Carrier 50LJ User Manual
48LJ, 50LJ/LW024
f
HEATING & COOLING
Single-Package Cooling Units
Installation, Start-Up and Service
Instructions
SAFETY CONSIDERATIONS
Installation and servicing of air conditioning equipment can
be hazardous due to system pressure and electrical compo
nents. Only trained and qualified service personnel should
install, repair or service air conditioning equipment.
Untrained personnel can perform basic maintenance func
tions of cleaning coils and filters and replacing filters. All
other operations should be performed by trained service per
sonnel. When working on air conditioning equipment, ob
serve precautions in the literature, tags and labels
attached to the unit, and the other safety precautions that
may apply.
Follow all safety codes, including ANSI Z223.1-1984.
Wear safety glasses and work gloves. Use quenching cloth
for unbrazing operations. Have fire extinguisher available
for all brazing operations.
FOR YOUR SAFETY
Do not store or use gasoline or other flammable vapors
and liquids in the vicinity of this or any other
appliance.
A WARNING
Improper installation, adjustments, alteration, service
or maintenance can cause injury or property damage.
Refer to this manual. For assistance or additional in
formation, consult a qualified installer, service agency
or the gas supplier.
A WARNING
Before performing service or maintenance operations
on unit, turn off main power switch to unit. Electrical
shock could cause personnel injury.
FOR YOUR SAFETY
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance. Do not touch any
electrical switch; do not use any phone in your build
ing. Immediately call your gas supplier from a neigh
bor’s phone. Follow the gas supplier’s instructions.
If you cannot reach your gas supplier, call the fire
department.
A CAUTION
Disconnect gas piping from unit when leak testing at
pressures greater than 0.5 psig. Pressures greater than
0.5 psig will cause gas valve damage resulting in a
hazardous condition. If gas valve is subjected to pres
sure greater than 0.5 psig, it must be replaced. When
pressure testing field-supplied gas piping at pressures
of 0.5 psig or less, the unit connected to such piping
must be isolated by manually closing the gas valve.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obiigations.
Book|1 |1 PC 111 Catalog No. 564-937 Printed in U S A Form 48/50LJ,LW-2SI Pg 1 2-92 Replaces; 4/50LJ,LW-1 SI
Tab la 1b
CONTENTS
Page
SAFETY CONSIDERATIONS .............................. 1
INSTALLATION ...................................................2-21
Rigging and Unit Placement ................................ 2
Roof Curb ...............................................................2
Roof Mount ............................................................ 2
Slab Mount
Alternate Unit Support Methods
............................................................
.........................
2
2
Positioning ............................................................ 2
Field-Fabricated Ductwork
Condensate Drain
...............................................
Outdoor-Air Inlet Adjustments
..................................
..........................
3
8
8
Install Outdoor-Air Hoods .................................. 12
Field Wiring Routing ........................................... 14
Field Electrical Connections
.............................
15
Gas Piping ........................................................... 21
Installing Flue/lnlet Hoods ................................. 21
START-UP ........................................................ 21-24
Unit Preparation .................................................. 21
Internal Wiring ..................................................... 21
Refrigerant Service Ports
Crankcase Heaters
.............................................
..................................
21
21
Compressor Oil ................................................... 21
Unit Voltage ......................................................... 21
Leak Test and Dehydration
Evaporator Fan, Belt and Sheaves
Condenser Fans and Motors
...............................
...................
.............................
21
22
22
Page
Return-Air Filters
Economizer Inlet Screens
................................................
..................................
22
22
Economizer Dampers and Potentiometer
Settings
Operating Sequences
..............................................................
.........................................
22
23
Ventilation Air Circulation
(Continuous Fan)
..............................................
24
Automatic Changeover Using Automatic
Changeover Thermostat ................................... 24
Head Pressure Control ....................................... 24
SERVICE
..........................................................
24-37
Service Access .................................................... 24
Cleaning ............................................................... 26
Lubrication ........................................................... 26
Adjustments
Refrigerant Feed Components
Acutrol™ Refrigerant Metering Device
........................................................
..........................
.............
26
29
29
Filter Drier ............................................................ 29
Protective Devices .............................................. 29
Relief Devices ...................................................... 30
Control Circuit, 115-V ....................................... 30
Control Circuit, 24-V ......................................... 30
Gas Heat ............................................................... 30
Electric Heat ....................................................... 32
Control Board Checkout
...................................
32
INSTALLATION
This book contains instructions for 48/50LJ vertical supply/
return units and 50LW horizontal supply/retum units.
IMPORTANT: These units are not designed for han
dling by forklift trucks.
Rigging and Unit Placement — Inspect unit for trans
portation damage. File claim with transportation agency.
Do not drop unit; keep upright. Use spreader bars over unit
to prevent sling or cable damage. Rollers may be used to
move unit across a roof. Level by using unit frame as ref
erence. See Fig. 1 for additional information. Unit physical
data is shown in Tables la and lb.
Roof Curb — Assemble and install as described in
instructions shipped with this accessory. Accessory roof curb
and information required to field fabricate a roof curb is
shown in Fig. 2a and 2b. Install insulation cant strips, roof
ing and counter flashing as required. For unit drains to func
tion properly, curb must be level or within tolerances shown
in Fig. 3.
Roof Mount — Check building codes for weight distri
bution requirements. Unit weight is shown in Tables la and
lb.
Slab Mount — Provide a level concrete slab that ex
tends beyond unit cabinet at least 6 Inches. Make a slab
8-in. thick with 4 in. above grade. (For condensate drain to
function properly, slab must be at least 4 in. above grade.
See Fig. 4.) Use gravel apron in front of condenser air inlet
to prevent grass and foliage from obstructing airflow.
Alternate Unit Support Methods Where the pre
ferred curb or slab mount cannot be used, support unit with
sleepers on perimeter, using curb support area. However, if
sleepers cannot be used, support long sides of unit (see
Fig. 5a — 5c) with three 4-in. x 4-in. pads equally spaced.
Unit may sag if supported by comers only.
Positioning — Provide clearance around and above unit
for airflow, safety, and service access. Allow 12 ft above
the unit, and at least 4 ft on all sides for rated performance
and code compliance. If unit has economizer, allow 6 ft
clearance on that side. For preferred service access, allow
6 ft clearance on all sides.
Do not install unit in an indoor location. Do not locate
air inlets near exhaust vents or other sources of contami
nated air.
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
IMPORTANT: Always line up the condenser end of
the unit tight against the roof curb.
NOTES:
1 Rig with 4 cables and spread with two 95-in. (2413-mm) and
2 “A” long suitable spreader bars.
2 Center of gravity and unit weight include economizer, but not econ
omizer hood
f
1 All panels must be in place when rigging.
2. Unit is not designed for handling by forklift truck.
A CAUTION
MODEL
48LJD
49LJE
50LJ
50LW
ROOF CURB
Lb
280
NOTICE TO RIGGERS
UNIT WEIGHT A
Lb
2895
2975
2565 1164
2775
Kg
127
Kg
1313
1349
1259
ACCESSORY/OPTION WEIGHTS
ECONOMIZER
WITHOUT HOOD
Lb
140 63.6
In.
85 91
85.91
6.14 1680
85.91
Kg
mm
2182
2182
2182
ECONOMIZER
Lb
155
B
In. mm In. mm
61 1549 43 1092
61 1549 43 1092
49 1245
61
HOOD
Kg
1549 43
44
POWER EXHAUST/
BAROMETRIC
RELIEF HOOD
Lb
70.3 130 59.1
3/4 IN (19 MM) NOTCHES
IN END OF SPREADERS
C
1118
1092
Kg
Fig. 1 — Rigging Labei
Field-Fabricated Ductwork — Secure all ducts to
building structure, using flexible duct connectors between
roofcurb and ducts as required. Ducts passing through an
unconditioned space must be insulated and covered with a
vapor barrier. Outlet grilles must not lie directly below unit
discharge.
48LJ UNITS — These units are field-convertible with the
use of an accessory horizontal conversion kit. They are shipped
from the factory as vertical supply/retum, but may be field
converted to horizontal supply/retum.
Attach field-fabricated ductwork to the roof curb. The
retum-air duct connection (inside dimensions) is 46.75-in.
long X 30.59-in. wide; the supply-air duct connection (in
side dimensions) is 38.63-in. long x 27-in. wide. Connect
ductwork to 16-gage roof curb material. Secure all ducts to
the building structure, using flexible duct connectors be
tween roof curb and ducts as required. Ducts passing through
an unconditioned space must be insulated and covered with
a vapor barrier. Outlet grilles must not lie directly below
unit discharge. The return duct must have a 90-degree el
bow before opening into the occupied building space if unit
is equipped with power exhaust.
Vertical discharge ducts are designed to be attached to
accessory roof curb. If unit is mounted on dunnage, it is
recommended that the ducts be supported by cross braces
as shown for accessory roof curb. Duct should be the same
size as shown on the roof curb certified drawing.
Units may be connected to horizontal supply/retum
ductwork with the use of the accessory horizontal conver
sion package.
50LJ UNITS — On these units, attach field-fabricated
ductwork to roof curb. The retum-air duct connection
(inside dimensions) is 49.81-in. long x 30.59-in. wide; the
supply-air duct connection (inside dimensions) is 37.87-in.
long X 31.02-in. wide. Connect ductwork to 16-gage roof
curb material. (See installation instractions shipped with
accessory roof curb.)
50LW UNITS — On these units, attach field-fabricated
ductwork to factory-supplied duct flanges mounted on the
side of the unit. See Fig. 5c. Duct flange height is approx
imately one inch; flange is 18-gage sheet metal. The hori
zontal supply and return duct openings (inside dimensions)
are 26.85-in. wide x 42.03-in. high.
Table 1a — Physical Data, 48LJ Units
BASE UNIT 48LJ
NOMINAL CAPACITY (tons) lb
OPERATING WEIGHT (lb)*
COMPRESSORS (2 each unit)
Capacity Steps (%)
REFRIGERANT
Operating Charge (lb), Sys 1/Sys 2
CONDENSER COILS
Face Area (sq ft)
Fins Per In. (Al)
EVAPORATOR COILS
Face Area (sq ft)
Fins Per In.
FURNACE SECTION
Number of Heat Exchangers
Input (MBtuh)
Output (MBtuh)
Temperature Rise (°F)
Burner Orifice Diameter (in. ...drill no.)
Pilot Orifice Diameter (in. ...drill no.)
Firing Stages
Number of Gas Valves
CONDENSER FANS (2 each unit)
Nominal Cfm
Nominal Hp
EVAPORATOR FANS (1 each unit)t
Nominal Cfm
Maximum Allowable Cfm
Maximum Allowable Rpm
Standard Motor and Drive
Motor Hp
Full Load Efficiency (%)
Motor Frame Size
Fan Pulley Pitch Diameter (in.)
Motor Pulley Pitch Diameter (in.)
Resulting Fan Rpm
Optional Motor and Drive
Motor Hp
Full Load Efficiency (%)
Motor Frame Size
Fan Pulley Pitch Diameter (In.)
Motor Pulley Pitch Diameter (in.)
Resulting Fan Rpm
Optional Power Exhaust
Motors...Hp
Fans...Diameter (in.)
Filters (Quantity...L x W xD)
20% Standard Efficiency Disposable
'Weights include economizer, but not rainhood. See Fig. 1 for weights of options and accessories.
tStandard fan motor is supplied with standard fan drive and belts Optional motor is supplied with optional fan drive,
Centrifugai Type, 18 x 15-in., 1.438-in. Fan Pulley Bore
D024
20
2895
Hermetric, 3600 Rpm
50, 100
R-22 Controlled by Acutrol™ Metering Device
3-Row, %-in. Tube Diameter
4-Row, %-in. Tube Diameter
16 0/16.0
24.75
17.0
20.3
15
5
242
194
10-40
.129...30
.046...56
2
1
Propelier Type, 30-in. Diameter, 1130 Rpm
13,000
1 0
8,000
10,000
1,200
1750 Rpm
5
84.3
184T
10.6
4.75
780
1750 Rpm
7.5
84.8
213T
8.0
4.12
900
Propeller Type, 1140 Rpm
1.. 1.0
1 .24
2. 18 X 24 X 2
4...24 X 24 X 2
E024
20
2975
10
475
380
30-60
.129 ..30
.055...54
2
2
pulleys, and belts. Other combinations are field supplied.
Table 1b — Physical Data, 50LJ/LW Units
BASE UNIT 50
NOMINAL CAPACITY (tons) 20
OPERATING WEIGHT (lb)*
COMPRESSORS (2 each unit)
Capacity Steps (%)
REFRIGERANT
Operating Charge (lb), Sys 1/Sys 2
CONDENSER COILS
Face Area (sq ft)
Fins Per In. (Al)
EVAPORATOR COILS
Face Area (sq ft)
Fins Per In.
CONDENSER FANS (2 each unit)
Nominal Cfm
Nominal Hp
EVAPORATOR FANS (1 each unit)t
Nominal Cfm
Maximum Allowable Cfm
Maximum Allowable Rpm
Standard Motor and Drive
Motor Hp
Full Load Efficiency (%)
Motor Frame Size
Fan Pulley Pitch Diameter (in.)
Motor Pulley Pitch Diameter (in.)
Resulting Fan Rpm
Optional Motor and Drive
Motor Hp
Full Load Efficiency (%)
Motor Frame Size
Fan Pulley Pitch Diameter (in.)
Motor Pulley Pitch Diameter (in.)
Resulting Fan Rpm
Optional Power Exhaust**
Motors...Hp
Fans...Diameter (in.)
Filters (Quantity...L x W xD)
20% Standard Efficiency Disposable
'Weights include economizer, but not rainhood. See Fig 1 for weights of options and accessories.
tStandard fan motor is supplied with standard fan drive, pulleys and belts Optional fan motor is supplied with op
tional fan drive, pulleys, and belts Other combinations are field supplied.
"Optional unit-mounted power exhaust not available on Model 50LW. Accessory power exhaust may be duct mounted
Centrifugal Type, 18 x 15-in., 1.438 in. Fan Pulley Bore
LJ024 LW024
20
2565
Hermetric, 3600 Rpm
50, 100
R-22 Controlled by Acutrol™ Metering Device
16.0/16.0
2775
3-Row, %-in. Tube Diameter
24.75
17.0
4-Row, %-in. Tube Diameter
20.3
15
Propelier Type, 30-in. Diameter, 1140 Rpm
13,000
1.0
8,000
10,000
1,200
1750 Rpm
5
84.3
184T
10.6
4.75
780
1750 Rpm
7.5
84.8
213T
80
4.12
900
Propeller Tyi
1. 1
1...24
De, 1140 Rpm
2...18 X 24 X 2
4 ..24 X 24 X 2
on 50LW installation
NOTES:
1. Roofcurb accessory 50DJ900401 is shipped disassembled.
2. Dimensions in ( ) are in millimeters.
3 Roofcurb: 16 gage steel.
4. A 90 degree return duct elbow shall be provided for vertical
Fig. 2a — Roof Curb Details, 48LJ/50LW024 Units
NOTES:
1. Roofcurb accessory 50DJ900391 is shipped disassembled.
2. Dimensions in ( ) are in millimeters.
3 Roofcurb: 16 gage steel.
4 A 90 degree return duct elbow shall be provided for vertical
return units equipped with power exhaust
5. A 90 degree supply duct elbow shall be provided for units
equipped with electric heat
Fig. 3 — Unit Leveling Tolerances
Condensate Drain — See Fig. 5a - 5c for drain
location. A drain assembly consisting of a 10-gage plate
with PA in. half coupling welded to it is shipped inside the
base unit, taped to the basepan in the filter section. Open
the access panel marked FILTER SECTION and fine drain
assembly and the 4 screws required to mount it in the left-
hand comer. After unit has been set in place on the roof,
remove drain assembly and attach it to the bottom of the
unit base rail using the screws provided. See Fig. 4. Use a
trap at least 4-in. deep and protect against freeze-up.
NOTE: To prevent the hazard of stagnant water build-up in the drain
pan of the evaporator section, unit can only be pitched as shown.
See Table 1 for allowable B tolerances.
DIMENSIONS (degrees and In.)
UNIT B
Deg In.*
48U 1 38 4.00
50LJ 1.00 3.25
50LW
'From edge of unit to horizontal
1.38
4.00
Deg
.50
C
In.* Deg In.*
.75
.50
D
.75
On slab mount applications, and when mounted on
sleepers, seal hole in bottom of base rail and attach drain
assembly as low as possible to side of base rail.
NOTE: Drain hole must be drilled in rail. There is no factorysupplied drain hole in the side of the base rail.
Outdoor-Air Inlet Adjustments
ECONOMIZER SETTINGS
Enthalpy Sensor (Fig. 61 — This sensor is located on the
partition separating the outdoor air from the return air. See
Fig. 7. The enthalpy setting adjustment is on the top of the
economizer motor. See Fig. 8. For maximum benefit of out
door air, set enthalpy control to the A setting. See Fig. 8
and 9.
Mixed-Air Thermistor — The mixed-air thermistor (MAT)
set point adjustment is on the top of the economizer motor.
This motor is located in the retum-air section, and is
accessed by opening the access panel marked FILTER
SECTION. See Fig. 8. Set MAT set point adjustment dial
to the desired setting. The factory setting is 55 F ± 5° F;
the range is 40 to 90 F. The MAT is located on the filter
rack.
Minimum Damper Position Set Point — The minimum po
sition adjustment is located on the cover of the economizer
motor. See Fig. 8. Adjust by setting the fan switch to ON
position (continuous fan operation), and setting the system
selector switch to OFF position. Then turn adjustment screw
slowly until the dampers assume the desired vent position.
Do not manually operate the damper motor, damage to the
motor my result.
BOTTOM OF
BASE RAIL
Fig. 4 — Condensate Drain Piping Details
UNIT SIZE
48LJD024 2895 1313.0
48LJE024 2975
WEIGHT* A
Lb
Kg
1349.4 1813 6-1%
mm
Ft-in.
1813 6-1%
B C D
mm Ft-in. mm
2182
7-1%
2182 7-1%
Ft-in.
682 2-2%
682 2-2%
‘See note 9.
NOTES:
1 Dimensions in [
2.
Center of gravity.
are in miilimeters
3 Ailow 12'-0" [3658] at top and 6'-0" [1829] on sides for service and op-
erationai clearance.
4. On multiunit applications allow 12'-0" [3658] between adjacent condens
ers and economizers.
5. For smaller service and operational clearances, contact Carrier Appli
cation Engineering Department.
6. Vertical discharge ducts are designed to be attached to accessory roof
curb. If unit is mounted on dunnage, it is recommended the ducts be
supported by cross braces as done on the accessory roof curb.
7 Always line up condenser end of unit tight against the roof curb.
8. Units with power exhaust require a 90 degree elbow in return air duct.
9. Weight of unit includes optional economizer. For unit without econo
mizer, deduct 130 lb (59 Kg).
Ft-in. mm Ft-in.
mm
12-9% 534 1-9
3909
12-9% 534 1-9
3909
E F
mm
2187
2187
Ft-in. mm
7-2%4
807
7-2%4 807
G
Ft-in.
2-7%
2-7%
POWER IN (SIDE).
0'-3/4'
[13] NPT LOW VOLTASE
0'-3 1/2'
[89] NPT FIELD POWER
(SEE VIEW A)
0'-7 13/16:
[199]
0'-5 13/16'
[146]
/—CONTROL BOX ACCESS DOOR
UNIT SIZE
50LJ024
WEIGHr
Lb
Kg
2565 1163.5
mm
1556
A
5-1V4
Ft-ln.
B
Ft-in
mm
5-6V8 3141 10-3'Vi 6
1680
C
D
mm Ft-in. mm Ft-in.
1-8"/i6 807 2-7% 2048 6-8%
526
E
mm Ft-in mm Ft-in.
*See note 10
NOTES:
1. Dimensions in [ ] are in miiiimeters.
Center of gravity.
3. Allow 12'-0" [3658] at top and 6'-0" [1829] on sides for service and operational clearance
4. On multiunit applications aliow 12'-0" [3658] between adjacent condensers and economizers
5. For smaller service and operational clearances, contact Carrier Application Engineering Department
6. Vertical discharge ducts are designed to be attached to accessory roof curb If unit is mounted on dunnage,
it is recommended the ducts be supported by cross braces as done on the accessory roof curb
7 Always line up condenser end of unit tight against the roof curb.
8 Units with power exhaust require a 90 degree elbow in return-air duct.
9. Units with electric heat require a 90 degree elbow in supply-air duct.
10 Weight of unit includes optional economizer For unit without economizer, deduct 130 lb (59 Kg)
F
Fig. 5b — Base Unit Dimensions, 50LJ024 Units
10
mm
534
E
Ft-in.
1-9
UNIT SIZE
50LW024 2775 1258 7 1803
WEIGHr
Lb
Kg
mm
\ B
Ft-in
mm Ft-in.
2182 7-1% 682
5-11
C
mm Ft-in.
2-2%
D
mm Ft-in.
3909 12-9%
*See note 10
NOTES:
1. Dimensions in [ ] are in miiiimeters.
2 ® Center of gravity.
3 Allow 12'-0" [3658] at top and 6'-0" [1829] on sides for service and operational clearance.
4 On multiunit applications allow 12'-0" [3658] between adjacent condensers and economizers.
5. For smaller service and operational clearances, contact Carrier Application Engineering Department
6. Always line up condenser end of unit tight against the roof curb.
7. Weight of unit includes optional economizer. For unit without economizer, deduct 130 lb (59 Kg)
POWER IN (SIDE:
(SEE VIEW A)
0'-7 13/161
[193]
0'-3/4' [19] NPT LOW VOLTAGE
0'-3 1/2' [89] NPT FIELD POWER
-CONTROL BOX ACCESS DOOR
ELECTRIC HEAT CONTROL
BOX ACCESS PANEL
-ACCESS PANEL
f
Fig. 5c - Base Unit Dimensions, 50LW024 Units
11
ENTHALPY SENSOR
Fig. 7 — Enthalpy Sensor Location
Fig. 6 — Enthalpy Sensor
■CONNECTOR
Fig. 9 — Setting "A" Operating Conditions
Install Outdoor-Air Hoods
ECONOMIZER HOODS — These hoods are shipped sep
arately from the base unit in a carton. This carton contains;
3 preassembled economizer hoods
1 filter angle
3 filter retainers
6 aluminum mesh cleanable filters, 16 in. x 20 in. x 2 in.
2 channel panels "I pj cross-section
1 channel clip J ®
1 fastener package (taped to a hood)
The fastener package contains;
8 capscrew bolts, V4—20 x '/2-in. long
8 nuts, '/4—20
18 screws, V4 AB x ys-in. long
8.3 ft of '/8-in. thick X '/2-in. wide seal strip with pressure-
sensitive adhesive on one side.
-ENTHALPY
-MINIMUM
POSITION
(CLOCKWISE
TO INCREASE)
Fig. 8 - Enthalpy Sensor Setting, Mixed Air
Thermistor (MAT) and Economizer Minimum
Position Adjustments (Top of Economizer Motor)
1. Remove the lag screws holding the economizer hoods
and channel panels to the shipping skid. (There are 4
lag screws per side.)
2. Remove the lag screws holding the filter angle and chan
nel clip to the shipping skid. (There are 2 lag screws
per part.)
3. The filters are wrapped to prevent shipping damage.
Remove the screws holding the filter retainers to the
hoods. (There are 4 screws per retainer.)
4. Remove wrap from filters. Do not reinstall until after
the hoods are mounted to the unit.
12
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