Bryant 549B Series Dimensions and installation guide

IMPORTANT — READ BEFORE INSTALLING
1. Read and become familiar with these installation in-
structions before installing this unit (Fig. 1).
2. Be sure the installation conforms to all applicable local
and national codes.
3. These instructions contain important information for the
proper maintenance and repair of this equipment.
Retain these instructions for future use.
CONTENTS Page
SAFETY CONSIDERATIONS ........................1
INSTALLATION .................................1-16
I. Locate the Unit .............................3
II. Unit Duct Connections ......................3
III. Rig and Place Unit ..........................3
IV. Field Connections ..........................6
PRE-START-UP ................................16,17
START-UP ....................................17-24
I. Compressor Rotation .......................17
II. Heating Section Start-Up and Adjustments
For Units With Accessory Electric Heat .......17
III. Cooling Section Start-Up and Adjustments ....18
IV. Indoor Airflow and Airflow Adjustments .......19
CARE AND MAINTENANCE .......................25
I. Air Filter ..................................25
SERVICE .....................................25-27
I. Cleaning .................................25
II. Lubrication ...............................26
III. Outdoor-Fan Adjustment ....................26
IV. Economizer Adjustment ....................26
V. Refrigerant Charge .........................26
VI. Replacement Parts .........................27
TROUBLESHOOTING ...........................28-30
START-UP CHECKLIST ..........................CL-1
SAFETY CONSIDERATIONS
Recognize safety information. This is the safety-alert symbol
( ). When you see this symbol on the unit and in instruc-
tions or manuals, be alert to the potential for personal
injury.
Understand the signal words — DANGER, WARNING, and
CAUTION. These words are used with the safety-alert sym-
bol. Danger identifies the most serious hazards which will
result in severe personal injury or death. Warning indicates
a situation that could result in personal injury. Caution is
used to identify unsafe practices which would result in minor
personal injury or product and property damage.
WARNING:Before performing service or mainte-
nance operations on unit, turn off main power switch
to unit. Electrical shock could cause personal injury.
1. The power supply (volts, hertz, and phase) must corre-
spond to that specified on unit rating plate.
2. The electrical supply provided by the utility must be suf-
ficient to handle unit load.
3. Refer to Locate the Unit section on page 3 and Fig. 2 for
locations of electrical inlets, condensate drain, duct con-
nections, and required clearances before setting unit in
place.
4. This installation must conform with local building codes
and with NEC (National Electrical Code) or NFPA
(National Fire Protection Association) 54 TIA-54-1.
Refer to provincial and local plumbing or wastewater codes
and other applicable local codes.
5. Approved for outdoor installation on wood flooring or on
class A, B, or C roof covering materials.
INSTALLATION
Unit is shipped in the vertical airflow configuration (see
Fig. 1). To convert to horizontal discharge, remove side duct
opening covers. Using the same screws, install covers with
insulation-side down (facing outside) on the unit over verti-
cal duct openings. Seals around duct openings must
be tight.
All units can be connected into existing duct systems that are
properly sized and designed to handle an airflow of 300 to
500 cfm per each 12,000 Btuh of rated cooling capacity.
Fig.1—Typical Unit
installation, start-up
and service instructions
SINGLE PACKAGE ROOFTOP
HIGH-EFFICIENCY HEAT PUMP UNITS
549B
Sizes 090,120
7
1
⁄ 2 and 10 Tons
Cancels: New II 549B-90-1
7/15/95

UNIT
549B
STANDARD
UNIT
WEIGHT
CORNER
WEIGHT
(A)
CORNER
WEIGHT
(B)
CORNER
WEIGHT
(C)
CORNER
WEIGHT
(D) ‘‘H’’ ‘‘J’’ ‘‘K’’
Lb Kg Lb Kg Lb Kg Lb Kg Lb Kg ft-in. mm ft-in. mm ft-in. mm
090 870 395 195 90 183 83 237 108 252 114 28-0
7
⁄ 8 9632 38-5
5
⁄ 16 91050 28-9
11
⁄ 16 9856
120 1000 454 231 105 214 97 269 122 286 130 28-10
7
⁄ 8 9885 48-1
5
⁄ 16 91253 38-0
3
⁄ 8 9924
Fig. 2 — Base Unit Dimensions
NOTES:
1. Dimensions in [ ] are in millimeters.
2. Center of Gravity.
3. Direction of airflow.
4. Ductwork to be attached to accessory roof curb only.
5. Minimum clearance (local codes or jurisdiction may prevail):
a. Bottom to combustible surfaces (when not using curb) 0 in., on horizon-
tal discharge units with electric heat, 1 in. clearance to ductwork for 1 ft.
b. Outdoor coil, for proper airflow, 36 in. one side, 12 in. the other. The
side getting the greater clearance is optional.
c. Overhead, 60 in. to assure proper outdoor fan operation.
d. Between units, control box side, 42 in. per NEC (National Electrical Code).
e. Between unit and ungrounded surfaces, control box side, 36 in. per NEC.
f. Between unit and block or concrete walls and other grounded surfaces,
control box side, 42 in. per NEC.
g. Horizontal supply and return end, 0 inches.
6. With the exception of the clearance for the outdoor coil and combustible
surfaces as stated in notes 5a, b, and c, a removable fence or barricade
requires no clearance.
7. Units may be installed on combustible floors made from wood or Class A,
B, or C roof covering material.
8. The vertical center of gravity is 18-7
1
⁄ 2 9[495] for 090, 28-69[610] for 120 up
from the bottom of the base rail.
CONNECTION SIZES
A1
3
⁄ 8 9Dia. [35] Field Power Supply Hole
B2
1
⁄ 2 9Dia. [64] Power Supply Knock-Out
C1
3
⁄ 4 9Dia. [44] Charging Port Hole
D
7
⁄ 8 9Dia. [22] Field Control Wiring Hole
E
3
⁄ 4 9-14 NPT Condensate Drain
F29Dia. [51] Power Supply Knock-Out
BOTTOM POWER CHART
These holes req’d for use with accessory packages —
CRBTMPWR001A00 (
1
⁄ 2 9,
3
⁄ 4 9) or CRBTMPWR002A00 (
1
⁄ 2 9,1
1
⁄ 4 9)
THREADED
CONDUIT SIZE WIRE USE REQ’D HOLE SIZES (MAX.)
1
⁄ 2 (24V
7
⁄ 8 9[22.2]
3
⁄ 4 (Power* 1
1
⁄ 8 9[28.4]
1
1
⁄ 4 (Power* 1
3
⁄ 4 9[44.4]
*Select either
3
⁄ 4 9or 1
1
⁄ 4 9for power, depending on wire size.
—2—

NOTE: When installing any accessory item, see the manu-
facturer’s installation instructions packaged with the acces-
sory. A qualified installer or agency must use only factory-
authorized kits or accessories when modifying this unit.
I. LOCATE THE UNIT
A. Clearance
Maintain clearance around and above unit to provide mini-
mum distance from combustible materials, proper airflow, and
service access. See Fig. 2 and 3.
Minimum clearance to combustibles (when not using curb) is
0 in. on vertical discharge units and 1 in. on horizontal dis-
charge units.
Minimum clearance to block walls or any other grounded sur-
face is 42 in. on all sides.
Minimum clearance of 42 in. should be provided between units
on side with control box. Between unit and ungrounded sur-
faces, control box side, clearance is 36 inches.
Minimum clearance around outdoor coil is 12 in. one side and
36 in. the other side (side getting greater clearance is
optional).
Overhead minimum clearance is 60 in.
Do not install unit in an indoor location. Do not locate unit
air inlets near exhaust vents or other sources of contami-
nated air.
Although unit is weatherproof, guard against water from higher
level runoff and overhangs.
Slab mounted units should be at least 4 in. above the highest
expected water, flood, and runoff levels. Do not use the unit if
it has been under water.
B. Roof Curb Mount
Assemble and install accessory roof curb in accordance with
instructions shipped with curb. See Fig. 4. Install insulation,
cant strips, roofing felt, and counter flashing as shown. Duct-
work must be attached to curb. If electric or control power is
to be routed through the basepan, attach the accessory thru-
the-bottom connections to the basepan in accordance with the
accessory installation instructions.Accessory electric connec-
tions must be installed before unit is in place on roof curb.
IMPORTANT: The gasketing of the unit to the roof curb is
critical for water integrity. Install gasket with the roof curb
as shown in Fig. 4. Improperly applied gasket can also result
in air leaks and poor unit performance.
Curb should be level. Unit leveling tolerances are shown in
Fig. 5. This is necessary for unit drain to function
properly.
C. Slab Mount (Horizontal Units Only)
Provide a level concrete slab that extends a minimum of
6 in. beyond unit cabinet. Install a gravel apron in front of
outdoor-coil air inlet to prevent grass and foliage from ob-
structing airflow.
NOTE: Horizontal units may be installed on a roof curb if
required.
II. UNIT DUCT CONNECTIONS
On vertical units, secure all ducts to roof curb and building
structure. Do not connect ductwork to unit.On horizontal units,
duct flanges should be attached to horizontal openings and
all ductwork should be secured to flanges.
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 in-
sulated and covered with a vapor barrier.
If a plenum return is used on a vertical unit, the return should
be ducted through the roof deck to comply with applicable
fire codes.
A minimum clearance to combustibles is not required
around ductwork on vertical discharge units. On horizontal
discharge units, a minimum clearance of 1 in. is required
for the first 12 in. of ductwork. Cabinet return-air static
shall not exceed –0.35 in. wg with Varislide™ economizer
−0.20 in. wg with PARABLADE economizer, or –0.45 in. wg
without economizer.
NOTE: Connection must be made to roof curb before unit is
set in place.
III. RIG AND PLACE UNIT
Inspect unit for transportation damage. File any claim with
transportation agency. Keep unit upright and do not drop.
Spreader bars are not required if top crating is left on unit.
Rollers may be used to move unit across a roof. Level by us-
ing unit frame as a reference. See Table 1 and Fig. 6 for ad-
ditional information. Operating weight is shown in Fig. 6.
Lifting holes are provided in base rails as shown in Fig. 6.
Refer to rigging instructions on unit.
A properly positioned unit will have the following clearances
between unit and roof curb:
1
⁄ 4 -in. clearance between roof curb
and base rails on each side and front of unit; 1
5
⁄ 32 -in. clear-
ance between roof curb and rear of unit. See Fig. 4, Views
A-A and C-C.
After unit is in position, remove polyethylene shipping wrap-
per and rigging skid.
Fig. 3 — Service and Operational Clearances
—3—

UNIT SIZE
549B ‘‘B’’ ‘‘C’’ ‘‘D’’ ALT DRAIN HOLE POWER CONTROL CONNECTOR
ACCESSORY
PACKAGE
090,120 28-8
7
⁄ 16 9[827] 18-10
15
⁄ 16 9[583] 1
3
⁄ 4 9[45]
3
⁄ 4 9NPT
1
⁄ 2 9NPT CRBTMPWR00A100
(Thru-the-Bottom)
1
1
⁄ 4 9NPT
1
⁄ 2 9NPT CRBTMPWR00A200
(Thru-the-Bottom)
Fig. 4 — Roof Curb Details
UNIT SIZE
549B ‘‘A’’ ROOF CURB ACCESSORY
090,120 18-29[356] CRRFCURB003A00
28-09[610] CRRFCURB004A00
NOTES:
1. Roof curb accessory is shipped unassembled.
2. Insulated panels.
3. Dimensions in [ ] are in millimeters.
4. Roof curb: galvanized steel.
5. Attach ductwork to curb (flanges of duct rest on curb).
6. Service clearance 4 ft on each side.
7. Direction of airflow.
—4—

Table 1 — Specifications
UNIT 549B 090 120
NOMINAL CAPACITY (tons) 7
1
⁄ 2 10
OPERATING WEIGHT (lb)
Unit 870 1000
With Varislide™ Economizer 914 1044
With PARABLADE Economizer 932 1062
Roof Curb 143 143
COMPRESSOR Scroll
Quantity 22
Oil (oz) (each compressor) 57 57
REFRIGERANT TYPE R-22
Operating Charge (lb-oz)
Circuit 1 5-3 9-11
Circuit 2 5-8 9-11
OUTDOOR FAN Propeller Type
Quantity...Diameter (in.) 2...22 2...22
Nominal Cfm 6500 7000
Motor Hp...Rpm
1
⁄ 4 ...1100
1
⁄ 4 ...1100
Watts Input (Total) 650 650
OUTDOOR COIL High-Efficiency Enhanced Copper Tubes, Lanced Aluminum Fins
Acutrol™ Feed Device
Rows...Fins/in. 2...17 2...17
Total Face Area (sq ft) 20.5 25.1
INDOOR FAN Centrifugal Type, Belt Drive
Size (in.) 1...15 x 15 1...15 x 15
Nominal Cfm 3000 4000
Maximum Continuous Bhp 2.90 4.20
Motor Frame 56 56
Fan Rpm Range 725-925 860-1080
Motor Bearing Type Ball Ball
Maximum Fan Rpm 2100 2100
Motor Pulley Pitch Diameter A/B (in.) 3.4/4.4 4.0/5.0
Nominal Motor Shaft Diameter (in.)
7
⁄ 87 ⁄ 8
Fan Pulley Pitch Diameter (in.) 8.0 8.0
Belt — Quantity...Type...Length (in.) 1...A...51 1...A...51
Pulley Center Line Distance (in.) 16.75-19.25 15.85-17.50
Speed Change per Full Turn of 50 45
Movable Pulley Flange (rpm)
Movable Pulley Maximum Full Turns 55
From Closed Position
Factory Setting — Full Turns Open 55
Factory Speed Setting (rpm) 725 860
Fan Shaft Diameter at Pulley (in.) 11
INDOOR COIL High Efficiency Enhanced Copper Tubes, Aluminum Double-Wavy Fins,
Acutrol Feed Device
Rows...Fins/in. 3...15 4...15
Total Face Area (sq ft) 8.9 11.1
HIGH-PRESSURE SWITCH (psig)
Standard Compressor Internal Relief 450±50
Cutout 428
Reset (Auto.) 320
LOSS-OF-CHARGE/LOW-PRESSURE
SWITCH (Liquid Line) (psig)
Cutout 7±3
Reset (Auto.) 22±7
FREEZE-PROTECTION THERMOSTAT
Opens (F) 30±5
Closes (F) 45±5
OUTDOOR-AIR INLET SCREENS Cleanable
Quantity...Size (in.) 1...20 x 25 x 1
1...16 x 25 x 1
RETURN-AIR FILTERS Throwaway
Quantity...Size (in.) 4...16 x 20 x 2 4...20 x 20 x 2
LEGEND
Bhp — Brake Horsepower
—5—

IV. FIELD CONNECTIONS
A. External Trap Condensate Drain
The unit’s
3
⁄ 4 -in. condensate drain connections are located
at the bottom and end of the unit. Unit discharge connec-
tions do not determine the use of drain connections; either
drain connection can be used with vertical or horizontal
applications.
When using the standard end drain connection, make sure
the plug in the alternate bottom connection is tight before
installing the unit.
To use the bottom drain connection for a roof curb instal-
lation, relocate the factory-installed plug from the bottom
connection to the end connection. See Fig. 7. The piping for
the condensate drain and external trap can be completed
after the unit is in place.
All units must have an external trap for condensate drain-
age. Install a trap at least 4-in. deep and protect against freeze-
up. See Fig. 8. If drain line is installed downstream from the
external trap, pitch the line away from the unit at 1 in. per
10 ft of run. Do not use a pipe size smaller than the unit
connection.
B. Field Duct Connections
NOTE: The design and installation of the duct system must
be in accordance with NFPA standards for the installation of
nonresidence-type air conditioning and ventilating systems,
NFPA No. 90A, or residence-type, NFPA No. 90B, and/or
local codes and ordinances.
Adhere to the following criteria when selecting, sizing, and
installing the duct system:
1. Remove appropriate panels from unit to obtain either
horizontal or vertical discharge. If units are installed in
horizontal discharge applications, remove vertical dis-
charge duct covers, save screws, and install covers on
vertical duct openings.
2. Select and size ductwork, supply-air registers, and return-
air grilles according to ASHRAE (American Society
of Heating, Refrigeration and Air Conditioning Engi-
neers) recommendations.
CAUTION: When drilling the duct system fastening
holes into the side of the unit for duct flanges, use ex-
treme care not to puncture the coil or coil tubes. See
Fig. 9.
MAXIMUM ALLOWABLE DIFFERENCE (in.)
A-B B-C A-C
0.5 1.0 1.0
Fig. 5 — Unit Leveling Tolerances
NOTES:
1. Dimension in ( ) is in millimeters.
2. Hook rigging shackles through holes in base rail, as shown in detail
9A.9Holes in base rails are centered around the unit center of grav-
ity. Use wooden top skid when rigging to prevent rigging straps from
damaging unit.
3. Unit weights do not include economizer. See Table 1 for economizer
weights.
CAUTION: All panels must be in place when rigging.
Fig. 6 — Rigging Details
UNIT
549B
OPERATING
WEIGHT DIMENSIONS
(A((B((C(
lb kg in. mm in. mm in. mm
090 870 395 87.38 2219 40.25 1022 41.31 1050
120 1000 454 87.38 2219 40.25 1022 49.31 1253
—6—

3. Use flexible transition between rigid ductwork and unit
to prevent transmission of vibration. The transition may
be screwed or bolted to duct flanges. Use suitable gas-
kets to ensure weather- and airtight seal.
4. When horizontal return is used, install external field-
supplied air filters in return-air ductwork where they
are easily accessible for service. Recommended filter sizes
are shown in Table 1.
5. For horizontal applications, be sure ductwork does not
cover nameplate.
6. Size all ductwork for maximum required airflow (either
heating or cooling) for unit being installed.Avoid abrupt
duct size increases or decreases.
7. Adequately insulate and weatherproof all ductwork
located outdoors. Insulate ducts passing through uncon-
ditioned space, and use vapor barrier in accordance with
latest issue of SMACNA (Sheet Metal and Air Condi-
tioning Contractors National Association) and ACCA
(Air Conditioning Contractors of America) minimum
installation standards for heating and air conditioning
systems. Secure all ducts to building structure.
A minimum clearance to combustibles is not required
around ductwork on vertical discharge units. On hori-
zontal discharge units, a minimum clearance of 1 in. is
required for the first 12 in. of ductwork.
8. Flash, weatherproof, and vibration isolate all openings
in building structure in accordance with local codes and
good building practices.
C. Electrical Connections
WARNING:The unit cabinet must have an un-
interrupted, unbroken, electrical ground to minimize the
possibility of personal injury if an electrical fault should
occur. This ground may consist of electrical wire con-
nected to the unit ground lug in the control compart-
ment, or conduit approved for electrical ground when
installed in accordance with NEC ANSI (American
National Standards Institute)/NFPA70-1990 (in Canada,
Canadian Electrical Code CSA [Canadian Standards
Association] C22.1) and local electrical codes. Failure
to adhere to this warning could result in personal
injury.
CAUTION: Failure to obey the following precau-
tions could result in damage to the unit being
installed:
Field Power Supply
1. Make all electrical connections in accordance with NEC
ANSI/NFPA 70-1990 and local electrical codes gov-
erning such wiring. In Canada, all electrical connec-
tions must be in accordance with CSA Standard C22.1
Canadian Electrical Code Part One and applicable local
codes. Refer to unit wiring diagram.
2. A unit disconnect switch is required within sight
from the unit. The disconnect switch may be mounted
on the unit corner post (see Fig. 2). When mounting dis-
connect switch, be sure the unit rating plate is not
obstructed.
NOTE: A factory-installed disconnect switch is available.
NOTE: Drain plug is shown in factory-installed position.
Fig. 7 — Condensate Drain Pan
NOTE: Trap should be deep enough to offset maximum unit static dif-
frence. A 4-in. trap is recommended.
Fig. 8 — External Trap Condensate Drain
Fig. 9 — Location of Coil Area
Not to be Drilled
—7—

3. Use only copper or copper-clad conductor for connec-
tions between field-supplied electrical disconnect switch
and unit. The use of aluminum wire is not recom-
mended. Maximum wire size is no. 2 AWG (American
Wire Gage) on units with heat (up to 34 kW). The maxi-
mum wire size is no. 2/0 AWG on units with heat (over
34 kW).
4. Units with accessory electric heat must also have the
correct single point box kit to meet UL (Underwriters’
Laboratories) requirements. Refer to installation instruc-
tions shipped with the accessory for more details.
5. Voltage to compressor terminals during operation must
be within voltage range indicated on unit nameplate (also
see Tables 2A and 2B). On 3-phase units, voltages be-
tween phases must be balanced within 2% and the cur-
rent within 10%. Use the formula shown in Tables 2A
and 2B, Note 2 to determine the percent voltage imbal-
ance. Operation on improper line voltage or excessive
phase imbalance constitutes abuse and may cause dam-
age to electrical components. Such operation would in-
validate any applicable warranty.
6. Insulate low-voltage wires for highest voltage con-
tained within conduit when low-voltage control wires are
run in same conduit as high-voltage wires. Install con-
duit through side panel openings. For units without ac-
cessory electric heat, install conduit between disconnect
and control box.
7. Do not damage internal components when drilling through
any panel to mount electrical hardware, conduit, etc.
8. Install power lines to terminal connections as shown in
Fig. 10.
9. For units with accessory electric heat, refer to accessory
installation instructions for wiring the accessory.
During operation, voltage to compressor terminals must be
within range indicated on unit nameplate (see Tables 2A and
2B). On 3-phase units, voltages between phases must be bal-
anced within 2%, and the current within 10%. Use the for-
mula shown in Tables 2A and 2B, Note 2 to determine the
percentage of voltage imbalance. Operation on improper line
voltage or excessive phase imbalance constitutes abuse and
may cause damage to electrical components. Such operation
would invalidate any applicable warranty.
High-Voltage Connections (Fig. 10)
The unit must have a separate electrical service with a field-
supplied, waterproof fused disconnect switch mounted at, or
within sight from, the unit. Refer to the unit rating plate for
maximum fuse/circuit breaker size and minimum circuit amps
(ampacity) for wire sizing. Be sure disconnect switch does not
obstruct unit rating plate. A factory-installed disconnect is
available.
The field-supplied disconnect switch box may be mounted on
the unit over the high-voltage inlet hole in the control corner
panel.
Proceed as follows to complete the high-voltage connections
to the unit:
1. Connect ground lead to chassis ground connection when
using separate ground wire.
2. Pigtails are provided for field power connection. Use
factory-supplied splices or UL-approved copper/aluminum
connector. Install conduit connectors in side panel power
supply knockout openings indicated in Fig. 2. Route power
lines through connector to unit control box.
NOTE: If accessory thru-the-bottom power connections are
used, refer to the accessory installation instructions for in-
formation on power wiring. Refer to Fig. 2 for drilling holes
in basepan.
Special Procedures for 208-V Operation
DANGER: Make sure that the power supply to the
unit is switched off before making any wiring changes.
Electrical shock can cause personal injury or death.
For operation on 208 v, disconnect the black wire from the
230-v orange wire on the transformer and connect it to the
200-v red wire from the transformer. Insulate the end of the
orange wire.
Control Voltage Connections
Install a factory-approved room thermostat. See Table 3,
page 11. Locate the thermostat on an inside wall in the space
to be conditioned where it will not be subjected to either a
cooling or heating source or direct exposure to sunlight. Mount
the thermostat 4 to 5 ft above the floor.
NOTE: For wire runs up to 50 ft, use no. 18 AWG insulated
wire (35 C minimum). For 51 to 75 ft, use no. 16 AWG insu-
lated wire (35 C minimum). For 76 to 155 ft, use no. 14 AWG
insulated wire (35 C minimum). All wire larger than no. 18
AWG cannot be connected directly to the thermostat and will
require a junction box and splice at the thermostat.
LEGEND
C—Contactor
COMP — Compressor
IFC — Indoor Fan Contactor
NEC — National Electrical Code
Field Wiring
Factory Wiring
Splice Connection (Factory-Supplied)
Fig. 10 — Power Wiring Connections
—8—

Route thermostat cable or equivalent single leads of colored
wire from subbase terminals to low-voltage connections on
unit (shown in Fig. 11) as described in Steps 1 through 4
below.
1. If unit is mounted on roof curb and accessory thru-the-
bottom service connections are used, route wire through
basepan.
2. Pass control wires through the hole provided on unit (see
connection D in Connection Sizes table in Fig. 2).
3. Feed wire through the raceway built into the corner post
to the 24-v barrier located on the left side of the control
box. See Fig. 12. The raceway provides the UL required
clearance between the high- and low-voltage wiring.
4. Connect thermostat wires to screw terminals of low-
voltage connector (see Fig. 11).
Table 2A — Electrical Data (Units Without Electrical Convenience Outlet)
UNIT
549B NOMINAL
VOLTAGE
(V-Ph-Hz)
VOLTAGE
RANGE COMPRESSOR OFM IFM ELECTRIC HEAT* POWER SUPPLY MINIMUM UNIT
DISCONNECT
SIZE
Min Max RLA LRA FLA FLA kW† FLA MCA MOCP FLA LRA
090
(7
1
⁄ 2 Tons)
208/230-3-60 187 254 12.4 88.0 1.4 7.5
—/—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—/—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
38.2/ 38.2
65.3/ 69.5
79.8/ 86.3
102.7/112.8
121.5/134.5
148.6/165.7
40/ 40**
70/ 70
80/ 90
110/125
125/150
150/175
40/ 40
65/ 69
79/ 85
100/109
117/129
142/158
242/242
264/267
275/281††
294/302††
309/319††
330/344††
460-3-60 414 508 6.4 44.0 0.7 3.4
—
13.9
16.5
27.8
33.0
41.7
—
16.7
19.8
33.4
39.7
50.2
19.2
40.1
44.0
61.0
68.8
82.0
20**
45**
45**
70
70
90
20
39
43
59
66
78
121
138
141
155
161
171
120
(10 Tons)
208/230-3-60 187 254 19.3 123.0 1.4 10.6
—/—
7.8/10.4
12.0/16.0
24.0/32.0
31.8/42.4
37.6/50.0
—/—
21.7/ 25.0
33.3/ 38.5
66.6/ 77.0
88.3/102.0
104.4/120.3
56.8/ 56.8
84.0/ 88.1
98.5/105.0
140.1/153.1
167.2/184.3
187.3/177.1
60/ 60**
90/ 90
100/110
150/175
175/200
200/200
60/ 60
85/ 89
98/104
136/148
161/177
180/198
337/337
358/362††
370/375††
403/414††
425/439††
441/457††
460-3-60 414 508 10.0 62.0 0.7 4.8
—
16.5
27.8
33.0
41.7
50.0
—
19.8
33.4
39.7
50.2
60.1
28.7
53.3
70.5
78.3
91.5
88.8
30**
60**
80
80
100
100
30
53
69
76
88
99
170
189
203
209
220††
230††
LEGEND
AHA — Adjustable Heat Anticipator
CC — Cooling Compensator
RC — 24 V Cooling
RH — 24 V Heating
TC — Thermostat-Cooling
TH — Thermostat-Heating
Field Wiring
Factory Wiring
Fig. 11 — Low-Voltage Connections With or
Without Economizer
Fig. 12 — Field Control Wiring Raceway
—9—

Table 2B — Electrical Data (Units With Electrical Convenience Outlet)
UNIT
549B NOMINAL
VOLTAGE
(V-Ph-Hz)
VOLTAGE
RANGE COMPRESSOR OFM IFM ELECTRIC HEAT* POWER SUPPLY MINIMUM UNIT
DISCONNECT
SIZE
Min Max RLA LRA FLA FLA kW† FLA MCA MOCP FLA LRA
009
(7
1
⁄ 2 Tons)
208/230-3-60 187 254 12.4 88.0 1.4 7.5
—/—
7.8/10.4
12.0/16.0
18.6/24.8
24.0/32.0
31.8/42.4
—/—
21.7/ 25.0
33.3/ 38.5
51.6/ 59.7
66.6/ 77.0
88.3/102.0
43.0/ 43.0
70.1/ 74.3
84.6/ 91.1
107.5/117.6
126.3/139.3
153.4/170.5
45/ 45**
80/ 80
90/100
110/125
150/150
175/175
46/ 46
71/ 75
84/ 90
105/115
122/134
147/163
247/247
269/272
280/285††
298/307††
313/324††
335/349††
460-3-60 414 508 6.4 44.0 0.7 3.4
—
13.9
16.5
27.8
33.0
41.7
—
16.7
19.8
33.4
39.7
50.2
21.4
42.3
46.1
63.1
71.0
84.1
25**
45**
50**
70
80
90
23
42
46
61
68
80
123
140
143
157
163
174
120
(10 Tons)
208/230-3-60 187 254 19.3 123.0 1.4 10.6
—/—
7.8/10.4
12.0/16.0
24.0/32.0
31.8/42.4
37.6/50.0
—/—
21.7/ 25.0
33.3/ 38.5
66.6/ 77.0
88.3/102.0
104.4/120.3
61.6/ 61.6
88.8/ 92.9
103.3/109.6
144.9/157.9
172.0/189.1
192.1/181.9
70/ 70
90/100
110/110
150/175
175/200
200/200
65/ 65
90/ 94
104/110
142/154
167/183
185/204
341/341
363/366††
375/380††
408/418††
430/443††
446/462††
460-3-60 414 508 10.0 62.0 0.7 4.8
—
16.5
27.8
33.0
41.7
50.0
—
19.8
33.4
39.7
50.2
60.1
30.9
55.6
72.6
80.5
93.6
91.0
35**
60**
80
90
100
100
33
55
71
78
90
102
172
191
205
211
222††
232††
LEGEND AND NOTES TO TABLES 2A AND 2B
LEGEND
FLA — Full Load Amps
HACR — Heating, Air Conditioning and Refrigeration
IFM — Indoor Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
NEC — National Electrical Code
OFM — Outdoor Fan Motor
RLA — Rated Load Amps
*Used to determine minimum disconnect per NEC.
†Heater capacity (kW) is based on heater voltage of 208 v, 240 v,
or 480 v. If power distribution voltage to unit varies from rated heater
voltage, heater kW will vary accordingly.
**Fuse or HACR circuit breaker.
††Factory-installed disconnect is not available for these units when elec-
tric heat package is installed.
NOTES:
1. In compliance with NEC requirements for multimotor and combina-
tion load and equipment (refer to NEC Articles 430 and 440), the
overcurrent protective device for the unit shall be fuse or HACR 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-
age of voltage imbalance.
% Voltage Imbalance
max voltage deviation from average voltage
= 100 x average voltage
EXAMPLE: Supply voltage is 460-3-60
AB = 452 v
BC = 464 v
AC = 455 v 452 + 464 + 455
Average Voltage = 3
1371
=3
= 457
Determine maximum deviation from average voltage:
(AB) 457 – 452=5v
(BC) 464 – 457=7v
(AC) 457 – 455=2v
Maximum deviation is 7 v.
Determine percentage 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.
—10—

Table 3 — Thermostats
TYPE
Manual Changeover (Standard)
2 Heat/2 Cool
Auto. Changeover (Standard)
2 Heat/2 Cool
Manual Changeover (Electronic Setback)
1 Heat/2 Cool
Auto. Changeover (Electronic Setback)
2 Heat/2 Cool
Defrost Board
The defrost board timer cycle is set to 30 minutes. To change
the cycle time, remove the wire from defrost board connected
to the 30 minute quick-connect. See Fig. 13. Connect the wire
to the 50 or 90 minute quick-connects on the defrost board
depending on the desired defrost time.
Heat Anticipator Setting
The room thermostat heat anticipator must be properly ad-
justed to ensure proper heating performance. Set the heat
anticipator using Table 4.
Failure to make a proper heat anticipator adjustment may
result in improper operation, discomfort to the occupants of
the conditioned space, and inefficient energy utilization; how-
ever, the required setting may be changed slightly to provide
a greater degree of comfort for a particular installation.
D. Accessory Installation
At this time, any required accessories should be installed on
the unit. Installation information can be found in the acces-
sory installation book.
Accessory Electric Heat
Each heater package consists of one or more electric heater
module kits and requires the correct single point kit. Refer to
Accessory Electric Heater and Single Point Box Installation
Instructions shipped with the heater for installation details.
NOTE: Factory-installed disconnect switch cannot be used with
some electric heater applications. See Tables 2A and 2B for
more information.
E. Disconnect Switch
The optional disconnect switch is non-fused. The switch has
the capability of being locked in place for safety purposes.
F. Optional Varislide™ Economizer
The optional economizer hood assembly is packaged and shipped
in the filter section. Damper blades and control boards are
installed at the factory and the economizer is shipped in the
vertical discharge position.
NOTE: Horizontal discharge block-off plate is shipped with
the air hood package. If unit is to be used for vertical dis-
charge applications, discard this plate.
Assembly
1. Determine if ventilation air is required in building. If
so, determine the minimum amount to be supplied by
each unit and record quantity of ventilation air needed
for use in Step 8.
2. Remove filter access panel by raising panel and swing-
ing panel outward. Panel is now disengaged from track
and can be removed. No tools are required to remove
filter access panel. Remove outdoor-air opening panel.
Save panels and screws. See Fig. 14. Remove optional
outdoor-air damper hood package from filter section.
3. Assemble outdoor-air hood top and side plates as shown
in Fig. 15. Install seal strips on hoop top and sides.
Put aside screen retainer and retainer screw for later
assembly. Do not attach hood to unit at this time.
Table 4 — Heat Anticipator Settings
UNIT
UNIT VOLTAGE
208/230 460
Heater
kW* Configuration Heater
kW*
Configuration
1-Stage 2-Stage 1-Stage 2-Stage
Stage 1 Stage 2 Stage 1 Stage 2
549B 10.4, 16.0 0.3 NA NA 13.9, 16.5
27.8, 33.0 0.3 NA NA
32.0, 24.8 0.6 0.3 0.3
42.4, 50.0 0.9 0.6 0.3 41.7, 50.0 0.6 0.3 0.3
*kW is based on 240 v and 480 v.
Fig. 13 — Defrost Board
—11—

4. On 120 units, install vertical discharge blockoff plate
over duct openings. See Fig. 16.
5. Slide economizer into unit and secure with screws. See
Fig. 17.
NOTE: Be sure to engage rear economizer flange under tabs
in vertical return-air opening.
6. To convert to horizontal discharge application:
a. Rotate the economizer 90 degrees until the econo-
mizer motor faces the outdoor section (see Fig. 18).
b. Rotate the barometric relief damper cover
90 degrees.
c. Install horizontal discharge block-off plate over the
opening on the access panel. (Block-off plate MUST
be installed before installing hood assembly.) See
Fig. 19.
7. Insert economizer plug into economizer harness. Re-
move tape from barometric relief damper. See Fig. 17.
8. If ventilation air is not required, proceed to Step 9. If
ventilation air is required, determine the minimum po-
sition setting for required airflow. See Fig. 20. Adjust
minimum position setting by adjusting the screws on
the position setting bracket. See Fig. 21. Slide bracket
until the top screw is in the position determined by
Fig. 20. Tighten screws.
9. Remove tape from outdoor-air thermostat (OAT). Fas-
ten OAT to inside of hood using screws and speed clips
provided. See Fig. 22. Make sure OAT terminals are
positioned up.
10. Replace outdoor-air opening panel using screws from
Step 2. Replace filter access panel. Ensure the filter
access panel slides along the tracks and is securely
engaged.
11. Fasten hood top and side plate assembly to outdoor-air
opening panel with screws provided.
12. Place knob supplied with economizer on OAT. See
Fig. 22. Set for 3° F below indoor room thermostat set-
ting. If accessory enthalpy control (EC) is used in place
of OAT, see instructions shipped with EC for installa-
tion and adjustment. See Fig. 22.
13. Connect OAT per Fig. 23.
14. Slide outdoor-air inlet screens into screen track on hood
side plate. While holding screens in place, fasten screen
retainer to hood using screws provided.
NOTE: Refer to Fig. 24 for economizer barometric relief damper
characteristics.
Fig. 14 — Panel Locations
Fig. 15 — Outdoor-Air Hood Details
Fig. 16 — Vertical Discharge Block-Off Plate
(Size 120 Only)
—12—

ECONOMIZER
CONTROL BOARD
WIRING
HARNESS
BAROMETRIC
RELIEF
DAMPER
ECONOMIZER
MOUNTING
SCREWS
ECONOMIZER
MOTOR
Fig. 17 — Varislide™ Economizer Installed in Unit
ECONOMIZER CONTROL BOARD
WIRING HARNESS ECONOMIZER MOTOR
Fig. 18 — Horizontal Varislide Economizer Installation
(90 Degree Rotation)
Fig. 19 — Horizontal Discharge Block-Off Plate
EXAMPLE:
Given —
Negative Pressure ..........................0.01 in. wg
Outdoor Air ................................1100cfm
Determine — Setting = 6
Fig. 20 — Varislide Economizer Minimum
Position Setting
43210
5
6
7
8
9
Fig. 21 — Varislide Economizer Minimum
Damper Setting
—13—

G. Optional PARABLADE Economizer
The optional PARABLADE economizer hood assembly is pack-
aged and shipped in the filter section. Damper blades and
control boards are installed at the factory and the econo-
mizer is shipped in the vertical discharge position.
NOTE: Horizontal discharge block-off plate is shipped with
the air hood package. The PARABLADE economizer can only
be used for vertical discharge applications. Discard this plate.
Assembly
1. Determine if ventilation air is required in building. If
so, determine the minimum amount to be supplied by
each unit and record quantity of ventilation air needed
for use in Step 7.
2. Remove filter access panel by raising panel and swing-
ing panel outward. Panel is now disengaged from track
and can be removed. No tools are required to remove
filter access panel. Remove outdoor-air opening panel.
See Fig. 14. Save panels and screws. Remove optional
economizer so the outdoor-air damper hood package can
be removed from the filter section.
MINIMUM
POSITION
OPEN
3
1
T
P
P1
T1
4
2
5
S
S
O
D
C
TR
B
REV. B
198818A
%
H
U
M
I
D
I
T
Y
90
70
60
30
10
DCBA
60 65 70
75
55
50 85
80
DAMPER
DAMPER
CLOSED
OPEN
OUTDOOR TEMP. °F
REV.
97-3672
CW–SETPOINTS–CCW
CONTACTSSHOWN IN HIGH ENTHALPY
RUSH AT 24VAC
3 mA MIN. AT 11 VDC
CONTACT RATINGS: 1.5A RUN, 3.5A IN
OR UNPOWERED STATE
1
2
3
TR
TR1
24VAC
ENTHALPY CONTROL
Fig. 22 — Varislide™ Economizer Outdoor-Air
Thermostat/Enthalpy Control Installation
LEGEND
OAT — Outdoor-Air Thermostat
NOTE: See unit wiring diagram for more details.
Fig. 23 — Wiring Connections for Outdoor-Air
Thermostat
Fig. 24 — Varislide Economizer Barometric
Relief Damper Characteristics
—14—

3. Assemble outdoor-air hood top and side plates as shown
in Fig. 15. Install seal strips on the hood top and sides.
Put aside screen retainer and retainer screw for later
assembly. Do not attach hood to unit at this time.
4. On 120 units, install vertical discharge blockoff plate
over duct openings. See Fig. 16.
5. Slide economizer into unit and secure with screws. See
Fig. 25.
NOTE: Be sure to engage rear economizer flange under tabs
in vertical return-air opening.
6. Insert economizer plug into economizer harness. Re-
move tape from barometric relief damper. See Fig. 25.
7. If ventilation air is not required, proceed to Step 8. If
ventilation air is required, perform the following:
a. Make sure the factory-installed jumper is in place
across terminals P and P1 on the economizer logic
module. T and T1 should be disconnected during
adjustment.
b. The 2 potentiometers with slots for adjustment are
located on the face of the economizer logic module.
Turn the lower potentiometer fully clockwise. The
damper should be fully closed. Turn the potentio-
meter gradually counterclockwise until the desired
position is reached.
c. Connect T and T1 to the 24 V power supply.
d. After installation is complete, calculate the mini-
mum airflow across the economizer. To calculate the
minimum airflow, the following data is needed: to-
tal cfm (cfm3), temperature of the total cfm (T3),
temperature of the return air (T2), and tempera-
ture of the entering outside air (T1). Cfm1is the
outside air cfm, which will be the minimum airflow.
Insert the data into the following equations:
T1(cfm1)+T
2(cfm2)=T
3
cfm3
cfm2= (cfm3– cfm1)
Therefore:
T1(cfm1)+T
2(cfm3– cfm1)=T
3
cfm3
Use this equation to determine cfm1, which is the
minimum airflow across the economizer.
(T3–T
2
) cfm3
cfm1=(T1–T
2
)
If cfm1does not match the desired minimum air-
flow from Step 1, readjust the minimum position set-
ting screw.
8. Determine the enthalpy changeover set point from
Fig. 26. The enthalpy changeover set point should be
set to return the outdoor air damper to the minimum
position when enthalpy rises above the set point. The
settings are A, B, C, and D. Set the enthalpy change-
over per the setting in Fig. 26.
9. Replace outdoor-air opening panel using screws from
Step 2. Replace filter access panel. Ensure the filter
access panel slides along the tracks and is securely en-
gaged. See Fig. 27.
10. Fasten hood and side plate assembly (Fig. 28) to outdoor-
air opening panel with screws provided.
11. Slide outdoor-air inlet screens into screen track on hood
side plate. While holding screens in place, fasten screen
retainer to hood using screws provided. See Fig. 29.
Fig. 25 — PARABLADE Economizer Installed in Unit
CONTROL
CURVE CONTROL POINT
(APPROX DEG.)
AT 50% RH
A73 [23]
B70 [21]
C67 [19]
D63 [17]
Fig. 26 — Enthalpy Settings for PARABLADE
Economizer
—15—

PRE-START-UP
WARNING:Failure to observe the following warn-
ings could result in serious personal injury:
1. Follow recognized safety practices and wear pro-
tective goggles when checking or servicing refrig-
erant system.
2. Do not operate compressor or provide any electric
power to unit unless compressor terminal cover is
in place and secured.
3. Do not remove compressor terminal cover until all
electrical sources have been disconnected.
4. Relieve all pressure from system before touching
or disturbing anything inside terminal box if
refrigerant leak is suspected around compressor
terminals.
5. Never attempt to repair soldered connection while
refrigerant system is under pressure.
6. Do not use torch to remove any component. Sys-
tem contains oil and refrigerant under pressure.
To remove a component, wear protective goggles
and proceed as follows:
a. Shut off electrical power to unit.
b. Recover refrigerant to relieve all pressure from
system using both high- and low-pressure ports.
c. Cut component-connecting tubing with tubing
cutter and remove component from unit.
d. Carefully unsweat remaining tubing stubs when
necessary. Oil can ignite when exposed to torch
flame.
Proceed as follows to inspect and prepare the unit for initial
start-up:
1. Remove all access panels.
2. Read and follow instructions on all WARNING,
CAUTION, and INFORMATION labels attached to, or
shipped with, unit.
3. Make the following inspections:
a. Inspect for shipping and handling damages such as
broken lines, loose parts, disconnected wires, etc.
b. Inspect for oil at all refrigerant tubing connections
and on unit base. Detecting oil generally indicates a
refrigerant leak. Leak-test all refrigerant tubing con-
nections using electronic leak detector, halide torch,
or liquid-soap solution. If refrigerant leak is de-
tected, see Refrigerant Leaks section on page 27.
c. Inspect all field and factory wiring connections. Be
sure that connections are completed and tight.
d. Inspect coil fins. If damaged during shipping and han-
dling, carefully straighten fins with a fin comb.
4. Verify the following conditions:
a. Make sure that outdoor-fan blade is correctly posi-
tioned in fan orifice. Blades should clear fan motor
and fan orifice ring.
Fig. 27 — Panels Reinstalled On Unit
Fig. 28 — Outdoor-Air Hood Installed on Unit
Fig. 29 — Filters Installed On Outdoor-Air Hood
—16—

b. Make sure that correct air filters are in place. (See
Table 1.) Do not operate unit without return-air
filters.
c. Make sure that condensate drain pan and trap are
filled with water to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose parts
have been removed.
e. Make sure outdoor-air inlet screens are in place.
5. Compressors are internally spring mounted. Do not loosen
or remove compressor holddown bolts.
6. Each unit system has 4 Schrader-type service ports: one
on the suction line, one on the liquid line, and 2 on the
compressor discharge line. Be sure that caps on the ports
are tight.
Unit is now ready for initial start-up.
START-UP
I. COMPRESSOR ROTATION
It is important to be certain the scroll compressor is rotating
in the proper direction. To determine whether or not com-
pressor is rotating in the proper direction:
1. Connect service gages to suction and discharge pres-
sure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pres-
sure does not rise to normal levels:
1. Note that the indoor fan is probably also rotating in the
wrong direction.
2. Turn off power to the unit.
3. Reverse any two of the unit 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 the compressor is rotating in the wrong direc-
tion, the unit makes an elevated level of noise and does not
provide heating/cooling.
II. HEATING SECTION START-UPAND ADJUSTMENTS FOR
UNITS WITH ACCESSORY ELECTRIC HEAT
CAUTION: Complete the required procedures given
in Pre-Start-Up section on this page before starting unit.
Do not jumper any safety devices when operating the unit.
A. Checking Heating Control Operation
Start and check the unit for proper heating control operation
as follows:
1. Turn on unit electrical supply.
2. Set system switch selector at HEAT position and fan switch
atAUTO. position. Set heating temperature lever above
room temperature.
3. First stage of thermostat energizes the indoor-fan mo-
tor, compressor, and outdoor fan second stage energizes
second-stage electric heater elements if installed. Check
heating effects at air supply grille(s). If electric heaters
do not energize, reset limit switch (located on indoor-
fan scroll) by depressing button located between termi-
nals on the switch.
4. The indoor fan and heaters will cycle off with no delay
after thermostat temperature is satisfied.
To shut off unit, set system switch selector at OFF position
or set heating selector lever below room temperature.
B. Heating Sequence of Operation
Units Without Economizer
Upon a call for heating through terminal W1, indoor fan con-
tactor (IFC), outdoor fan contactor (OFC), C1, and C2 are en-
ergized. On units equipped for 2 stages of heat, when addi-
tional heat is needed, the HC is energized through W2.
Units With Economizer/Two-Position Damper (If Accessory
Heater is Installed)
When the room thermostat calls for heat through terminal
W1, the IFC, OFC, C1, and C2 are energized. On units equipped
for 2 stages of heat, when additional heat is needed, the heater
contactor is energized through W2. The indoor-fan motor is
energized, and the economizer damper moves to the mini-
mum position. If the two-position damper is used, the outdoor-
air damper opens to the minimum position whenever the in-
door fan runs. When the thermostat is satisfied, the damper
moves to the fully closed position.
C. Safety Relief
A soft solder joint in the suction line at the G1 service port
fitting provides pressure relief under abnormal temperature
and pressure conditions.
D. Ventilation (Continuous Fan)
Set fan and system switch selectors at ON and OFF posi-
tions, respectively. Indoor fan operates continuously to pro-
vide constant air circulation.
E. Safety Check of Limit Control
Amanual-reset limit control is located on the indoor-air blower.
The control shuts off the unit in the event of fan failure.
—17—

III. COOLING SECTION START-UP AND ADJUSTMENTS
CAUTION: Complete the required procedures given
in the Pre-Start-Up section on page 16 before starting
the unit.
Do not jumper any safety devices when operating the
unit.
Do not operate the compressor in cooling when the out-
door temperature is below 25 F (unless accessory low
ambient kit is installed).
Do not rapid-cycle the compressor. Allow 5 minutes be-
tween ‘‘on’’ cycles to prevent compressor damage.
A. Checking Cooling Control Operation
Start and check the unit for proper cooling control operation
as follows:
1. Place room thermostat SYSTEM switch selector in OFF
position. Observe that blower motor starts when FAN
switch is placed in ON position and shuts down when
FAN switch is placed in AUTO. position.
2. Place SYSTEM switch selector in COOL position and
FAN switch in AUTO. position. Set cooling control be-
low room temperature. Observe that compressor, con-
denser fan, and evaporator blower motors start. Observe
that cooling cycle shuts down when control setting is
satisfied.
3. Check unit charge. See Section B below.
4. To shut off unit, set system switch selector at OFF po-
sition. Resetting thermostat at a position above room tem-
perature shuts unit off temporarily until space
temperature exceeds thermostat setting. Units are
equipped with Cycle-LOC™ protection device. Unit shuts
down on any safety trip and remains off; an indicator
light on the thermostat comes on. Check reason for safety
trip.
5. When using an auto.-changeover room thermostat, place
both SYSTEM and FAN switches in AUTO. positions.
Observe that unit operates in heating mode when tem-
perature control is set above room temperature and
operates in cooling mode when temperature control is
set below room temperature.
6. Compressor restart is accomplished by manual reset at
the thermostat by turning the switch selector to OFF
position and then ON position.
B. Checking and Adjusting Refrigerant Charge
The refrigerant system is fully charged with R-22 refriger-
ant, tested, and factory sealed.
NOTE: Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R-22
charge. This unit uses charging charts to determine proper
charge. See Refrigerant Charge section on page 26 for fur-
ther details.
C. Unit Controls
All compressors have the following internal-protection
controls:
High-Pressure Relief Valve — This valve (internal to the com-
pressor) opens when the pressure differential between the low
and high side becomes excessive and will automatically reset
when pressure returns to normal.
Compressor Overload — This overload interrupts power to
the compressor when either the current or internal tempera-
ture becomes excessive, and automatically resets when the
internal temperature drops to a safe level. This overload may
require up to 60 minutes (or longer) to reset; therefore, if the
internal overload is suspected of being open, disconnect the
electrical power to the unit and check the circuit through the
overload with an ohmmeter or continuity tester.
D. Cooling Sequence of Operation
Units Without Economizer
When the thermostat calls for cooling, terminals G and Y1
are energized. The indoor-fan contactor (IFC), and com-
pressor contactor no. 1 (C1) are energized and the indoor-fan
motor, compressor no. 1, and outdoor fans start. The outdoor-
fan motors run continuously while unit is cooling. If the ther-
mostat calls for a second stage of cooling by energizing Y2,
compressor contactor no. 2 (C2) is energized and compressor
no. 2 starts.
Units with Varislide™ Economizer
When the outdoor-air temperature is above the OAT setting
and the room thermostat calls for cooling, the compressor con-
tactor no. 1 is energized to start compressor no. 1 and outdoor-
fan motor. The indoor-fan motor (IFM) is energized and the
economizer damper moves to the minimum position. Upon a
further call for cooling, compressor contactor no. 2 will be en-
ergized, starting compressor no. 2.After the thermostat is sat-
isfied and the IFM is deenergized, the damper moves to the
fully closed position.
When the outdoor-air temperature is below the OAT setting
and the thermostat calls forY1 and G, the economizer damper
moves to the minimum position when the indoor fan starts.
The first stage of cooling is provided by the economizer. If the
supply-air temperature is above 57 F, a switch on the supply-
air thermostat is closed between the T2 terminal and the
24 vac terminal. This causes the damper to continue to modu-
late open until the supply-air temperature falls below 55 F
or the damper reaches the fully open position.
When the supply-air temperature is between 55 F and 52 F,
the supply-air thermostat has open switches between the T2
and 24 vac terminals and between the T1 and 24 vac termi-
nals. This causes the economizer damper to remain in an in-
termediate open position.
If the supply-air temperature falls below 52 F, a switch on
the supply-air thermostat is closed between the T1 terminal
and the 24 vac terminal. This causes the damper to modu-
late closed until the supply-air temperature rises above 55 F
or the damper reaches the minimum position.
When the supply-air temperature is between 55 F and 57 F,
the supply-air thermostat has open switches between the T2
and 24 vac terminals. This causes the economizer damper to
remain in an intermediate open position.
If the outdoor air alone cannot satisfy the cooling require-
ments of the conditioned space, economizer cooling is inte-
grated with mechanical cooling, providing second stage
cooling. Compressor no. 1 and outdoor fan will be energized,
and the position of the economizer damper will be deter-
mined by the supply-air temperature. Compressor no. 2 is
locked out.
When the second stage of cooling is satisfied, the compressor
and outdoor-fan motor will be deenergized. The damper po-
sition will be determined by the supply-air temperature.
When the first stage of cooling is satisfied, the damper will
move to fully closed position.
—18—

Units with PARABLADE Economizer
When the outdoor air is above the enthalpy control setting,
and the room thermostat calls for cooling, the compressor con-
tactor no. 1 is energized to start compressor no. 1 and the
outdoor fan motor. The indoor fan motor is energized and
the economizer damper moves to the minimum position. Upon
further call for cooling, compressor contactor no. 2 is ener-
gized, starting compressor no. 2. After the room thermostat
is satisfied the damper will spring return to the fully closed
position.
When the outdoor air is below the enthalpy control setting
and the thermostat calls for cooling, the economizer outdoor-
air damper is opened proportionally to maintain between 50
and 56 F at the mixed air sensor. If outside air alone cannot
satisfy the cooling requirements, economizer cooling is inte-
grated with mechanical cooling and the second compressor is
locked out. When the room thermostat is satisfied, the damper
will spring return to the fully closed position.
Time GuardtII Device
If the unit is equipped with accessory Time Guard II recycle
timer, the unit will delay 5 minutes between compressor starts.
Low-Pressure/Loss-of-Charge Switch (LPS)
When the refrigerant liquid-line pressure drops below 7 psig,
the LPS opens 24-v power to the compressor contactor and
stops the compressor. When the pressure reaches 22 psig, the
switch resets and the compressor is allowed to come back on.
High-Pressure Switch (HPS)
When the refrigerant high-side pressure reaches 428 psig, the
HPS opens 24-v power to the compressor contactor and stops
the compressor. When the pressure drops to 320 psig, the switch
resets and the compressor is allowed to restart.
Freeze-Protection Thermostat (FPT)
When the indoor coil leaving-refrigerant temperature drops
below 30 F, the FPT opens 24-v power to the compressor con-
tactor and stops the compressor. When the leaving refriger-
ant temperature warms to 45 F, the switch resets and the
compressor is allowed to restart.
E. Defrost
When the temperature of the outdoor coil drops below 28 F
as sensed by the defrost thermostat (DFT2) and the defrost
timer is at the end of a timed period (adjustable at 30, 50, or
90 minutes), reversing valve solenoids (RVS1 and RVS2) are
energized and the OFC is deenergized. This switches the po-
sition of the reversing valves and shuts off the outdoor fan.
The electric heaters (if installed) will be energized.
The unit continues to defrost until the coil temperature as
measured by DFT2 reaches 65 F, or the duration of defrost
cycle completes a 10-minute period.
During the defrost mode, if circuit 1 defrosts first, RVS1 will
oscillate between heating and cooling modes until the defrost
mode is complete.
At the end of the defrost cycle, the electric heaters (if in-
stalled) will be deenergized; the reversing valves switch and
the outdoor-fan motor will be energized. The unit will not op-
erate in the heating mode.
If the space thermostat is satisfied during a defrost cycle, the
unit will continue in the defrost mode until the time or tem-
perature constraints are satisfied.
IV. INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS
CAUTION: For cooling operation, the recommended
airflow is 300 to 500 cfm per each 12,000 Btuh of rated
cooling capacity. For heating operation, the airflow must
produce a temperature rise that falls within the range
stamped on the unit rating plate.
Adjust indoor-fan speed to meet jobsite conditions (Table 1).
For units with electric heat, required minimum cfm is 2250
for 549B090; 2550 for 549B102 and 3000 for 549B120 with
the following exceptions in Table 5.
Table 5 — Required Minimum Cfm Exceptions
UNIT
549B UNIT VOLTAGE HEATER kW UNIT CONFIGURATION REQUIRED
MINIMUM
CFM
120
208/230 42.4 Horizontal 3200
208/230 50.0 Horizontal 3200
460 50.0 Horizontal or
Vertical 3200
Table 6 shows fan rpm at motor pulley settings. Table 7 shows
motor performance. Refer to Tables 8-11 to determine fan speed
settings.
Table 6 — Fan Rpm at Motor Pulley Settings*
UNIT
549B MOTOR PULLEY TURNS OPEN
0
1
⁄ 2 11
1
⁄ 2 22
1
⁄ 2 33
1
⁄ 2 44
1
⁄ 2 5
090 925 905 885 865 845 825 805 785 765 745 725
120 1080 1060 1035 1015 990 970 950 925 905 880 860
*Approximate fan rpm shown.
Table 7 — Indoor-Fan Motor Data
UNIT
549B UNIT PHASE MAXIMUM
CONTINUOUS
BHP*
MAXIMUM
OPERATING
WATTS* UNIT
VOLTAGE MAXIMUM
AMP
DRAW
090 Three 2.90 2615 208/230 7.9
460 3.6
120 Three 4.20 3775 208/230 11.1
460 5.0
LEGEND
Bhp — Brake Horsepower
*Extensive motor and electrical testing on these units ensures that the full horsepower and watts range
of the motors can be utilized with confidence. Using your fan motors up to the ratings shown in this
table will not result in nuisance tripping or premature motor failure. Unit warranty will not be affected.
—19—

Table 8 — 549B090 Air Delivery — Vertical Discharge Units
AIRFLOW
(Cfm)
BELT DRIVE MOTOR
External Static Pressure (in. wg)
0.2 0.4 0.6 0.8 1.0 1.2
Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp
2250 511 0.52 592 0.74 659 0.95 722 1.19 778 1.43 829 1.68
2300 518 0.55 599 0.77 665 0.98 727 1.22 783 1.47 834 1.72
2400 534 0.61 613 0.84 677 1.06 738 1.30 794 1.55 844 1.81
2500 549 0.67 627 0.90 690 1.14 750 1.38 805 1.64 855 1.91
2550 557 0.71 633 0.94 697 1.18 756 1.42 811 1.69 861 1.96
2600 565 0.74 639 0.97 703 1.22 761 1.46 816 1.74 866 2.01
2700 581 0.81 652 1.04 717 1.31 773 1.55 827 1.83 878 2.12
2800 597 0.89 665 1.12 733 1.40 786 1.66 839 1.93 889 2.23
2900 613 0.97 679 1.20 745 1.50 799 1.76 850 2.04 900 2.34
3000 629 1.06 694 1.29 759 1.59 812 1.88 862 2.15 911 2.46
3100 646 1.15 709 1.39 772 1.70 825 1.99 875 2.28 923 2.58
3200 662 1.25 724 1.50 785 1.80 840 2.11 887 2.41 934 2.71
3300 679 1.35 740 1.61 798 1.91 854 2.24 900 2.54 946 2.85
3400 696 1.46 756 1.73 811 2.02 868 2.37 914 2.69 959 3.00
3500 712 1.57 771 1.85 824 2.14 881 2.50 928 2.84 971 3.16
3600 729 1.69 787 1.98 839 2.21 894 2.64 942 2.99 984 3.22
3700 746 1.85 803 2.12 854 2.42 907 2.78 956 3.15 997 3.49
3750 755 1.89 811 2.20 862 2.49 914 2.85 963 3.23 — —
AIRFLOW
(Cfm)
BELT DRIVE MOTOR (cont)
External Static Pressure (in. wg)
1.4 1.6 1.8 2.0
Rpm Bhp Rpm Bhp Rpm Bhp Rpm Bhp
2250 884 1.97 937 2.33 947 2.66 1022 3.10
2300 885 2.00 939 2.36 979 2.69 1025 3.12
2400 892 2.08 944 2.40 987 2.76 1039 3.20
2500 902 2.18 949 2.48 1002 2.84 1041 3.25
2550 908 2.24 953 2.53 1003 2.87 1045 3.28
2600 913 2.29 957 2.58 1004 2.91 1050 3.31
2700 924 2.40 967 2.70 1010 3.01 1056 3.37
2800 935 2.52 978 2.62 1019 3.13 1061 3.47
2900 946 2.65 989 2.96 1030 3.27 — —
3000 957 2.78 1000 3.09 1040 3.41 — —
3100 968 2.91 1011 3.24 ————
3200 980 3.04 1022 3.38 ————
3300 991 3.18 ——————
3400 1003 3.32 ——————
3500 1014 3.48 ——————
3600 ————————
3700 ————————
3750 ————————
LEGEND
Bhp — Brake Horsepower Input to Fan
NOTES:
1. Boldface indicates a field-supplied drive is required. (See Note 7.)
2. indicates field-supplied motor and drive are required.
3. indicates maximum usable bhp of factory-installed motor.
4. Maximum continuous bhp is 2.90. Extensive motor and electrical test-
ing on these units ensures that the full range of the motor can be
utilized with confidence. Using your fan motors up to the ratings shown
will not result in nuisance tripping or premature motor failure. Unit
warranty will not be affected.
5. Values include losses for filters, unit casing, and wet coils.
6. Use of a field-supplied motor may affect wire sizing. Contact distribu-
tor to verify.
7. Standard motor drive range: 725 to 925 rpm. All other rpms require
field-supplied drive.
8. Interpolation is permissible. Do not extrapolate.
—20—