Anti-recycle timer (compressor start cycle time)
• Anti-coincident timer (delay compressor starts)
Unit Keys
This section is used to:
• Set time
• Set unit options
Oper Data Key
The microprocessor control center is capable of displaying
the following:
• Return and leaving liquid temperature
• Low leaving liquid temperature cutout setting
• Low ambient temperature cutout setting
• Outdoor air temperature
• English or Metric data
• Suction pressure cutout setting
• Each system suction pressure

• Discharge pressure (optional)
• Liquid Temperature Reset via a Johnson Controls
ISN DDC or Building Automation System (by
others) via a 4 to 20 milliamp or 0 to10VDC input
• Anti-recycle timer status for each system
• Anti-coincident system start timer condition
• Compressor run status
• No cooling load condition
• Day, date and time
• Daily start/stop times
• Holiday status
• Automatic or manual system lead/lag control
• Lead system definition
• Compressor starts and operating hours
• (each compressor)
• Status of hot gas valves, evaporator heater
• and fan operation
• Run permissive status
• Number of compressors running
• Liquid solenoid valve status
• Load and unload timer status
• Water pump status
Provisions are included for: pumpdown at shutdown;
optional remote chilled water temperature reset and
two steps of demand load limiting from an external
building automation system. Unit alarm contacts are
standard.
The operating program is stored in non-volatile memory
battery backed RAM to eliminate chiller failure due
to AC powered failure/battery discharge. Programmed
setpoints are retained in lithium battery-backed RTC
memory for 5 years minimum.
COMMUNICATIONS
• Native communication capability for BACnet
(MS/TP) and Modbus.
• Optional communication available for N2 and
LON via eLink Gateway option.
* Intensity of Protection European Standard
** International Electrotechnical Commission
BUILDING AUTOMATION SYSTEM
INTERFACE
The Microprocessor Board can accept a 4 to 20 milliamp,
or 0 to10VDC input to reset the leaving chiller
liquid temperature from a Building Automation System.
• The standard unit capabilities include remote
start-stop, remote water temperature reset via a
PWM 4 to 20 milliamp or 0 to 10VDC input signal
or up to two stages of demand (load) limiting
depending on model.
• The standard control panel can be directly connected
to a Johnson Controls Building Automated
System.
POWER PANEL
Each panel contains:
• Compressor power terminals
• Compressor motor starting contactors per I.E.C.**
• Control power terminals to accept incoming for
110-1-50 control power
• Fan contactors and overload current protection
The power wiring is routed through liquid-tight conduit
to the compressors and fans.
ACCESSORIES AND OPTIONS
Power Options
Compressor Power Connections
Single-point terminal block connection(s) are provided
as standard. The following power connections are
available as options. (See electrical data for specific
voltage and options availability.) (Factory-mounted)
Single-Point Supply Terminal Block
Includes enclosure, terminal-block and interconnecting
wiring to the compressors. Separate external protection
must be supplied, by others, in the incoming compressor-
power wiring. (Do not include this option if either
the Single-Point Non-Fused Disconnect Switch or Single-
Point Circuit Breaker options have been included.)

Single-Point Non-Fused Disconnect Switch
Unit-mounted disconnect switch with external, lockable
handle (in compliance with Article 440-14 of N.E.C.),
can be supplied to isolate the unit power voltage for servicing.
Separate external fusing must be supplied, by
others in the power wiring, which must comply with the
National Electrical Code and/or local codes.
Single-Point Circuit Breaker
A unit mounted circuit breaker with external, lockable
handle (in compliance with N.E.C. Article 440-14), can
be supplied to isolate the power voltage for servicing.
(This option includes the Single-Point Power connection.)
Control Transformer
Converts unit power voltage to 115-1-60 (2.0 or 3.0
KVA capacity). Factory mounting includes primary
and secondary wiring between the transformer and the
control panel. (Factory-mounted)
Control Options
Ambient Kit (Low)
Units will operate to 25°F (-3.9°C). This accessory includes
all necessary components to permit chiller operation
to 0°F (-18°C). (This option includes the Discharge
Pressure Transducer / Readout Capability option.) For
proper head pressure control in applications below 30°F
(-1°C) where wind gusts may exceed 5 mph, it is recommended
that Optional Condenser Louvered Enclosure
Panels also be included. (Factory-mounted)
High Ambient Kit With Sunshield
Allows units to operate when the ambient temperature
is above 115°F (46°C). Includes sun shield panels and
discharge pressure transducers.
Language LCD and Keypad Display
Spanish, French, German, and Italian unit LCD controls
and keypad display available. Standard language
is English.
Compressor, Piping, Evaporator Options
Low Temperature Glycol
Replaces standard Thermostatic Expansion Valves
with Electronic Expansion Valves to achieve leaving
glycol temperatures as low as 10°F (-12°C). Required
for any leaving liquid temperature below 30°F (-1°C).
Electronic Expansion Valves permit operation at both
low temperatures and comfort cooling applications
without a capacity loss or derate at either condition.
(Factory installed)
Chicago Code Relief Valves
Unit will be provided with relief valves to meet Chicago
code requirements. (Factory-Mounted)
Service Suction Isolation Valve
Service suction (ball-type) isolation valves are added
to unit per system (discharge service ball-type isolation
valve is standard on each circuit). (Factory-Mounted)
Hot Gas By-Pass
Permits continuous, stable operation at capacities below
the minimum step of compressor unloading to as low
as 5% capacity (depending on both the unit and operating
conditions) by introducing an artificial load on the
cooler. Hot gas by-pass is installed on only refrigerant
system #1 on two-circuited units. (Factory-Mounted)
Flanges (ANSI/AWWA C-606 couplings Type)
Consists of (2) Flange adapter for grooved end pipe (standard
150 psi [10.5 bar] cooler). (Not available on optional
DX cooler 300 PSIG DWP waterside.) (Field-mounted)
Flow Switch
A thermal dispersion type flow switch provides accurate,
low maintenance flow proving and is included
standard. It is factory wired and installed in the extension
pipe between evaporator outlet and edge of chiller.
The extension pipe is secured to the chiller frame
for shipping to avoid risk of damage to evaporator
and is easily attached to the evaporator at startup using
the supplied ANSI/AWWA C-606 connector. The
flow switch can be deleted if alternate or existing flow
switch is field supplied.

Heat Recovery Condenser
A partially condensing refrigerant to liquid condenser
recovers heat off both refrigerant circuits and rejects
into a single liquid circuit. Factory installed between
the compressor discharge and the condenser (air) coils
to capture the maximum amount of heat. Capable of
recovering up to 85% total heat of rejection (cooling
load plus work input); temperatures as high as 140°F
(60°C) are possible.
Hydro-Kit
Factory installed Hydro-Kit suitable for water and glycol
systems with up to 35% glycol at leaving temperatures
down to 20°F. The hydro-kit option is available
in a single or dual configuration (dual as standby duty
only), with totally enclosed permanently lubricated
pump motors.
The hydro-kit option comes standard with a balancing
valve, discharge check valve, discharge shutoff valve,
thermal dispersion flow switch, pressure ports, inlet
wye-strainer, bleed and drain valves and frost protection.
Service shut off valves, additional pressure ports and expansion
tanks are optional within the hydro-kit option.
Condenser and Cabinet Options
MCHX Condenser protection against corrosive environments
is available by choosing any of the following
options. For additional application recommendations,
refer to FORM 150.12-ES1. (Factory-Mounted)
Post-Coated Dipped MCHX Condenser
The unit MCHX is constructed with post dipped-epoxy
MCHX condenser. This is recommended for seashore
and other corrosive applications (with the exception of
strong alkalies, oxidizers and wet bromine, chlorine
and fluorine in concentrations greater than 100 ppm).
Enclosure Panels (Unit)
Tamperproof Enclosure Panels prevent unauthorized
access to units. Enclosure Panels can provide an aesthetically
pleasing alternative to expensive fencing.
Additionally, for proper head pressure control, Johnson
Controls recommends the use of Condenser Louvered
Panels for winter applications where wind gusts may
exceed five miles per hour. The following types of enclosure
panels are available:
• Wire Panels (Full Unit) - Consists of welded
wire-mesh guards mounted on the exterior of the
unit. Prevents unauthorized access, yet provides
free air flow. (Factory-Mounted)
• Wire/Louvered Panels - Consists of welded
wire-mesh panels on the bottom part of unit and
louvered panels on the condenser section of the
unit. (Factory-Mounted)
• Louvered Panels (MCHX Condenser Only)
- Louvered Panels are mounted on the sides and
ends of the MCHX condenser for protection.
(Factory-Mounted)
• Louvered Panels (Full Unit) - Louvered panels
surround the front, back, and sides of the unit.
They prevent unauthorized access and visually
screen unit components. Unrestricted air flow
is permitted through generously sized louvered
openings. This option is applicable for any outdoor
design ambient temperature up to 115°F
(46°). (Factory-Mounted)
MCHX End Hail Guard
Louvered panel attached to exposed MCHX end. (Factory-
Mounted)
Sound Attenuation
One or both of the following sound attenuation options
are recommended for residential or other similar sound
sensitive locations:
• Compressor Acoustic Sound Blanket - Each
compressor is individually enclosed by an acoustic
sound blanket. The sound blankets are made
with one layer of acoustical absorbent textile fiber
of 5/8” (15mm) thickness; one layer of antivibrating
heavy material thickness of 1/8” (3mm).
Both are closed by two sheets of welded PVC,
reinforced for temperature and UV resistance.
(Factory-Mounted)
• Ultra Quiet Fans - Lower RPM, 8-pole fan motors
are used with steeper-pitch fans. (Factory-
Mounted)
Vibration Isolators
Level adjusting, spring type 1” (25.4mm) or seismic
deflection or neoprene pad isolators for mounting under
unit base rails. (Field-mounted)