Carrier 50Tj016 028 Users Manual

50TJ016-028 to the manual 545c823f-e874-4567-93b4-7a1ac17ea64f

2015-01-24

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50TJ016-028
Single-Package Rooftop Units
Electric Cooling with Electric Heat Option

Installation, Start-Up and
Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . .1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
Step 1 — Provide Unit Support . . . . . . . . . . . . . . . . . . . . . .1
• ROOF CURB
• ALTERNATE UNIT SUPPORT
Step 2 — Rig and Place Unit . . . . . . . . . . . . . . . . . . . . . . . . .1
• POSITIONING
• ROOF MOUNT
Step 3 — Field Fabricate Ductwork . . . . . . . . . . . . . . . . . .7
Step 4 — Make Unit Duct Connections . . . . . . . . . . . . . . .7
Step 5 — Trap Condensate Drain . . . . . . . . . . . . . . . . . . . .7
Step 6 — Make Electrical Connections . . . . . . . . . . . . . .8
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
• OPTIONAL NON-FUSED DISCONNECT
• OPTIONAL CONVENIENCE OUTLET
Step 7 — Make Outdoor-Air Inlet
Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
• MANUAL OUTDOOR-AIR DAMPER
• OPTIONAL ECONOMI$ER
Step 8 — Install Outdoor-Air Hood. . . . . . . . . . . . . . . . . .12
Step 9 — Install All Accessories . . . . . . . . . . . . . . . . . . . .15
• MOTORMASTER® I CONTROL INSTALLATION
• MOTORMASTER III CONTROL INSTALLATION
Step 10 — Install Humidistat for Optional
MoistureMiser Dehumidification Package . . . . . . . . .16
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-24
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-31
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32,33
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . CL-1

SAFETY CONSIDERATIONS
Installation and servicing 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 literature, tags and labels attached to the unit, and
other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for unbrazing operations. Have
fire extinguishers available for all brazing operations.

Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.

IMPORTANT: Units have high ambient operating limits. If limits are exceeded, the unit will automatically
lock the compressor out of operation. Manual reset will
be required to restart the compressor.

INSTALLATION
Step 1 — Provide Unit Support
ROOF CURB — Assemble and install accessory roof curb or
horizontal adapter roof curb in accordance with instructions
shipped with the curb or horizontal adapter. Accessory roof
curb and horizontal adapter roof curb and information required
to field fabricate a roof curb or horizontal adapter roof curb are
shown in Fig. 1 and 2. Install insulation, cant strips, roofing,
and counter flashing as shown. Ductwork can be secured to
roof curb before unit is set in place.
IMPORTANT: The gasketing of the unit to the roof curb
or adapter roof curb is critical for a leak-proof seal.
Install gasket supplied with the roof curb or adapter roof
curb as shown in Fig. 1. Improperly applied gasket can
result in air leaks and poor unit performance.
Curb or adapter roof curb should be level. This is necessary
to permit unit drain to function properly. Unit leveling tolerance is ± 1/16 in. per linear ft in any direction. Refer to Accessory Roof Curb or Horizontal Adapter Roof Curb Installation Instructions for additional information as required.
ALTERNATE UNIT SUPPORT — When the curb or adapter
cannot be used, support unit with sleepers using unit curb or
adapter support area. If sleepers cannot be used, support long
sides of unit with a minimum of 3 equally spaced 4-in. x 4-in.
pads on each side.

Step 2 — Rig and Place Unit — Inspect

unit for
transportation damage. File any claim with transportation
agency. Keep unit upright, and do not drop. 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 a reference; leveling tolerance is ± 1/16 in. per linear ft in any direction. See Fig. 3 for additional information. Unit weight is
shown in Table 1.
Four lifting holes are provided in ends of unit base rails as
shown in Fig. 3. Refer to rigging instructions on unit.
POSITIONING — Provide clearance around and above unit
for airflow, safety, and service access (Fig. 4 and 5).
Do not install unit in an indoor location. Do not locate air inlets near exhaust vents or other sources of contaminated air.
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
ROOF MOUNT — Check building codes for weight distribution requirements.

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 111
Catalog No. 535-034
Printed in U.S.A.
Form 50TJ-17SI
Pg 1
2-01
Replaces: 50TJ-14SI
Book 1
Tab 1b

PKG. NO. REF.
CRRFCURB010A00
CRRFCURB011A00
CRRFCURB012A00

CURB HEIGHT
1′-2″ (305)
2′-0″ (610)
2′-0″ (610)

Fig. 1 — Roof Curb Details

DESCRIPTION
Standard Curb 14″ High
Standard Curb for Units Requiring High Installation
Side Supply and Return Curb for High Installation

Direction of airflow.

ALL

UNIT

Deg.
.28

A
in.
.45

Deg.
.28

DIMENSIONS* (degrees and inches)
in.
.43

5. Roof curb: 16 ga. (VA03-56) stl.
6. A 90 degree elbow must be installed on the supply ductwork
below the unit discharge for units equipped with electric
heaters.
NOTE: To prevent the hazard of stagnant water build-up in the drain
pan of the indoor section, unit can only be pitched as shown.

NOTES:
1. Roof curb accessory is shipped disassembled.
2. Insulated panels: 1″ thick neoprene coated 11/2 lb density.
3. Dimensions in ( ) are in millimeters.

UNIT
50TJ
016
020
024
028

NOTE: For preassembled horizontal adapter roof curb part no.
CRRFCURB013A00, the accessory kit includes a factory-designed,
high-static, transition duct. For horizontal curb part no.
CRRFCURB012A00, a field-supplied transition duct is required.

MAXIMUM
SHIPPING WEIGHT
Lb
1550
1650
1700
1850

Kg
703
748
771
839

DIMENSIONS
A
Ft-in.
6-111/2
6-111/2
6-111/2
6-111/2

B
mm
2121
2121
2121
2121

Ft-in.
4- 0
3-10
3- 7
3- 5

mm
1219
1168
1092
1041

NOTES:
1. Dimensions in ( ) are in millimeters.
2. Refer to Fig. 4 and 5 for unit operating weights.
3. Remove boards at ends of unit and runners prior to rigging.
4. Rig by inserting hooks into unit base rails as shown. Use corner
post from packaging to protect coil from damage. Use bumper
boards for spreader bars.
5. Weights do not include optional EconoMi$er. See Fig. 4 and 5 for
EconoMi$er weight. See Table 1 for MoistureMiser weight.
6. Weights given are for aluminum evaporator and condenser coil
plate fins.

Fig. 2 — Horizontal Adapter Roof Curb
and Roof Curb

All panels must be in place when rigging.

Fig. 3 — Rigging Details

STD UNIT
WEIGHT
Lb
Kg
1550
703
1650
748

ECONOMI$ER
WEIGHT
Lb
Kg
80
36.3
80
36.3

CORNER
(B)
Lb
Kg
365
166
384
174

POWER EXHAUST/BAROMETRIC RELIEF
(ACCESSORY ONLY)

CORNER
(A)
Lb
Kg
391
177
399
181

Fig. 4 — Base Unit Dimensions, 50TJ016,020

50TJ016
50TJ020

UNIT

CORNER
(C)
Lb
Kg
384
174
402
182
mm
1041
1016

DIM A
Ft-in.
3-5
3-4

mm
1067
1067

DIM B
Ft-in.
3-6
3-6

Direction of airflow.

mm
559
508

DIM C
Ft-in.
1-10
1- 8

5. Ductwork to be attached to accessory roof curb only.
6. Minimum clearance:
• Rear: 7′-0″ (2134) for coil removal. This dimension can be
reduced to 4′-0″ (1219) if conditions permit coil removal from the
top.
• Left side: 4′-0″ (1219) for proper condenser coil airflow.
• Front: 4′-0″ (1219) for control box access.
• Right side: 4′-0″ (1219) for proper operation of damper and
power exhaust if so equipped.
• Top: 6′-0″ (1829) to assure proper condenser fan operation.
• Local codees or jurisdiction may prevail.
7. With the exception of clearance for the condenser coil and the
damper/power exhaust as stated in Note #6, a removable fence or
barricade requires no clearance.
8. Dimensions are from outside of corner post. Allow 0′-5/16″ (8) on
each side for top cover drip edge.
9. See drawing 50TJ500352 for service option details.

NOTES:
1. Refer to print for roof curb accessory dimensions.
2. Dimensions in [ ] are in millimeters.
3.
Center of gravity.

CORNER
(D)
Lb
Kg
410
186
439
199

STD UNIT
WEIGHT
Lb
Kg
1700
771
1850
839

ECONOMI$ER
WEIGHT
Lb
Kg
80
36.3
80
36.3

CORNER
(B)
Kg
179
187

Lb
394
412

POWER EXHAUST/BAROMETRIC RELIEF
(ACCESSORY ONLY)

CORNER
(A)
Kg
190
194

Lb
419
428

Fig. 5 — Base Unit Dimensions, 50TJ024,028

50TJ024
50TJ028

UNIT

CORNER
(C)
Kg
193
232

Lb
425
511

mm
1016
965

DIM A
Ft-in.
3-4
3-2

mm
1041
1092

DIM B
Ft-in.
3-5
3-7

Direction of airflow.

mm
508
508

DIM C
Ft-in.
1-8
1-8

NOTES:
1. Refer to print for roof curb accessory dimensions.
2. Dimensions in [ ] are in millimeters.
3.
Center of gravity.

CORNER
(D)
Kg
210
226

Lb
463
499

Table 1 — Physical Data
016
208/230, 460 v
15
1550
80

UNIT 50TJ
NOMINAL CAPACITY (tons)
OPERATING WEIGHT
EconoMi$er
MoistureMiser Dehumidification
Package
COMPRESSOR/MANUFACTURER

Quantity...Model (Ckt 1, Ckt 2)

Pulley Center Line Distance (in.)
Speed Change per Full Turn of
Movable Pulley Flange (rpm)
Movable Pulley Maximum Full Turns
From Closed Position
Factory Speed
Factory Speed Setting (rpm
Fan Shaft Diameter at Pulley (in.)
HIGH-PRESSURE SWITCH (psig)
Cutout
Reset (Auto)
LOW-PRESSURE SWITCH (psig)
Cutout
Reset (Auto)
FREEZE PROTECTION THERMOSTAT (F)
Opens
Closes
OUTDOOR-AIR INLET SCREENS
Quantity...Size (in.)
RETURN-AIR FILTERS
Quantity...Size (in.)
POWER EXHAUST

028

18
1650

20
1700

25
1850

40
1...ZR16M3,
1...ZR125KC
60, 40
2
136, 106

15-5
16-0
20-13
12-3
13-6
13- 0
Copper Tubes, Aluminum Lanced,
Cross-Hatched
Aluminum Pre-Coated, or Copper Plate Fins
2...17
3...15
3...15
4...15
21.7
21.7
21.7
21.7
Propeller Type
10,500
10,500
14,200
14,200
3...22
3...22
2...30
2...30
1/ ...1050
1/ ...1050
1...1075
1...1075
2
2
1100
1100
3400
3400
Cross-Hatched 3/8-in. Copper Tubes, Aluminum Lanced or
Copper Plate Fins, Face Split
2...17
3...15
3...15
4...15
17.5
17.5
17.5
17.5
Centrifugal Type
2...10 x 10
2...10 x 10
2...12 x 12
2...12 x 12
2...12 x 12
Belt
Belt
Belt
Belt
Belt
6000
6000
7200
8000
10,000
3.7
3.0
5
7.5
10
1725
1725
1745
1745
1740
8.7 [208/230, 575 v]
10.2 [208/230, 575 v]
4.25
3.45
5.90
9.5 [460 v]
11.8 [380, 460 v]
3/8-in.

Rows...Fins/in.
Total Face Area (sq ft)
EVAPORATOR FAN
Quantity...Size (in.)
Type Drive
Nominal Cfm
Motor Hp
Motor Nominal Rpm
Maximum Continuous Bhp

Nominal Fan Shaft Diameter (in.)
Belt, Quantity...Type...Length (in.)

024

10-10
10-10

Rows...Fins/in.
Total Face Area (sq ft)
CONDENSER FAN
Nominal Cfm
Quantity...Diameter (in.)
Motor Hp...Rpm
Watts Input (Total)
EVAPORATOR COIL

Motor Bearing Type
Maximum Allowable Rpm
Motor Pulley Pitch Diameter
Min/Max (in.)
Nominal Motor Shaft Diameter (in.)
Fan Pulley Pitch Diameter (in.)

020

Scroll, Copeland
1...ZR108KC,
1...ZR125KC,
1...ZR94KC
1...ZR108KC
55, 45
55, 45
2
2
106, 81
106,106
R-22
TXV

2...ZR94KC
50, 50
2
81, 81

Capacity Stages (%)
Number of Refrigerant Circuits
Oil (oz) (Ckt 1, Ckt 2)
REFRIGERANT TYPE
Expansion Device
Operating Charge (lb-oz)
Circuit 1*
Circuit 2
CONDENSER COIL

Motor Frame Size
Nominal Rpm High/Low
Fan r/s Range

575 v

Low-Medium Static
High Static
Low-Medium Static
High Static
Low-Medium Static
High Static
Low-Medium Static
High Static
Low-Medium Static
High Static

Low-Medium Static
High Static

56H
—
891-1179
1227-1550
Ball
1550
3.1/4.1
3.7/4.7
7/8
6.0
5.2
13/16
1...BX...42
1...BX...42
13.5-15.5
48
55

56H
—
1159-1429
—
Ball
1550
4.3/5.3
—
7/8
6.4
—
13/16
1...BX...45
—
13.5-15.5
44
—

184T
—
910-1095
1069-1287
Ball
1550
4.9/5.9
4.9/5.9
11/8
9.4
8.0
17/16
1...BX...50
1...BX...48
13.3-14.8
37
34

213T
—
1002-1225
1193-1458
Ball
1550
5.4/6.6
5.4/6.6
13/8
9.4
7.9
17/16
1...BX...53
1...BX...50
14.6-15.4
37
44

215T
—
1066-1283
1332-1550
Ball
1550
4.9/5.9
4.9/5.9
13/8
8.0
6.4
17/16
2...BX...50
2...BX...47
14.6-15.4
36
45

6
3.5
1035
1389
13/16

6
3.5
1296
—
13/16

6
3.5
1002
1178
17/16

6
3.5
1120
1328
17/16

6
3.5
1182
1470
17/16

426
320
27
44
30 ± 5
45 ± 5
Cleanable
2...20 x 25 x 1
1...20 x 20 x 1
Throwaway†
4...20 x 20 x 2
4...16 x 20 x 2
1/ Hp, 208/230-460 v Motor Direct Drive, Propeller-Fan (Factory-Wired for 460 v)
2

LEGEND
Bhp — Brake Horsepower
TXV — Thermostatic Expansion Valve

†The 50TJ028 units requires 2-in. industrial-grade filters capable of handling
face velocities of up to 625 ft/min (such as American Air Filter no. 5700 or
equivalent).
NOTE: The 50TJ016-028 units have a low-pressure switch (standard) located
on the suction side.

*Circuit 1 uses the lower portion of condenser coil and lower portion of evaporator coils; and Circuit 2 uses the upper portion of both coils.

Step 3 — Field Fabricate Ductwork — Secure all

Step 4 — Make Unit Duct Connections — Unit
is shipped for through-the-bottom duct connections. Ductwork
openings are shown in Fig. 6. Field-fabricated concentric ductwork may be connected as shown in Fig. 7 and 8. Attach all
ductwork to roof curb and roof curb basepans. Refer to installation instructions shipped with accessory roof curb for more
information.

ducts to building structure. Use flexible duct connectors between unit and ducts as required. Insulate and weatherproof all
external ductwork, joints, and roof openings with counter
flashing and mastic in accordance with applicable codes.
Ducts passing through an unconditioned space must be insulated and covered with a vapor barrier.
The 50TJ units with electric heat require a 1-in. clearance
for the first 24 in. of ductwork.
Outlet grilles must not lie directly below unit discharge.
NOTE: A 90-degree elbow must be provided in the ductwork
to comply with UL (Underwriters’ Laboratories) codes for use
with electric heat.

Step 5 — Trap Condensate Drain — See Fig. 4, 5,
and 9 for drain location. Plug is provided in drain hole and
must be removed when unit is operating. One 3/4-in. halfcoupling is provided inside unit evaporator section for condensate drain connection. An 81/2 in. x 3/4-in. diameter nipple and a
2-in. x 3/4-in. diameter pipe nipple are coupled to standard
3/ -in. diameter elbows to provide a straight path down through
4
holes in unit base rails (see Fig. 10). A trap at least 4-in. deep
must be used.

For vertical supply and return units, tools or parts could
drop into ductwork and cause an injury. Install a 90 degree
turn in the return ductwork between the unit and the conditioned space. If a 90 degree elbow cannot be installed, then
a grille of sufficient strength and density should be installed
to prevent objects from falling into the conditioned space.
Due to electric heater, supply duct will require 90 degree
elbow.

Shaded area indicates block-off panels.
NOTE: Dimensions A, A′, and B, B′ are obtained from field-supplied
ceiling diffuser.

Fig. 8 — Concentric Duct Details

NOTE: Do not drill in this area; damage to basepan may result in
water leak.

Fig. 6 — Air Distribution — Thru-the-Bottom
(50TJ020-028 Shown)

3/4" FPT DRAIN
CONNECTION

1-3/8"
DRAIN HOLES

Fig. 9 — Condensate Drain Details
(50TJ016,020 Shown)
NOTE: Do not drill in this area; damage to basepan may result in
water leak.

Fig. 7 — Concentric Duct Air Distribution
(50TJ020-028 Shown)
7

IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company immediately.
Unit failure as a result of operation on improper line voltage
or excessive phase imbalance constitutes abuse and may cause
damage to electrical components.
FIELD CONTROL WIRING — Install a Carrier-approved
accessory thermostat assembly according to the installation instructions included with the accessory. Locate thermostat assembly on a solid wall in the conditioned space to sense average temperature.
Route thermostat cable or equivalent single leads of no. 18
AWG (American Wire Gage) colored wire from subbase terminals through conduit in unit to low-voltage connections as
shown on unit label wiring diagram and in Fig. 12.
NOTE: For wire runs up to 50 ft, use no. 18 AWG insulated
wire (35 C minimum). For 50 to 75 ft, use no. 16 AWG insulated wire (35 C minimum). For over 75 ft, use no. 14 AWG
insulated wire (35 C minimum). All wire larger than no. 18
AWG cannot be directly connected to the thermostat and will
require a junction box and splice at the thermostat.
Set heat anticipator settings as indicated in Table 3. Settings
may be changed slightly to provide a greater degree of comfort
for a particular installation.

Fig. 10 — Make Electrical Connections

Step 6 — Make Electrical Connections
FIELD POWER SUPPLY — Unit is factory wired for voltage shown on nameplate.
When installing units, provide a disconnect, per NEC
(National Electrical Code) requirements, of adequate size
(Table 2).
All field wiring must comply with NEC and local
requirements.
Route power lines through control box access panel or unit
basepan (Fig. 4 and 5) to connections as shown on unit wiring
diagram and Fig. 11.
Operating voltage to compressor must be within voltage
range indicated on unit nameplate. On 3-phase units, voltages
between phases must be balanced within 2% and the current
must be balanced within 10%.

The correct power phasing is critical in the operation of the
scroll compressors. An incorrect phasing will cause the
compressor to rotate in the wrong direction. This may lead
to premature compressor failure.
Use the following formula to determine the percentage of
voltage imbalance.
Percentage of Voltage Imbalance
TB1 MAXIMUM WIRE SIZE

max voltage deviation from average voltage
= 100 x
average voltage

UNIT
50TJ
All

EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v

Fig. 11 — Field Power Wiring Connections

1371
3

= 457
Determine maximum deviation from average voltage:
(AB) 457 – 452 = 5 v
(BC) 464 – 457 = 7 v
(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percent voltage imbalance:

THERMOSTAT ASSEMBLY
REMOVABLE JUMPER

= 1.53%
This amount of phase imbalance is satisfactory as it is below the maximum allowable 2%.

BLK

BRN

WHT

VIO

7
457

ORN

RED

Percentage of Voltage Imbalance = 100 x

LEGEND
Equipment
Ground
Thousand Circular Mils
National Electrical Code
Terminal Block

PNK

455 + 464 + 455
3

—
—
—
—
—

575
2/0

BLU

Average Voltage =

EQUIP
GND
kcmil
NEC
TB

VOLTAGE
460
2/0

208/230,380
350 kcmil

UNIT LOW-VOLTAGE CONNECTIONS

Fig. 12 — Field Control Thermostat Wiring
8

Table 2 — Electrical Data
UNIT
50TJ

NOMINAL VOLTAGE
COMPRESSOR
OFM
IFM
VOLTAGE RANGE
No. 1
No. 2
(3 Ph,
Min Max RLA LRA RLA LRA Qty Hp FLA (ea) Hp
FLA
60 Hz)

208/230

187 253 28.8 195 28.8 195

0.5

1.7

380

342 418 15.0 123 15.0 123

0.5

1.7

460

414 508 14.7

14.7

0.5

0.8

575

518 633 10.8

10.8

0.5

0.75

187 253 30.1 225 28.8 195

0.5

1.7

460

414 508 15.5 114 14.7

0.5

0.8

575

518 633 12.1

0.5

0.75

208/230

187 253 37.8 239 30.1 225

6.6

380

342 418 21.2 145 16.7 140

3.9

460

414 508 17.2 125 15.5 114

3.3

575

518 633 12.4

3.4

016
(15 Tons)

208/230

020
(18 Tons)

024
(20 Tons)

10.8

80 12.1

POWER
EXHAUST
FLA LRA

—
4.6
—
4.6
3.7 10.5/11.0
—
4.6
—
4.6
—
2.3
—
3.7
3.9
2.3
—
2.3
—
2.3
—
2.3
3.7
4.8
—
2.3
—
2.3
—
2.1
3.0
3.9
—
2.1
—
4.6
—
4.6
5.0 15.8/15.8
—
4.8
—
4.6
—
2.3
—
2.3
5.0
7.9
—
2.3
—
2.3
—
5.0
6.0
2.1
—
4.6
—
7.5 25.0/25.0 4.6
—
4.6
—
4.6
—
2.3
—
7.5
15.0
2.3
—
2.3
—
2.3
—
2.3
7.5
13.0
—
2.3
—
2.3
—
7.5
10.0
2.1

—
18.8
—
18.8
—
18.8
—
18.8
—
6.0
—
6.0
—
6.0
—
6.0
—
6.0
—
6.0
—
6.0
—
4.8
—
4.8
—
18.8
—
18.8
—
18.8
—
18.8
—
6.0
—
6.0
—
6.0
—
6.0
—
4.8
—
18.8
—
18.8
—
18.8
—
18.8
—
6.0
—
6.0
—
6.0
—
6.0
—
6.0
—
6.0
—
6.0
—
4.8

ELECTRIC
HEAT*

POWER
SUPPLY

FLA

MCA

MOCP†

—
—
26/34
26/34
42/56
42/56
56/75**
56/75**
—
—
20
20
35
35
—
—
32
32
55
55
80**
80**
—
—
50**
50**
—
—
26/34
26/34
42/56
42/56
56/75**
56/75**
—
—
32
32
55
55
80**
80**
—
—
—
—
26/34
26/34
42/56
42/56
56/75**
56/75**
—
—
20
20
35
35
—
—
32
32
55
55
80**
80**
—
—

—
—
71/82
71/82
117/135
117/135
156/180
156/180
—
—
30
30
52
52
—
—
39
39
66
66
96
96
—
—
48
48
—
—
71/82
71/82
117/135
117/135
156/180
156/180
—
—
39
39
66
66
96
96
—
—
—
—
71/82
71/82
117/135
117/135
156/180
156/180
—
—
30
30
52
52
—
—
39
39
66
66
96
96
—
—

81/81
85/86
102/116
108/122
159/149
165/155
169/194
175/200
43
45
43
46
70
73
40
43
55
58
72
75
102
105
30
32
67
70
87/87
92/92
109/122
114/128
166/155
172/161
176/200
182/206
44
47
59
61
76
79
106
109
34
36
116/116
120/120
120/134
126/140
178/166
183/172
187/211
193/217
66
68
66
68
84
87
57
59
65
68
82
85
112
115
44
46

100/100
110/110
110/125
110/125
175/175
175/175
200/225
200/225
50
60
50
60
80
80
50
50
60
60
80
80
110
110
40
40
70
70
110/110
110/110
110/125
125/150
175/175
175/175
200/225
200/225
50
60
60
70
90
90
125
125
40
40
150/150
150/150
150/150
150/150
200/175
200/175
200/225
200/225
80
80
80
80
90
90
70
70
70
70
90
90
125
125
50
50

Table 2 — Electrical Data (cont)
NOMINAL VOLTAGE
COMPRESSOR
OFM
IFM
VOLTAGE RANGE
No. 1
No. 2
(3 Ph,
Min Max RLA LRA RLA LRA Qty Hp FLA (ea) Hp
FLA
60 Hz)

UNIT
50TJ

028
(25 Tons)

FLA —
HACR —
IFM —
LRA —
MCA —
MOCP—
NEC —
OFM —
RLA —

208/230

187 253 41.0 350 37.8 239

6.6

380

342 418 21.8 151 21.2 145

3.9

460

414 508 21.8 158 17.2 125

2.8

575

518 633 17.3 125 12.4

3.4

POWER
EXHAUST
FLA LRA

—
4.6
—
4.6
10.0 28.0/28.0
—
4.6
—
4.6
—
2.3
—
10.0
17.0
2.3
—
2.3
—
2.3
—
2.3
10.0
14.6
—
2.3
—
2.3
—
10.0
13.0
2.1

ELECTRIC
HEAT*
kW

FLA

—
—
—
18.8
—
—
—
26/34
71/82
18.8 26/34
71/82
—
42/56 117/135
18.8 42/56 117/135
56/75** 156/180
18.8 56/75** 156/180
—
—
—
6.0
—
—
—
20
30
6.0
20
30
—
35
52
6.0
35
52
—
—
—
6.0
—
—
—
32
39
6.0
32
39
—
55
66
6.0
55
66
—
80**
96
6.0
80**
96
—
—
—
4.8
—
—

POWER
SUPPLY
MCA

MOCP†

130/130
135/135
130/138
135/143
181/170
187/176
191/215
197/221
73
76
73
76
87
90
66
68
67
70
84
87
114
117
54
56

150/150
175/175
150/150
175/175
200/175
200/200
200/225
200/225
90
90
90
90
90
90
80
80
80
80
90
100
125
125
70
70

Example: Supply voltage is 460-3-60.

LEGEND
Full Load Amps
Heating, Air Conditioning and Refrigeration
Indoor (Evaporator) Fan Motor
Locked Rotor Amps
Minimum Circuit Amps
Maximum Overcurrent Protection
National Electrical Code
Outdoor (Condenser) Fan Motor
Rated Load Amps

AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
=

*Heater capacity (kW) is based on heater voltage of 208 v, 240 v,
380 v, 480 v, and 575 v. Heaters are rated at 240 v, 380 v, 480 v, or
600 v. If power distribution voltage to unit varies from rated heater
voltage, heater kW will vary accordingly.
†Fuse or HACR circuit breaker.
**Heaters are field installed only.
NOTES:
1. In compliance with NEC requirements for multimotor and combination load equipment (refer to NEC Articles 430 and 440), the
overcurrent protective device for the unit shall be fuse or HACR
breaker. Canadian units may be fuse or circuit breaker.
2. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage is greater than 2%. Use the following formula to determine
the percent of voltage imbalance.
% Voltage Imbalance
max voltage deviation from average voltage
= 100 x
average voltage

452 + 464 + 455
3
1371
3

= 457
Determine maximum deviation from average voltage.
(AB) 457 – 452 = 5 v
(BC) 464 – 457 = 7 v
(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percent of voltage imbalance.
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
3. MCA calculation for units with electric heaters over 50 kW =
(1.25 x IFM amps) + (1.00 x heater FLA).

Step 7 — Make Outdoor-Air Inlet Adjustments

OPTIONAL NON-FUSED DISCONNECT — On units with
the optional non-fused disconnect, incoming power will be
wired into the disconnect switch. Refer to Fig. 13 for wiring
for 100 and 200 amp disconnect switches. Units with an
MOCP under 100 will use the 100 amp disconnect switch.
Units with an MOCP over 100 will use the 200 amp disconnect switch. Refer to the applicable disconnect wiring diagram.
To prevent breakage during shipping, the disconnect handle and shaft are shipped and packaged inside the unit control
box. Install the disconnect handle before unit operation. To install the handle and shaft, perform the following procedure:
1. Open the control box door and remove the handle and
shaft from shipping location.
2. Loosen the Allen bolt located on the disconnect switch.
The bolt is located on the square hole and is used to hold
the shaft in place. The shaft cannot be inserted until the
Allen bolt is moved.
3. Insert the disconnect shaft into the square hole on the disconnect switch. The end of the shaft is specially cut and
the shaft can only be inserted in the correct orientation.
4. Tighten the Allen bolt to lock the shaft into position.
5. Close the control box door.
6. Attach the handle to the external access door with the two
screws provided. When the handle is in the ON position,
the handle will be vertical. When the handle is in the OFF
position, the handle will be horizontal.
7. Turn the handle to the OFF position and close the door.
The handle should fit over the end of the shaft when the
door is closed.
8. The handle must be in the OFF position to open the control box door.
OPTIONAL CONVENIENCE OUTLET — On units with
optional convenience outlet, a 115-v GFI (ground fault interrupt) convenience outlet receptacle is provided for field wiring.
Field wiring should be run through the 7/8-in. knockout provided in the basepan near the return air opening.

MANUAL OUTDOOR-AIR DAMPER — All units (except
those equipped with a factory-installed economizer) have a
manual outdoor-air damper to provide ventilation air. Damper
can be preset to admit up to 25% outdoor air into return-air
compartment. To adjust, loosen securing screws and move
damper to desired setting. Then retighten screws to secure
damper (Fig. 14).
OPTIONAL ECONOMI$ER
EconoMi$er Motor Control Module (Fig. 15-17) — Set the
ECONSP dial to the ‘‘D’’ setting (Fig. 16). The control module
is located on the EconoMi$er motor. See Fig. 15 and 17.
Damper Vent Position Setting
1. Set fan switch at ON position (continuous fan operation)
and close night switch if used.
2. Set system selector switch to OFF position.
3. Turn Min Pos (%) dial slowly until dampers assume desired vent position. Do not manually operate EconoMi$er
motor since damage to motor will result.

Fig. 14 — 25% Outdoor-Air Section Details

6T3 4T2 2T1 LOAD

CONTROL
MODULE

5L3 3L2 1L1 LINE

ACTUATOR

ECONOMI$ER

NOTE: The disconnect takes the place of TB-1 as shown on the unit
wiring diagram label and the component arrangement label.

Fig. 15 — EconoMi$er Damper Assembly
— End View

Fig. 13 — Optional Non-Fused Disconnect Wiring

Table 3 — Heat Anticipator Settings
UNIT
50TJ

UNIT
VOLTAGES
208/230-3-60

016-028

380-3-60
460-3-60
575-3-60

kW*

STAGE 1

STAGE 2

26/34
42/56
56/75
20
35
32
55
80
50

.40
.66
.66
.40
.40
.40
.40
.66
.66

.66
.40
.66
.40
.66
.40
.66
.66
.66

5. Loosen sheet metal screws for base unit top panel located
above outdoor-air inlet opening, and remove screws for
hood side panels located on the sides of the outdoor-air
inlet opening.
6. Match notches in hood top panel to unit top panel screws.
Insert hood flange between unit top panel flange and unit.
Tighten screws.
7. Hold hood side panel flanges flat against unit, and install
screws removed in Step 5.
8. Insert outdoor-air inlet screens and spacer in channel created by lower filter retainer and filter support bracket.
9. Attach remaining short section of filter support bracket.
OUTDOOR AIR ENTHALPY SENSOR INSTALLATION — Perform the following procedure to install the outdoor air enthalpy sensor (part no. CROUTENT001A00).
1. Remove the outdoor air temperature sensor cover. See
Fig. 21. Save cover and screws.
2. Disconnect the wiring from the installed outdoor air temperature sensor. See Fig. 22.
3. Use a 1/4-in. nut driver to remove the 2 screws securing
the outdoor air temperature sensor to the sheet metal.
4. Mount the outdoor air enthalpy sensor in the outdoor air
temperature sensor location using the screws removed in
Step 3.
5. Connect the outdoor air enthalpy sensor wiring harness to
the EconoMi$er control module and sensor.
6. Re-install sensor cover saved from Step 1.
RETURN AIR TEMPERATURE SENSOR OR RETURN
AIR ENTHALPY SENSOR INSTALLATION — Perform the
following procedure to install the return air temperature sensor
(part no. CRRETTMP001A00) or return air enthalpy sensor
(part no. CRRETENT001A00).
1. Attach the sensor to the mounting bracket using 2 selftapping 1/2-in. screws provided.
2. Mount the bracket to the inside of the return air opening
flange using a 1/4-in. nut driver and 2 no. 6 sheet metal
screws.
NOTE: The sensor must be mounted in an upright position.
3. Feed the sensor wiring through the bushing in
EconoMi$er to secure wires.
4. Route sensor wiring harness from sensor to EconoMi$er
control module. Secure wiring harness to the original harness using tie wraps.
5. Wire the sensor to the EconoMi$er control module. See
Fig. 23 and 24.

*Heater kW is based on heater voltage of 208 v, 240 v, 380 v, 480 v,
and 575 v.

Fig. 16 — EconoMi$er Control Module
Adjustment Potentiometers

CONTROL MODULE

ACTUATOR

Fig. 17 — EconoMi$er Control Module Location

Step 8 — Install Outdoor-Air Hood — The same
type of factory-installed hood is used on units with 25% air
ventilation and units with an EconoMi$er.
NOTE: The hood top panel, upper and lower filter retainers,
hood drain pan, baffle (028), and filter support bracket are
secured opposite the condenser end of the unit. The screens,
hood side panels, remaining section of filter support bracket,
seal strip, and all other hardware are in a package located
inside the return-air filter access panel (Fig. 18).
1. Attach seal strip to upper filter retainer. See Fig. 19.
2. Assemble hood top panel and side panels, upper filter retainer, and hood drain pan (Fig. 20).
3. Secure lower filter retainer and long section of filter support bracket to unit. See Fig. 20. Leave screws loose on
028 units.
4. Slide baffle (size 028 unit) behind lower filter retainer and
tighten screws.

Fig. 18 — Outdoor-Air Hood Component Location

SENSOR
COVER

OUTSIDE AIR SENSOR

Fig. 19 — Seal Strip Location
(Air Hood Cross-Sectional View)
BAFFLE (028 ONLY)

Fig. 21 — Outdoor-Air Sensor Location
MOUNTING SCREW

LOWER FILTER
RETAINER

FILTER SUPPORT
BRACKET
SENSOR
WIRING
CONNECTIONS

HOOD TOP
PANEL

MOUNTING
SCREW

HOOD SIDE
PANELS (2)
BAFFLE
(028 ONLY)

WIRING
HARNESS

Fig. 22 — Outdoor-Air Sensor Details
LOWER
FILTER
RETAINER

Refer to Table 4 to determine the sensors required for each
strategy.
Differential Enthalpy Switchover Strategy — The differential enthalpy switchover strategy must be selected manually, if
required. To enable, press and hold the CONFIG button for 30
seconds, then release. The LED will flash twice to indicate the
change of configuration.
To return to single enthalpy mode, press and hold the CONFIG button for 30 seconds. The LED will flash once to indicate
the change of configuration.
DISCHARGE AIR THERMISTOR (DAT) — The discharge
air thermistor is factory-mounted on the supply-fan housing in
the fan section of the unit. The DAT is factory-wired to the
EconoMi$er Control Module.
CO2 CONTROL SETUP — If a CO2 sensor is not being
used, proceed to the next section. If a CO2 sensor is being used,
perform the following:
1. Determine the value at which you want the minimum
position of the dampers to begin opening to allow a
greater amount of outdoor air to enter. The range is
800 to 1,400 ppm.
2. Locate the CO2 SP (PPM) potentiometer and adjust to the
desired set point. See Fig. 16.

FILTER SUPPORT
BRACKET
HOOD DRAIN PAN
UPPER FILTER RETAINER

NOTE: The outdoor-air hood comes with a baffle which is used on
028 units only; discard baffle for 016-024 units.

Fig. 20 — Outdoor-Air Hood Details
COMMISSIONING — The EconoMi$er saves energy when
it uses outdoor air to provide free cooling instead of mechanical air conditioning. The EconoMi$er switchover strategy determines if the outdoor air is suitable for free cooling. The
EconoMi$er chooses the switchover strategy with the most energy savings, provided that the required sensors are connected
and functioning normally.
IMPORTANT: If a sensor stops functioning normally (becomes unreliable), the EconoMi$er
switches to the next best strategy.

DRY BULB CHANGEOVER SET UP — Determine the dry
bulb changeover set point from Table 5. The settings are A, B,
C and D. Locate the ECON SP potentiometer and set the dry
bulb changeover set point. See Fig. 16. When the OAT is above
this set point, the damper is limited to minimum position
setting.
If a potentiometer fails, its setting will default to the values
in Table 6.

MECHANICAL COOLING LOCKOUT — Determine the
outdoor-air temperature at which you want the mechanical
cooling (compressors) to be disabled. Locate the mechanical
cooling lockout (MECH CLG LOCKOUT) potentiometer. To
disable this feature, turn the potentiometer counterclockwise
(CCW) to the OFF position. Otherwise, set the value between
10 and 60 F. Mechanical cooling will not operate when the outdoor air temperature is below this value. See Fig. 16.

Table 4 — EconoMi$er Switchover Control Strategy
ECONOMI$ER SWITCHOVER
STRATEGY
Dry Bulb

SENSORS REQUIRED
Outdoor Air Enthalpy
Return Air Temperature

Outdoor Air Temperature

Return Air Enthalpy

Single Enthalpy
Differential Temperature

X
X

Differential Enthalpy*

*Must be selected manually.

Table 5 — Changeover Set Points
SETTINGS
Dry Bulb (°F)
Single Enthalpy* (Btu/lb)
Differential Temperature*
(°F, Not Adjustable)
Differential Enthalpy*
(Btu/lb, Not Adjustable)

Table 6 — Default Potentiometer Settings

A
73
27

B
69
25

C
66
24

D
63
22

POTENTIOMETER

DEFAULT SETTING

CO2 SP (PPM)
MECH CLG LOCKOUT
ECON SP
MIN POS (%)

1,000
50 F
D
20

*Field-installed accessory.

COM
DAT
DM
GND
OAH
OAT
POT
RAH
RAT
REM

—
—
—
—
—
—
—
—
—
—

LEGEND
Common
Discharge Air Thermistor
Damper Motor
Ground
Outdoor-Air Enthalpy Sensor
Outdoor-Air Temperature Sensor
Potentiometer
Return-Air Enthalpy Sensor
Return-Air Temperature Sensor
Remote

*OAT sensor shipped with economizer option. OAH, RAT, RAH and CO2 are field-installed accessories.

Fig. 23 — Typical EconoMi$er Sensor Wiring
14

VENTILATION AIR (Minimum Position Set Up) — If ventilation air is not required, skip this section. If ventilation air is
required, perform the following:
1. The indoor fan must be on to set the ventilation air.
Either put the thermostat in the continuous fan mode or
jumper the R and G terminals at the rooftop unit connection board.
2. Locate the minimum position (MIN POS) potentiometer.
Turn the potentiometer full CCW to fully close the outdoor air dampers. Turn the potentiometer gradually
clockwise (CW) to the desired position. See Fig. 16.
3. Replace the filter access panel. See Fig. 18. Ensure the filter access panel is securely engaged.
4. Calculate the minimum airflow across the EconoMi$er.
a. Calculate % of outside air using the following
formula.
% Outdoor air through EconoMi$er
Mixture Temp – Return Air Temp
% Outdoor air =
Outdoor Temp – Return Air Temp

Personal Injury Hazard. Avoid possible injury by keeping fingers away from damper blades.

Step 9 — Install All Accessories — After all the
factory-installed options have been adjusted, install all fieldinstalled accessories. Refer to the accessory installation instructions included with each accessory.
MOTORMASTER® I CONTROL INSTALLATION
(50TJ016 and 020 Only)
Install Field-Fabricated Wind Baffles — Wind baffles must
be field-fabricated for all units to ensure proper cooling cycle
operation at low ambient temperatures. See Fig. 25 for baffle
details. Use 20-gage, galvanized sheet metal, or similar
corrosion-resistant metal for baffles. Use field-supplied screws
to attach baffles to unit. Screws should be 1/4-in. diameter and
5/ -in. long. Drill required screw holes for mounting baffles.
8

b. Multiply total CFM by percentage outdoor air, this
gives outdoor air volume in CFM.

To avoid damage to the refrigerant coils and electrical components, use recommended screw sizes only. Use care
when drilling holes.

Unoccupied Control
(Part number on the control
must be AD-DME1701-1
or AD-DME1711-1.)
Outdoor Air Enthalpy
CROUTENT001A00

Unoccupied
Contact
T
C O
O U
T T
M PW

Violet

24 VAC must be present
on BI for the system to be
unoccupied.

Tan
Violet
W hite
Red

Return Air Enthalpy
CRRETENT001A00

Tan
Violet
W hite
Red

Violet
T
C O
O U
T T
M PW

CO2 Sensors:
3 3ZCSENCO 2

NOT
USED

Remote
Minimum Position

24 VAC
20 VA

2 to 10 VDC at
0 to 2000 ppm

CO 2 (+)
CO 2
COM
DAT
COM
REM
POT
COM
LED
COM

1k ohm Potentiometer

OAT
COM
OAH
+15V
RAT
COM
RAH
+15V

470 ohm
5 watt
Resistor

20 mA LED
Remote
LED

Field-supplied W iring

W iring Included

Fig. 24 — Typical EconoMi$er Sensor Wiring
15

Line
Voltage

Install Motormaster I Controls — Only one Motormaster I
control is required per unit. The Motormaster I control must be
used in conjunction with the Accessory 0° F Low Ambient Kit
(purchased separately). The Motormaster I device controls outdoor fan no. 1 while outdoor fans no. 2 and 3 are sequenced off
by the Accessory 0° F Low Ambient Kit.
Accessory 0° F Low Ambient Kit — Install the Accessory 0° F
Low Ambient Kit per instruction supplied with accessory.
Sensor Assembly — Install the sensor assembly in the location
shown in Fig. 26.
Motor Mount — To ensure proper fan height, replace the existing motor mount with the new motor mount provided with
accessory.
Transformer (460 and 575-v Units Only) — On 460 and
575-volt units a transformer is required. The transformer is
provided with the accessory and must be field-installed.
Motormaster I Control — Recommended mounting location is
on the inside of the panel to the left of the control box. The
control should be mounted on the inside of the panel, vertically, with leads protruding from bottom of extrusion.
MOTORMASTER® III CONTROL INSTALLATION
(50TJ024 and 028 Only)
Install Field-Fabricated Wind Baffles — Wind baffles must
be field-fabricated for all units to ensure proper cooling cycle
operation at low ambient temperatures. See Fig. 25 for baffle
details. Use 20-gage, galvanized sheet metal, or similar
corrosion-resistant metal for baffles. Use field-supplied screws
to attach baffles to unit. Screws should be 1/4-in. diameter and
5/8-in. long. Drill required screw holes for mounting baffles.
NOTE: Dimensions in ( ) are in mm.

Fig. 25 — Wind Baffle Details
To avoid damage to the refrigerant coils and electrical components, use recommended screw sizes only. Use care
when drilling holes.

NOTE: If unit power is supplied through the roof curb and
basepan of the unit, mount the Motormaster III control on the
corner post adjacent to the conduit running from the basepan to
the bottom of the control box.

Replace Outdoor Motor — Replace outdoor fan motor no. 1
with motor included in accessory kit. Existing motor is not
Motormaster® III compatible.
Install Motormaster III Controls — Only one Motormaster
III control is required per unit.
Sensor — Install the sensor for thermistor input control in the
location shown in Fig. 27. Connect sensor leads to the purple
and grey control signal leads on the Motormaster III control.
Signal Selection Switch — Remove the cover of the Motormaster III control. Set the switch to accept the thermistor sensor input signal. Set the frequency to match the unit power supply (60 Hz).
Motormaster III Control — Recommended mounting location
is beneath the control box, mounted to the partition that separates the control box section from the indoor section.

Step 10 — Install Humidistat for Optional
MoistureMiser Dehumidification Package —
MositureMiser dehumidification package operation can be
controlled by field installation of a Carrier-approved humidistat. To install the humidistat perform the following procedure:
1. Locate humidistat on a solid interior wall in the conditioned space. Location should be a well ventilated area
to sense average humidity.
2. Route thermostat cable or equivalent single leads of colored wire from Humidistat terminals through conduit in
unit to the low voltage connection on the 2-pole terminal
strip (TB3) as shown in Fig. 28 and Fig. 29.

SENSOR
LOCATION

HAIRPIN END

50TJ016

50TJ020

50TJ024

50TJ028

NOTE: All sensors are located on the eighth hairpin up from the
bottom.

Fig. 26 — Motormaster® I Sensor Locations

Fig. 27 — Motormaster III Sensor Locations

LLSV
LPS
TB
TRAN

—
—
—
—

LEGEND
Liquid Line Solenoid Valve
Low Pressure Switch
Terminal Block
Transformer

Fig. 28 — Typical MoistureMiser Dehumidification Package
Humidistat Wiring Schematic (460V Unit Shown)
17

1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pressure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pressure does not rise to normal levels:
1. Note that the evaporator fan is probably also rotating in
the wrong direction.
2. Turn off power to the unit.
3. Reverse any two of the incoming power leads.
4. Turn on power to the compressor.
The suction and discharge pressure levels should now move
to their normal start-up levels.
NOTE: When compressors are rotating in the wrong direction,
the unit will have increased noise levels and will not provide
heating and cooling.
After a few minutes of reverse operation, the scroll compressor internal overload protection will open, which will activate the unit’s lockout and requires a manual reset. Reset is accomplished by turning the thermostat on and off.

Fig. 29 — Typical MoistureMiser Dehumidification
Package Control Box

START-UP
Use the following information and Start-Up Checklist on
page CL-1 to check out unit PRIOR to start-up.

Evaporator Fan — Fan belt and variable pulleys are factory installed. Remove tape from the fan pulley. See Table 7 for
Air Quantity Limits. See Tables 8-10 for Fan Performance
data. Be sure that fans rotate in the proper direction. See
Tables 11-13 for Static Pressure information for accessories
and options. See Table 14 for fan rpm at various fan motor pulley settings. To alter fan performance, see Evaporator-Fan Performance Adjustment section, page 25.

Unit Preparation — Check that unit has been installed in
accordance with these installation instructions and all applicable codes.

Internal Wiring — Check all electrical connections in
unit control boxes; tighten as required.

Crankcase Heater (Size 028 and Units with
MoistureMiser Dehumidification Package
Only) — Heater is energized as long as there is power to unit

Table 7 — Air Quantity Limits
UNIT
50TJ
016
020
024
028

and compressor is not operating.
IMPORTANT: Unit power must be on for 24 hours prior
to start-up. Otherwise, damage to compressor may
result.

MINIMUM CFM

MAXIMUM CFM

4500
5400
6000
7000

7,500
9,000
10,000
11,250

Condenser Fans and Motors — Fans and motors
are factory set. Refer to Condenser-Fan Adjustment section
(page 26) as required.

Compressor Mounting — Compressors are internally
spring mounted. Do not loosen or remove compressor holddown bolts.

Return-Air Filters — Check that correct filters are installed in filter tracks. See Table 1. Do not operate unit without
return-air filters.

Refrigerant Service Ports — Each refrigerant system has a total of 3 Schrader-type service gage ports. One port
is located on the suction line, one on the compressor discharge
line, and one on the liquid line. In addition Schrader-type
valves are located underneath the low-pressure switches. Be
sure that caps on the ports are tight.

Outdoor-Air Inlet Screens — Outdoor-air inlet screens
must be in place before operating unit.
Accessory EconoMi$er Adjustment — Remove filter access panel. Check that outdoor-air damper blades are
closed and return-air damper blades are open.
EconoMi$er operation and adjustment is described in Base
Unit Operation and EconoMi$er Adjustment sections
(pages 23 and 27), respectively.

Compressor Rotation — It is important to be certain
the compressors are rotating in the proper direction. To determine whether or not compressors are rotating in the proper direction:

Table 8 — Fan Performance — 50TJ016
50TJ016 (15 TONS)*
Airflow
(Cfm)
4500
4800
5100
5400
5700
6000
6300
6600
6900
7200
7500

Rpm
684
715
747
779
812
845
878
912
946
981
1016

0.2
Bhp
1.28
1.47
1.67
1.90
2.14
2.40
2.68
2.98
3.29
3.63
3.99

Watts
1102
1265
1442
1635
1844
2068
2309
2566
2841
3133
3443

Available External Static Pressure (in. wg)
0.6
0.8
Rpm Bhp Watts Rpm Bhp Watts
887 1.70 1466
977 1.92 1652
910 1.90 1638
997 2.12 1828
934 2.12 1825 1018 2.34 2019
959 2.35 2027 1040 2.58 2226
985 2.60 2245 1063 2.84 2448
1011 2.87 2478 1087 3.11 2685
1039 3.16 2728 1112 3.41 2939
1067 3.47 2994 1138 3.72 3209
1096 3.80 3277 1165 4.05 3496
1125 4.15 3578
—
—
—
—
—
—
—
—
—

Rpm
791
817
844
872
901
931
961
992
1023
1055
1087

0.4
Bhp
1.49
1.68
1.89
2.12
2.37
2.64
2.92
3.22
3.55
3.89
4.25

Rpm
1285
1297
1311
1326
1342
1359
—
—
—
—
—

Available External Static Pressure (in. wg)
1.6
1.8
1.9
Bhp Watts Rpm Bhp Watts Rpm Bhp
2.82 2430 1353 3.05 2633 1386 3.17
3.04 2619 1364 3.27 2825 1396 3.40
3.27 2823 1376 3.51 3031 1408 3.64
3.53 3043 1390 3.77 3254 1421 3.90
3.80 3278 1405 4.05 3492 1435 4.17
4.09 3530 1421 4.34 3746
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

Watts
1283
1451
1633
1831
2044
2273
2518
2780
3059
3355
3669

Rpm
1061
1078
1097
1117
1138
1160
1183
1207
1232
—
—

1.0
Bhp
2.13
2.34
2.57
2.81
3.07
3.35
3.65
3.97
4.31
—
—

Watts
1841
2021
2216
2426
2652
2893
3151
3425
3716
—
—

Rpm
1418
1428
1439
1452
1466
—
—
—
—
—
—

2.0
Bhp
3.29
3.52
3.76
4.02
4.30
—
—
—
—
—
—

Watts
2839
3033
3242
3467
3708
—
—
—
—
—
—

Rpm
1139
1155
1171
1189
1209
1229
1250
1273
—
—
—

1.2
Bhp
2.36
2.57
2.80
3.05
3.31
3.60
3.90
4.22
—
—
—

Watts
2034
2217
2416
2629
2858
3103
3365
3642
—
—
—

50TJ016 (15 TONS)* (cont)
Airflow
(Cfm)
4500
4800
5100
5400
5700
6000
6300
6600
6900
7200
7500

Rpm
1214
1228
1243
1259
1277
1295
1315
—
—
—
—

1.4
Bhp
2.59
2.80
3.04
3.29
3.56
3.84
4.15
—
—
—
—

Watts
2230
2417
2618
2835
3067
3316
3580
—
—
—
—

LEGEND
Bhp — Brake Horsepower
FIOP — Factory-Installed Option
Watts — Input Watts to Motor

Watts
2736
2928
3136
3360
3600
—
—
—
—
—
—

2. Static pressure losses (i.e., EconoMi$er) must be added to
external static pressure before entering Fan Performance table.
3. Interpolation is permissible. Do not extrapolate.
4. Fan performance is based on wet coils, clean filters, and
casing losses. See Table 11 for accessory/FIOP static pressure
information.
5. Extensive motor and drive testing on these units ensures that
the full horsepower and watts range of the motor can be utilized
with confidence. Using your fan motors up to the watts or bhp
rating shown will not result in nuisance tripping or premature
motor failure. Unit warranty will not be affected.
6. Use of a field-supplied motor may affect wiring size. Contact
your Carrier representative for details.

*Standard low-medium static drive range is 891 to 1179 rpm (for
208/230, 380 and 460 v units) or 1159 to 1429 rpm (for 575-v
units). Alternate high-static drive range is 1227 to 1550 (for 208/
230, 380, and 460 v units). The alternate high-static drive is not
available for 50TJ016 575-v units. Other rpms require a field-supplied drive.
NOTES:
1. Maximum continuous bhp is 4.25 (208/230, 380 and 460 v) or
3.45 (575 v) and the maximum continuous watts are 3775 (208/
230, 380, and 460 v) or 3065 (575 v). Do not adjust motor rpm
such that motor maximum bhp and/or watts is exceeded at the
maximum operating cfm.

Table 9 — Fan Performance — 50TJ020 and 024
50TJ020, 024 (18 and 20 TONS)*
Airflow
(Cfm)
5,500
6,000
6,500
7,000
7,500
8,000
8,500
9,000
9,500
10,000

Rpm
682
730
778
828
878
928
979
1030
1082
1134

0.2
Bhp
1.99
2.38
2.82
3.31
3.84
4.42
5.05
5.73
6.46
7.25

Watts
1675
2005
2373
2780
3227
3715
4245
4817
5433
6093

Rpm
760
802
846
892
938
985
1033
1082
1131
1180

0.4
Bhp
2.29
2.68
3.13
3.62
4.15
4.74
5.38
6.06
6.80
7.59

Watts
1922
2257
2630
3042
3494
3986
4521
5098
5718
6382

Available External Static Pressure (in. wg)
0.6
0.8
Rpm Bhp Watts Rpm Bhp Watts
832 2.59 2177
901 2.90 2441
871 2.99 2516
935 3.31 2783
911 3.44 2893
972 3.76 3164
953 3.94 3310 1011 4.26 3583
996 4.48 3766 1051 4.81 4043
1040 5.07 4263 1093 5.40 4544
1085 5.71 4801 1136 6.05 5086
1131 6.40 5382 1180 6.74 5671
1178 7.14 6007 1225 7.49 6299
1226 7.94 6675 1270 8.29 6971

Rpm
965
997
1031
1067
1105
1144
1185
1227
1270
1313

1.0
Bhp
3.22
3.63
4.09
4.59
5.14
5.74
6.39
7.09
7.84
8.65

Watts
2712
3057
3440
3863
4326
4830
5375
5964
6595
7271

Rpm
1249
1270
1294
1320
1348
1379
1411
1445
1480
—

2.0
Bhp
4.96
5.37
5.83
6.35
6.91
7.52
8.18
8.90
9.67
—

Watts
4167
4516
4906
5337
5810
6325
6883
7484
8129
—

Rpm
1027
1056
1087
1121
1156
1194
1232
1272
1313
1356

1.2
Bhp
3.56
3.97
4.43
4.93
5.49
6.09
6.74
7.44
8.20
9.01

Watts
2990
3337
3722
4148
4613
5120
5669
6260
6895
7574

50TJ020, 024 (18 and 20 TONS)* (cont)
Airflow
(Cfm)
5,500
6,000
6,500
7,000
7,500
8,000
8,500
9,000
9,500
10,000

Rpm
1086
1112
1142
1173
1207
1242
1279
1317
1356
1397

1.4
Bhp
3.89
4.31
4.77
5.28
5.83
6.44
7.10
7.80
8.56
9.37

Watts
3275
3623
4010
4438
4906
5415
5966
6561
7198
7881

Rpm
1142
1167
1194
1224
1255
1289
1324
1360
1398
1438

Available External Static Pressure (in. wg)
1.6
1.8
1.9
Bhp Watts Rpm Bhp Watts Rpm Bhp
4.24 3567 1197
4.59 3864 1223 4.77
4.66 3915 1219
5.01 4213 1245 5.19
5.12 4304 1245
5.47 4602 1270 5.65
5.63 4733 1273
5.98 5033 1296 6.17
6.19 5203 1302
6.55 5504 1326 6.73
6.80 5714 1334
7.16 6018 1357 7.34
7.45 6268 1368
7.82 6573 1389 8.00
8.16 6865 1403
8.53 7173 1424 8.71
8.93 7505 1440
9.29 7815 1460 9.48
9.74 8190 1477 10.11 8503
—
—

LEGEND
Bhp — Brake Horsepower
FIOP — Factory-Installed Option
Watts — Input Watts to Motor

2.
3.
4.

*Standard low-medium static drive range for the 020 size is 910 to
1095 rpm. Standard low-medium static drive range for the 024 size
is 1002 to 1225 rpm. Alternate high-static drive range for the
020 size is 1069 to 1287. Alternate high-static drive range for the
024 size is 1193 to 1458 rpm. Other rpms require a field-supplied
drive.
NOTES:
1. Maximum continuous bhp for the 020 size is 5.90. Maximum
continuous bhp for the 024 size is 8.7 (208/230, 575 v) or 9.5
(380, 460 v). The maximum continuous watts for the 020 size is
5180. The maximum continuous watts for the 024 size is 7915

Watts
4015
4364
4754
5184
5657
6171
6728
7328
7972
—

(208/230, 575 v) or 8640 (380, 460 v). Do not adjust motor rpm
such that motor maximum bhp and/or watts is exceeded at the
maximum operating cfm.
Static pressure losses (i.e., EconoMi$er) must be added to
external static pressure before entering Fan Performance table.
Interpolation is permissible. Do not extrapolate.
Fan performance is based on wet coils, clean filters, and casing
losses. See Table 12 for accessory/FIOP static pressure
information.
Extensive motor and drive testing on these units ensures that
the full horsepower and watts range of the motor can be utilized
with confidence. Using your fan motors up to the watts or bhp
rating shown will not result in nuisance tripping or premature
motor failure. Unit warranty will not be affected.
Use of a field-supplied motor may affect wiring size. Contact
your Carrier representative for details.

Table 10 — Fan Performance — 50TJ028
50TJ028 (25 TONS)*
Airflow
(Cfm)
7,000
7,500
8,000
8,500
9,000
9,500
10,000
10,500
11,000
11,250

Rpm
845
896
948
1001
1053
1106
1159
1213
1266
1293

Available External Static Pressure (in. wg)
0.2
0.4
0.6
0.8
1.0
1.2
Bhp Watts Rpm Bhp Watts Rpm Bhp Watts Rpm Bhp Watts Rpm Bhp Watts Rpm Bhp Watts
3.26 2693
909 3.60 2979
969 3.96 3272 1028 4.32 3574 1083 4.70 3883 1137 5.08
4,200
3.82 3156
956 4.17 3450 1014 4.54 3752 1069 4.91 4060 1123 5.29 4375 1174 5.68
4,698
4.43 3667 1005 4.80 3969 1060 5.17 4278 1112 5.56 4593 1163 5.94 4915 1213 6.34
5,243
5.11 4226 1054 5.49 4537 1106 5.87 4853 1156 6.26 5175 1205 6.66 5504 1253 7.06
5,838
5.85 4836 1104 6.23 5155 1154 6.63 5478 1202 7.02 5808 1248 7.43 6142 1294 7.84
6,483
6.65 5498 1155 7.04 5824 1202 7.44 6155 1248 7.85 6492 1293 8.26 6833 1336 8.68
7,179
7.52 6214 1206 7.92 6547 1251 8.33 6886 1295 8.74 7229 1338 9.16 7577 1380 9.59
7,929
8.45 6984 1257 8.86 7325 1300 9.28 7671 1342 9.70 8020 1384 10.13 8375 1424 10.56
8,733
9.45 7810 1309 9.87 8159 1350 10.29 8511 1391 10.73 8868 1431 11.16 9229 1470 11.60
9,594
9.97 8245 1334 10.40 8597 1375 10.83 8953 1415 11.26 9313 1454 11.70 9677 1493 12.15 10,045

50TJ028 (25 TONS)* (cont)
Available External Static Pressure (in. wg)
Airflow
1.4
1.6
1.8
(Cfm)
Rpm Bhp Watts Rpm Bhp Watts Rpm Bhp Watts
7,000 1189 5.47 4,524 1239 5.87 4,854 1288 4.91 5191
7,500 1224 6.08 5,026 1272 6.48 5,362 1320 5.56 5703
8,000 1261 6.75 5,577 1307 7.16 5,917 1353 6.26 6263
8,500 1299 7.47 6,177 1344 7.89 6,523 1388 7.02 6873
9,000 1338 8.26 6,828 1382 8.68 7,179 1424 7.85 7534
9,500 1379 9.11 7,530 1421 9.54 7,887 1462 8.74 8247
10,000 1421 10.02 8,286 1461 10.46 8,648 1501 9.70 9014
10,500 1464 11.00 9,096 1503 11.45 9,464 1541 10.73 9835
—
—
—
11,000 1508 12.05 9,963 1546 12.50 10,336
—
—
—
—
—
11,250 1530 12.60 10,417 —
2. Static pressure losses (i.e., EconoMi$er) must be added to
external static pressure before entering Fan Performance table.
3. Interpolation is permissible. Do not extrapolate.
4. Fan performance is based on wet coils, clean filters, and casing
losses. See Table 12 for accessory/FIOP static pressure
information.
5. Extensive motor and drive testing on these units ensures that
the full horsepower and watts range of the motor can be utilized
with confidence. Using your fan motors up to the watts or bhp
rating shown will not result in nuisance tripping or premature
motor failure. Unit warranty will not be affected.
6. Use of a field-supplied motor may affect wiring size. Contact
your Carrier representative for details.

LEGEND
Bhp — Brake Horsepower
FIOP — Factory-Installed Option
Watts — Input Watts to Motor
*Standard low-medium static drive range is 1066 to 1283 rpm. Alternate high-static drive range is 1332 to 1550. Other rpms require a
field-supplied drive.
NOTES:
1. Maximum continuous bhp is 10.2 (208/230, 575 v) or 11.8 (380,
460 v) and the maximum continuous watts are 9510 (208/230,
575 v) or 11,000 (380, 460 v). Do not adjust motor rpm such
that motor maximum bhp and/or watts is exceeded at the maximum operating cfm.

Table 11 — Accessory/FIOP Static Pressure (in. wg) — 50TJ016
COMPONENT
EconoMi$er
Glycol Coil
Electric Heat (kW)
20
26/34
32
35
42/56
50
55
56/75
80

4500
0.04
0.22

5000
0.05
0.26

CFM
6000
0.07
0.35

7200
0.09
0.44

7500
0.10
0.46

0.06
0.06
0.06
0.07
0.07
0.09
0.07
0.09
0.09

0.07
0.07
0.07
0.08
0.08
0.10
0.08
0.10
0.10

0.09
0.09
0.09
0.12
0.12
0.15
0.12
0.15
0.15

0.11
0.11
0.11
0.15
0.16
0.20
0.15
0.20
0.20

0.12
0.12
0.12
0.17
0.17
0.21
0.17
0.21
0.21

LEGEND
FIOP — Factory-Installed Option

NOTES:
1. The static pressure must be added to external static pressure.
The sum and the evaporator entering-air cfm should then be
used in conjunction with the Fan Performance tables to determine blower rpm and watts.
2. Heaters are rated at 240 v, 380 v, 480 v, and 600 v.

Table 12 — Accessory/FIOP Static Pressure (in. wg) — 50TJ020-028
CFM

COMPONENT
EconoMi$er
Glycol Coil
Electric Heat (kW)
20, 26/34
32
35, 42/56
55
56/75
80

5400
0.06
0.30

6000
0.07
0.35

7200
0.09
0.44

9000
0.11
0.58

10,000
0.12
0.66

11,250
0.14
0.77

0.08
0.08
0.11
0.11
0.14
0.14

0.09
0.09
0.12
0.12
0.15
0.15

0.11
0.11
0.15
0.15
0.20
0.20

0.15
0.15
0.19
0.19
0.24
0.24

0.17
0.17
0.21
0.21
0.26
0.26

0.20
0.20
0.24
0.24
0.29
0.29

LEGEND
FIOP — Factory-Installed Option

Table 13 — MoistureMiser Dehumidification
Package Static Pressure Drop (in. wg)
UNIT SIZE
50TJ
016
020
024
028

UNIT NOMINAL
TONS
15
18
20
25

CFM PER TON
300
400
500
.040
.071
.111
.058
.102
.160
.071
.126
.197
.111
.197
.308

Table 14 — Fan Rpm at Motor Pulley Settings*
UNIT
50TJ

1/2

11/2

016 (208/230, 380, 460 v)†
016 (208/230, 380, 460 v)**
016 (575 v)†
020†
020**
024†
024**
028†
028**

††
††
††
††
††
††
††
††
††

1179
1559
1429
1095
1287
1225
1458
1283
—

1150
1522
1403
1077
1265
1209
1434
1269
—

1121
1488
1376
1058
1243
1187
1407
1247
1551

MOTOR PULLEY TURNS OPEN
21/2
3
31/2
4
1093
1455
1349
1040
1222
1165
1381
1225
1524

*Approximate fan rpm shown.
†Indicates standard drive package.
**Indicates alternate drive package.
††Due to belt and pulley size, pulley cannot be set to this number of
turns open.

1064
1422
1323
1021
1200
1143
1354
1203
1497

1035
1389
1296
1002
1178
1120
1328
1182
1470

1006
1356
1269
984
1156
1098
1301
1160
1443

41/2

51/2

978
1323
1242
965
1134
1076
1275
1138
1415

949
1289
1215
947
1112
1053
1248
1116
1388

920
1256
1188
928
1091
1031
1222
1095
1361

891
1227
1159
910
1069
1002
1193
1066
1332

Base Unit Operation

FREEZE PROTECTION THERMOSTAT(S) — A freeze
protection thermostat (FPT) is located on the top and bottom of
the evaporator coil. It detects frost build-up and turns off the
compressor, allowing the coil to clear. Once frost has melted,
the compressor can be reenergized by resetting the compressor
lockout.
HEATING, UNITS WITH ECONOMI$ER (If Accessory or
Optional Heater is Installed) — When the room thermostat
calls for heat, the heating controls are energized as described in
the Heating, Units Without EconoMi$er section. The IFM is
energized and the EconoMi$er damper modulates to the minimum position. When the thermostat is satisfied, the damper
modulates closed.
UNITS WITH MOISTUREMISER DEHUMIDIFICATION
PACKAGE — When thermostat calls for cooling, terminals G
and Y1 and/or Y2 and the compressor contactor C1 and/or C2
are energized. The indoor (evaporator) fan motor (IFM), compressors, and outdoor (condenser) fan motors (OFM) start. The
OFMs run continuously while the unit is in cooling. As shipped
from the factory, both MoistureMiser dehumidification circuits
are always energized.
If MoistureMiser circuit modulation is desired, a fieldinstalled, wall-mounted humidistat is required. If the MoistureMiser humidistat is installed and calls for the MoistureMiser subcooler coil to operate, the humidistat internal
switch closes. This energizes the 3-way liquid line solenoid
valve coils (LLSV1 for circuit 1 and LLSV2 for circuit 2) of
the MoistureMiser circuits, forcing the warm liquid refrigerant
of the liquid line to enter the subcooler coils. See Fig. 30.
As the warm liquid passes through the subcooler coils, it is
exposed to the cold supply airflow coming off the evaporator
coils and the liquid is further cooled to a temperature approaching the evaporator coil leaving-air temperature. The state of the
refrigerant leaving the subcooler coils is a highly subcooled liquid refrigerant. The liquid then enters a thermostatic expansion
valve (TXV) where the liquid is dropped to the evaporator
pressure. The TXVs can throttle the pressure drop of the liquid
refrigerant and maintain proper conditions at the compressor
suction valves over a wide range of operating conditions. The
liquid proceeds to the evaporator coils at a temperature lower
than normal cooling operation. This lower temperature is what
increases the latent and sensible capacity of the evaporator
coils.
The 2-phase refrigerant passes through the evaporators and
is changed into a vapor. The air passing over the evaporator
coils will become colder than during normal operation as a result of the colder refrigerant temperatures. However, as it passes over the subcooler coils, the air will be warmed, decreasing
the sensible capacity and reducing the sensible heat of the rooftop unit.
As the refrigerant leaves the evaporator, the refrigerant
passes a subcooler control low-pressure switch (S-LPS1 for
circuit 1 or S-LPS2 for circuit 2) in the suction line. This lowpressure switch will deactivate the MoistureMiser package
when the suction pressure reaches 60 psig. The subcooler control low-pressure switch is an added safety device to protect
against evaporator coil freeze-up during low ambient operation. The subcooler control low-pressure switch will only
deactivate the 3-way liquid line solenoid valve in the MoistureMiser circuit. The compressors will continue to run as long
as there is a call for cooling, regardless of the position of the
subcooler control low-pressure switch. The 3-way solenoid
valve and the MoistureMiser package will be reactivated only
when the call for cooling has been satisfied, the subcooler control low-pressure switch has closed above 80 psig, and a new
call for cooling exists. The crankcase heaters on the scroll compressors provide additional protection for the compressors due
to the additional refrigerant charge in the subcooler.

COOLING, UNITS WITHOUT ECONOMI$ER — When
thermostat calls for cooling, terminals G and Y1 are energized.
The indoor (evaporator) fan contactor (IFC), and compressor
contactor no. 1 (C1) are energized and evaporator-fan motor,
compressor no. 1 and condenser fans start. The condenser-fan
motors run continuously while unit is cooling. If the thermostat
calls for a second stage of cooling by energizing Y2, compressor contactor no. 2 (C2) is energized and compressor no. 2
starts.
HEATING, UNITS WITHOUT ECONOMI$ER (If Accessory or Optional Heater is Installed) — Upon a call for heating through terminal W1, IFC and heater contactor no. 1 (HC1)
are energized. On units equipped for 2 stages of heat, when additional heat is needed, HC2 is energized through W2.
COOLING UNITS WITH ECONOMI$ER — When the
OAT is above the ECON SP set point and the room thermostat
calls for Stage 1 cooling (R to G + Y1), the indoor-fan motors
(IFM) is energized and the EconoMi$er damper modulates to
minimum position. The compressor contactor and OFC are
energized to start the compressor and outdoor-fan motor
(OFM). After the thermostat is satisfied, the damper modulates
to the fully closed position when the IFM is deenergized.
When the OAT is below the ECON SP setting and the room
thermostat calls for Stage 1 cooling (R to G + Y1), the
EconoMi$er modulates to the minimum position when the
IFM is energized. The EconoMi$er provides Stage 1 of cooling
by modulating the return and outdoor air dampers to maintain a
55 F supply air set point. If the supply-air temperature (SAT) is
greater than 57 F, the EconoMi$er modulates open, allowing a
greater amount of outdoor air to enter the unit. If the SAT drops
below 53 F, the outdoor air damper modulates closed to reduce
the amount of outdoor air. When the SAT is between 53 and
57 F, the EconoMi$er maintains its position.
If outdoor air alone cannot satisfy the cooling requirements
of the conditioned space, and the OAT is above the MECH
CLG LOCKOUT set point, the EconoMi$er integrates free
cooling with mechanical cooling. This is accomplished by the
strategies below.
NOTE: Compressors have a two-minute Minimum On and
Minimum Off, which are accomplished by the strategies
below.
1. If Y1 is energized, and the room thermostat calls for Y2
(2-stage thermostat), the compressor and OFC are energized. The position of the EconoMi$er damper is maintained at its current value.
2. If Y1 is energized for more than 20 minutes, and Y2 is
not energized (whether or not a 2-stage thermostat is
used), the compressor and OFC are energized. The position of the EconoMi$er damper is maintained at its current value.
3. If Y1 is energized, and compressor no. 1 is already energized (see Step 2) and the room thermostat calls for Y2,
compressor no. 1 continues to operate. If Y2 remains
energized for more than 20 minutes, compressor no. 2 is
energized.
NOTE: Compressor no. 2 cannot be energized unless there is a
signal for Y2 from the space thermostat.
4. If compressor no. 2 is energized, and the Y2 signal from
the thermostat is satisfied, compressors 1 and 2 are deenergized. Re-asserting Y2 will start compressor no. 1 and
(after a 20-minute interstage delay) compressor no. 2.
5. If compressor no. 1 is energized and the thermostat is satisfied, compressor no. 1, the OFM, and IFM are deenergized and the EconoMi$er modulates closed.
When the OAT is below the MECH CLG LOCKOUT set
point, the compressors remain off.
23

Fig. 30 — MoistureMiser Operation Diagram
CONDENSER COIL — Clean condenser coil annually and
as required by location and outdoor-air conditions. Inspect coil
monthly — clean as required.
CONDENSATE DRAIN — Check and clean each year at
start of cooling season.
FILTERS — Clean or replace at start of each heating and cooling season, or more often if operating conditions require. Refer
to Table 1 for type and size.
NOTE: The 50TJ028 unit requires industrial grade throwaway
filters capable of withstanding face velocities up to 625 fpm.
Ensure that replacement filters for the 50TJ028 units are rated
for 625 fpm.
OUTDOOR-AIR INLET SCREENS — Clean screens with
steam or hot water and a mild detergent. Do not use throwaway
filters in place of screens.

When the humidistat is satisfied, the humidistat internal
switch opens, cutting power to and deenergizing the LLSVs.
The refrigerant is routed back through the evaporators and the
sub-cooler coils are removed from the refrigerant loops. When
the thermostat is satisfied, C1 and C2 are deenergized and the
compressors, IFM, and OFMs shut off. If the thermostat
fan selector switch is in the ON position, the IFM will run
continuously.

SERVICE

Before performing service or maintenance operations on
unit, turn off main power switch to unit. Turn off accessory
heater power switch if applicable. Electrical shock could
cause personal injury.

Lubrication
COMPRESSORS — Each compressor is charged with the
correct amount of oil at the factory. Conventional white oil
(Sontext 200LT) is used. White oil is compatible with 3GS oil,
and 3GS oil may be used if the addition of oil is required. See
compressor nameplate for original oil charge. A complete recharge should be four ounces less than the original oil charge.
When a compressor is exchanged in the field it is possible that
a major portion of the oil from the replaced compressor may
still be in the system. While this will not affect the reliability of
the replacement compressor, the extra oil will add rotor drag
and increase power usage. To remove this excess oil, an access
valve may be added to the lower portion of the suction line at

Cleaning — Inspect unit interior at beginning of each heating and cooling season and as operating conditions require.
Remove unit top panel and/or side panels for access to unit
interior.
EVAPORATOR COIL — Clean as required with a commercial coil cleaner.
NOTE: The 50TJ028 unit has a mist eliminator screen attached
to the evaporator coil to prevent condensate runoff at high wetbulb conditions. Check periodically and clean as necessary.

the inlet of the compressor. The compressor should then be run
for 10 minutes, shut down, and the access valve opened until
no oil flows. This should be repeated twice to make sure the
proper oil level has been achieved.
FAN SHAFT BEARINGS — For size 016 units, bearings are
permanently lubricated. No field lubrication is required. For
size 020-028 units, the bearings are of the pillow block type
and have grease fittings. The bearing opposite the motor end
has an extended tube line so it can be lubricated from the motor
side. Lubricate the bearings twice annually.
Typical lubricants are given below:
MANUFACTURER
Texaco
Mobil
Sunoco
Texaco

6. Remove belt.
7. Rotate motor mount assembly back past original position
toward evaporator coil.
8. Remove motor mounting nuts D and E (both sides).
9. Lift motor up through top of unit.
10. Reverse above procedure to reinstall motor.
11. Check and adjust belt tension as necessary.
50TJ020-028 UNITS (See Fig. 33) — The 50TJ020-028
units use a fan motor mounting system that features a slide-out
motor mounting plate. To replace or service the motor, slide out
the bracket.
1. Remove the evaporator-fan access panel and the heating
control access panel.
2. Remove the center post (located between the evaporator
fan and heating control access panels) and all screws securing it.
3. Loosen nuts on the two carriage bolts in the motor mounting base.
4. Using jacking bolt under motor base, raise motor to top of
slide and remove belt. Secure motor in this position by
tightening the nuts on the carriage bolts.
5. Remove the belt drive.
6. Remove jacking bolt and tapped jacking bolt plate.
7. Remove the 2 screws that secure the motor mounting
plate to the motor support channel.
8. Remove the 3 screws from the end of the motor support
channel that interfere with the motor slide path.
9. Slide out the motor and motor mounting plate.
10. Disconnect wiring connections and remove the 4 mounting bolts.
11. Remove the motor.
12. To install the new motor, reverse Steps 1-11.

LUBRICANT
Regal AFB-2*
Mobilplex EP No. 1
Prestige 42
Multifak 2

*Preferred lubricant because it contains rust and oxidation inhibitors.

CONDENSER AND EVAPORATOR-FAN MOTOR
BEARINGS — The condenser and evaporator-fan motors
have permanently-sealed bearings, so no field lubrication is
necessary.

Evaporator Fan Performance Adjustment
(Fig. 31-33) — Fan motor pulleys are factory set for speed
shown in Table 1.
To change fan speeds:
1. Shut off unit power supply.
2. a. Size 016 Only: Loosen belt by loosening fan motor
mounting plate nuts.
b. Size 020-028 Only: Loosen nuts on the 2 carriage
bolts in the motor mounting base. Install jacking
bolt and plate under motor base (bolt and plate are
shipped in installer’s packet). See Fig. 33. Using
bolt and plate, raise motor to top of slide and
remove belt. Secure motor in this position by tightening the nuts on the carriage bolts.
3. Loosen movable-pulley flange setscrew (see Fig. 31).
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed. Increasing fan speed increases load on motor. Do not exceed maximum speed specified in Table 1.
See Table 7 for air quantity limits.
5. Set movable flange at nearest keyway of pulley hub and
tighten setscrew. (See Table 1 for speed change for each
full turn of pulley flange.)
6. Replace and tighten belts. See Belt Tension Adjustment
section on page 26.
To align fan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft.
3. Make angular alignment by loosening motor from
mounting plate.

Evaporator Fan Service and Replacement
50TJ016 UNITS (See Fig. 32)
NOTE: To remove belts only, follow Steps 1-6.
1. Remove filter and supply-air section panels.
2. Remove unit top panel.
3. Loosen carriage nuts A and B holding motor mount assembly to fan scroll side plates.
4. Loosen screw C.
5. Rotate motor mount assembly (with motor attached) as
far as possible away from evaporator coil.

Fig. 31 — Evaporator-Fan Pulley Alignment
and Adjustment
25

4. Tighten setscrews and replace rubber hubcap to prevent
hub from rusting to motor shaft.
5. Fill hub recess with permagum if rubber hubcap is
missing.

NOTE: A 31/2-in. bolt and threaded plate are included in the
installer’s packet. They should be added to the motor support channel below the motor mounting plate to aid in raising the motor. The
plate part number is 50DP503842. The adjustment bolt is 3/8-16 x
13/4 in.-LG.

Fig. 32 — 50TJ016 Evaporator-Fan
Motor Section

Fig. 33 — 50TJ020-028 Evaporator-Fan
Motor Section

Belt Tension Adjustment — To adjust belt tension:
1. Loosen fan motor bolts.
2. Adjust belt tension:
a. Size 016 Units: Move motor mounting plate up or
down for proper belt tension (1/2 in. deflection with
one finger).
b. Size 020-028 Units: Turn motor jacking bolt to move
motor mounting plate up or down for proper belt tension (3/8 in. deflection at midspan with one finger [9
lb force]).
3. Tighten nuts.
4. Adjust bolts and nut on mounting plate to secure motor in
fixed position.

NOTE: Dimensions are in inches).

Fig. 34 — Condenser-Fan Adjustment,
50TJ016,020

Condenser-Fan Adjustment
50TJ016,020 UNITS (Fig. 34)
1. Shut off unit power supply.
2. Remove access panel(s) closest to the fan to be adjusted.
3. Loosen fan hub setscrews.
4. Adjust fan height on shaft using a straightedge placed
across the fan orifice.
5. Tighten setscrews and replace panel(s).
6. Turn on unit power.
50TJ024,028 UNITS (Fig. 35)
1. Shut off unit power supply.
2. Remove fan top-grille assembly and loosen fan hub
screws.
3. Adjust fan height on unit, using a straightedge placed
across the fan orifice.

NOTE: Dimensions are in inches.

Fig. 35 — Condenser-Fan Adjustment,
50TJ024,028
26

EconoMi$er Adjustment

sensor fault must be corrected to enable EconoMi$er to revert
to normal operation.
If the CONFIG button is pressed and held for more than
30 seconds and released, the EconoMi$er controller will enable
the enthalpy comparison strategy (with outdoor air enthalpy
and return air enthalpy sensors installed).

LED INDICATION — The EconoMi$er controller features
an onboard diagnostic LED (light-emitting diode) that flashes
to indicate its status. See Table 15 for flash codes. The controller also has terminal connections (REM LED) for remotely
mounting an LED, if desired. The flash code priorities are as
follows:
1. On/Off or continuous flash
2. Critical fault
3. Non-critical fault
If any sensors are opened, shorted, or removed, the
EconoMi$er determines whether the failure is critical or noncritical and flashes the appropriate code. If a non-critical sensor
fault occurs (i.e., outdoor air humidity), the EconoMi$er automatically reconfigures its control strategy to a more appropriate
mode. If a critical sensor fault occurs (i.e., supply air sensor),
the EconoMi$er reverts to a safe mode of operation until the
sensor problem is resolved.
MANUAL CONFIGURATION PUSHBUTTON — The
EconoMi$er controller also features an onboard button (CONFIG) to help troubleshoot the system. See Fig. 16. The button
can perform 3 different functions.
Pressing the CONFIG button for more than three seconds,
but less than ten seconds and then releasing will start the automatic test procedure. The damper will modulate fully open,
wait, and modulate closed. This process takes three minutes to
complete. Use this feature to determine if the actuator can be
commanded.
If the CONFIG button is pressed and held for ten seconds
and less than 30 seconds then released, the EconoMi$er controller reconfigures its mode of operation based on the sensors
that are connected and functioning normally, and cancels the
automatic test procedure.
If the EconoMi$er controller recognized a non-critical
sensor fault, and flashed a code (i.e., FLASH 6, outdoor air
humidity sensor fault) the FLASH CODE will be cleared, and
normal operation begins. Ensure faulty sensor is removed
before clearing faults.
If the EconoMi$er controller recognizes a critical sensor
fault, and flashes a code (i.e., FLASH 4, discharge air thermostat fault) the FLASH code will not be cleared, and the
EconoMi$er will remain in the safe operation mode. The

Power Failure — Dampers have a spring return. In event
of power failure, dampers will return to fully closed position
until power is restored. Do not manually operate damper
motor.

Refrigerant Charge — Amount of refrigerant charge is
listed on unit nameplate and in Table 1. Refer to Carrier GTAC
II; Module 5; Charging, Recovery, Recycling, and Reclamation
section for charging methods and procedures. Unit panels must
be in place when unit is operating during charging procedure.
NOTE: Do not use recycled refrigerant as it may contain contaminants.
NO CHARGE — Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refrigerant (refer to Table 1).
LOW CHARGE COOLING — Using cooling charging chart
(see Fig. 36), add or remove refrigerant until conditions of the
chart are met. Note that charging chart is different from those
normally used. An accurate pressure gage and temperaturesensing device is required. Charging is accomplished by ensuring the proper amount of liquid subcooling. Measure liquid line
pressure at the liquid line service valve using pressure gage.
Connect temperature sensing device to the liquid line near the
liquid line service valve and insulate it so that outdoor ambient
temperature does not affect reading.
TO USE THE COOLING CHARGING CHART — Use the
above temperature and pressure readings, and find the intersection point on the cooling charging chart. If intersection point on
chart is above line, add refrigerant. If intersection point on
chart is below line, carefully recover some of the charge. Recheck suction pressure as charge is adjusted. NOTE: Indoor-air
CFM must be within normal operating range of unit. All outdoor fans must be operating.
The TXV (thermostatic expansion valve) is set to maintain
between 15 and 20 degrees of superheat at the compressors.
The valves are factory set and should not require re-adjustment.

Non-Critical Fault

Critical Fault

Table 15 — EconoMi$er Control Module Flash Code Identification
FLASH CODE
Constant On
Constant Off
Continuous
Flash
Flash One
Flash Two
Flash Three

CAUSE
Normal operation
No power
CONFIG button pushed and held
between 3 and 9 seconds
Control board fault
Thermostat fault (i.e., Y2 without Y1)
Actuator fault

Flash Nine

Carbon Dioxide (CO2) sensor fault

ACTION TAKEN BY ECONOMI$ER
Normal operation.
No operation.
Outdoor air damper is stroked fully open, then closed
(automatic test procedure takes 3 minutes to complete).
System shutdown.
System shutdown until corrected.
Revert to mechanical cooling only.
Continue operation with damper at minimum position.
Revert to mechanical cooling only.
Continue operation with damper at minimum position.
Disable mechanical cooling lockout.
Continue operation with dry bulb or dry bulb differential switchover.
Continue operation with single enthalpy EconoMi$er
switchover or dry bulb EconoMi$er switchover (without
humidity sensor).
Continue operation with single enthalpy, differential dry
bulb, or dry bulb EconoMi$er switchover.
Continue operation without ventilation control.

Flash Ten

Onboard adjustment potentiometer fault

Continue operation with default potentiometer settings.

Flash Four

Discharge air thermistor fault

Flash Five

Outdoor air temperature sensor fault

Flash Six

Outdoor air humidity sensor fault

Flash Seven

Return air temperature sensor fault

Flash Eight

Return air humidity sensor fault

Compressor Lockout — If any of the safeties (high-pressure,
low-pressure, freeze protection thermostat, compressor internal
thermostat) trip, or if there is loss of power to the compressors,
the CLO (compressor lockout) will lock the compressors off.
To reset, manually move the thermostat setting.
EVAPORATOR FAN MOTOR PROTECTION — A manual reset, calibrated trip, magnetic circuit breaker protects
against overcurrent. Do not bypass connections or increase the
size of the breaker to correct trouble. Determine the cause and
correct it before resetting the breaker.
CONDENSER-FAN MOTOR PROTECTION — Each
condenser-fan motor is internally protected against
overtemperature.
HIGH- AND LOW-PRESSURE SWITCHES — If either
switch trips, or if the compressor overtemperature switch activates, that refrigerant circuit will be automatically locked out
by the CLO. To reset, manually move the thermostat setting.
FREEZE PROTECTION THERMOSTAT (FPT) — An FPT
is located on the top and bottom of the evaporator coil. It detects frost build-up and turns off the compressor, allowing the
coil to clear. Once the frost has melted, the compressor can be
reenergized.

LIQUID TEMPERATURE AT LIQUID VALVE (DEG F)

BOTH CIRCUITS
ALL OUTDOOR FANS MUST BE OPERATING
140

120
ADD CHARGE IF ABOVE CURVE

100

REDUCE CHARGE IF BELOW CURVE
60

40
50

150
100
200
250
350
300
LIQUID PRESSURE AT LIQUID VALVE (PSIG)

400

Fig. 36 — Cooling Charging Chart

Relief Devices — All units have relief devices to protect

MOISTUREMISER SYSTEM CHARGING — The system
charge for units with the MoistureMiser option is greater than
that of the standard unit alone. The charge for units with this
option is indicated on the unit nameplate drawing. To charge
systems using the MoistureMiser Dehumidification package,
fully evacuate, recover, and re-charge the system to the nameplate specified charge level. To check or adjust refrigerant
charge on systems using the MoistureMiser Dehumidification
package, charge per the standard subcooling charts. The subcooler MUST be deenergized to use the charging charts. The
charts reference a liquid pressure (psig) and temperature at a
point between the condenser coil and the subcooler coil. A tap
is provided on the unit to measure liquid pressure entering the
subcooler (leaving the condenser).

against damage from excessive pressures (e.g., fire). These devices protect the high and low side.

Control Circuit, 24-V — This control circuit is protected against overcurrent by a 3.2-amp circuit breaker. Breaker
can be reset. If it trips, determine cause of trouble before
resetting.

Replacement Parts — A complete list of replacement
parts may be obtained from any Carrier distributor upon
request.
EconoMi$er LEDs — The EconoMi$er control module
has an LED for diagnostic purposes. The flash code identification is shown in Table 15.

Filter Drier — Replace whenever refrigerant system is exposed to atmosphere.

Optional Hinged Access Doors — When the optional
service package is ordered or the if the hinged access doors
option is ordered, the unit will be provided with external and
internal hinged access doors to facilitate service.
Four external hinged access doors are provided. All external
doors are provided with 2 large 1/4 turn latches with folding
bail-type handles. (Compressor access doors have one latch.) A
single door is provided for filter and drive access. One door is
provided for control box access. The control box access door is
interlocked with the non-fused disconnect which must be in the
OFF position to open the door. Two doors are provided for access to the compressor compartment.
Two internal access doors are provided inside the filter/
drive access door. The filter access door (on the left) is secured
by 2 small 1/4 turn latches with folding bail-type handles. This
door must be opened prior to opening the drive access door.
The drive access door is shipped with 2 sheet metal screws
holding the door closed. Upon initial opening of the door, these
screws may be removed and discarded. The door is then held
shut by the filter access door, which closes over it.

Protective Devices
COMPRESSOR PROTECTION
Overcurrent — Each compressor has internal line break motor
protection, except the circuit no. 1 on the 50TJ028 unit. Compressor no. 1 on the 50TJ028 unit uses an electronic module located with the compressor junction box, to provide motor protection. This electronic module monitors winding and discharge temperatures. If these temperatures reach the trip
values, the module interrupts the control line and causes the
compressor to switch off.
Crankcase Heater — Only the 50TJ028 unit and units with
the optional MoistureMiser Dehumidification system are
equipped with a 70-watt crankcase heater to prevent absorption
of liquid refrigerant by oil in the crankcase when the compressor is idle. The crankcase heater is energized whenever there is
a main power to the unit and the compressor is not energized.
IMPORTANT: After prolonged shutdown or servicing,
energize the crankcase heaters for 24 hours before starting the compressors.

A
B
C

ELECTRIC HEAT
208/240 v Amps
200/230 v kW
71.3/82.3
25.7/34.2
117/135
42.2/56.1
156/180
56.2/74.8

Fig. 37 — Typical Wiring Schematic (50TJ024, 208/230-3-60 Shown)
29

Fig. 37 — Typical Wiring Schematic (50TJ024, 208/230-3-60 Shown) (cont)

Fig. 38 — Typical Component Arrangement (50TJ024 Shown)
30

LEGEND AND NOTES FOR FIG. 37 AND 38
LEGEND
AHA
—
BRK W/AT —
C
—
CB
—
CC
—
CH
—
CLO
—
COMP
—
CR
—
DAT
—
DM
—
DU
—
EC
—
EQUIP
—
FL
—
FLA
—
FPT
—
FU
—

Adjustable Heat Anticipator
Breaks with Amp Turns
Contactor, Compressor
Circuit Breaker
Cooling Compensator
Crankcase Heater
Compressor Lockout
Compressor Motor
Control Relay
Discharge Air Thermistor
Damper Motor
Dummy Terminal
Enthalpy Control
Equipment
Fuse Link
Full Load Amps
Freeze Protection Thermostat
Fuse

GND
HC
HPS
HTR
IFC
IFCB
IFM
IFR
L
LOR
LPS
LS
NEC
OAT
OFC
OFM
OP
PL
PRI

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

Ground
Heater Contactor
High-Pressure Switch
Heater
Indoor-Fan Contactor
Indoor-Fan Circuit Breaker
Indoor-Fan Motor
Indoor-Fan Relay
Light
Lockout Relay
Low-Pressure Switch
Limit Switch
National Electrical Code
Outdoor-Air Thermostat
Outdoor-Fan Contactor
Outdoor-Fan Motor
Overcurrent Protection
Plug Assembly
Primary

TB
TC
TH
TRAN

—
—
—
—

Terminal Block
Thermostat Cooling
Thermostat Heating
Transformer
Terminal (Marked)
Terminal (Unmarked)
Terminal Block
Splice
Factory Wiring
Field Control Wiring
Option/Accessory Wiring
To indicate common potential
only; not to represent wiring.

NOTES:
1. Compressor and fan motor(s) thermally protected; 3-phase motors protected
against primary single-phasing conditions.
2. If any of the original wire furnished must be replaced, it must be replaced with
type 90 C wire or its equivalent.
3. TRAN1 is wired for 230 v (60 Hz) or 220 v (50 Hz) operation. If unit is 208 v, disconnect the black wires from the ORN TRAN wire and reconnect to the RED
TRAN wire, apply wirenuts to wires.
5. IFCB must trip amps is equal to or less than 140% FLA.
6. The CLO locks out the compressor to prevent short cycling on compressor overload and safety devices. Before replacing CLO, check these devices.
7. Jumpers are omitted when unit is equipped with EconoMi$er.
8. Number(s) indicates the line location of used contacts. A bracket over (2) numbers signifies a single-pole, double-throw contact. An underlined number signifies a normally closed contact. Plain (no line) number signifies a normally open
contact.

TROUBLESHOOTING
Refer to Tables 16-18 for troubleshooting details.
Table 16 — Cooling Service Analysis
PROBLEM
Compressor and
condenser fan
will not start.

CAUSE
Power failure.
Fuse blown or circuit breaker tripped.
Defective thermostat, contactor, transformer, or control
relay.
Insufficient line voltage.
Incorrect or faulty wiring.
Thermostat setting too high.
Compressor will not start Faulty wiring or loose connections in compressor circuit.
but condenser fan runs.
Compressor motor burned out, seized, or internal overload open.
Defective overload.
Compressor locked out
One leg of 3-phase power dead.
Compressor cycles
(other than normally
satisfying thermostat).

Refrigerant overcharge or undercharge.

Defective compressor.
Insufficient line voltage.
Blocked condenser.
Defective overload.
Defective thermostat.
Faulty condenser-fan motor.
Restriction in refrigerant system.
Dirty air filter.
Compressor operates
continuously.
Unit undersized for load.
Thermostat set too low.
Low refrigerant charge.
Air in system.
Condenser coil dirty or restricted.
Excessive head pressure. Dirty air filter.
Dirty condenser coil.
Refrigerant overcharged.
Faulty TXV.

Head pressure too low.
Excessive suction
pressure.

Air in system.
Condenser air restricted or air short-cycling.
Low refrigerant charge.
Restriction in liquid tube.
High heat load.
Faulty TXV.

Refrigerant overcharged.
Suction pressure too low. Dirty air filter.
Low refrigerant charge.
Metering device or low side restricted.
Faulty TXV.
Insufficient evaporator airflow.
Temperature too low in conditioned area.
Field-installed filter drier restricted.
LEGEND
TXV — Thermostatic Expansion Valve

REMEDY
Call power company.
Replace fuse or reset circuit breaker.
Replace component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
Check wiring and repair or replace.
Determine cause. Replace compressor.
Determine cause and replace.
Determine cause for safety trip and reset lockout.
Replace fuse or reset circuit breaker.
Determine cause.
Recover refrigerant, evacuate system, and recharge
to nameplate.
Replace and determine cause.
Determine cause and correct.
Determine cause and correct.
Determine cause and replace.
Replace thermostat.
Replace.
Locate restriction and remove.
Replace filter.
Decrease load or increase unit size.
Reset thermostat.
Locate leak, repair, and recharge.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
Replace filter.
Clean coil.
Recover excess refrigerant.
1. Check TXV bulb mounting and secure tightly to
suction line.
2. Replace TXV if stuck open or closed.
Recover refrigerant, evacuate system, and recharge.
Determine cause and correct.
Check for leaks, repair, and recharge.
Remove restriction.
Check for source and eliminate.
1. Check TXV bulb mounting and secure tightly to
suction line.
2. Replace TXV if stuck open or closed.
Recover excess refrigerant.
Replace filter.
Check for leaks, repair, and recharge.
Remove source of restriction.
1. Check TXV bulb mounting and secure tightly to
suction line.
2. Replace TXV if stuck open or closed.
Increase air quantity. Check filter and replace if
necessary.
Reset thermostat.
Replace.

Table 17 — EconoMi$er Troubleshooting
PROBLEM
Damper Does Not
Open

POTENTIAL CAUSE
Indoor (Evaporator) Fan is
Off

No Power to EconoMi$er
Controller
No Power to G Terminal
Controller Fault
Thermostat Fault

Actuator Fault

Minimum Position Set
Incorrectly
EconoMi$er Changeover
Set Point Set Too High or
Too Low
Discharge Air
Thermistor Faulty
Outdoor Air Temperature
Sensor Faulty
Supply Air Low Limit
Strategy Controlling

EconoMi$er
Operation Limited to
Minimum Position

Damper Position
Less than Minimum
Position Set Point
Damper Does Not
Return to Minimum
Position
Damper Does Not
Close on Power Loss
IFM
PL

CO2 Ventilation Strategy
Controlling
Damper Travel is
Restricted

REMEDY
Check to ensure that 24 vac is present at Terminal C1 (Common Power)
on the IFC (Indoor [Evaporator] Fan Contactor) or that 24 vac is present at
the IFO (Indoor [Evaporator] Fan On) terminal. Check whether 24 vac is
present at PL6-1 (red wire) and/or PL6-3 (black wire). If 24 vac is
not present, check wiring (see unit label diagram).
Check proper thermostat connection to G on the connection board.
Check to ensure that 24 vac is present across Terminals 24 VAC and
24 V COM on the EconoMi$er control. If 24 vac is not present, check wiring
(see unit label diagram). If 24 vac is present, STATUS light should be on
constantly.
If IFM is on, check to ensure 24 vac is present on G Terminal of the
EconoMi$er controller. If 24 vac is not present, check wiring (see unit
label diagram).
If STATUS light is flashing one flash, the EconoMi$er controller is
experiencing a fault condition. Cycle power to the controller. If condition
continues, replace the EconoMi$er controller.
If STATUS light is flashing two flashes, the EconoMi$er controller senses that
the thermostat is wired incorrectly. Check wiring between the thermostat
and the connection board in the electrical panel. The fault condition is
caused by Y2 being energized before Y1.
Check the wiring between the EconoMi$er controller and the actuator.
Hold CONFIG button between 3 and 10 seconds to verify the
actuator’s operation. (This process takes 3 minutes to complete.)
Verify that the MIN POS (%) is set greater than zero. Adjust MIN POS (%)
to 100% to verify operation, and then set to correct setting.
Set at correct value. See Table 5.
If STATUS light is flashing 4 flashes, Discharge Air Thermistor is
faulty. Check wiring or replace sensor.
If STATUS light is flashing 5 flashes, Outdoor Air Temperature Sensor is
faulty. Check wiring or replace sensor.
The supply-air temperature is less than 45 F, causing the minimum
position to be decreased. Refer to the Start-Up instructions. Verify correct
setting of MIN POS (%). If correct, EconoMi$er is operating correctly.
If a CO2 sensor is being used, and the damper position is greater than
minimum position, the ventilation control strategy is controlling. Refer to
The Start-Up instructions. EconoMi$er is operating correctly.
Check to ensure the damper is not blocked.

LEGEND
— Indoor Fan Motor
— Plug

Table 18 — MoistureMiser Dehumidification Subcooler Service Analysis
PROBLEM
Subcooler will not energize

Subcooler will not deenergize
Low system capacity

CAUSE
No power to subcooler
control transformer.
No power from subcooler
control transformer to liquid line three way valve.

Liquid line three-way valve
will not operate.
Liquid Line three-way valve
will not close.
Low refrigerant charge or
frosted coil.

REMEDY
Check power source. Ensure all wire connections
are tight.
1. Fuse open; check fuse. Ensure continuity of wiring.
2. Subcooler control low pressure switch open.
Cycle unit off and allow low-pressure switch
to reset. Replace switch if it will not close.
3. Transformer bad; check transformer.
1. Solenoid coil defective; replace.
2. Solenoid valve stuck closed; replace.
Valve is stuck open; replace.
1. Check charge amount. See system charging
section.
2. Evaporator coil frosted; check and replace
subcooler control low pressure switch if necessary.

SERVICE TRAINING

Packaged Service Training programs are an excellent way to increase your knowledge of the equipment
discussed in this manual, including:
• Unit Familiarization
• Installation Overview

• Maintenance
• Operating Sequence

A large selection of product, theory, and skills programs are available, using popular video-based formats
and materials. All include video and/or slides, plus companion book.
Classroom Service Training which includes “hands-on” experience with the products in our labs can
mean increased confidence that really pays dividends in faster troubleshooting and fewer callbacks. Course
descriptions and schedules are in our catalog.
CALL FOR FREE CATALOG 1-800-962-9212
[ ] Packaged Service Training
[ ] Classroom Service Training

Copyright 2001 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 111
Catalog No. 535-034
Printed in U.S.A.
Form 50TJ-17SI
Pg 34
2-01
Replaces: 50TJ-14SI
Book 1
Tab 1b

MODEL NO.:

SERIAL NO.:

DATE:

TECHNICIAN:

PRE-START-UP:

VERIFY THAT ALL PACKING MATERIALS HAVE BEEN REMOVED FROM UNIT
VERIFY INSTALLATION OF INDOOR FAN MOTOR ADJUSTMENT BOLT (016 UNITS) OR ADJUSTMENT
BOLT AND PLATE (020-028 UNITS)
VERIFY INSTALLATION OF ECONOMI$ER HOOD
VERIFY THAT CONDENSATE CONNECTION IS INSTALLED PER INSTRUCTIONS
VERIFY THAT ALL ELECTRICAL CONNECTIONS AND TERMINALS ARE TIGHT
CHECK THAT FILTERS AND SCREENS ARE CLEAN AND IN PLACE
VERIFY THAT UNIT IS LEVEL
CHECK FAN WHEEL AND PROPELLER FOR LOCATION IN HOUSING/ORIFICE, AND VERIFY SETSCREW
IS TIGHT
VERIFY THAT FAN SHEAVES ARE ALIGNED AND BELTS ARE PROPERLY TENSIONED
VERIFY THAT SCROLL COMPRESSOR IS ROTATING IN THE CORRECT DIRECTION
VERIFY THAT CRANKCASE HEATER HAS BEEN ENERGIZED FOR 24 HOURS (SIZE 028 AND UNITS WITH
OPTIONAL MOISTUREMISER DEHUMIDIFICATION SYSTEM ONLY)

START-UP:
ELECTRICAL
SUPPLY VOLTAGE

L1-L2

L2-L3

L3-L1

COMPRESSOR AMPS — COMPRESSOR NO. 1

L31

— COMPRESSOR NO. 2
SUPPLY FAN AMPS

EXHAUST FAN AMPS

ELECTRIC HEAT AMPS (IF SO EQUIPPED)

TEMPERATURES
OUTDOOR-AIR TEMPERATURE

F DB (Dry-Bulb)

RETURN-AIR TEMPERATURE

F DB

COOLING SUPPLY AIR

ELECTRIC HEAT SUPPLY AIR (IF SO EQUIPPED)

F WB (Wet-Bulb)
F

PRESSURES
REFRIGERANT SUCTION
CIRCUIT NO. 1
REFRIGERANT DISCHARGE CIRCUIT NO. 1

PSIG
PSIG

CIRCUIT NO. 2
CIRCUIT NO. 2

VERIFY REFRIGERANT CHARGE USING CHARGING CHART ON PAGE 28.

PSIG
PSIG

GENERAL

ECONOMI$ER MINIMUM VENT AND CHANGEOVER SETTINGS TO JOB REQUIREMENTS
VERIFY INSTALLATION OF ALL OPTIONS AND ACCESSORIES

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
1
PC 111
Catalog No. 535-034
Printed in U.S.A.
Form 50TJ-17SI
Pg CL-1
2-01
Replaces: 50TJ-14SI
1b

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - CUT ALONG DOTTED LINE
CUT ALONG DOTTED LINE

START-UP CHECKLIST

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Author                          : Carrier Corporation

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