Carrier WeatherExpert 48LC B14 Series User manual

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53480267-01 Printed in U.S.A. Form 48LCB-14-26-02SI Pg 1 9-19 Replaces: 48LCB-14-26-01SI
Installation Instructions
CONTENTS
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . 1
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Rated Indoor Airflow (cfm) . . . . . . . . . . . . . . . . . . . . . 2
INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Jobsite Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Step 1 — Plan for Unit Location . . . . . . . . . . . . . . . . 19
• ROOF MOUNT
Step 2 — Plan for Sequence of Unit Installation . . . 19
• CURB-MOUNTED INSTALLATION
• PAD-MOUNTED INSTALLATION
• FRAME-MOUNTED INSTALLATION
Step 3 — Inspect Unit . . . . . . . . . . . . . . . . . . . . . . . . 19
Step 4 — Provide Unit Support. . . . . . . . . . . . . . . . . 20
• ROOF CURB MOUNT
• SLAB MOUNT (HORIZONTAL UNITS ONLY)
• ALTERNATE UNIT SUPPORT (IN LIEU OF CURB OR
SLAB MOUNT)
Step 5 — Field Fabricate Ductwork . . . . . . . . . . . . . 24
Step 6 — Rig and Place Unit . . . . . . . . . . . . . . . . . . . 24
• POSITIONING ON CURB
Step 7 — Horizontal Duct Connection . . . . . . . . . . . 24
Step 8 — VAV Duct Pressure Transducer and Field
Tubing Installation . . . . . . . . . . . . . . . . . . . . . . . . . 24
Step 9 — Install Outside Air Hood . . . . . . . . . . . . . . 25
Step 10 — Economizer - Horizontal Airflow Units . 26
Step 11 — Install Flue Hood and Combustion Air
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Step 12 — Install Gas Piping. . . . . . . . . . . . . . . . . . . 26
• GAS SUPPLY LINE
• FACTORY-OPTION THRU-BASE CONNECTIONS
Step 14 — Make Electrical Connections . . . . . . . . . 29
• FIELD POWER SUPPLY
• UNITS WITHOUT FACTORY-INSTALLED NON-
FUSED DISCONNECT OR HACR
• UNITS WITH FACTORY-INSTALLED NON-FUSED
DISCONNECT OR HACR
• ALL UNITS
• CONVENIENCE OUTLETS
• HACR
• FACTORY-OPTION THRU-BASE CONNECTIONS
• UNITS WITHOUT THRU-BASE CONNECTIONS
• UNIT WITHOUT THRU-BASE CONNECTION KIT
• HEAT ANTICIPATOR SETTINGS
• TRANSFORMER CONNECTION FOR 208-V POWER
SUPPLY
VAV-RTU Open Controller. . . . . . . . . . . . . . . . . . . . . 35
Integrated Staging Control (ISC) Board . . . . . . . . . . 36
• SEQUENCE OF OPERATION
Variable Air Volume (VAV) with Variable Frequency
Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
• MULTI-SPEED VFD DISPLAY KIT (FIELD-
INSTALLED OPTION)
• CONNECTING THE KEYPAD TO THE VFD
• PROGRAM THE VFD FOR INDOOR FAN CONTROL
Smoke Detectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
• RETURN AIR SENSOR TUBE INSTALLATION
• SMOKE DETECTOR TEST MAGNET
• ADDITIONAL APPLICATION DATA
Step 15 — Install Accessories . . . . . . . . . . . . . . . . . 52
Pre-Start and Start-Up . . . . . . . . . . . . . . . . . . . . . . . 52
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . CL-1
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only
trained and qualified service personnel should install, repair, or
service air-conditioning equipment.
Untrained personnel can perform basic maintenance functions of
cleaning coils and filters and replacing filters. All other operations
should be performed by trained service personnel. When working
on air-conditioning equipment, observe precautions in the litera-
ture, tags and labels attached to the unit, and other safety precau-
tions that may apply.
Follow all safety codes, including ANSI (American National Stan-
dards Institute) Z223.1. Wear safety glasses and work gloves. Use
quenching cloth for unbrazing operations. Have fire extinguisher
available for all brazing operations.
It is important to recognize safety information. This is the safety-
alert symbol . When you see this symbol on the unit and in in-
structions or manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is used
to identify unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
WARNING
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in death, serious
personal injury and/or property damage.
Disconnect gas piping from unit when pressure testing at pres-
sure greater than 0.5 psig (3450 Pa). Pressures greater than
0.5 psig will cause gas valve damage resulting in hazardous
condition. If gas valve is subjected to pressure greater than
0.5 psig, it must be replaced before use. When pressure testing
field-supplied gas piping at pressures of 0.5 psig or less, a unit
connected to such piping must be isolated by closing the man-
ual gas valve(s).
WeatherExpert®48LC*B14-26
Single Package Rooftop Gas Heating/Electric Cooling Unit
with Multi-Zone VAV (Variable Air Volume) Operation
with Puron®(R-410A) Refrigerant

2
GENERAL
See Fig. 2-16 for unit dimensions. See Table 2 for operating
weights.
Rated Indoor Airflow (cfm)
Table 1 lists the rated indoor airflow used for the AHRI efficiency
rating for the units covered in this document.
WARNING
FIRE HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Inlet pressure tap set screw must be tightened and 1/8-in. NPT
pipe plug must be installed to prevent gas leaks.
WARNING
FIRE HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Manifold pressure tap set screw must be tightened and 1/8-in.
NPT pipe plug must be installed to prevent gas leaks.
WARNING
CARBON-MONOXIDE POISONING HAZARD
Failure to follow instructions could result in severe personal
injury or death due to carbon-monoxide poisoning, if combus-
tion products infiltrate into the building.
Check that all openings in the outside wall around the vent
(and air intake) pipe(s) are sealed to prevent infiltration of
combustion products into the building.
Check that furnace vent (and air intake) terminal(s) are not ob-
structed in any way during all seasons.
AVERTISSEMENT
RISQUE D’INTOXICATION AU MONOXYDE DE
CARBONE
Si ces directives ne sont pas suivies, cela peut entraîner des
blessures graves ou une intoxication au monoxyde de carbone
pouvant causer la mort, si des produits de combustion s’infil-
trent dans le bâtiment.
Vérifier que toutes les ouvertures pratiquées dans le mur ex-
térieur autour du ou des tuyaux d’évent (et de la prise d’air)
sont scellées de manière à empêcher l’infiltration de produits
de combustion dans le bâtiment.
Veiller à ce que la ou les sorties de l’évent de l’appareil de
chauffage (et la prise d’air) ne soient, en aucune façon, ob-
struées, quelle que soit la saison.
GAS VALVE
INLET PRESSURE
TAP SET SCREW
MANIFOLD
GAS VALVE
MANIFOLD PRESSURE
TAP SET SCREW
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal injury or
death.
Before performing service or maintenance operations on unit,
turn off main power switch to unit and install lock(s) and lock-
out tag(s). Ensure electrical service to rooftop unit agrees with
voltage and amperage listed on the unit rating plate. Unit may
have more than one power switch.
WARNING
PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could cause personal injury or
death.
Relieve pressure and recover all refrigerant before system re-
pair or final unit disposal.
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from refriger-
ants and oils.
CAUTION
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care and
wear appropriate protective clothing, safety glasses and gloves
when handling parts and servicing air conditioning equipment.
Table 1 — Rated Indoor Airflow
UNIT FULL LOAD AIRFLOW (CFM)
48LC*B14 4375
48LC*B17 4875
48LC*B20 5690
48LC*B24 6500
48LC*B26 7500

3
Fig. 1 — 48LC*B14-26 Model Number Nomenclature
48LCDB24A1A5-1N0A0
123456789
10 11 12 13 14 15 16 17 18
Model Series - WeatherExpert
®
LC - Ultra High Efficiency
Unit Heat Type
48 - Gas Heat Packaged Rooftop
Cooling Tons
14 - 12.5 ton
17 - 15 ton
20 - 17.5 ton
24 - 20 ton
26 - 23 ton
Heat Options
D = Low Gas Heat
E = Medium Gas Heat
F = High Gas Heat
S = Low Heat w/ Stainless Steel Exchanger
R = Medium Heat w/ Stainless Steel Exchanger
T = High Heat w/ Stainless Steel Exchanger
Sensor Options
A = None
B = RA Smoke Detector
C = SA Smoke Detector
D = RA + SA Smoke Detector
E = CO
2
F = RA Smoke Detector and CO
2
G = SA Smoke Detector and CO
2
H = RA + SA Smoke Detector and CO
2
Indoor Fan Motor Options
1 = Standard Static / Vertical Supply, Return Air Flow
2 = Medium Static / Vertical Supply, Return Air Flow
3 = High Static / Vertical Supply, Return Air Flow
4 = Ultra High Static / Vertical Supply, Return Air Flow
5 = Standard Static / Horizontal Supply, Return Air Flow
6 = Medium Static / Horizontal Supply, Return Air Flow
7 = High Static / Horizontal Supply, Return Air Flow
8 = Ultra High Static / Horizontal Supply, Return Air Flow
Coil Options: Fin/Tube (Condenser – Evaporator – Hail Guard)
A = Al/Cu – Al/Cu
B = Precoat Al/Cu – Al/Cu
C = E-coat Al/Cu – Al/Cu
D = E-coat Al/Cu – E-coat Al/Cu
E = Cu/Cu – Al/Cu
F = Cu/Cu – Cu/Cu
M = Al/Cu – Al/Cu – Louvered Hail Guard
N = Precoat Al/Cu – Al/Cu – Louvered Hail Guard
P = E-coat Al/Cu – Al/Cu – Louvered Hail Guard
Q = E-coat Al/Cu – E-coat Al/Cu – Louvered Hail Guard
R = Cu/Cu – Al/Cu – Louvered Hail Guard
S = Cu/Cu – Cu/Cu – Louvered Hail Guard
Voltage
1 = 575/3/60
5 = 208-230/3/60
6 = 460/3/60
Design Revision
- = Factory Design Revision
Intake / Exhaust Options (required on each unit)
B = Temperature Low Leak Economizer
with Barometric Relief
C = Temperature Low Leak Economizer
with Centrifugal Power Exhaust - Vertical Only
E = Enthalpy Low Leak Economizer
with Barometric Relief
F = Enthalpy Low Leak Economizer
with Centrifugal Power Exhaust - Vertical Only
N = Temperature Ultra Low Leak Economizer
with Barometric Relief
P = Temperature Ultra Low Leak Economizer
with Centrifugal Power Exhaust - Vertical Only
R = Enthalpy Ultra Low Leak Economizer
with Barometric Relief
S = Enthalpy Ultra Low Leak Economizer
with Centrifugal Power Exhaust - Vertical Only
Service Options
0 = None
1 = Unpowered Convenience Outlet
2 = Powered Convenience Outlet
3 = Hinged Panels
4 = Hinged Panels and
Unpowered Convenience Outlet
5 = Hinged Panels and
Powered Convenience Outlet
Packaging
0 = Standard
1 = LTL
Electrical Options
A = None
B = HACR Circuit Breaker
C = Non-Fused Disconnect
Example:
Position:
Refrigerant System
B = Three stage cooling capacity control
with multi-zone VAV operation
Base Unit Controls
1 = VAV-RTU Open Controller
(required on each model)
NOTE: Not all possible options can be displayed above. Refer to other support material or your local Carrier Expert

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Fig. 2 — 48LC*B14 Vertical Airflow

5
Fig. 3 — 48LC*B14 Horizontal Airflow

6
Fig. 4 — 48LC*B14 Back View and Condensate Drain Location

7
Fig. 5 — 48LC*B14 Corner Weights and Clearances

8
Fig. 6 — 48LC*B14 Bottom View

9
Fig. 7 — 48LC*B17-20 Vertical Airflow

10
Fig. 8 — 48LC*B17-20 Horizontal Airflow

11
Fig. 9 — 48LC*B17-20 Back View and Condensate Drain Location

12
Fig. 10 — 48LC*B17-20 Corner Weights and Clearances

13
Fig. 11 — 48LC*B17-20 Bottom View

14
Fig. 12 — 48LC*B24-26 Vertical Airflow

15
Fig. 13 — 48LC*B24-26 Horizontal Airflow

16
Fig. 14 — 48LC*B24-26 Back View and Condensate Drain Location

17
Fig. 15 — 48LC*B24-26 Corner Weights and Clearances

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Fig. 16 — 48LC*B24-26 Bottom View

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INSTALLATION
Jobsite Survey
Complete the following checks before installation.
1. Consult local building codes and the NEC (National Elec-
trical Code) ANSI/NFPA 70 for special installation
requirements.
2. Determine unit location (from project plans) or select unit
location.
3. Check for possible overhead obstructions which may inter-
fere with unit lifting or rigging.
Step 1 — Plan for Unit Location
Select a location for the unit and its support system (curb or other)
that provides for the minimum clearances required for safety. This
includes the clearance to combustible surfaces, unit performance
and service access below, around, and above unit as specified in
unit drawings. See Fig. 5, 10, and 15.
NOTE: Consider also the effect of adjacent units.
Be sure that the unit is installed such that snow will not block the
combustion air intake or flute outlet.
Unit may be installed directly on wood flooring or on Class A, B,
or C roof-covering material when roof curb is used.
Do not install unit in an indoor location. Do not locate air inlets
near exhaust vents or other sources of contaminated air. For proper
unit operation, adequate combustion and ventilation air must be
provided in accordance with Section 5.3 (Air for Combustion and
Ventilation) of the National Fuel Gas Code, ANSI Z223.1 (Ameri-
can National Standards Institute) and NFPA (National Fire Protec-
tion Association) 54 TIA-54-84-1. In Canada, installation must be
in accordance with the CAN1-B149 installation codes for gas
burning appliances.
Although unit is weatherproof, avoid locations that permit water
from higher level runoff and overhangs to fall onto the unit.
Locate mechanical draft system flue assembly at least 4 ft (1.2 m)
from any opening through which combustion products could enter
the building, and at least 4 ft (1.2 m) from any adjacent building
(or per local code). Locate the flue assembly at least 10 ft (3.05 m)
from an adjacent unit’s fresh air intake hood if within 3 ft (0.91 m)
of same elevation (or per local code). When unit is located adja-
cent to public walkways, flue assembly must be at least 7 ft
(2.1 m) above grade.
Select a unit mounting system that provides adequate height to al-
low installation of condensate trap per requirements. Refer to
Step 11 — Install External Condensate Trap and Line – for re-
quired trap dimensions.
ROOF MOUNT
Check building codes for weight distribution requirements. Unit
operating weight is shown in Table 2.
Step 2 — Plan for Sequence of Unit Installation
The support method used for this unit will dictate different se-
quences for the steps of unit installation. For example, on curb-
mounted units, some accessories must be installed on the unit
before the unit is placed on the curb. Review the following for rec-
ommended sequences for installation steps.
CURB-MOUNTED INSTALLATION
1. Install curb
2. Install field-fabricated ductwork inside curb
3. Install thru-base service connection fittings (affects curb and
unit)
4. Rig and place unit
5. Remove top skid
6. Install outside air hood
7. Install smoke detector tube
8. Install combustion air hood
9. Install flue hood
10. Install gas piping
11. Install condensate line trap and piping
12. Make electrical connections
13. Install other accessories
PAD-MOUNTED INSTALLATION
1. Prepare pad and unit supports
2. Rig and place unit
3. Remove duct covers and top skid
4. Install smoke detector return air sensor tube
5. Install field-fabricated ductwork at unit duct openings
6. Install outside air hood
7. Install combustion air hood
8. Install flue hood
9. Install gas piping
10. Install condensate line trap and piping
11. Make electrical connections
12. Install other accessories
FRAME-MOUNTED INSTALLATION
Frame-mounted applications generally follow the sequence for a
curb installation. Adapt as required to suit specific installation
plan.
Step 3 — Inspect Unit
Inspect unit for transportation damage. File any claim with trans-
portation agency.
Confirm before installation of unit that voltage, amperage and cir-
cuit protection requirements listed on unit data plate agree with
power supply provided.
On units with hinged panel option, check to be sure all latches are
tight and in closed position.
Locate the carton containing the outside air hood parts; see Fig. 17
and 25. Do not remove carton until unit has been rigged and locat-
ed in final position.
Table 2 — Operating Weights
48LC*B UNIT LB (KG)
14 17 20 24 26
Base Unit 1853 (842.3) 2095 (952.3) 2201 (1000.7) 2347 (1067.0) 2492 (1132.6)
Economizer 246 (112) 246 (112) 246 (112) 246 (112) 246 (112)
Powered Outlet 35 (16) 35 (16) 35 (16) 35 (16) 35 (16)
Curb
14-in./356 mm 240 (109) 240 (109) 255 (116) 255 (116) 273 (124)
24-in./610 mm 340 (154) 340 (154) 355 (161) 355 (161) 355 (161)

20
Fig. 17 — Typical Access Panel and Compressor
Locations
Step 4 — Provide Unit Support
ROOF CURB MOUNT
Accessory roof curb details and dimensions are shown in Fig. 20-
22. Assemble and install accessory roof curb in accordance with
instructions shipped with the curb.
NOTE: The gasketing of the unit to the roof curb is critical for a
watertight seal. Install gasket supplied with the roof curb as shown
in Fig. 20-22. Improperly applied gasket can also result in air leaks
and poor unit performance.
Curb should be level. This is necessary for unit drain to function
properly. Unit leveling tolerances are shown in Fig. 18. Refer to
Accessory Roof Curb Installation Instructions for additional infor-
mation as required.
Install insulation, cant strips, roofing felt, and counter flashing as
shown. Ductwork must be attached to curb and not to the unit.
Thru-the-base power connection must be installed before the unit
is set on the roof curb. If field-installed thru-the-roof curb gas con-
nections are desired remove knockout in basepan located in the
gas section, see Fig. 17 for location. Gas connections and power
connections to the unit must be field installed after the unit is in-
stalled on the roof curb.
Fig. 18 — Unit Leveling Tolerances
If electrical and control wiring is to be routed through the basepan,
remove the knockouts in the basepan located in the control box ac-
cess area (see Fig. 17). For basepan knockout locations for vertical
airflow units, see Fig. 2, 7, or 12; for horizontal airflow units, see
Fig. 3, 8, or 13. Attach the service connections to the basepan.
SLAB MOUNT (HORIZONTAL UNITS ONLY)
Provide a level concrete slab that extends a minimum of 6-in.
(150 mm) beyond unit cabinet. Install a gravel apron in front of
condenser coil air inlet to prevent grass and foliage from obstruct-
ing airflow.
NOTE: Horizontal units may be installed on a roof curb if
required.
ALTERNATE UNIT SUPPORT (IN LIEU OF CURB OR
SLAB MOUNT)
A non-combustible sleeper rail can be used in the unit curb sup-
port area. If sleeper rails cannot be used, support the long sides of
the unit with a minimum of 4 equally spaced 4-in. x 4-in. (102 mm
x 102 mm) pads on each side. Locate pads so that they support the
rails. Make sure to avoid the fork openings.
Fig. 19 — Rigging Details
CONTROL BOX
ACCESS PANEL
FILTER AND
INDOOR COIL
ACCESS PANEL
INDOOR BLOWER
ACCESS PANEL
GAS HEAT
ACCESS PANEL COMPRESSOR
(EACH SIDE)
HOOD CARTON LOCATION
(REAR ACCESS PANEL)
A-B
0.25 (6)
B-C
0.5 (12)
A-C
0.5 (12)
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
A
B
C
"B"
"C"
"A"
(914-1371)
36"-54"
DETAIL A
SEE DETAIL A
PLACE ALL SEAL STRIP
IN PLACE BEFORE PLACING
UNIT ON ROOF CURB.
DUCT END
NOTES:
1. Dimensions in ( ) are inches.
2. Hook rigging shackles through holes in base rail, as shown in detail “A.” Holes in base rails are centered around the unit center of gravity. Use
wooden top to prevent rigging straps from damaging unit.
UNIT MAX WEIGHT DIMENSIONS
ABC
lb kg in. mm in. mm in. mm
48LC*B14 2135 970 127.8 3249 59.1 1501 52.3 1328
48LC*B17 2377 1080 141.5 3595 65.5 1664 60.3 1532
48LC*B20 2483 1129 141.5 3595 65.5 1664 60.3 1532
48LC*B24 2629 1195 157.8 4007 72.8 1849 60.3 1532
48LC*B26 2774 1261 157.8 4007 72.8 1849 60.3 1532