American Standard YC 100B Series Owner's manual

YC-IOM-12
18-EB60D14
Library Service Literature
Product Section Unitary
Product Rooftop Lt. Comm.
Model YC
Literature Type Installation/ Oper/ Maint
Sequence 12
Date October 2001
File No. SV-UN-RT-YC-IOM-12 10/01
Supersedes New
Since the manufacturer has a policy of continuous product improve-
ment, it reserves the right to change specifications and design without
notice. The installation and servicing of the equipment referred to in this
booklet should be done by qualified, experienced technicians.
© American Standard Inc. 2001
Models:
YC*150 - 301 (60 Hz)
YC*125 - 250 (50 Hz)
INSTALLATION
OPERATION
MAINTENANCE
Customer Property — Contains wiring, service,
and operation information. Please retain.
Packaged Gas Electric
12-1/2 Thru 25 Ton
IMPORTANT NOTE: All phases of this installation must comply with the NATIONAL, STATE & LOCAL CODES. In
addition to local codes, the installation must conform with National Electric Code -ANSI/NFPA NO. 70 LATEST
REVISION. These units are equipped with an electronic unit control processor, (UCP) that provides service functions
which are significantly different from conventional units. Refer to the TEST MODES and START-UP PROCEDURES
before attempting to operate or perform maintenance on this unit.

2
Table of Contents
Literature Change History ........................................... 3
Unit Description........................................................... 4
Standard Controls Description .................................... 4
System Input Devices & Functions ............................. 4
Unit Inspection ............................................................ 6
Unit Clearances .......................................................... 6
Unit Dimensions & Weight Information ....................... 7
Roof Curb.................................................................. 10
Rigging .......................................................................11
General Unit Requirements........................................11
Factory Installed Economizer.................................... 12
Return Air Smoke Detector ....................................... 12
Main Electrical Power Requirements ........................ 12
Low Voltage Wiring (AC & DC) Requirements .......... 12
Requirements for Gas Heat ...................................... 12
Condensate Drain Connection .................................. 12
Filter Installation ........................................................ 13
Field Installed Power Wiring...................................... 13
Main Unit Power Wiring ............................................ 13
Field Installed Control Wiring .................................... 14
Controls using DC Analog Input/Outputs .................. 14
Controls using DC Communication Links ................. 14
Space Temperature Averaging .................................. 18
Pre-Installation Checklist........................................... 21
Voltage Imbalance..................................................... 21
Electrical Phasing ..................................................... 22
Compressor Crankcase Heaters............................... 22
UnitStart-up .............................................................. 23
Test Modes................................................................ 23
UnitStart-up .............................................................. 25
Verifying Proper Air Flow........................................... 25
Return Air Smoke Detector ....................................... 25
Economizer Start-Up ................................................. 25
UnitStart-up .............................................................. 26
CompressorStart-Up ................................................ 26
Gas Heat Units.......................................................... 26
Final System Setup ................................................... 27
Fan Belt Adjustment .................................................. 27
Maintenance ............................................................. 28
Monthly Maintenance ................................................ 28
Filters ........................................................................ 28
Return Air Smoke Detector Maintenance.................. 28
Cooling Season......................................................... 28
Heating Season ........................................................ 28
Coil Cleaning............................................................. 29
System Status Checkout Procedure ......................... 31
Trouble Shooting ....................................................... 32
Service Failure .......................................................... 32
Simultaneous Heat and Cool Failure ........................ 32
System Failure .......................................................... 32
Heat Failure .............................................................. 32
Cool Failure............................................................... 32
Service Failure .......................................................... 32

3
Literature Change History
YC-IOM-12 (October 2001)
First issue of manual; provides Installation, Operation, and
Maintenance instructions for 12-1/2 through 25 Ton pack-
aged gas/electric units.
Overview of Manual
Note: One copy of this document ships inside the
control panel of each unit and is customer property.
It must be retained by the unit’s maintenance
personnel.
This booklet describes proper installation, operation, and
maintenance procedures for air cooled systems. By carefully
reviewing the information within this manual and following
the instructions, the risk of improper operation and/or compo-
nent damage will be minimized.
It is important that periodic maintenance be performed to
help assure trouble free operation. A maintenance schedule
is provided at the end of this manual. Should equipment fail-
ure occur, contact a qualified service organization with quali-
fied, experienced HVAC technicians to properly diagnose
and repair this equipment.
Note: Do Not release refrigerant to the atmosphere!
If adding or removing refrigerant is required, the
service technician must comply with all federal,
state, and local laws.
General Information
Model Number Description
All products are identified by a multiple-character model
number that precisely identifies a particular type of unit. An
explanation of the alphanumeric identification code is pro-
vided below. Its use will enable the owner/operator, installing
contractors, and service engineers to define the operation,
specific components, and other options for any specific unit.
When ordering replacement parts or requesting service, be
sure to refer to the specific model number and serial number
printed on the unit nameplate.

4
General Information
Unit Nameplate
A Mylar unit nameplate is located on the unit’s corner
support just above the main power entrance access into the
control panel. It includes the unit model number, serial
number, electrical characteristics, refrigerant charge, as well
as other pertinent unit data.
Compressor Nameplate
The nameplate for the compressors are located on the com-
pressor terminal box.
Hazard Identification
Warnings are provided throughout this manual to indi-
cate to installing contractors, operators, and service
personnel of potentially hazardous situations which, if
not avoided, COULD result in death or serious injury.
Cautions are provided throughout this manual to indi-
cate to installing contractors, operators, and service
personnel of potentially hazardous situations which, if
not avoided, MAY result in minor or moderate injury.
Unit Description
Before shipment, each unit is leak tested, dehydrated,
charged with refrigerant and compressor oil, and run tested
for proper control operation.
The condenser coils are aluminum fin, mechanically bonded
to copper tubing.
Direct-drive, vertical discharge condenser fans are provided
with built-in thermal overload protection.
Standard Controls Description
Standard controls for these units is a microelectronic control
system that is referred to as “Unit Control Processor” (UCP).
The acronym UCP is used extensively throughout this docu-
ment when referring to the control system network.
These modules through Proportional/Integral control algo-
rithms perform specific unit functions that governs unit op-
eration in response to; zone temperature, supply air tem-
perature, and/or humidity conditions depending on the appli-
cation. The stages of capacity control for these units is
achieved by starting and stopping the compressors.
The UCP is mounted in the control panel and is factory wired
to the respective internal components. The UCP receives
and interpret information from other unit modules, sensors,
remote panels, and customer binary contacts to satisfy the
applicable request for cooling.
UEM - Unit Economizer Module (Optional)
The UEM monitors the supply air temperature, return air
temperature, minimum position setpoint (local or remote),
power exhaust setpoint, ambient dry bulb/enthalpy sensor or
comparative humidity (return air humidity against ambient
humidity) sensors, if selected, to control the dampers to an
accuracy of +/- 5% of the stroke. The actuator is spring re-
turned to the closed position any time power is lost to the
unit. It is capable of delivering up to 25 inch pounds of torque
and is powered by 24 VAC. Refer to the sequence of opera-
tion “Cooling with an Economizer” for the proper DIP Switch
settings for dry bulb/Enthalpy control.
CTI - Conventional Thermostat Interface (Optional)
This module is a field installed option to allow some conven-
tional thermostats to be used in conjunction with the. It uti-
lizes the conventional wiring scheme of R, Y1, Y2, W1, W2/
X, and G.
Applicable thermostats to be used with the CTI module are:
Vendor Part # Trane Part #
Honeywell T7300
Honeywell T874D1082 BAYSTAT011
Enerstat MS-1N BAYSTAT003
TCI - Trane Communication Interface (Optional)
This module is used when the application calls for either an
ICSTM building management type control system and/or a
High Temperature limit device. It allows the control and moni-
toring of the system through an ICS panel. The module can
be ordered from the factory or ordered as a kit to be field in-
stalled. Follow the installation instruction that ship with each
kit when field installation is necessary.
System Input Devices & Functions
The UCP must have a mode input in order to operate the
rooftop unit. The flexibility of having several mode capabili-
ties depends upon the type of sensor and/or remote panel
selected to interface with the UCP. The possibilities are: Fan
selection ON or AUTO. System selection HEAT, COOL,
AUTO, and OFF.
The descriptions of the following basic Input Devices used
within the UCP network are to acquaint the operator with
their function as they interface with the various modules. Re-
fer to the unit’s electrical schematic for the specific module
connections.
The following controls are available from the factory for field
installation.
Supply Fan Failure Input (Optional)
The Fan Failure Switch can be connected Actively or Pas-
sively to sense indoor fan operation:
Passive - FFS (Fan Failure Switch) When the fan proving
switch is connected to the Fan/Filter Status terminal (J5-1)
on the UCP, if air flow through the unit is not proven by
the differential pressure switch (factory set point 0.05 “
w.c.) within 40 seconds nominally, the UCP will energize
the clogged filter output and the LED at the remote panel
will be turned “On”.

5
General Information
Active - AFF (Active Fan Failure) When the fan proving
switch is connected across terminals J5-3 & J5-4 on the
unit economizer module (UEM), if air flow through the unit
is not proven by the differential pressure switch (factory
set point 0.05 “ w.c.) within 40 seconds nominally, the
UCP will shut off all mechanical operations, lock the sys-
tem out, send a diagnostic to ICS, and the SERVICE LED
will flash. The system will remain locked out until a reset
is initiated either manually or through ICS.
Clogged Filter Switch (Optional)
The unit mounted clogged filter switch monitors the pressure
differential across the return air filters. It is mounted in the fil-
ter section and is connected to the UCP. A diagnostic SER-
VICE signal is sent to the remote panel if the pressure differ-
ential across the filters is at least 0.5" w.c.. The contacts will
automatically open when the pressure differential across the
filters decreases to approximately 0.4" w.c.. The switch dif-
ferential can be field adjusted between 0.17" w.c. to 5.0" w.c.
± 0.05" w.c. to correspond to the desired dirty filter condition.
The clogged filter output is energized when the supply fan is
operating and the clogged filter switch has been closed for at
least 2 minutes. The system will continue to operate regard-
less of the status of the filter switch.
Compressor Disable (CPR1/2)
This input incorporates the low pressure control (LPC) of
each refrigeration circuit and can be activated by opening a
field supplied contact installed in series with the LPC.
If this circuit is open before the compressor is started, the
compressor will not be allowed to operate. Anytime this cir-
cuit is opened for 5 continuous seconds during compressor
operation, the compressor for that circuit is immediately
turned “Off”. The compressor will not be allowed to restart for
a minimum of 3 minutes should the LPC close.
If four consecutive open conditions occur during the first
three minutes of operation, the compressor for that circuit will
be locked out, a diagnostic communicated to the remote
panel (if installed), and a manual reset will be required to re-
start the compressor.
Low Pressure Control
This input incorporates the low pressure and can be acti-
vated by opening a field supplied contact.
Anytime this circuit is opened for 5 continuous seconds, the
compressor for that circuit is turned off immediately. The
compressor will not be allowed to restart for a minimum of 3
minutes.
If four consecutive open conditions occur during the first
three minutes of operation, the compressor will be locked
out, a diagnostic communicated to ICSTM if applicable, and a
manual reset will be required to restart the compressor.
High Pressure Control
The high pressure controls are wired in series between the
compressor outputs on the UCP and the compressor
contactor coils. If the high pressure control switch opens, the
UCP senses a lack of current while calling for cooling and
locks the compressor out.
On dual circuit units, if the high pressure control opens, the
compressor on the affected circuit is locked out. Amanual re-
set for the affected circuit is required.
Power Exhaust Control (Optional)
The power exhaust fan is started whenever the position of
the economizer dampers meets or exceed the power ex-
haust set point when the indoor fan is on.
The set point panel is located in the return air section and is
factory set at 25%.
Lead/Lag Control (Dual Circuit Only)
Lead/Lag is a selectable input located on the UCP. The UCP
is configured from the factory with the Lead/Lag control dis-
abled. To activate the Lead/Lag function, simply cut the wire
(52F) connected to J1-7 at the UCP. When it is activated,
each time the designated lead compressor is shut off due to
the load being satisfied, the lead compressor or refrigeration
circuit switches. When the UCP is powered up, i.e. after a
power failure, the control will default to the number one cir-
cuit compressor.
Remote Zone Sensor (BAYSENS016A)
This bullet type temperature sensor can be used for; outside
air (ambient) sensing, return air temperature sensing, supply
air temperature sensing, remote temperature sensing (un-
covered. Wiring procedures vary according to the particular
application and equipment involved. Refer to the unit’s wiring
diagrams for proper connections.
Remote Zone Sensor (BAYSENS017B)
This electronic sensor can be used with BAYSENS006B,
008B, 010B, 019A, 020A, or 021A Remote Panels. When
this sensor is wired to a BAYSENS019A or BAYSENS020A
Remote Panel, wiring must be 18 AWG Shielded Twisted
Pair (Belden 8760 or equivalent). Refer to the specific Re-
mote Panel for wiring details.

6
General Information
Unit Inspection
As soon as the unit arrives at the job site
[ ] Verify that the nameplate data matches the data on the
sales order and bill of lading (including electrical data).
[ ] Verify that the power supply complies with the unit name-
plate specifications.
[ ] Visually inspect the exterior of the unit, including the roof,
for signs of shipping damage.
[ ] Check for material shortages. Refer to the Component
Layout and Shipwith Location illustration.
PRODUCT CONTAINS FIBERGLASS WOOL!
Disturbing the Insulation in this product during in-
stallation, maintenance or repair will expose you to
airborne particles of glass wool fibers and ceramic
fibers known to the state of California to cause can-
cer through inhalation. Glasswool fibers may also
cause respiratory, skin or eye irritation.
Precautionary Measures
-Avoid breathing fiberglass dust.
-Use a NIOSH approved dust/mist respirator.
-Avoid contact with the skin or eyes. Wear long-
sleeved, loose-fitting clothing, gloves, and eye
protection.
-Wash clothes separately from other clothing:
rinse washer thoroughly.
-Operations such as sawing, blowing, tear-out, and
spraying may generate fiber concentrations requiring
additional respiratory protection. Use the appropriate
NIOSH approved respiration in these situations.
First Aid Measures
Eye Contact - Flush eyes with water to remove
dust. If symptoms persist, seek medical attention.
Skin Contact - Wash affected areas gently with soap
and warm water after handling.
If the job site inspection of the unit reveals damage or mate-
rial shortages, file a claim with the carrier immediately.
Specify the type and extent of the damage on the “bill of lad-
ing” before signing.
[ ] Visually inspect the internal components for shipping dam-
age as soon as possible after delivery and before it is
stored. Do not walk on the sheet metal base pans.
NO STEP SURFACE!
FOR ACCESS TO COMPONENTS, THE BASE SHEET
METAL SURFACE MUST BE REINFORCED.
Bridging between the unit's main supports may
consist of multiple 2 by 12 boards or sheet metal
grating.
Failure to comply can cause severe personal injury or
death from falling.
[ ] If concealed damage is discovered, notify the carrier’s ter-
minal of damage immediately by phone and by mail. Con-
cealed damage must be reported within 15 days.
Request an immediate joint inspection of the damage by
the carrier and the consignee. Do not remove damaged
material from the receiving location. Take photos of the
damage, if possible. The owner must provide reasonable
evidence that the damage did not occur after delivery.
[ ] Notify the appropriate sales representative before install-
ing or repairing a damaged unit.
Storage
Take precautions to prevent condensate from forming inside
the unit’s electrical compartments and motors if:
a. the unit is stored before it is installed; or,
b. the unit is set on the roof curb, and temporary heat is
provided in the building. Isolate all side panel service
entrances and base pan openings (e.g., conduit
holes, S/A and R/A openings, and flue openings) from
the ambient air until the unit is ready for startup.
Note: Do not use the unit’s heater for temporary
heat without first completing the startup procedure
detailed under “Starting the Unit”.
The manufacturer will not assume any responsibility for
equipment damage resulting from condensate accumulation
on the unit’s electrical and/or mechanical components.
Unit Clearances
Figure 3-1 illustrates the minimum operating and service
clearances for either a single or multiple unit installation.
These clearances are the minimum distances necessary to
assure adequate serviceability, cataloged unit capacity, and
peak operating efficiency.
Providing less than the recommended clearances may result
in condenser coil starvation, “short-circuiting” of exhaust and
economizer airflows, or recirculation of hot condenser air.

7
General Information
Unit Dimensions & Weight Information
Overall unit dimensional data for each unit is illustrated in Fig-
ure 3-2.
A Center-of-Gravity illustration and the dimensional data is
shown in Figure 3-5.
Table 3-1 lists the typical unit operating and point loading
weights.
Figure 3-1
Typical Installation Clearances for Single & Multiple Unit
Applications

8
General Information
Figure 3-2
Unit Dimensional Data
UNITS A B C D E F G H J K
YC*100B 63-5/16 93 -3/4 13/16 49 25 -5/8 2 -3/16 8 -3/8 44 -15/16 51 -5/16 2
YC*125C 49 63-5/16 94-5/16 39-3/8 6-13/16 13/16 8-3/8 2-3/16 28-5/8 2
YC*150D,151C 50-1/8 71-5/16 107-5/16 48-3/8 6-5/8 13/16 8-3/8 2-11/16 29-5/16 2
YC*155B,175C
YC*180B,210C
YC*181C,200B 54 85-5/16 122-5/16 64-1/2 6-13/16 13/16 8-15/16 2-11/16 33-3/16 3
YC*211C,240B
YC*241C,250B
YC*300B,301C
* Downflow orHorizontal

9
General Information
Table 3-1
Typical Unit Weights & Point Loading Data
Unit Net Corner Wts. (lbs)
ModelsWeightABCD
YC*100B 1247 425 331 215 276
YC*125C 1300 430 342 234 294
YC*150D 1458 495 373 254 336
YC*151C 1547 523 383 271 370
YC*155B 1538 535 387 259 357
YC*180B 1665 600 395 266 404
YC*181C 2005 686 504 345 470
YC*175C 1619 553 415 279 372
YC*210C 1821 618 463 317 424
YC*211C 2088 701 538 369 480
YC*200B 2025 714 532 333 447
YC*240B 2088 738 526 343 481
YC*241C 2186 751 568 373 494
YC*250B 2082 721 552 351 458
YC*300B 2082 721 552 351 458
YC*301C 2191 755 569 373 495
* Downflow or Horizontal
Note: Corner weights are given for information only.
Unitis to be supported continuouslybya curb or
equivalentframe support.
Foundation
Horizontal Units
If the unit is installed at ground level, elevate it above the
snow line. Provide concrete footings at each support location
with a “full perimeter” support structure or a slab foundation
for support. Refer to Table 3-1 for the unit’s operating and
point loading weights when constructing a footing foundation.
Anchor the unit to the slab using hold down bolts or isolators.
Isolators should be installed to minimize the transmission of
vibrations into the building.
For rooftop applications, ensure the roof is strong enough to
support the combined unit and support structural weight. Re-
fer to Table 3-1 for the unit operating weights. Anchor the unit
to the roof with hold-down bolts or isolators.
Check with a roofing contractor for proper waterproofing pro-
cedures.
Ductwork
Figure 3-3 illustrates the supply and return air openings as
viewed form the rear of the unit. Refer to Table 3-2 for the
unit opening dimensional data.
Elbows with turning vanes or splitters are recommended to
minimize air noise due to tubulance and to reduce static
pressure. The first elbow in the ductwork leaving the unit
should be downstream of the supply air opening at least 3-1/
2 times the diameter of the supply fan.
When attaching the ductwork to the unit, provide a water
tight flexible connector at the unit to prevent operating
sounds from transmitting through the ductwork.
All outdoor ductwork between the unit and the structure
should be weather proofed after installation is completed.
Figure 3-3
Horizontal Unit Supply & Return Air Openings

10
General Information
Table 3-2
Horizontal Unit Supply & Return Air Opening Dimensional Data
UNITS A B C D E F G H
YCH100B 22-1/2 18 17-3/16 2 3-15/16 41-7/16 16
YCH125C
YCH150D,151C 26-1/2 19-9/16 24-9/16 2 3-15/16 42-1/2 6
YCH155B,180B
YCH175C,210C
YCH181C,200B 26-1/2 24-1/16 27-9/16 2 3-15/16 46-7/16 5-3/8
YCH211C,240B
YCH241C,250B
YCH300B,301C
Roof Curb
Downflow
The roof curbs for these units consists of a “full perimeter”
enclosure to support the unit.
Before installing any roof curb, verify;
1. That it is the correct curb for the unit,
2. That it includes the necessary gaskets and
hardware,
3. That the purposed installation location provides
the required clearance for proper operation.
4. Insure that the curb is level and square. The top
surface of the curb must be true to assure an
adequate curb-to-unit seal.
Step-by-step curb assembly and installation instructions ship
with each accessory roof curb kit. Follow the instructions
carefully to assure proper fit-up when the unit is set into
place.
Note: To assure proper condensate flow during
operation, the unit (and curb) must be as level as
possible.
If the unit is elevated, a field constructed catwalk around the
unit is strongly recommended to provide easy access for unit
maintenance and service.
Recommendations for installing the Supply Air and Return
Air ductwork joining the roof curb are included in the curb in-
struction booklet. Curb ductwork must be fabricated and in-
stalled by the installing contractor before the unit is set into
place.
Note: For sound consideration, cut only the holes in
the roof deck for the ductwork penetrations. Do not
cut out the entire roof deck within the curb
perimeter.
If a Curb Accessory Kit is not used:
a. The ductwork can be attached directly to the factory-
provided flanges around the unit’s supply and return
air openings. Be sure to use flexible duct connections
at the unit.
b. For “built-up” curbs supplied by others, gaskets must
be installed around the curb perimeter flange and the
supply and return air opening flanges.
Ductwork
Figure 3-4 illustrates the supply and return air openings as
viewed form the top of the unit. Refer to Table 3-3 for the unit
opening dimensional data.
Elbows with turning vanes or splitters are recommended to
minimize air noise due to tubulance and to reduce static
pressure. The first elbow in the ductwork leaving the unit
should be downstream of the supply air opening at least 3-1/
2 times the diameter of the supply fan.
Figure 3-4
Downflow Unit Supply & Return Air Openings