Ingersoll-Rand YSC033G Installation and operating instructions

SAFETY WARNING
Only qualified personnel should install and service the equipment. The installation, starting up, and servicing
of heating, ventilating, and air-conditioning equipment can be hazardous and requires specific knowledge and
training. Improperly installed, adjusted or altered equipment by an unqualified person could result in death or
serious injury. When working on the equipment, observe all precautions in the literature and on the tags,
stickers, and labels that are attached to the equipment.
Installation, Operation,
and Maintenance
Packaged Rooftop Air Conditioners
Precedent™ — Cooling and Gas/Electric
3to10Tons–60Hz
Model Numbers YSC033G - YSC063G YHC037E - YHC067E
YSC036 - YSC060G YHC036E - YHC072E
YSC072F - YSC120F YHC120F
YHC048F - YHC060F YHC072F - YHC102F
RT-SVX21U-EN
May 2016

© 2016 Ingersoll Rand All rights reserved RT-SVX21U-EN
Introduction
Read this manual thoroughly before operating or servicing
this unit.
Warnings, Cautions, and Notices
Safety advisories appear throughout this manual as
required.Your personal safety and the proper operation of
this machine depend upon the strict observance of these
precautions.
Important Environmental Concerns
Scientific research has shown that certain man-made
chemicals can affect the earth’s naturally occurring
stratospheric ozone layer when released to the
atmosphere. In particular, several of the identified
chemicals that may affect the ozone layer are refrigerants
that contain Chlorine, Fluorine and Carbon (CFCs) and
those containing Hydrogen, Chlorine, Fluorine and
Carbon (HCFCs). Not all refrigerants containing these
compounds have the same potential impact to the
environment.Trane advocates the responsible handling of
all refrigerants-including industry replacements for CFCs
such as HCFCs and HFCs.
Important Responsible Refrigerant
Practices
Trane believes that responsible refrigerant practices are
important to the environment, our customers, and the air
conditioning industry. All technicians who handle
refrigerants must be certified.The Federal Clean Air Act
(Section 608) sets forth the requirements for handling,
reclaiming, recovering and recycling of certain
refrigerants and the equipment that is used in these
service procedures. In addition, some states or
municipalities may have additional requirements that
must also be adhered to for responsible management of
refrigerants. Know the applicable laws and follow them. Copyright
This document and the information in it are the property of
Trane, and may not be used or reproduced in whole or in
part without written permission.Trane reserves the right
to revise this publication at any time, and to make changes
The three types of advisories are defined as follows:
WARNING Indicates a potentially hazardous
situation which, if not avoided, could
result in death or serious injury.
CAUTIONsIndicates a potentially hazardous
situation which, if not avoided, could
result in minor or moderate injury. It
could also be used to alert against
unsafe practices.
NOTICE Indicates a situation that could result in
equipment or property-damage only
accidents.
WARNING
Proper Field Wiring and Grounding
Required!
Failure to follow code could result in death or serious
injury. All field wiring MUST be performed by qualified
personnel. Improperly installed and grounded field
wiring poses FIRE and ELECTROCUTION hazards.To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes.
WARNING
Personal Protective Equipment (PPE)
Required!
Failure to wear proper PPE for the job being undertaken
could result in death or serious injury. Technicians, in
order to protect themselves from potential electrical,
mechanical, and chemical hazards, MUST follow
precautions in this manual and on the tags, stickers,
and labels, as well as the instructions below:
• Before installing/servicing this unit, technicians
MUST put on all PPE required for the work being
undertaken (Examples; cut resistant gloves/sleeves,
butyl gloves, safety glasses, hard hat/bump cap, fall
protection, electrical PPE and arc flash clothing).
ALWAYS refer to appropriate Material Safety Data
Sheets (MSDS)/Safety Data Sheets (SDS) and OSHA
guidelines for proper PPE.
• When working with or around hazardous chemicals,
ALWAYS refer to the appropriate MSDS/SDS and
OSHA/GHS (Global Harmonized System of
Classification and Labelling of Chemicals) guidelines
for information on allowable personal exposure
levels, proper respiratory protection and handling
instructions.
• If there is a risk of energized electrical contact, arc, or
flash, technicians MUST put on all PPE in accordance
with OSHA, NFPA 70E, or other country-specific
requirements for arc flash protection, PRIOR to
servicing the unit. NEVER PERFORM ANY
SWITCHING, DISCONNECTING, OR VOLTAGE
TESTING WITHOUT PROPER ELECTRICAL PPE AND
ARC FLASH CLOTHING. ENSURE ELECTRICAL
METERS AND EQUIPMENT ARE PROPERLY RATED
FOR INTENDED VOLTAGE.

Introduction
RT-SVX21U-EN 3
to its content without obligation to notify any person of
such revision or change.
Trademarks
All trademarks referenced in this document are the
trademarks of their respective owners.
Revision History
• Added Air-Fi™ Wireless Communication Interface
• Unit start-up, removal of MMC
• Limited warranty updates

4 RT-SVX21U-EN
Table of Contents
Model Number Descriptions - 3 to 10 Tons (T/Y)
6
Model Number Notes ................. 7
Model Number Descriptions - 3 to 5 Tons (T/Y -
17 Plus) ................................. 9
Model Number Notes ................ 10
General Information .................... 11
Unit Inspection ..................... 11
Storage ........................... 11
Unit Nameplate .................... 11
Compressor Nameplate .............. 11
Microchannel Coil Barcode ID ......... 11
Unit Description .................... 11
Economizer Control Actuator (Optional) 11
System Input Devices & Functions ..... 12
Low Pressure Control ................ 13
High Pressure Control ............... 13
Power Exhaust Control (Optional) ..... 13
Lead/Lag Control (Dual Circuit Only) . . . 13
Evaporator Frost Control ............. 14
Discharge Line Temp Switch (DLTS) . . . 15
Smoke Detector Sensor (Optional) ..... 15
Phase Monitor ..................... 15
Single Zone Variable Air Volume / Displace-
ment Ventilation (Optional) ........... 15
Human Interface - 5 Inch Color Touchscreen
(Optional) ......................... 15
Unit Dimensions ........................ 16
Installation ............................. 24
Pre-Installation ....................... 24
Procedure ........................... 24
Foundation .......................... 26
Horizontal Units .................... 26
Ductwork ............................ 27
Roof Curb ........................... 28
Downflow ......................... 28
Rigging ........................... 29
General Unit Requirements ............ 29
Factory Installed Economizer ..........30
Temperature Limit Switch Usage for Gas
Heat Units ..........................30
Horizontal Discharge Conversion (3 to 5 Ton
Units) ................................31
TCO1 Instructions .....................31
Horizontal Discharge Conversion (6 to 10 Ton
Units) ................................32
TCO1 Instructions .....................33
Return Air Smoke Detector .............33
Air-Fi™ Wireless Communication Interface 34
Main Electrical Power Requirements .....34
Through-the-Base Gas Installation .......35
Requirements for Gas Heat .............35
Condensate Drain Configuration .........36
Filter Installation ......................36
Field Installed Power Wiring ............37
Main Unit Power ......................37
Standard Wiring .....................37
Optional TBUE Wiring (Through-the-Base
Electrical Option) ....................37
Field-Installed Control Wiring ..........38
Control Power Transformer ...........38
Controls Using 24 VAC ...............38
Controls using DC Analog Input/Outputs
(Standard Low Voltage Multi
conductor Wire) .....................39
DC Conductors ......................39
Space Temperature Averaging (ReliaTel™ On-
ly) ...................................44
Pre-Start ................................47
Voltage Imbalance .....................47
Electrical Phasing (Three Phase Motors) ..47
Compressor Crankcase Heaters (Optional) 48
ReliaTel™ Controls ..................48
Test Modes ...........................49
ReliaTel™ Controls ..................49
Electromechanical Controls Test
Procedure ..........................50

Table of Contents
RT-SVX21U-EN 5
Unit Start-Up ........................... 51
Verifying Proper Air Flow .............. 51
Units with 5-Tap Direct Drive Indoor Fan 51
Units with Belt Drive Indoor Fan ....... 51
Units with Direct Drive Indoor Fan - Electro-
mechanical Control ................. 52
ReliaTel™ Units with Direct Drive Indoor Fan
(10 Tons Standard Efficiency, 6(074) to 10
Tons High Efficiency) ................ 52
Units with Constant CFM Direct Drive Indoor
Fan ............................... 53
17 Plus units with the constant CFM direct
drive indoor fan .................... 53
Variable Air Volume Applications (Traditional
VAV) .............................. 54
Supply Duct Static Pressure Control .... 55
Traditional VAV Standalone Operation . 55
Supply Air Temperature Reset ........ 55
Return Air Smoke Detector ........... 55
Economizer Start-Up ................ 56
Compressor Start-Up ................ 57
Dehumidification Option ............. 57
Gas Heat Units ..................... 57
Final System Setup ................. 57
Maintenance ........................... 59
Fan Belt Adjustment - Belt Drive Units ... 59
Monthly Maintenance ................. 60
Filters ............................. 60
Return Air Smoke Detector Maintenance 60
Condensate Overflow Switch ......... 60
Cooling Season .................... 60
Heating Season .................... 60
Coil Cleaning ....................... 61
Annual Maintenance .................. 62
Troubleshooting ........................ 63
ReliaTel™ Control .................... 63
System Status Checkout Procedure ..... 63
Method 1 .......................... 63
Resetting Cooling and Ignition Lockouts 65
Zone Temperature Sensor (ZTS) Service Indi-
cator ................................ 65
Clogged Filter Switch .................65
Fan Failure Switch ...................65
Condensate Overflow Switch ..........65
Zone Temperature Sensor (ZTS) Tests ...65
Test 1 - Zone Temperature Thermistor
(ZTEMP) ...........................65
Test 2 - Cooling Set Point (CSP) and Heating
Set Point (HSP) ......................65
Test 3 - System Mode and Fan Selection .65
Test 4 - LED Indicator Test, (SYS ON, HEAT,
COOL & SERVICE) ...................66
Relative Humidity Sensor Test .........66
Programmable & Digital Zone Sensor
Test ...............................66
ReliaTel™ Refrigeration Module (RTRM) De-
fault Chart ..........................66
Unit Operation without a Zone Sensor . .66
Unit Economizer Control (ECA) Troubleshoot-
ing ...................................67
ReliaTel™ Control ...................67
Electromechanical Control ............67
Unit Economizer Control (ECA) Test Proce-
dures ................................69
Electromechanical Control ............69
Troubleshooting procedures for Direct Drive
Plenum Fan ...........................69
Unit Wiring Diagrams Numbers ...........70
Limited Warranty ........................73
Combination Gas Electric Air Conditioner .73
YCD, YCH, YSC and YHC (Parts Only) . . .73
Models Less Than 20 Tons for Commercial
Use* ..............................73

6 RT-SVX21U-EN
Model Number Descriptions-3to10Tons(T/Y)
Digit 1 - Unit Type
T DX Cooling
Y DX Cooling, Gas Heat
Digit2-Efficiency
S Standard Efficiency
H High Efficiency
Digit 3 - Airflow
C Convertible
Digit 4,5,6 - Nominal Gross
Cooling Capacity (MBh)
033 3Ton (13 SEER)
036 3Ton
043 4Ton (13 SEER)
048 4Ton
060 5Ton
063 5Ton (13 SEER)
072 6Ton
074 6Ton, Dual Compressor
090 7½Ton, Single Compressor
092 7½Ton, Dual Compressor
102 8½ Ton
120 10Ton
Digit 7 - Major Design Sequence
E R-410A Refrigerant
F MicrochannelType Condenser
Coils24
G MicrochannelType Evaporator and
Condenser Coils
Digit 8 - Voltage Selection
1 208/230/60/1
3 208-230/60/3
4 460/60/3
W 575/60/3
Digit 9 - Unit Controls
E Electromechanical
R ReliaTel™ Microprocessor
Digit 10 - Heating Capacity
Note: Applicable to Digit 1,T models
only
0 No Electric Heat
A 5 kW (1 phase)1
B 6 kW (3 phase)
C 9 kW (3 phase)
D 10 kW (1 phase)1
E 12 kW (3 phase)
F 14 kW (1 phase)1
G 18 kW (1&3 phase)
J 23 kW (3 phase)
K 27 kW (3 phase)
N 36 kW (3 phase)
P 54 kW (3 phase)
Note: Applicable to Digit 1,Y models
only
L Low Heat
M Medium Heat
H High Heat
X Low Heat, Stainless Steel Heat
Exchanger
Y Medium Heat, Stainless Steel Heat
Exchanger
Z High Heat, Stainless Steel Heat
Exchanger
Digit 11 - Minor Design
Sequence
A First Sequence21
B Second Sequence20
Digit 12,13 - Service Sequence
** Factory Assigned
Digit 14 - Fresh Air Selection
0 No Fresh Air
A Manual Outside Air Damper 0-50%4
B Motorized Outside Air Damper
0-50%29
C Economizer, Dry Bulb 0-100%
without Barometric Relief7
D Economizer, Dry Bulb 0-100% with
Barometric Relief7
E Economizer, Reference Enthalpy
0-100% without Barometric Relief3,7
F Economizer, Reference Enthalpy
0-100% with Barometric Relief3,7
G Economizer, Comparative Enthalpy
0-100% without Barometric Relief3,7
H Economizer, Comparative Enthalpy
0-100% with Barometric Relief3,7
K Low Leak Economizer with
Barometric Relief
M Low Leak Economizer with Reference
Enthalpy with Barometric Relief
P Low Leak Economizer with
Comparative Enthalpy with
Barometric Relief
Digit 15 - Supply Fan/DriveType/
Motor
0 Standard Drive6
1 Oversized Motor
2 Optional Belt Drive Motor18
6 Single Zone VAV27,34
7 Multi-Speed Indoor Fan28
E VAV Supply AirTemperature Control
Standard Motor34
Digit 16 - Hinged Service
Access/Filters
0 Standard Panels/Standard Filters
A Hinged Access Panels/Standard
Filters
B Standard Panels/2” MERV 8 Filters
C Hinged Access Panels/2” MERV 8
Filters
D Standard Panels/2” MERV 13 Filters
E Hinged Access Panels/2” MERV 13
Filters
Digit 17 - Condenser Coil
Protection
0 Standard Coil
1 Standard Coil with Hail Guard
2 Black Epoxy Pre-Coated Condenser
Coil26
3 Black Epoxy Pre-Coated
Condenser Coil with Hail Guard26
4 CompleteCoat™ Condenser Coil
5 CompleteCoat™ Condenser Coil
with Hail Guard
Digit 18 - Through-the-Base
Provisions
Note: Applicable to Digit 1,T orY
models
0 NoThrough-the-Base Provisions
A Through-the-Base Electric8
Note: Applicable to Digit 1,Y models
only
B Through-the-Base Gas Piping16
C Through-the-Base Electric and Gas
Piping16
Digit 19 - Disconnect/Circuit
Breaker (three-phase only)
0 No Disconnect/No Circuit Breaker
1 Unit Mounted Non-Fused
Disconnect8
2 Unit Mounted Circuit Breaker8
Digit 20 - Convenience Outlet
0 No Convenience Outlet
A Unpowered Convenience Outlet
B Powered Convenience Outlet
(three-phase only)9
Digit 21 - Communications
Options3
0 No Communications Interface
1 Trane® Communications Interface
2 LonTalk® Communications
Interface
3 Novar 2024 Controls31
4 Novar 3051 Controls without Zone
Sensor31
5 Novar 3051Controls Interface with
DCV31
6 BACnet® Communications Interface
7 Air-Fi™ Wireless Communications35
Digit 22 - Refrigeration System
Option
0 Standard Refrigeration System10
B Dehumidification Option22,23
Digit 23 - Refrigeration Controls
Note: Applicable to Digit7=E,F,G
0 No Refrigeration Control5
1 Frostat™11 ,30
2 Crankcase Heater2
3 Frostat™11 ,30 and Crankcase Heater2
Digit 24 - Smoke Detector17
0 No Smoke Detector
A Return Air Smoke Detector12,13
B Supply Air Smoke Detector
C Supply and Return Air Smoke
Detectors12,13
D Plenum Smoke Detector

Model Number Descriptions-3to10Tons(T/Y)
RT-SVX21U-EN 7
Digit 25 - System Monitoring
Controls
0 No Monitoring Control14
1 Clogged Filter Switch14
2 Fan Failure Switch14
3 Discharge Air SensingTube14
4 Clogged Filter Switch and Fan
Failure Switch14
5 Clogged Filter Switch and Discharge
Air SensingTube14
6 Fan Failure Switch and Discharge Air
SensingTube14
7 Clogged Filter Switch, Fan Failure
Switch and Discharge Air
SensingTube14
8 Novar Return Air Sensor
(NOVAR 2024)15,31
9 Novar Zone Temp Sensor
(NOVAR 3051)19,31
A Condensate Drain Pan Overflow
Switch
B Clogged Filter Switch14 and
Condensate Drain Pan Overflow
Switch
C Fan Failure Switch14 and Condensate
Drain Pan Overflow Switch
D Discharge Air Sensing14 and
Condensate Drain Pan Overflow
Switch
E Clogged Filter Switch14, Fan Failure
Switch14 and Condensate Drain Pan
Overflow Switch
F Clogged Filter Switch14, Discharge
Air SensingTube14 and Condensate
Drain Pan Overflow Switch
G Fan Failure Switch, Discharge Air
SensingTube14 and Condensate
Drain Pan Overflow Switch
H Clogged Filter Switch14, Fan Failure
Switch14, Discharge Air Sensing14
and Condensate Drain Pan Overflow
Switch
Digit 26 - System Monitoring
Controls
0 No Monitoring Controls
A Demand Control Ventilation
(CO2)32,33
B Low Leak Economizer with FDD
(Fault Detection & Diagnostics)
C FDD (Fault Detection & Diagnostics)
with DCV (Demand Control
Ventilation)
Digit 27 - Unit Hardware
Enhancements
0 No Enhancements
1 Stainless Steel Drain Pan
Digit 31 - Advanced Unit
Controls
0 Standard Unit Controls
1 Human Interface
Model Number Notes
1. Available on 3 to 5 ton models.
2. Crankcase heaters are optional
on (T,Y)SC (036, 048, 060, 072,
090, 102, 120); standard on
(T,Y)HC (036, 048, 060, 072, 074,
092, 102, 120).
3. Not available with
electromechanical controls.
4. Manual outside air damper will
ship factory supplied within the
unit, but must be field installed.
5. High pressure control is standard
on all units.
6. Multi-speed, direct drive motor
with no belt drive option is
standard on 3 to 5 ton, standard
efficiency, 13/14 SEER units.
Multi-speed, direct drive motor
with a belt drive option is
available for 3 to 5 ton, 15 SEER
units. On 6 to 10 tons, multispeed
direct drive is standard on all 10
ton and 6 (074) to 8½ ton high
efficiency. Belt drive is standard
on all other units.
7. Economizer with barometric
relief is for downflow configured
units only. Order economizer
without barometric relief for
horizontal configuration.
Barometric relief for horizontal
configured units must be ordered
as field installed accessory.
8. Through-the-base electric
required when ordering
disconnect/circuit breaker
options.
9. Requires use of disconnect or
circuit breaker.
10. Standard metering devices are
TXVs.
11. Frostat™ cannot be field installed
in electro-mechanical units.
12. The return air smoke detector
may not fit up or work properly on
the Precedent™ units when used
in conjunction with 3rd party
accessories such as bolt on heat
wheels, economizers and power
exhaust. Do not order the return
air smoke detectors when using
this type of accessory.
13. Return air smoke detector cannot
be ordered with Novar controls.
14. These options are standard when
ordering Novar controls.
15. This option is used when
ordering Novar controls.
16. Includes gas piping and shutoff
(field assembly required).
17. Not available with high
temperature duct sensor
accessory.
18. Digit 15 = 2
19. Novar sensor utilized with
Digit 21 = (4) Novar 3051 controls
without zone sensor.
20. Available for gas/electric, 3 to 5
tons, high efficiency, single phase
models.
21. Available for all models except
gas/electric, 3 to 5 tons high
efficiency, single phase.
22. Requires selection of 2” pleated
filters (option B or C) for Digit 16.
23. Not available on all single phase
or standard efficiency.
24. Standard onT/YSC 6, 7½ (single
and dual systems), 8½, 10 ton
standard efficiency models and
Digit 15 = 0
Standard Efficiency
3 Phase (3 to 5 Ton) = Multispeed Direct Drive
Motor
3 Phase (6 to 8½ Ton) = Belt Drive
3Phase(10 Ton) = UltraHigh EfficiencyDirect
Drive Plenum Fan
High Efficiency
1 Phase = High Efficiency Multispeed Direct
Drive Motor
3 Phase (3 to 5 ton) = High Efficiency
Multispeed Direct Drive Motor
3Phase(3to5tonw/Dehumidification)=Belt
Drive Motor
3 Phase [6 (074) to 10 ton] = Ultra High
Efficiency Direct Drive Plenum Fan
Not Available
Standard Efficiency
3 to 5 Tons and 10 Ton w/575V
High Efficiency
3 to 5 Tons w/Standard Indoor Motor w/460V
High Efficiency 575V
Standard Efficiency
3 Phase = Not Available
High Efficiency
1 Phase = Not Available
3 Phase (3 to 5 tons) = May be Ordered
3 Phase (3 to 5 tons w/dehumidification) =
Not Available
3 Phase (6 to 10 tons) = Not Available

Model Number Descriptions-3to10Tons(T/Y)
8 RT-SVX21U-EN
T/YHC 4, 5, 6, 7½, 8½, 10 ton
MCHE high efficiency models
(except for 4, 5, 6 ton
dehumidification models).
25. Not available on high efficiency
575V.
26. Epoxy coil and epoxy with hail
guard options are not available
for units with microchannel
condenser coil.
27. Single zone VAV is only available
on 6 to 10 tons high efficiency and
10 ton standard efficiency
products with ReliaTel™ controls.
28. Multi-speed indoor fan available
only on 6, 7½ & 8½ tons high
efficiency, and 10 ton products
with ReliaTel™ controls.
29. Motorized outside air damper is
not available on multi-speed or
SZVAV (single zone variable air
volume) products.
30. Frostat™ standard onY/TSC033
to 063G electromechanical, multi-
speed and SZVAV (single zone
variable air volume) products.
31. Novar is not available with SZVAV
products.
32. Demand control ventilation not
available with electromechanical
controls.
33. Demand control ventilation
option includes wiring only.The
C02sensor is a field-installed only
option.
34. Discharge air sensing is also
standard equipment on units
with single zone and supply air
temperature control VAV.
35. Must be used with BACnet® open
protocol.

Model Number Descriptions-3to5Tons(T/Y - 17 Plus)
RT-SVX21U-EN 9
Model Number Descriptions-3to5Tons(T/Y - 17 Plus)
Digit 1 - Unit Type
T DX Cooling
Y DX Cooling, Gas Heat
Digit2-Efficiency
S Standard Efficiency
H High Efficiency
Digit 3 - Airflow
C Convertible
Digit 4,5,6 - Nominal Gross
Cooling Capacity (MBh)
037 3Ton
047 4Ton
067 5Ton
Digit 7 - Major Design Sequence
E R-410A Refrigerant
Digit 8 - Voltage Selection
3 208-230/60/3
4 460/60/3
W 575/60/3
Digit 9 - Unit Controls
R ReliaTel™ Microprocessor
Digit 10 - Heating Capacity
Note: Applicable to Digit 1,T models
only
0 No Electric Heat
B 6 kW (3 phase)
E 12 kW (3 phase)
G 18 kW (1&3 phase)
J 23 kW (3 phase)
Note: Applicable to Digit 1,Y models
only
L Low Heat
M Medium Heat
H High Heat
X Low Heat, Stainless Steel Heat
Exchanger
Y Medium Heat, Stainless Steel Heat
Exchanger
Z High Heat, Stainless Steel Heat
Exchanger
Digit 11 - Minor Design
Sequence
A First Sequence16
Digit 12,13 - Service Sequence
** Factory Assigned
Digit 14 - Fresh Air Selection
0 No Fresh Air
A Manual Outside Air Damper 0-50%2
B Motorized Outside Air Damper
0-50%
C Economizer, Dry Bulb 0-100%
without Barometric Relief5
D Economizer, Dry Bulb 0-100%
with Barometric Relief5
E Economizer, Reference Enthalpy
0-100% without Barometric Relief5
F Economizer, Reference Enthalpy
0-100% with Barometric Relief5
G Economizer, Comparative
Enthalpy 0-100% without
Barometric Relief5
H Economizer, Comparative
Enthalpy 0-100% with Barometric
Relief5
K Low Leak Economizer with
Barometric Relief
M Low Leak Economizer with Reference
Enthalpy with Barometric Relief
P Low Leak Economizer with
Comparative Enthalpy with
Barometric Relief
Digit 15 - Supply Fan/DriveType/
Motor
0 Standard Drive4
6 Single Zone VAV34
E VAV Supply AirTemperature Control
Standard Motor34
Digit 16 - Hinged Service
Access/Filters
0 Standard Panels/Standard Filters
A Hinged Access Panels/Standard
Filters
B Standard Panels/2” MERV 8 Filters
C Hinged Access Panels/2” MERV 8
Filters
D Standard Panels/2” MERV 13 Filters
E Hinged Access Panels/2” MERV 13
Filters
Digit 17 - Condenser Coil
Protection
0 Standard Coil
1 Standard Coil with Hail Guard
2 Black Epoxy Pre-Coated Condenser
Coil
3 Black Epoxy Pre-Coated
Condenser Coil with Hail Guard
4 CompleteCoat™ Condenser Coil
5 CompleteCoat™ Condenser Coil
with Hail Guard
Digit 18 - Through the Base
Provisions
0 NoThrough-the-Base Provisions
A Through-the-Base Electric6
B Through-the-Base Gas Piping13
C Through-the-Base Electric and Gas
Piping13
Digit 19 - Disconnect/Circuit
Breaker (three-phase only)
0 No Disconnect/No Circuit Breaker
1 Unit Mounted Non-Fused
Disconnect6
2 Unit Mounted Circuit Breaker6
Digit 20 - Convenience Outlet
0 No Convenience Outlet
A Unpowered Convenience Outlet
B Powered Convenience Outlet
(three-phase only)7
Digit 21 - Communications
Options
0 No Communications Interface
2 LonTalk® Communications
Interface
3 Novar 2024 Controls
4 Novar 3051 Controls without Zone
Sensor
5 Novar 3051Controls Interface with
DCV
6 BACnet® Communications Interface
7 Air-Fi™ Wireless Communications22
Digit 22 - Refrigeration System
Option
0 Standard Refrigeration System8
B Dehumidification Option17
Digit 23 - Refrigeration Controls
Note: Applicable to Digit7=E
0 No Refrigeration Control3
1 Frostat™
2 Crankcase Heater1
3 Frostat and Crankcase Heater1
Digit 24 - Smoke Detector14
0 No Smoke Detector
A Return Air Smoke Detector9,10
B Supply Air Smoke Detector
C Supply and Return Air Smoke
Detectors9,10
D Plenum Smoke Detector
Digit 25 - System Monitoring
Controls
0 No Monitoring Control11
1 Clogged Filter Switch11
2 Fan Failure Switch11
3 Discharge Air SensingTube11
4 Clogged Filter Switch and Fan
Failure Switch11
5 Clogged Filter Switch and Discharge
Air SensingTube11
6 Fan Failure Switch and Discharge Air
SensingTube11
7 Clogged Filter Switch, Fan Failure
Switch and Discharge Air
SensingTube11

Model Number Descriptions-3to5Tons(T/Y - 17 Plus)
10 RT-SVX21U-EN
8 Novar Return Air Sensor
(NOVAR 2024)12,20
9 Novar Zone Temp Sensor
(NOVAR 3051)15,20
A Condensate Drain Pan Overflow
Switch
B Clogged Filter Switch11 and
Condensate Drain Pan Overflow
Switch
C Fan Failure Switch11 and Condensate
Drain Pan Overflow Switch
D Discharge Air Sensing11 and
Condensate Drain Pan Overflow
Switch
E Clogged Filter Switch11 , Fan Failure
Switch11 and Condensate Drain Pan
Overflow Switch
F Clogged Filter Switch11 , Discharge
Air SensingTube11 and Condensate
Drain Pan Overflow Switch
G Fan Failure Switch11 , Discharge Air
SensingTube11 and Condensate
Drain Pan Overflow Switch
H Clogged Filter Switch11 , Fan Failure
Switch11 , Discharge Air Sensing11
and Condensate Drain Pan Overflow
Switch
Digit 26 - System Monitoring
Controls
0 No Monitoring Controls
A Demand Control Ventilation
(CO2)18,19
B Low Leak Economizer with FDD
(Fault Detection & Diagnostics)
C FDD (Fault Detection & Diagnostics)
with DCV (Demand Control
Ventilation)
Digit 27 - Unit Hardware
Enhancements
0 No Enhancements
1 Stainless Steel Drain Pan
Digit 31 - Advanced Unit
Controls
0 Standard Unit Controls
1 Human Interface
Model Number Notes
1. Standard on all variable stage
units.
2. Manual outside air damper will
ship factory supplied within the
unit, but must be field installed.
3. High pressure control is standard
on all units.
4. Direct drive is standard for 3 to 5
ton variable stage units.
5. Economizer with Barometric
Relief is for downflow configured
units only. Order Economizer
without Barometric Relief for
horizontal configuration.
Barometric Relief for horizontal
configured units must be ordered
as field installed accessory.
6. Through the base electric
required when ordering
disconnect/circuit breaker
options.
7. Requires use of Disconnect or
Circuit Breaker.
8. Standard metering devices are
TXVs.
9. The return air smoke detector
may not fit up or work properly on
the Precedent units when used in
conjunction with 3rd party
accessories such as bolt on heat
wheels, economizers and power
exhaust. Do not order the return
air smoke detectors when using
this type of accessory.
10. Return Air Smoke Detector
cannot be ordered with Novar
Controls.
11. These options are standard when
ordering Novar Controls.
12. This option is used when
ordering Novar Controls.
13. Includes gas piping and shutoff
(field assembly required).
14. Not available with high
temperature duct sensor
accessory.
15. Novar Sensor utilized with
Digit 21 = (4) Novar 3051 Controls
without Zone Sensor.
16. Available forT/Y 3,4,5 ton high
efficiency models.
17. Requires selection of 2” Pleated
Filters (option B or C) for Digit 16.
18. Demand Control Ventilation not
available with electromechanical
controls.
19. Demand Control Ventilation
Option includes wiring only.The
CO2sensor is a field-installed
only option.
20. Novar is not available with SZVAV
products.
21. Discharge Air Sensing is also
standard equipment on units
with Single Zone and Supply Air
Temperature Control VAV.
22. Must be used with BACnet® open
protocol.
Digit 15 = 0, 6
3 Phase (3-5 ton) - High Efficiency Constant
CFM
Not Available
High Efficiency
3-5 ton w/Standard Indoor Motor w/460V or
575V

RT-SVX21U-EN 11
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
nameplate specifications.
• Visually inspect the exterior of the unit, including the
roof, for signs of shipping damage.
If the job site inspection of the unit reveals damage or
material shortages, file a claim with the carrier
immediately. Specify the type and extent of the damage on
the “bill of lading” before signing.
• Visually inspect the internal components for shipping
damage as soon as possible after delivery and before
it is stored. Do not walk on the sheet metal base pans.
• If concealed damage is discovered, notify the carrier’s
terminal of damage immediately by phone and by
mail. Concealed 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
installing or repairing a damaged unit.
Storage
Take precautions to prevent condensate from forming
inside the unit’s electrical compartments and motors if:
1. the unit is stored before it is installed; or,
2. 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,
Supply Air and Return Air openings, and flue
openings) from the ambient air until the unit is ready
for start-up.
Note: Do not use the unit’s heater for temporary heat
without first completing the start-up procedure
detailed under “Unit Start-Up,” p. 51”.
The manufacturer will not assume any responsibility for
equipment damage resulting from condensate
accumulation on the unit’s electrical and/or mechanical
components.
Unit Nameplate
A Mylar unit nameplate is located on the unit’s corner
support next to the filter access 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 side
of the compressor.
Microchannel Coil Barcode ID
Barcode decal used for coil part identification can be
located on the header and top of coil's inlet/outlet side.
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 either aluminum fin, mechanically
bonded to copper tubing or all aluminum microchannel.
Direct-drive, vertical discharge condenser fans are
provided with built-in thermal overload protection.
There are two control systems offered for these units.The
electromechanical control option uses a thermostat to
perform unit functions.The ReliaTel™ Control Module is a
microelectronic control system that is referred to as
“Refrigeration Module” (RTRM).The acronym RTRM is
used extensively throughout this document when
referring to the control system network.
These modules through Proportional/Integral control
algorithms perform specific unit functions that governs
unit operation in response to; zone temperature, supply air
temperature, and/or humidity conditions depending on
the application.The stages of capacity control for these
units are achieved by starting and stopping the
compressors.
The RTRM is mounted in the control panel and is factory
wired to the respective internal components.The RTRM
receives and interprets information from other unit
modules, sensors, remote panels, and customer binary
contacts to satisfy the applicable request for cooling.
Economizer Control Actuator (Optional)
Electromechanical Control
The ECA monitors the mixed air temperature, ambient dry
bulb temperature and local minimum position setpoint
sensors, if selected, to control dampers to an accuracy of
+/- 5% of stroke.The actuator is spring returned to the
closed position any time that power is lost to the unit. It is
capable of delivering up to 25 inch pounds of torque and
is powered by 24 VAC.
ReliaTel™ Control
The ECA monitors the mixed air temperature, return air
temperature, minimum position setpoint (local or
remote), power exhaust setpoint, CO2setpoint, CO2, and
ambient dry bulb/enthalpy sensor or comparative
humidity (return air humidity against ambient humidity)
sensors, if selected, to control dampers to an accuracy of

General Information
12 RT-SVX21U-EN
+/- 5% of stroke.The actuator is spring returned to the
closed position any time that power is lost to the unit. It is
capable of delivering up to 25 inch pounds of torque and
is powered by 24 VAC.
RTCI - ReliaTel™ Trane Communication
Interface (Optional)
This module is used when the application calls for an
ICSTM building management type control system. It
allows the control and monitoring of the system through
an ICS panel.The module can be ordered from the factory
or ordered as a kit to be field installed. Follow the
installation instruction that ships with each kit when field
installation is necessary.
RLCI - ReliaTel™ LonTalk® Communication
Interface (Optional)
This module is used when the application calls for an
ICSTM building management type control system that is
LonTalk. It allows the control and monitoring of the system
through an ICS panel.The module can be ordered from the
factory or ordered as a kit to be field installed. Follow the
installation instruction that ships with each kit when field
installation is necessary.
RBCI - ReliaTel™ BACnet Communications
Interface (Optional)
This module is used when the application calls for an open
BACnet protocol. It allows the control and monitoring of
the system through an ICS panel.The module can be
ordered from the factory or as a kit to be field installed.
Follow the installation instructions that ships with each kit
when field installation is necessary.
RTOM - ReliaTel™ Options Module (Standard
on 17 Plus, 6Ton (074), 7.5 Ton & 8.5 Ton High
Efficiency with ReliaTel, 10 Ton with ReliaTel)
The RTOM monitors the supply fan proving, clogged filter,
supply air temperature, exhaust fan setpoint, supply air
tempering, Frostat™, smoke detector, andVariable Speed
Fan Control (17 Plus units only). Refer to system input
devices and functions for operation.
System Input Devices & Functions
The RTRM must have a zone sensor or thermostat input in
order to operate the unit.The flexibility of having several
mode capabilities depends upon the type of zone sensor or
thermostat selected to interface with the RTRM.
The descriptions of the following basic Input Devices used
within the RTRM network are to acquaint the operator with
their function as they interface with the various modules.
Refer 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 to sense indoor
fan operation:
FFS (Fan Failure Switch) If air flow through the unit is not
proven by the differential pressure switch connected to the
RTOM (factory set point 0.07 “w.c.) within 40 seconds
nominally, the RTRM will shut off all mechanical
operations, lock the system out, send a diagnostic to ICS,
and the SERVICE output 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 filter section and is connected to the
RTOM. A diagnostic SERVICE signal is sent to the remote
panel if the pressure differential 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 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 regardless of the
status of the filter switch.
Note: On units equipped with factory installed MERV 13
filters, a clogged filter switch with different
pressure settings will be installed.This switch will
close when the differential pressure is
approximately 0.8' w.c. and open when the
differential falls to 0.7" w.c.
Condensate Drain Pan Overflow Switch
(Optional)
ReliaTel™ Option
This input incorporates the Condensate Overflow Switch
(COF) mounted on the drain pan and the ReliaTel Options
Module (RTOM). When the condensate level reaches the
trip point for 6 continuous seconds, the RTOM will shut
down all unit functions until the overflow condition has
cleared.The unit will return to normal operation after 6
continuous seconds with the COF in a non-tripped
condition. If the condensate level causes unit shutdown
more than 2 times in a 3 days period, the unit will be
locked-out of operation requiring manual reset of
diagnostic system through Zone Sensor or Building
Automation System (BAS). Cycling unit power will also
clear the fault.
Electromechanical Option
This input incorporates the condensate overflow switch
(COF), COF Relay, COFTime Delay. When the condensate
level reaches the trip point, the COF relay energizes and
opens the 24VAC control circuit which disables the unit.
Once the 24VAC control circuit is opened, a delay timer will
prevent unit start-up for three minutes.

General Information
RT-SVX21U-EN 13
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 on the LTB.
If this circuit is open before the compressor is started, the
compressor will not be allowed to operate. Anytime this
circuit is opened for 1 continuous second 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
contacts 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 restart the compressor.
Low Pressure Control
ReliaTel™ Control
When the LPC is opened for 1 continuous second, 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 an active
call for cooling, the compressor will be locked out, a
diagnostic communicated to ICS™, if applicable, and a
manual reset required to restart the compressor. On dual
compressor units only the affected compressor circuit is
locked out.
Electromechanical Control
When the LPC is opened, the compressor for that circuit is
turned off immediately.The compressor will restart when
the LPC closes.
High Pressure Control
ReliaTel™ Control
The high pressure controls are wired in series between the
compressor outputs on the RTRM and the compressor
contactor coils. If the high pressure control switch opens,
the RTRM senses a lack of current while calling for cooling
and locks the compressor out.
If four consecutive open conditions occur during an active
call for cooling, the compressor will be locked out, a
diagnostic communicated to ICS™, if applicable, and a
manual reset required to restart the compressor. On dual
compressor units only the affected compressor circuit is
locked out.
Electromechanical Control
When the HPC is opened, the compressor for that circuit is
turned off immediately.The compressor will restart when
the HPC closes.
Power Exhaust Control (Optional)
ReliaTel™ Control
The power exhaust fan is started whenever the position of
the economizer dampers meets or exceed the power
exhaust setpoint when the indoor fan is on.
With the optional ventilation override accessory, the
power exhaust fan is independent of the indoor fan.
The setpoint panel is located in the return air section and
is factory set at 25%.
Electromechanical Control
The power exhaust fan is started whenever the indoor fan
is on and the adjustable damper limit switch DLS is closed.
Lead/Lag Control (Dual Circuit Only)
ReliaTel™ Control Only
Lead/Lag is a selectable input located on the RTRM.The
RTRM is configured from the factory with the Lead/Lag
control disabled.To activate the Lead/Lag function, simply
cut the wire connected to J3-8 at the RTRM. 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
RTRM is powered up, i.e. after a power failure, the control
will default to the number one circuit compressor. Lead/
Lag is not available on Multi-Speed Indoor Fan, or Single
Zone Variable Air Volume (SZVAV) products.
Zone Sensor Module (ZSM) (BAYSENS106*)
This electronic sensor features three system switch
settings (Heat, Cool, and Off) and two fan settings (On
and Auto). It is a manual changeover control with single
setpoint. (Cooling Setpoint Only)
Zone Sensor Module (ZSM) (BAYSENS108*)
This electronic sensor features four system switch settings
(Heat, Cool, Auto, and Off) and two fan settings (On and
Auto). It is a manual or auto changeover control with dual
setpoint capability. It can be used with a remote zone
temperature sensor BAYSENS077*.
Zone Sensor (BAYSENS110*)
This electronic sensor features four system switch settings
(Heat, Cool, Auto, and Off) and two fan settings (On and
Auto) with four system status LED’s. It is a manual or auto
changeover control with dual setpoint capability. It can be
used with a remote zone temperature sensor
BAYSENS077*.
Wall Mounted Relative Humidity Sensor
(BAYSENS036*)
Field installed, wall mounted humidity sensor is used to
control activation of Enhanced Dehumidification and the
Hot Gas Reheat Dehumidification options. Humidity set
points can be selected for relative humidity levels between

General Information
14 RT-SVX21U-EN
40% and 60% by adjusting the DEHUMID setting on the
ReliaTel Options Module. See Figure 45, p. 40.
Duct Mounted Relative Humidity Sensor
(BAYSENS037*)
Field installed, duct mounted humidity sensor is used to
control activation of Enhanced Dehumidification and the
hot gas reheat dehumidification options. Humidity set
points can be selected for relative humidity levels between
40% and 60% by adjusting the DEHUMID setting on the
ReliaTel Options Module. See Figure 45, p. 40.
Programmable Zone Sensor - (BAYSENS119*)
This 7 day programmable sensor features 2, 3 or 4 periods
for Occupied or Unoccupied programming per day. If the
power is interrupted, the program is retained in
permanent memory. If power is off for an extended period
of time, only the clock and day may have to be reset.
The Zone Sensor allows selection of 2, 3 or 4 system
modes (Heat, Cool, Auto, and Off), two fan modes (On and
Auto). It has dual temperature selection with
programmable start time capability.
The occupied cooling set point ranges between 45 and 98
º F.The heating set point ranges between 43 and 96ºF.
A liquid crystal display (LCD) displays zone temperature,
temperature set points, day of the week, time, and
operational mode symbols.
The Option Menu is used to enable or disable applicable
functions, i.e.; Morning Warm-up, Economizer minimum
position override during unoccupied status, Fahrenheit or
Centigrade, Supply air tempering, Remote zone
temperature sensor, 12/24 hour time display, Smart fan,
and Computed recovery.
During an occupied period, an auxiliary relay rated for 1.25
amps @ 30 volts AC with one set of single pole double
throw contacts is activated.
Status Inputs (4 Wires Optional)
The ZSM can be wired to receive four (4) operating status
signals from the RTRM (HEAT, COOL, SYSTEM “ON”,
SERVICE).
Four (4) wires from the RTRM should be connected to the
appropriate terminals (7, 8,9&10)ontheZSM.
Remote Zone Sensor (BAYSENS073*)
This electronic sensor features remote zone sensing and
timed override with override cancellation. It is used with a
Trane Integrated Comfort™ building management
system.
Remote Zone Sensor (BAYSENS074*)
This electronic sensor features single setpoint capability
and timed override with override cancellation. It is used
with aTrane Integrated Comfort™ building management
system.
Remote Zone Sensor (BAYSENS016*)
This bullet type temperature sensor can be used for
outside air (ambient) sensing, return air temperature
sensing, supply air temperature sensing, remote
temperature sensing (uncovered).Wiring procedures vary
according to the particular application and equipment
involved. Refer to the unit’s wiring diagrams for proper
connections.
Remote Zone Sensor (BAYSENS077*)
This electronic sensor can be used with BAYSENS106*,
108*, 110*, 119* Remote Panels. When this sensor is wired
to a BAYSENS119* Remote Panel, wiring must be 18 AWG
ShieldedTwisted Pair (Belden 8760 or equivalent). Refer to
the specific Remote Panel for wiring details.
Wireless Zone Sensor (BAYSENS050*)
This electronic sensor features five system settings (Auto,
Off, Cool, Heat, and Emergency Heat) and with On and
Auto fan settings. It is a manual or auto changeover control
with dual setpoint capability. Other features include a
timed override function, lockable system settings, and
Fahrenheit or Celsius temperature display. Included with
the wireless zone sensor will be a receiver that is to be
mounted inside the unit, a mounting bracket, and a wire
harness.
Electromechanical Control
The unit must have a thermostat to operate.
•BAYSTAT151
•Single Stage - 1 Heat/1 Cool
•BAYSTAT155
•Multi Stage - 3 Heat/2 Cool - Can be Used for
Economizer Operation
• BAYSENS150
•Multi stage - 3 Heat/2 Cool Programmable
Thermostat
High Temperature Sensor (BAYFRST001*)
This sensor connects to the RTRM Emergency Stop Input
on the LTB and provides high limit “shutdown” of the unit.
The sensor is used to detect high temperatures due to a
high thermal event in the air conditioning or ventilation
ducts.The sensor is designed to mount directly to the
sheet metal duct. Each kit contains two sensors.The return
air duct sensor (X1310004001) is set to open at 135ºF.The
supply air duct sensor (X1310004002) is set to open at
240ºF.The control can be reset after the temperature has
been lowered approximately 25ºF below the cutout
setpoint.
Evaporator Frost Control
ReliaTel™ Option
This input incorporates the Frostat™ control (FOS)
mounted in the indoor coil circuit and can be activated by

General Information
RT-SVX21U-EN 15
closing a field supplied contact installed in parallel with
the FOS.
If this circuit is closed before the compressor is started, the
compressor will not be allowed to operate. Anytime this
circuit is closed for 1 continuous second 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
FOS open.
Frostat is standard on multi-speed indoor motors and
single zone VAV products (SZVAV).
Electromechanical Option
This input incorporates the Frostat™ control (FOS)
mounted in the indoor coil circuit or on suction line before
equalizer port ofTXV and can be activated by opening a
field supplied contact installed in series with the FOS.
If this circuit is open before the compressor is started, the
compressor will not be allowed to operate. Anytime this
circuit is opened during compressor operation, the
compressor for that circuit is immediately turned “Off”.The
compressor will restart when the FOS closes. Frostat™ is
standard onYSC033G-063G electromechanical control
products.
Discharge Line Temp Switch (DLTS)
The DLTS is looped in series with HPC and LPC. It prevents
compressor from overheating (over 300 Fº dome temp) in
case of indoor fan failure (cooling) or outdoor fan failure
(heating).
Smoke Detector Sensor (Optional)
This sensor provides high limit“shutdown” of the unit and
requires a manual reset.The sensor is used to detect
smoke in the air conditioning or ventilation ducts.
Notes:
•The supply air smoke detector samples supply air.The
return and plenum air smoke detectors sample return
air.The smoke detectors are designed to shut off the
unit if smoke is sensed.This function is performed by
sampling the airflow entering the unit at the return air
opening. Follow the instructions provided below to
assure that the airflow through the unit is sufficient for
adequate sampling. Failure to follow these instructions
will prevent the smoke detectors from performing its
design function.
•Airflow through the unit is affected by the amount of
dirt and debris accumulated on the indoor coil and
filters.To insure that airflow through the unit is
adequate for proper sampling by the return air smoke
detector, complete adherence to the maintenance
procedures, including recommended intervals
between filter changes, and coil cleaning is required.
•Periodic checks and maintenance procedures must be
performed on the smoke detector to insure that it will
function properly. For detailed instructions concerning
these checks and procedures, refer to the appropriate
section(s) of the smoke detector Installation and
Maintenance Instructions provided with the literature
package for this unit.
In order for the supply air smoke detector or return air
smoke detector to properly sense smoke in the supply air
stream or return air stream, the air velocity entering the
smoke detector unit must be between 500 and 4000 feet
per minute. Equipment covered in this manual will
develop an airflow velocity that falls within these limits
over the entire airflow range specified in the evaporator
fan performance tables.
Phase Monitor
This sensor monitors voltage between the 3 conductors of
the 3 phase power supply.Two LED lights are provided:
• The green light indicates that a balanced 3 phase
supply circuit is properly connected.
• The red light indicates that unit operation has been
prevented.There are two conditions that will prevent
unit operation:
•The power supply circuit is not balanced with the
proper phase sequence of L1, L2, L3 for the 3
conductors of a 3 phase circuit.
•The line to line voltage is not between 180 volts and
633 volts.
Single Zone Variable Air Volume /
Displacement Ventilation (Optional)
This sensor offers full supply fan modulation across the
available airflow range. In addition to full supply fan
modulation, the unit controls the discharge air
temperature to a varying discharge air temperature
setpoint in order to maintain SpaceTemperature.
Human Interface - 5 Inch Color
Touchscreen (Optional)
The 5 inch ColorTouchscreen Human Interface provides an
intuitive user interface to the rooftop unit that speeds up
unit commissioning, shortens unit troubleshooting times,
and enhances preventative maintenance measures.The
human interface includes several features including:
• Data trending capabilities by means of time series
graphs
• Historical alarm messages
• Real-time sensor measurements
• On board system setpoints
• USB port that enables the downloading of component
runtime information as well as trended historical
sensor data
• Customized reports

16 RT-SVX21U-EN
Unit Dimensions
Figure 1, p. 16 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.
Figure 1. Typical installation clearances for single & multiple unit applications
Side by Side
Note 2 End to End
Note 2, 3
7’0”
2134 MM
6’0”
1829 MM
3’0”
914 MM
Note 1 Single Unit
3’0”
914 MM
3’0”
914 MM
4’0”
1219 MM
Note 4
9 1/8”
232 MM
12 1/2”
318 MM 12”
305 MM 16 3/4”
426 MM
YSC033-063G & YHC036, YHC037E Units YSC072-120F, YHC048-120F, YHC047-067E Units
Notes:
1. For horizontal discharge unit,
this measurement is reduced to
1’6” (457 MM) to minimize duct
extensions.
2. When equipped with economizer
or barometric relief damper, clearance
distance is to be measured from
protruding hood instead of base.
3. Clearance is the same if any unit
is rotated 180°.
4. Addition clearance required when
barometric damper or economizer
is installed.

Unit Dimensions
RT-SVX21U-EN 17
Figure 2. 3 to 5 tons standard efficiency
Notes:
1. All dimensions are in inches/millimeters.
2. ½ NPT Gas Connection
EVAPORATOR SECTION
ACCESS PANEL
ALTERNATE
CONDENSATE DRAIN
3/4 - 14 NPT DIA. HOLE
1/2 NPT GAS CONNECTION
TOP PANEL
CONDENSER FAN
CONDENSER COIL
UNIT CONTROL WIRE
7/8” (22 MM) DIA. HOLE
SERVICE GAUGE PORT ACCESS
1 3/8” (35 MM) DIA. HOLE
UNIT CONTROL WIRE
2” (51 MM) DIA. HOLE
40 7/8”
1038 MM
4 1/4”
108 MM
69 7/8”
1749 MM 42 1/4”
1073 MM
23 9/16”
598 MM
5 5/8”
143 MM
9 5/8”
244 MM
CONTROL AND COMPRESSOR
ACCESS PANEL
44 1/4”
1124 MM
7 5/8”
194 MM
5 9/16”
141 MM
4 1/4”
108 MM
20 1/4”
514 MM
Figure 3. 3 ton high efficiency
Notes:
1. All dimensions are in inches/millimeters.
2. ½ NPT Gas Connection

Unit Dimensions
18 RT-SVX21U-EN
Figure 4. 3-5 ton standard efficiency, 3 ton high efficiency - roof curb
Note: All dimensions are in inches/millimeters.
7
44
44
MM
MM
44
44
MM
MM
1038
1038
MM
MM
1053
1053
MM
MM
8 3/8”
213 MM
Figure 5. 3-5 ton standard efficiency, 3 ton high efficiency - unit clearance and roof opening
Note: All dimensions are in inches/millimeters.
CLEARANCE 36” (914 MM)

Unit Dimensions
RT-SVX21U-EN 19
Figure 6. 6, 7½ (single) ton standard efficiency, 4-5 ton high efficiency
Note: All dimensions are in inches/millimeters.
Figure 7. 6, 7½ (single) ton standard efficiency, 4-5 ton high efficiency - roof curb
Note: All dimensions are in inches/millimeters.
(2130 MM)
(356 MM)

Unit Dimensions
20 RT-SVX21U-EN
Figure 8. 6, 7½ (single) ton standard efficiency, 4-5 ton high efficiency - unit clearance and roof opening
Note: All dimensions are in inches/millimeters.
Figure 9. 7½ ton (dual) - 10 ton standard efficiency,6-8½(MCHE) ton high efficiency, 6 ton dehumidification
Note: All dimensions are in inches/millimeters.
(TC MODELS)
2” ELECTRICAL CONNECTION
(SINGLE POINT POWER
WHEN HEAT INSTALLED)
1/2 NPT GAS CONNECTION
(80 mbh, 120 mbh)
3/4 NPT GAS CONNECTION
(150 mbh, 200 mbh, 250 mbh)
(YC MODELS)