Features and Benets ............................................................................................................................................................5
Electrical Data ......................................................................................................................................................................67
Weights and Dimensions ......................................................................................................................................................84
Unit Placement ...................................................................................................................................................................109
• Cooling only units with heating options including
gas, electric, steam or hot water with modulation
• Exhaust or return fan options
• Various airflow path configurations for discharge
and return/exhaust air
• Optional humidifier, sound attenuator, or air blender
• Low ambient temperature option
• Variable frequency drive (VFD) options on all
fans (Figure 1)
2
Figure 1: VFD Displays
Johnson Controls
LD27639
Product Highlights and Options (Continued)
5513350-JTG-1018
• Reliability and Serviceability
• Multiple refrigeration circuits
• Coil corrosion protection option
• Convenience outlet option
• Optional viewports
• Single point latching door option
• Internal air handler light option
• Replaceable core filter drier option
• Suction, liquid, and discharge line shutoff valve
options
• Pressure transducer options
• Start-up wizard
• Indoor Environmental Quality
• Double wall construction with foam insulation
• Modulating hot gas reheat (HGRH) option
• Final filtration options, including high efficiency
particulate air (HEPA) filters
• Ultraviolet (UV) lights option (Figure 2)
• Controls
• 5.5-inch, 5 row × 35 character (256 × 64 dot matrix) organic light-emitting diode (OLED) display
with full numeric keypad and navigation buttons
as standard
• Optional WiFi hotspot capability via a mobile ac-
cess portal (MAP) device provides additional unit
control when it is not always possible to physi-
cally access the unit
• Smart Equipment technology enabling self-discovery on Verasys™ Building Automation Sys-
tems (BAS)
• The controller supports the BACnet
®
cation protocol and is designed and certified by
BACnet Testing Laboratory (BTL) to meet the requirements of the advanced application control
profile
• Twinning algorithms to allow multiple units to
function as one on common supply and return
duct shafts
• Variable air volume (VAV) and single zone VAV
(SZVAV) control
• Building pressurization controls
communi-
• Stainless steel drain pan
• Condensate overflow switch option
• Airflow measurement options for outside air, sup-
ply fan, and return fan
LD27640
Figure 2: UV Lights
Johnson Controls
3
5513350-JTG-1018
Component Location
Exhaust Air
13
5
4
2
1
3
8
9
11
10
6
7
12
1. Economizer
2. Evaporator coil
3. Direct drive plenum (DDP) supply fan
4. Modulating or staged gas heat
Figure 3: 25–50 Ton Packaged Rooftop Unit Cabinet Assembly
4
Outside Air
5. Condenser maintenance safety tie-off
6. Condenser fans
7. Scroll compressors
8. Condenser coil cleaning hatch
LD26878
9. Double wall construction
10. Unit controller
11. Filter section
12. Collapsible rain hoods
13. Exhaust/return fan
Johnson Controls
5513350-JTG-1018
Features and Benefits
General
The 25–50 ton packaged rooftop platform is designed with
all the flexibility needed for today’s applications but with
tomorrow's requirements in mind. Realizing that efficiency
requirements are continuously pushing the envelope of
technology, the NexusPremier™ delivers today the energy
efficiency levels exceeding those mandated by the U.S.
Department of Energy for 2023. All cooling only and electric heat units have an integrated energy efficiency ratio
(IEER) in excess of 13.2. All units with gas or hydronic heat
have an IEER in excess of 13. For these particular rooftop
units, when equipped with a variable speed drive compressor, they deliver efficiency levels in excess of those suggested by the highest tier of the Consortium of Energy Ef-
ficiency (CEE) for 2019.
The NexusPremier is also designed for serviceability. With
small details—such as a maintenance safety tie-off (Item 5 in
Figure 3) on the roof of the condenser section that complies
with OSHA requirements, along with a single handle latching
mechanism for doors—the unit was designed for easy service. Options to make the unit serviceable include a convenience outlet to power lights and tools; internal lights in the air
handler section; viewports in doors of serviceable compartments to enable easier unit inspection; and extended grease
lines to simplify fan bearing lubrication for belt-driven fans.
Standard direct drive supply fan (Item 3 in Figure 3) do not
require lubricating fan bearings or changing belts. Numerous
refrigeration options are also available, including replaceable
core filter driers, liquid and suction isolation valves, as well as
high and low pressure transducers in each circuit that enable
easier sub-cooling and superheat measurements.
Besides options, there are also standard features to ensure
straightforward and safe servicing of the units, including
coil cleaning hatches (Item 8 in Figure 3) in the condenser
section to make cleaning condenser coils effortless, and
door safety latches to keep doors safe when opened in a
pressurized compartment. A discrete high and low voltage
compartment minimizes the amount of safety equipment re-
quired when only the low voltage compartment is accessed.
Selection Navigator is an online program available to assist in providing unit selections, performance reports, and
outputs to assist in design of the unit. Certain options may
require the assistance of the local sales office.
In order to facilitate its application, Selection Navigator
also provides building information modeling (BIM) files of
the specific unit selected. This aids in modeling placement
and integration of the rooftop unit into the overall building
design.
This packaged rooftop product is a sophisticated, highly
configurable rooftop unit. A controller is standard on each
unit with specific sequences of operation correlated to the
options selected. The Selection Navigator provides the
specific sequences of operation for the unit options select-
ed, eliminating confusion of the unit's capability.
Although the many options make customizing unlikely, it is
possible to have custom mechanical and sequences of operations designed into the unit from the factory for ultimate
convenience and reliability.
1. Economizer (Item 1 in Figure 3)
In order to deliver maximum efficiency, rooftop units
need an efficient economizer. The rooftop unit offers
various options for economizer control and fault de-
tection, as well as damper leakage rates and cycle
life to meet different regulatory requirements.
The amount of fresh air can also be optionally measured to ensure and record appropriate fresh air to
the conditioned space. An air blender option is also
available to deliver optimal comfort to the conditioned
space.
2. Refrigeration System (Items 2, 6, and 7 in Figure 3)
The refrigeration system is built to reliably deliver
cooling through a variety of loads. Two independent
refrigeration circuits ensure that in the unlikely event
of a compressor failure, the second circuit can still deliver cooling to the space. An interlaced tube and fin
evaporator provide maximum cooling performance
even at part loads. The microchannel condenser re-
duces the risk of refrigerant leaks and minimizes the
amount of refrigerant in the unit.
Standard fixed speed scroll compressors of different sizes deliver excellent part-load efficiency and
control, which eliminates the need for inefficient hot
gas bypass valves at low load conditions. Optional
variable speed drive scroll compressor configurations are available for stable and efficient discharge
air temperature (DAT) control regardless of the load.
For application flexibility, optional corrosion protection is available for the evaporator and condenser, as
well as intrusion protection options for the condenser.
Realizing that the refrigeration system is the heart
of the rooftop, when optionally equipped with transducers, the unit controller can display sub-cooling or
superheat. Additionally, low ambient operation is an
available option with a variable speed condenser fan.
Johnson Controls
5
5513350-JTG-1018
Features and Benefits (Continued)
Maximized serviceability is also available with options such as replaceable core filter driers as well as
discharge, liquid, and suction line isolation valves.
The standard unit is equipped with accessible sight
glasses to verify proper refrigerant flow as well as
conveniently located condenser coil cleaning hatches to facilitate maintenance.
3. Direct Drive Plenum (DDP) Supply Fan (Item 3 in
Figure 3)
A direct drive plenum (DDP) supply fan (Figure 4)
provides outstanding reliability and efficiency, such
as eliminating the possibility of interrupting condi-
tioned air supply due to a broken belt or polluting
conditioned air with belt dust. The supply fan can
be optionally equipped with an airflow measurement
station to precisely measure the amount of air delivered to the conditioned space.
LD27636
Figure 4: DDP Supply Fan
The speed of the supply fan is controlled by a vari-
able frequency drive (VFD). A redundant VFD is
optionally available to ensure uptime in the unlikely
event of a VFD failure.
4. Heating Options (Item 4 in Figure 3)
Gas heat options are available either in staged or
modulating control. The flexibility of heater sizes
meets the specific application heating needs. Electric
heat is also available with size and staging/modulating options (Figure 5). Either hot water or steam heat
options are also available. All modulating heat options can be controlled precisely to temper the sup-
ply air, which is especially important when fresh air is
needed in cold climates.
5. Double Wall Construction (Item 9 in Figure 3)
The air handler section of the rooftop unit provides
foam injected double wall construction for maximum
unit rigidity and cleanability of the interior surfaces
for long term indoor air quality (IAQ). This construction of the walls, roof, and floor provides an insulating
value that minimizes unit sweating and contributes to
the overall unit efficiency.
LD27637
Figure 5: Electric Heat
6. Controls System (Item 10 in Figure 3)
The rooftop unit’s sophisticated options are intelligently controlled by a best-in-class controls platform
built exclusively for this application.
A 5.5-inch, 5 row × 35 character (256 × 64 dot matrix)
6) with full numerical and optimized navigational key-
pad, conveniently located in the low voltage compartment, is the nerve center. The control system can be
optionally augmented with a WiFi hotspot capability
for local or line-of-sight smart device control.
The control platform minimizes commissioning time
when connected to the Verasys™ Building Automation Systems (BAS), with self-discovery of the rooftop
unit and its points by the BAS.
6
Johnson Controls
5513350-JTG-1018
Features and Benefits (Continued)
The unit controller has sequences of operation for
standalone applications. These sequences cover
simple applications such as single zone variable air
volume (SZVAV) control of the supply fan and compressors in accordance with ASHRAE 90.1-2016,
as well as demand control ventilation (DCV) that
ensures adequate fresh air to the building. Complex
applications are also supported, like the twinning of
multiple rooftops on a common supply and return
duct shaft for the ultimate in redundancy for critical
spaces, such as Medical Office Buildings (MOBs).
7. Blank Section (Figure 7)
Blank sections can be provided for field installed ac-
cessories or to accommodate the installation of specific factory components including an air blender, final filters, humidifier, or sound attenuator.
The rooftop unit can be equipped with a final filter
before the conditioned air is delivered from the rooftop into the supply duct. Various final filter options
are available to meet critical needs including high ef-
ficiency particulate air (HEPA) filtration. Differential
pressure measuring options can be supplied to meet
the requirements for ASHRAE 170-2017.
For cold northern climates where heat tends to dry
out the supply air, a humidifier option with a stainless
steel drain pan is also available.
In order to mitigate sound originating in the rooftop unit
from reaching the conditioned space, optional sound
attenuators in the rooftop unit can be factory-installed.
8. Exhaust/Return Fan (Item 13 in Figure 3)
The rooftop units enable installation flexibility with the
option of either exhaust or return fan to control the
building static pressure. Return ductwork with shorter runs and lower static requirements usually only
need an exhaust fan. The return fan is available to
overcome the static imposed by longer return ducts.
Refer to the Variable Air Volume for Rooftop Units
Application Guide (Form 5515844-JAD).
Figure 6: OLED Display
Figure 7: Final Filter Section
Final Filters
Blank Section
LD27638
LD26881
Optional airflow measurement is available for units
equipped with a return fan. This makes it possible
to precisely understand and log the different airflows
through the rooftop unit.
9. Hot Gas Reheat (HGRH) (Figure 9)
Occupant comfort can be a challenge during shoul-
der months when low loads and high humidity occur.
In many cases, the combined efforts of refrigeration
system compressor multistep control, an interlaced
evaporator coil, and the supply fan modulation of SZVAV control are sufficient. The rooftop unit provides
an optional modulating hot gas reheat (HGRH) coil
to further reduce the humidity level within the space.
10. Indoor Air Quality (IAQ)
To meet the critical needs of IAQ, the rooftop unit
provides a stainless steel evaporator drain pan for
longevity and to facilitate cleanability. The drain pan
can be optionally equipped with an overflow switch to
warn of improper drainage and minimize the potential
for damage to the conditioned space. Ultraviolet (UV)
light banks are also an available option that minimize
mold and bacteria growth and assists in keeping the
evaporator coil clean.
Johnson Controls
7
5513350-JTG-1018
Features and Benefits (Continued)
11. Energy Recovery Wheel (ERW) (Figure 8)
The rooftop unit provides an option for an energy re-
covery wheel (ERW) as an integral part of the unit.
This device uses exhaust air to condition the fresh
air brought into the unit and the conditioned space,
increasing the overall rooftop efficiency. As a factoryinstalled option, the ERW ensures reliability, minimizes field labor, and simplifies long-term maintenance
of the device.
12. Airow Flexibility
Whether a rooftop unit is mounted on a roof or on a
grade, the orientation of airflow from the rooftop to
the conditioned space and vice versa is important.
The NexusPremier was specifically designed to provide discharge airflow either at the bottom, top, left,
or right.
Similarly, the return airflow is designed for maximum
flexibility vertically in either direction as well as hori-
zontally in either direction. Depending on selected
options, an end return is also possible. This airflow
flexibility minimizes installation costs and maximizes
possible locations for this flexible rooftop unit.
A: Cooling Only
B: Staged Gas Aluminized Burner
C: Staged Gas Stainless Steel
G: Modulating Gas Stainless Steel
K: Steam Coil
L: Hot Water Coil
M: Electric Heat
Digit 6A: Electric Heat Capacity
0: None
1: Low Heat
3: High Heat
4: Low Heat with Silicon Controlled Rectifier
(SCR)
6: High Heat with SCR
1: Low Heat without Valves
2: Low Heat with Valves
3: High Heat without Valves
4: High Heat with Valves
Digit 7: Unit Type
A: Single Zone VAV (SZVAV) (No Duct Pressure
Transducer)
B: Variable Air Volume (VAV) (Duct Pressure
Transducer)
Digit 8: Motor Control Options
1: Supply Fan Variable Frequency Drive (VFD)
2: Supply Fan VFD with Line Reactor
3: Supply Fan VFD with Bypass (Redundant
VFD)
4: Supply Fan VFD with Line Reactor and
Bypass (Redundant VFD)
5: Supply Fan VFD and Return/Exhaust Fan VFD
6: Supply Fan VFD with Line Reactor and
Return/Exhaust Fan VFD with Line Reactor
7: Supply Fan VFD and Return/Exhaust Fan
VFD with Bypass (Redundant VFD for Supply
Fan and Bypass for Return or Exhaust Fan)
8: Supply Fan VFD with Line Reactor and
Return/Exhaust Fan VFD with Line Reactor with Bypass (Redundant VFD for Supply Fan
and Bypass for Return or Exhaust Fan
Digit 9: Voltage
A: 208-230 V 3Ph 60 Hz, Single Point Terminal
Block
B: 208-230 V 3Ph 60 Hz, Dual Point Terminal
Block
C: 208-230 V 3Ph 60 Hz, Single Point Non Fused DISC
D: 208-230 V 3Ph 60 Hz, Single Point Terminal
Block, 65KA Short-Circuit Current Rating (SCCR)
E: 208-230 V 3Ph 60 Hz, Dual Point Terminal
Block, 65KA SCCR
F: 208-230 V 3Ph 60 Hz, Single Point Non Fused DISC, 65KA SCCR
G: 460 V 3Ph 60 Hz, Single Point Terminal Block
H: 460 V 3Ph 60 Hz, Dual Point Terminal Block
J: 460 V 3Ph 60 Hz, Single Point Non-Fused
DISC
K: 460 V 3Ph 60 Hz, Single Point Terminal
65KA SCCR
L: 460 V 3Ph 60 Hz, Dual Point Terminal Block,
65KA SCCR
M: 460 V 3Ph 60 Hz, Single Point Non-Fused
DISC, 65KA SCCR
N: 575 V 3Ph 60 Hz, Single Point Terminal Block
P: 575 VA 3Ph 60 Hz, Dual Point Terminal Block
Q: 575 V 3Ph 60 Hz, Single Point Non-Fused
DISC
R: 575 V 3Ph 60 Hz, Single Point Terminal
65KA SCCR
S: 575 V 3Ph 60 Hz, Dual Point Terminal Block,
65KA SCCR
T: 575 V 3Ph 60 Hz, Single Point Non-Fused
DISC, 65KA SCCR
Block,
Block,
Digit 10: Return Configuration
A: Bottom Return, Right Outside Air (OA), Side
Exhaust
B: Bottom Return, Right OA, Front Exhaust
C: Bottom Return, Left OA, Side Exhaust
D: Bottom Return, Left OA, Front Exhaust
E: Top Return, Right OA, Side Exhaust
F: Top Return, Right OA, Front Exhaust
G: Top Return, Left OA, Side Exhaust
H: Top Return, Left OA, Front Exhaust
J: Left Return, Right OA, Front Exhaust
K: Right Return, Left OA, Front Exhaust
L: Front Return, Left OA, Right Exhaust
M: Front Return, Right OA, Left Exhaust
N: Bottom Return, No OA, No Exhaust Air (EA)
(No Return Fan Available)
P: Top Return, No OA, No EA (No Return Fan
Available)
Q: Left Return, No OA, No EA (No Return Fan
Available)
R: Right Return, No OA, No EA (No Return Fan
Available)
S: Front Return, No OA, No EA (No Return Fan
Available)
Digit 11: Discharge Locations
1: Bottom Discharge, from Discharge Plenum
2: Bottom Discharge, Discharge through Heat
Section
3: Top Discharge, from Discharge Plenum
4: Right Discharge, from Discharge Plenum
5: Left Discharge, from Discharge Plenum
6: Left Discharge, Discharge through Heat
Section
Digit 12: Supply Configuration
A: None
B: Small Blank
C, D: Large Blank
F:
Small Blank with Humidifier and Stainless Steel
(SST) Drain Pan
H, K: Large
L: Small Blank Sound Attenuator
M, N: Large Blank Sound Attenuator
P: Small Blank Final Filter
Q, T: Large Blank with Sound Attenuator and
S, V: Large Blank with Sound Attenuator and
Digit 13: Final Filter Options
1:
MERV 15 Bag Final Filters with 2-inch MERV 8
Filters
2: MERV 14 Rigid Final Filters with 2-inch MERV
8 Filters
3: MERV 17 High Efficiency Particulate Air
(HEPA) Final Filters with 2-inch MERV 8 Filters
4: MERV 14/15 Filter Rack (No Filters)
5: HEPA Filter Rack (No Filters)
6: None
Blank with Humidifier and SST Drain
Pan
Final Filter
Humidifier and SST Drain Pan
49
Johnson Controls
9
5513350-JTG-1018
Nomenclature (Continued)
Digit 14: Final Filter Control Options
0: None
1: Combined Pre and Post Filter Transducer
2: Separate Pre and Post Filter Transducer
3: Combined Pre and Post Filter Transducer and
Combined Magnehelic Gauge
4: Separate Pre and Post Filter Transducer and
Magnehelic Gauge
5: Combined Pre and Post Filter Magnehelic
Gauge
6:
Separate Pre and Post Filter Magnehelic Gauge
7: Combined Pre and Post Filter Transducer,
Separate Pre and Post Filter Magnehelic Gauge
Digit 15: Supply Fan
A: Direct Drive Plenum (DDP) Supply Fan with
1-inch Spring Isolation
B: DDP Supply Fan with 2-inch Spring Isolation
C: DDP Supply Fan with 2-inch Spring Isolation
5: Inlet Guard and Shaft Grounding Ring
6: Airflow Measurement Station and Shaft
Grounding Ring
7: Shaft Grounding Ring, Inlet Guard and Airflow
Measurement Station
Digits 19: Building Pressure Control
0: None
1: Barometric Damper
2: Exhaust with VFD and Backdraft Damper
3: Modulating Damper (On/Off Exhaust Fan Only
without VFD)
4:
Modulating Damper (Return Fan Only with VFD)
Digit 20: Return/Exhaust Fan
A: None
B: Exhaust Fan with 1-inch Spring Isolation
C: Exhaust Fan with 2-inch Spring Isolation
D: Exhaust Fan with 2-inch Spring Isolation and
Seismic Restraint
E: Return Fan with 1-inch Spring Isolation
F: Return Fan with 2-inch Spring Isolation
G: Return Fan with 2-inch Spring Isolation and
Seismic Restraint
Digit 21: Return/Exhaust Fan Motor
Horsepower
A: None
E: 3 HP
F: 5 HP
G: 7.5 HP
H: 10 HP
J: 15 HP
K: 20 HP
Ring
E: Belt Guards
F: Belt Guards and Shaft Grounding Ring
G: Return Fan Airflow Measurement Station
H: Return Fan Airflow Measurement Station and
Shaft Grounding Ring
J: Extended Grease Lines and Belt Guards
K: Extended Grease Lines and Belt Guards
and Shaft Grounding Ring
L: Extended Grease Lines and Return Fan
Airflow Measurement Station
M: Extended Grease Lines and Return Fan
Airflow Measurement Station and Shaft
Grounding
N: Belt Guards and Return Fan Airflow
Measurement Station
P: Belt Guards and Return Fan Airflow Measure-
ment Station and Shaft Grounding Ring
Q: Extended Grease Lines and Belt Guards and
Return Fan Airflow Measurement Station
R: Extended Grease Lines and Belt Guards and
Return Fan Airflow Measurement Station and
Shaft Grounding Ring
Digits 24: Return/Exhaust Fan Drive
A: None
B–K: RPM
Digit 25: Evaporator Options
G: Aluminum Fin Evaporator with SST Drain Pan
H: Aluminum Fin Evaporator with SST Drain Pan
with Condensate Overflow Switch
J: E-Coat Aluminum Fin Evaporator with SST
Drain Pan
K: E-Coat Aluminum Fin Evaporator with SST
Drain Pan with Condensate Overflow Switch
L: Copper Fin Evaporator with SST Drain Pan
M: Copper Fin Evaporator with SST Drain Pan
with Condensate Overflow Switch
Digit 26: Condenser Coil Options
1: None
2: With Wire Guards
3: Full Louvered Panels
4: Partial Louvered Panels
5: E-Coat Condenser without Guards
6: E-Coat Condenser with Wire Guards
0: None
1: Combined Pre and Post Filter Transducer
2: Separate Pre and Post Filter Transducer
3: Combined Pre and Post Filter Transducer and
Combined Magnehelic Gauge
4: Separate Pre and Post Filter Transducer and
Magnehelic Gauge
5: Combined Pre and Post Filter Magnehelic
Gauge
6:
Dual Enthalpy Economizer, Low Leak Dampers
F: Dry Bulb Economizer, Low Leak Dampers
with Air Measurement Station
G: Single Enthalpy Economizer, Low Leak
Dampers with Air Measurement Station
H: Dual Enthalpy Economizer, Low Leak
Dampers with Air Measurement Station
Dampers with Air Measurement Station
U: Single Enthalpy Economizer, Ultra Low Leak
Dampers with Air Measurement Station
V: Dual Enthalpy Economizer, Ultra Low Leak
Dampers with Air Measurement Station
10
Johnson Controls
Nomenclature (Continued)
5513350-JTG-1018
Digit 30: Energy Recovery Options
0: None
1: Low CFM Energy Recovery Wheel (ERW)
without VFD
2: Low CFM ERW with VFD
3: High CFM ERW without VFD
4: High CFM ERW with VFD
Digit 31: Refrigeration System
Piping Options
A: None
B: Suction and Discharge Valves
C: Suction, Discharge, and Liquid Valves
D: Suction, Discharge, and Liquid Valves with
Replaceable Core Filter Driers
E: Hot Gas Reheat (HGRH)
F: Suction and Discharge Valves with HGRH
G: Suction, Discharge, and Liquid Valves with
HGRH
H: Suction, Discharge, and Liquid Valves with
Replaceable Core Filter Driers with HGRH
N: E-Coat HGRH
P: Suction and Discharge Valves with E-Coat
HGRH
Q: Suction, Discharge, and Liquid Valves with
E-Coat HGRH
R: Suction, Discharge, and Liquid Valves with
Replaceable Core Filter Driers with E-Coat
D: Supply Smoke Detector
E: Return Smoke Detector
F: Supply and Return Smoke Detector
G: Convenience Outlet with Supply Smoke
Detector
H: Convenience Outlet with Return Smoke
Detector
J: Convenience Outlet with Supply and Return
Smoke Detectors
K: Convenience Outlet and Internal Lights with
Supply Smoke Detector
L: Convenience Outlet and Internal Lights with
Return Smoke Detector
M: Convenience Outlet and Internal Lights with
Supply and Return Smoke Detectors
Digit 33: Controls Options
A: None
B: Low Ambient
D: Subcool and Superheat Measurement
E: Low Ambient with Subcool and Superheat
Measurement
Digit 34: Interface Options
A: BACnet® MS/TP, Modbus™, N2
B: BACnet IP
G: BACnet® MS/TP, Modbus™, N2 with Mobile
0: None
1: Gas Heat, Side Penetration
2: Gas Heat, Bottom Penetration
3: Gas Heat, High Altitude Kit Natural Gas (NG),
Side Penetration
4: Gas Heat, High Altitude Kit NG, Bottom
Penetration
5: Gas Heat, High Altitude Kit Liquid Propane
(LP), Side Penetration
6: Gas Heat, High Altitude Kit LP, Bottom
Penetration
7: Gas Heat, LP Conversion Kit, Side Penetra-
tion
8: Gas Heat, LP Conversion Kit, Bottom
Penetration
Digit 37: Security Options
0: None
1: Supply and Return Opening Burglar Bars
Digit 38: Door Options
0: None
1: Viewport
2: Single Handle with Padlock
3: Single Handle with Padlock and Viewport
Digit 39: Cabinet Shipping Options
1: Single Piece Construction
Digit 40: Curb Options
A: No Roof Curb
C: Pedestal Curb
Digit 41: Pre-Evap Options
0: None
1, 2: Blank Pre-Evap Extension, No Air Blender
3, 4: Blank Pre-Evap Extension, with Air Blender
Digit 42: Shipped Loose Options
0: None
1: Spare Belts for Return/Exhaust
Digit 43: Construction Standard
0: None
Digit 44: Supply Fan VFD Frequency
A–Z: Internal Use Only
Digit 45: Supply Fan Brake
Horsepower
A–L: Internal Use Only
Digit 46: Future 3
0: None
Digit 47: Future 4
0: None
Digit 48: Testing and Special
Quotation (SQ)
0: None
T: Record Test Report
M: Mechanical Special
1: Mechanical Special and Record Test Report
S: Software Special
3: Software Special and Record Test Report
B: Mechanical and Software Special
5: Mechanical and Software Special and Record
Test Report
Digit 49: Generation/Revision Level
1: First Generation
Johnson Controls
11
5513350-JTG-1018
Selection Procedure Examples
GIVEN:
Required Cooling Capacity290,000 Btuh
Required Sensible Cooling 210,000 Btuh
Required Heating180,000 Btuh
Entering Air on Evaporator80.0°F dry bulb (DB)/
67.0°F wet bulb (WB)
Outside Design Temperature95.0°F
Supply Fan CFM12,000 CFM
2-inch Throwaway Filters
Variable Air Volume (VAV)
Calculating Cooling/Heating Capacity
1. Assume that the required cooling capacity and required sensible capacity include the space load requirements as well as the ventilation load requirements.
2. Calculate the supply fan motor heat Btuh addition.
d. Refer to Table 6 on page 28, and find the ca-
pacity of units that meet 331.0 total cooling ca-
pacity (TMBH) and 210 sensible cooling capacity
(SMBH) at 12,000 CFM, 95.0°F ambient, 80.0°F
entering dry bulb (EDB), and 67.0°F entering wet
bulb (EWB) onto the coil. A 30-ton unit can pro-
duce 362 TMBH and 287 SMBH.
e. Calculate the leaving air temperature.
1. Calculate sensible unit capacity with motor
heat included.
• Sensible Btuh = 287 MBH - 41.0 MBH
= 246.0 MBH
2. Calculate dry bulb supply air temperature
(SAT).
• Sensible Btuh = CFM x 1.085 x ∆T
• ∆T = 246,000 Btuh / (12,000 CFM x
1.085)
• ∆T = 18.9°F
• Dry bulb SAT = entering air tempera-
ture – ∆T
a. See Select Fan Speed and Horsepower Require-
ments for Supply Fan on page 13 to determine
the horsepower (HP) of the supply fan. The example is based on a 14.91 HP requirement.
b. Calculate sensible Btuh addition as a result of the
supply fan HP.
• Supply fan sensible Btuh addition = 14.91
HP x 2,750 (constant for motor heat calculation)
• Supply fan sensible Btuh addition = 41,003
Btuh
c. Calculate the total capacity requirement.
• Total capacity = required cooling capacity
(Btuh) + supply fan motor HP (Btuh)
• Total capacity = 290,000 Btuh + 41,003 Btuh
• Total capacity = 331,003 Btuh
• Dry bulb SAT = 80.0°F – 18.9°F = 61.1 °F
3. Calculate enthalpy delta.
• Total capacity Btuh = CFM x 4.5 x ∆h
• ∆h = 363,000 Btuh / (12,000 CFM x 4.5)
• ∆h = 6.7 Btu/lb
4. Calculate wet bulb SAT.
• Leaving enthalpy = enthalpy entering –
enthalpy delta (reference psychometric
chart to convert unit wet bulb temperature to Btu/lb)
• Leaving enthalpy = 31.6 Btu/lb – 6.7
Btu/lb
• Leaving enthalpy = 24.9 Btu/lb
• Wet bulb SAT = 57.7°F
5. Leaving air temperature = 61.1°F / 57.7°F
The 30 ton unit will meet the cooling requirements.
From the nomenclature, digit 3 will be B for 30 ton
capacity. Digit 4 will be 1 for standard capacity, stan-
dard efficiency as assumed.
12
Johnson Controls
5513350-JTG-1018
Selection Procedure Examples (Continued)
3. For gas heating capacity, reference Table 16 on page
57.
a. If the unit being selected will use gas heat, refer
to Table 16. Trace down to the output column.
b. Find the output that exceeds the 180,000 Btuh
requirement.
The 250 MBH output exceeds this requirement.
c. This option is available on the 30 ton unit.
From the nomenclature, select digit 5, option B for
staged gas, option C for staged gas with stainless
steel burner, or option G for modulating gas with
stainless steel burner.
From digit 6B, select option 1 for 250 MBH. The re-
sulting model number will show C1 for digits 5 and 6,
assuming staged gas with stainless steel burner was
selected.
4. For electric heating capacity, reference Table 17 on page 58.
a. If the unit being selected will use electric heat, re-
fer to Table 17. Trace down to the output column.
b. Find the output that exceeds the 180,000 Btuh
requirement at the given 460-3-60 voltage.
The 60 kW output exceeds this requirement.
c. This option is available on the 30 ton unit.
From the nomenclature, select digit 5, option M for
electric heat.
From digit 6A, select either option 1 with low staged
electric heat or option 4 with low silicon controlled
rectifier (SCR) electric heat. The resulting model
number will show M4 for digits 5 and 6, assuming
low SCR electric heat was selected.
5. For steam heating capacity for a 30 ton unit, reference
Table 22 on page 60 and Table 23 on page 61.
a. Assume the unit being selected will use a 10 psig
steam supply.
b. Find the output that exceeds the 180,000 Btuh
requirement with 12,000 CFM and 10 psig.
From the nomenclature, select digit 5, option K for
steam coil.
From digit 6C, select either option 1 for low heat without valves or option 2 for low heat with valves. The
resulting model number will show K2 for digits 5 and
6, assuming the unit is field provided with valves.
6. For hot water heating capacity for a 30 ton unit, refer-
ence Table 18 on page 58 and Table 19 on page
59.
a. Assume a hot water supply temperature of
140.0°F and 20 GPM.
b. Find the output that exceeds the 180,000 Btuh
requirement with 12,000 CFM at 140.0°F and 60
GPM.
The low heat option on Table 18 exceeds this re-
quirement.
c. This option is available on the 30 ton unit.
From the nomenclature, select digit 5, option L for hot
water coil heat.
From digit 6C, select either option 1 for low heat without valves or option 2 for low heat with valves. The
resulting model number will show L2 for digits 5 and 6,
assuming the unit is field provided with valves.
Select Fan Speed and Horsepower
Requirements for Supply Fan
1. Reference Table 27 on page 64 for the 30 ton unit.
a. Make any necessary additions to the static re-
sistance for the ductwork. Refer to Table 26 on
page 62:
+ gas heat (250 MBH)0.04 iwg
+ throwaway filters0.13 iwg
Total Static Resistance (TSP)5.50 iwg
0.09 iwg
0.69 iwg
The low heat option on Table 22 exceeds this re-
quirement.
c. This option is available on the 30 ton unit.
Johnson Controls
b. Enter Table 27 at 12,000 CFM and 5.50 iwg TSP:
RPM = 1768
BHP = 14.91
13
5513350-JTG-1018
Selection Procedure Examples (Continued)
2. From the nomenclature, select digit 15, option A to
opt for direct drive plenum (DDP) supply fan with
1-inch spring isolation. Select digit 16, option E for
20 HP supply fan motor. Select digit 17, option 2 for
ODP premium efciency, 1,800 RPM.
Select Fan Speed and Horsepower
Requirements of Exhaust Fan
1. Reference Table 29 on page 65 for the 30 ton unit. In the following example, a unit is designed for exhaust air capacity of 7,000 CFM.
a. Make any necessary additions to the static resis-
tance. To find the exhaust air damper pressure
drop, refer to Table 26 on page 62:
Return duct static pressure (assumed) 0.25 iwg
+ exhaust air damper pressure drop0.33 iwg
TSP0.58 iwg
b. Enter at 7,000 CFM and 0.58 iwg TSP:
RPM = 634 (interpolated)
BHP = 2.72 (interpolated)
2. From the nomenclature, select digit 19, option 2 for
exhaust with variable frequency drive (VFD) and
backdraft damper; digit 20, option B for the exhaust
fan with 1-inch spring isolation; and digit 21, option
E for 3 HP exhaust fan motor. The resulting model
number will show 2BE for digits 19, 20, and 21.
Select Energy Recovery Wheel (ERW)/
Hot Gas Reheat (HGRH)/Sound Attenuator/
Humidifier
Refer to Selection Navigator or contact the local sales office
for more information on available options and accessories.
Example Model Number
The following model number is an example based on the options selected in the previous sections.
G V B 1 C – 1 B 5 G A – 1 A 6 0 A – E 2 0 2 B – E 2 A D G – 2 C 0 E 0 – D M A A 3 – 1 0 0 1 A – 0 0 0 C G – 0 0 0 1
7
5
3
4
3. Capacity 30 Ton20. Forward Curved Exhaust Fan with 1-inch Spring Isolation
4. Standard Capacity, Standard Efciency21. Exhaust Fan Motor, 3 HP
5. Staged Gas Stainless Steel22. Exhaust Fan Motor Type, ODP Premium Efciency 1,800 RPM
*NOTE: Correction factors at sea level to calculate for actual tempera-
ture conditions.
The examples below will assist in determining the airflow
performance of NexusPremier™ at specific altitudes.
Example 1: What are the corrected cubic feet per minute
(CFM), static pressure, and brake horse power (BHP) at
an elevation of 5,000 feet if the airflow performance data is
6,000 CFM, 1.4 inches of water gauge (iwg), and 2.0 BHP?
Solution: At an elevation of 5,000 feet, the supply fan still
delivers 6,000 CFM if the revolutions per minute (RPM) is
unchanged. However, the altitude correction must be used
to determine the static pressure and BHP. Since no tem-
perature data is given, we assume an air temperature of
70.0°F. Table 3 shows the correction factor to be 0.832.
Corrected static pressure = 1.4 x 0.832 = 1.16 iwg
Corrected BHP = 2.0 x 0.832 = 1.66
Example 2: A system, located at 5,000 feet of elevation is
to deliver 6,000 CFM at a static pressure of 1.4 iwg. Use
the unit blower tables to select the RPM, blower speed, and
the BHP requirement.
Solution: As in the example above, no temperature information is given, so 70.0°F is assumed.
EnterTable 27 on page 64 at 6,000 CFM and static pres-
sure of 1.68 iwg. The RPM listed is the same RPM needed
at 5,000 feet.
Using interpolation, the corresponding BHP listed in the
table is 2.25. This value must be corrected for elevation.
BHP at 5,000 feet = 2.25 x 0.832 = 1.87
Example 3: Plot fan performance using Table 26 on page
62.
Plot the fan performance at cooling sea level (0 feet) elevation. Design conditions are a 25-ton unit producing 10,000
CFM at 1.5 external static pressure (ESP) with additional
static losses for a wet evaporator coil, bottom return air,
bottom supply air, outside air, and angled filter rack with
2-inch MERV 8 filters.
Wet evaporator coil standard capacity
additional static loss = 0.41 iwg
Bottom return air additional static loss = 0.05 iwg
Bottom supply air additional static loss = 0.06 iwg
Outside air additional static loss = 0.30 iwg
Air filter additional static loss = 0.11 iwg
The 1.4 iwg static pressure given is at an elevation of 5,000
feet. The first step is to convert this static pressure to equivalent sea level conditions.