Trane Precedent YSC060-120 User manual

Packaged Gas/Electric
Rooftop Units
Precedent™
YSC060-120
50 Hz
RT-PRC017-ENFebruary 2004

© 2004 American Standard Inc. All rights reserved RT-PRC017-EN
Introduction
Precedent™ . . . The same Trane
quality... with added flexibility.
Precedent is a flexible line of packaged
units that covers a wide variety of
applications.
Reliatel™microprocessor controls
provide superior flexibility for the
simplest to the most sophisticated
applications. In addition to controls,
Precedent offers many other outstanding
features and option choices.
With its sleek compact cabinet, rounded
corners and beveled top, it may just be
the most aesthetically pleasing
packaged unit on the planet. And, of
course, Precedent carries the Trane
reputation for excellence, quality, and
reliability.
It’s hard to stop a Trane .
From simple applications, to the most
complex, Precedent has the solution.

Introduction
Features and Benefits
Application Considerations
Selection Procedure
Model Number Description
General Data
Performance Data
Zone Controls
Electrical Data
Jobsite Connection
Dimensional Data
Weights
Mechanical Specifications
3
Contents
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Features and
Benefits
Unit Cabinet
The compact cabinet with rounded
corners takes up less room and is less
costly to ship. The beveled and ribbed
top is not only aesthetically pleasing, it is
designed to prevent water from pooling.
Single Point Power
A single electrical connection powers the
unit.
Compressors
Precedent™contains the best
compressor technology available to
achieve the highest possible
performance. Our compressor line
includes Trane built Climatuff™
reciprocating and scrolls.
Easy Access Panels
Easy access panels reduce the number of
possible water entry points.
Low Ambient Cooling
All Precedent units have cooling
capabilities down to -18°C (0°F) as
standard.
Unit Base
For added water integrity, Precedent has
a raised 29 mm (11/8") lip around the
unit’s downflow supply and return to
prevent water from blowing into the
ductwork.
Sloped Drain Pans
Every Precedent unit has a non-
corrosive, removable, double-sloped
drain pan that’s easy to clean and
reversible to allow installation of drain
trap on either side of the unit.
Through the Base Condensate
Every unit includes provisions for
through the base condensate drain
connections. This allows the drain to be
connected through the roof curb instead
of a roof penetration.
Foil-Faced Insulation
All panels in the Evaporator section of
the unit have cleanable foil-faced
insulation. All edges are either captured
or sealed to ensure no fibers get into the
airstream.
Convertible Units
• The units ship in a downflow
configuration. They can be easily
converted to horizontal by simply
moving two panels.
• Units come complete with horizontal
duct flanges so the contractor doesn’t
have to field fabricate them. These
duct flanges are a time and cost saver.
Easy Access Panels
Remove two screws for access to the
standardized internal components and
wiring.
Easy-Adjust Idler Arm
With the Easy-Adjust Idler Arm, the belt
and sheaves can be quickly adjusted
without moving the mounted fan motor.
The result is a major savings in time and
money. Patented Condenser Coil
Precedent boasts a patented 1+1+1
Hybrid coil, permanently gapped for
easy cleaning.
Colored And Numbered Wiring
You save time and money tracing wires
and diagnosing the unit.

5RT-PRC017-EN
Features and
Benefits
Standardized Components
•Components are placed in the same
location on all Precedent™units.
Familiarize yourself with one Precedent
and you are familiar with every
Precedent.
Easy Access Low Voltage Terminal
Board
Precedent’s Low Voltage Terminal Board
is external to the electrical control
cabinet. It is extremely easy to test
operation of all unit functions. This is
another cost and time saving installation
feature.
Low Voltage Connections
The wiring of the low voltage
connections to the unit and the zone
sensors is as simple as 1-1, 2-2, and 3-3.
This simplified system makes it easy for
the installer to wire.
Single-Side Service
Single-side service is standard on all
Precedent units.
Progressive Tubular Heat Exchanger
The compact cabinet features a tubular
heat exchanger in low, medium and high
heat capacities.
The heat exchanger is fabricated using
stainless steel burners and corrosion-
resistant aluminized steel tubes as
standard on all models. It has an induced
draft blower to pull the gas mixture
through the burner tubes. The heater
has a direct spark ignition system which
doubles as a safety device to prove the
flame.
Flexible Applications
• Only two roof curbs for the 5-10 ton
Precedent line. . .simplifies curb
selection.
•ReliaTel microprocessor controls to
meet either the simple or the more
complex application.
•Low or high gas heat capacities.
• Airflow is outstanding. The Precedent
can replace an older machine with old
ductwork and, in many cases, improve
comfort through better air distribution.
• Belt drive —standard or oversized
supply fan motors meet a wide airflow
range.
• Precedent offers ultimate flexibility.
Options and components are not pre-
packaged at the factory. Units are built
to order in our standard “shortest in
the industry”ship cycle time.

RT-PRC017-EN6
Features and
Benefits
Micro Controls
Several years ago, Trane was the first to
introduce microprocessor controls into
the Light Commercial Market. That
design, along with immeasurable
experience, has provided the technology
for Trane’s second-generation ReliaTel™
microprocessor controls.
ReliaTel Micro:
• Provides unit control for heating,
cooling, and ventilating by utilizing
input from sensors that measure
outdoor and indoor temperature.
• Improves quality and reliability
through the use of time-tested
microprocessor controls and logic.
• Prevents the unit from short cycling,
considerably improving compressor
life.
• Ensures that the compressor will run
for a specific amount of time, which
allows oil to return for better
lubrication, enhancing the reliability of
the compressor.
• Reduces the number of components
required to operate the unit, thereby
reducing possibilities for component
failure.
• Eliminates the need for field-installed
components with its built-in anti-short-
cycle timer, time delay relay and
minimum ‘’on’’ time controls. These
controls are factory tested to assure
proper operation.
• Requires no special tools to run the
Precedent unit through its paces
during testing. Simply place a jumper
between Test 1 and Test 2 terminals on
the Low Voltage Terminal Board and
the unit will walk through its
operational steps. The unit
automatically returns control to the
zone sensor after stepping through the
test mode a single time, even if the
jumper is left on the unit.
• As long as the unit has power and the
LED is lit, the Micro is operational. The
light indicates that the Micro is
functioning properly.
• Features expanded diagnostic
capabilities when used with Trane’s
Integrated Comfort™ Systems.
• As an energy benefit, softens electrical
‘’spikes’’ by staging on fans,
compressors and heaters.
• The Intelligent Fallback or Adaptive
Control is a benefit to the building
occupant. If a component goes astray,
the unit will continue to operate at
predetermined temperature set points.
• Intelligent Anticipation is a standard
feature of the Micro. Functioning
constantly, the Micro and zone sensors
work together in harmony, to provide
tight comfort control.

7RT-PRC017-EN
Features and
Benefits
Factory-installed Options
Hinged Access Doors
These doors permit easy access to the
filter, fan/heat, and compressor/control
sections. They reduce the potential roof
damage from screws or sharp access
door corners.
Economizer
Equipped with either dry bulb, reference
or comparative enthalpy sensing, this
feature provides free cooling as the
outdoor temperature and/or humidity
decreases. Economizers, correctly
installed, offer valuable energy savings.
Factory-installed economizers save time
and ensure proper installation.
Phase Monitor
Phase monitor shall provide 100%
protection for motors and compressors
against problems caused by phase loss,
phase imbalance, and phase reversal.
Phase monitor is equipped with an LED
that provides an ON or FAULT indicator.
Clogged Filter/Fan Fail Switches
These sensors allow a zone sensor
service light or Integrated Comfort
System to indicate a dirty filter or a fan
that’s not working. The field installation
charges for these valuable feedback
devices often eliminate them from
consideration. Factory installation can
make such features a good investment.
COMM3/4 Communication Interface
Available factory or field-installed. This
module, when applied with ReliaTel™,
easily interfaces withTrane’s Integrated
Comfort™ System.
The following options round-out the
complete line of Precedent™ options:
— 0 - 50% Manual or Motorized
Outside Air
— Discharge Air Sensor
— Hail Protection Quality Coil Guards
— Wide array of Zone Sensors and
Thermostats
— Liquid Propane Conversion Kits
— Factory built Roof Curb
One of Our Finest Assets:
Trane Sales Representatives are a
Support group that can assist you with:
— Product
— Application
— Service
— Training
— Special Applications
— Specifications
— Computer Programs and much more
Precedent has the features and benefits
that make it first class in the light
commercial rooftop market. Designed
with input from field contractors and
engineers, its airflow performance is
outstanding.
Precedent…The same Trane
quality…with added flexibility.

RT-PRC017-EN8
Features and
Benefits
VariTrac
WhenTrane’s changeover VAV System
for light commercial applications is
coupled with Precedent, it provides the
latest in technological advances for
comfort management systems and can
allow thermostat control in every zone
served by VariTrac.
• We perform a 100% coil leak test at the
factory. The evaporator and condenser
coils are leak tested at 1375 kPa (200
psig) and pressure tested to 3100 kPa
(450 psig).
• All parts are inspected at the point of
final assembly. Sub-standard parts are
identified and rejected immediately.
• The requirement for cycle testing of
heat exchangers is 10,000 cycles by
ANSI Z21.47. This is the standard
required by both UL and AGA for cycle
test requirments. Trane requires the
design to be tested to 2½ times this
current standard.
• Every unit receives a 100% unit run test
before leaving the production line to
make sure it lives up to rigorousTrane
requirements.
We test designs at our factory not on
our customers!
Quality And Reliability Testing
• All Precedent™designs were rigorously
rain tested at the factory to ensure
water integrity.
• Actual shipping tests were performed
to determine packaging requirements.
Units were test shipped around the
country to determine the best
packaging.
• Factory shake and drop tests were
used as part of the package design
process to help assure that the unit
arrives at the job site in top condition.
• Rigging tests include lifting a unit into
the air and letting it drop one foot,
assuring that the lifting lugs and rails
hold up under stress.
VariTrac ™

9RT-PRC017-EN
Application
Considerations
Heating Operation
The heat exchanger is manufactured
with aluminized steel. To prevent
condensation within the heat exchanger,
do not exceed 50% outside air.
Condensate Trap
The evaporator is a draw-thru
configuration. A trap must be field
provided prior to start-up on the cooling
cycle.
Clearance Requirements
The recommended clearances identified
with unit dimensions should be
maintained to assure adequate service,
maximum capacity and peak operating
efficiency. Actual clearances which
appear inadequate should be reviewed
with the local Trane sales personnel.
Unit Pitch
These units have reversible sloped
condensate drain pans. Units must be
installed level; any unit slope must be
toward side of unit where condensate
drain is connected.
Application of this product should be
within the cataloged airflow and cooling
considerations.
Low Ambient Cooling
The Precedent™line features, as
standard, low ambient cooling down to
-18°C (0°F). Contact your local Trane
Representative for more assistance with
low ambient cooling applications.
Barometric Relief
This product offers an optional
barometric relief damper for use in
conjunction with economizer option.
This option consists of gravity dampers
which open with increased pressure. As
the building air pressure increases, the
pressure in the unit return air section
also increases, opening the dampers and
relieving the conditioned space.
NOTE: THE EFFECTIVENESS OF
BAROMETRIC RELIEF DAMPER DURING
ECONOMIZING OPERATION IS SYSTEM
RELATED. PRESSURE DROP OF THE
RETURN AIR SYSTEM SHOULD BE
CONSIDERED TO CONTROL BUILDING
PRESSURIZATION.

RT-PRC017-EN10
Selection
Procedures - SI Units
Cooling Capacity
Step 1 — Calculate the building’s total
and sensible cooling loads at design
conditions. Use the Trane calculation
form or any other standard accepted
method.
Example: The following are the building
cooling requirements:
a. Electrical Characteristics: 380-415/50/3
b. Summer Design Conditions: Entering
Evaporator Coil: 27° DB/ 19° WB
Outdoor Ambient: 35°
c. Total Cooling Load: 16.5 kW
d. Sensible Cooling Load: 11.8 kW
e. Airflow: 3400 m3/h External Static
Pressure: 125 Pa
f. Downflow Configuration
Step 2 — Size the equipment usingTable
PD-1 to match the cooling loads at
design conditions.
Table PD-1 shows that aYSC060AD has
a gross cooling capacity of 17.8 kW and
14.4 kW sensible capacity at 35 DB
ambient and 3400 m3/h with 27 DB/ 19
WB air entering the evaporator.
Use the following formula to calculate
fan motor heat, which can be found in
the notes in Table PD-8:
Fan motor heat (kW)
= 1.144 x (Fan kW) + 0.132
For example: With 3400 m3/h and 125 Pa,
specified by the engineer, Table PD-8
shows 0.73 kW for a high heat model.
Fan motor heat =
1.144 x 0.73 + 0.132 = 0.97kW
Net Total Cooling =
17.8 kW - 0.97 = 16.8 kW
Net Sensible Cooling Capacity
14.4 kW - 0.97 = 13.4 kW.
Heating Capacity
Step 1 — Calculate the building heating
load using the Trane calculation form or
other standard accepted method.
Step 2 — Size the system heating
capacity to match the calculated
building heating load. The following
are building heating requirements:
a. Total heating load of 17.6 kW
b. 3400 m3/h
c. Fuel - Natural gas
For the YSC060AD there are two
heating capacities available, 19.6 kW
and 29.3 kW input models shown in
Table PD-32. The output capacities of
these furnaces are 15.7 kW and 23.4 kW
respectively.The high heat model with
23.4 kW best matches the building
requirements, indicating a YHC060AD*
should be selected.
Air Delivery Selection
External static pressure drop through
the air distribution system has been
calculated to be 150 Pa. Enter Table PD-
8 for a YSC060AD*H at 3400 m3/h and
150 Pa static pressure. The standard
motor will give the desired airflow.
Accessory Selection
Select accessories needed to
accommodate the application.