Bryant 549J Series User manual

1
549J
SINGLE PACKAGE ROOFTOP
HEAT PUMP
SIZES 07 -- 09 with PURONR(R--410A) REFRIGERANT
Installation Instructions
NOTE: Read the entire instruction manual before starting
the installation.
TABLE OF CONTENTS
SAFETY CONSIDERATIONS 2....................
Rated Indoor Airflow (cfm) 3.....................
REFRIGERATION SYSTEM COMPONENTS 8.......
INSTALLATION 10..............................
Jobsite Survey 10...............................
Step 1 -- Plan for Unit Location 10.................
Roof Mount 10..............................
Step 2 -- Plan for Sequence of Unit Installation 10.....
Curb--Mounted Installation 10..................
Pad--Mounted Installation 10...................
Frame--Mounted Installation 10.................
Step 3 -- Inspect Unit 10..........................
Step 4 -- Provide Unit Support 10..................
Roof Curb Mount 10.........................
Slab Mount (Horizontal Units Only) 12..........
Alternate Unit Support
(In Lieu of Curb or Slab Mount) 12.............
Step 5 -- Field Fabricate Ductwork 12...............
For Units with Accessory Electric Heaters 12.....
Step 6 -- Rig and Place Unit 12....................
Positioning on Curb 13.......................
Step 7 -- Convert to Horizontal and Connect
Ductwork 13...........................
Step 8 -- Install Outside Air Hood 14...............
Economizer and Two Position Damper Hood
Package Removal and Setup — Factory Option 14..
Economizer Hood and Two--Position Hood 14.....
Step 9 -- Install External Condensate Trap
and Line 15............................
Step 10 -- Make Electrical Connections 15...........
Field Power Supply 15........................
Units with Factory--Installed
Non--Fused Disconnect 16.....................
Units Without Factory--Installed
Non--Fused Disconnect 17.....................
All Units 17................................
Convenience Outlets 17.......................
Factory Option Thru--Base Connections 18.......
Units Without Thru--Base Connections 19........
All Units 19................................
Field Control Wiring 19.......................
Thermostat 19...............................
Central Terminal Board 20......................
Commercial Defrost Control 20..................
Unit Without Thru--Base Connection Kit 22.......
Heat Anticipator Settings 22...................
Electric Heaters 22............................
Single Point Boxes & Supplementary Fuses 23....
Single Point Boxes without Fuses 23............
Low--Voltage Control Connections 23............
Variable Frequency Drive (VFD) 2--Speed
Indoor Fan Motor System (Factory--Installed) 23....
EconoMi$erRX (Factory--Installed Option) 24......
Product Description 24........................
System Components 24.......................
Specifications 24..............................
W7220 Economizer Module 24.................
Electrical 24................................
Inputs 24...................................
Outputs 25.................................
Environmental 25............................
Economizer Module Wiring Details 25...........
S--Bus Sensor Wiring 25......................
CO2Sensor Wiring 26........................
Interface Overview 26..........................
User Interface 26............................
Keypad 26.................................
Menu Structure 27.............................
Setup and Configuration 27.....................
Time--out and Screensaver 27..................
Sequence of Operation 33.......................
Enthalpy Settings 36...........................
Two--Speed Fan Operation 36....................
Checkout 37.................................
Power Up 37................................
Initial Menu Display 37.......................

2
Power Loss (Outage or Brownout) 38............
Status 38...................................
Checkout Tests 38...........................
Troubleshooting 38............................
Alarms 38..................................
Clearing Alarms 38..........................
2--Speed Indoor Fan Control System with Variable
Frequency Drive (Factory--Installed Option) 38.......
RTU Open Controller System 39.................
Supply Air Temperature (SAT) Sensor 41.........
Outdoor Air Temperature (OAT) Sensor 41.......
EconoMi$erR242...........................
Field Connections 42..........................
Space Temperature (SPT) Sensors 42............
Indoor Air Quality (CO2)Sensor 43.............
Outdoor Air Quality Sensor 44.................
Space Relative Humidity Sensor or Humidistat 44..
Smoke Detector/Fire Shutdown (FSD) 44.........
Connecting Discrete Inputs 44..................
Communication Wiring -- Protocols 45............
General 45.................................
Local Access 46.............................
RTU Open Controller Troubleshooting 46........
Outdoor Air Enthalpy Control 47.................
Differential Enthalpy Control 47................
Return Air Enthalpy Sensor 47.................
Smoke Detectors 48...........................
Additional Application Data 48.................
Step 11 -- Adjust Factory--Installed Options 48........
Step 12 -- Install Accessories 49...................
Step 13 -- Check Belt Tension 49...................
UNIT START--UP CHECKLIST 51..................
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical
shock or other conditions which may cause personal injury
or property damage. Consult a qualified installer, service
agency, or your distributor or branch for information or
assistance. The qualified installer or agency must use
factory--authorized kits or accessories when modifying this
product. Refer to the individual instructions packaged with
the kits or accessories when installing.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloths for brazing operations and
have a fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions attached to
the unit. Consult local building codes and appropriate
national electrical codes (in USA, ANSI/NFPA70,
National Electrical Code (NEC); in Canada, CSA C22.1)
for special requirements.
It is important to recognize safety information. This is the
safety--alert symbol . When you see this symbol on the
unit and in instructions or manuals, be alert to the
potential for personal injury.
Understand the signal words DANGER, WARNING,
CAUTION, and NOTE. These words are used with the
safety--alert symbol. DANGER identifies the most serious
hazards which will result in severe personal injury or
death. WARNING signifies hazards which could result in
personal injury or death. CAUTION is used to identify
unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal
injury or death.
Before performing service or maintenance operations
on unit, always turn off main power switch to unit and
install lockout tag. Unit may have more than one
power switch.
!WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
Puronr(R--410A) refrigerant systems operate at
higher pressures than standard R--22 systems. Do not
use R--22 service equipment or components on Puron
refrigerant equipment.
!WARNING
PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could cause personal
injury or death.
Relieve pressure and recover all refrigerant before
system repair or final unit disposal.
Wear safety glasses and gloves when handling
refrigerants. Keep torches and other ignition sources
away from refrigerants and oils.
!WARNING

3
CUT HAZARD
Failure to follow this caution may result in personal
injury.
Sheet metal parts may have sharp edges or burrs. Use
care and wear appropriate protective clothing, safety
glasses and gloves when handling parts and servicing
heat pump units.
CAUTION
!Rated Indoor Airflow (cfm)
The table to the right lists the rated indoor airflow used
for the AHRI efficiency rating for the units covered in this
document.
Model Number Full Load Airflow (cfm)
549J*07A 2400
549J*07D 2400
549J*08D 3000
549J*09D 3400
Model
J - Puron
®
(R-410A) Refrigerant
Unit Type
549 - High Efficiency
Packaged Heat Pump
with optional electric heat
Packaging & 2-Speed Indoor Fan Motor
A = Standard Packaging, electro-mechanical
controls that require W7212 EconoMi$er
®
IV
B = LTL Packaging, electro-mechanical controls
that require W7212 EconoMi$er IV
C = Standard Packaging, electro-mechanical
controls that require W7220 EconoMi$er X
D = Standard Packaging and 2 speed indoor
fan motor
E = LTL Packaging and 2 speed indoor fan motor
F = LTL Packaging, electro-mechanical controls
that require W7220 EconoMi$er X
Cooling Tons
07 - 6 tons
08 - 7.5 tons
09 - 8.5 tons
Heat Level
(Field installed electric heaters available)
000 = No Heat
Indoor Fan Options
1 = Standard Static Option
2 = Medium Static Option
3 = High Static/ Option
Refrig. System/Gas Heat Options
A = One-Stage cooling models
D = Two-Stage cooling models
Coil Options (Outdoor - Indoor - Hail Guard)
A = Al/Cu - Al/Cu
B = Precoat Al/Cu - Al/Cu
C = E-coat Al/Cu - Al/Cu
D = E-coat Al/Cu - E-coat Al/Cu
E = Cu/Cu - Al/Cu
F = Cu/Cu - Cu/Cu
M = Al/Cu -Al/Cu — Louvered Hail Guard
N = Precoat Al/Cu - Al/Cu — Louvered Hail Guard
P = E-coat Al/Cu - Al/Cu — Louvered Hail Guard
Q = E-coat Al/Cu - E-coat Al/Cu — Louvered Hail Guard
R = Cu/Cu - Al/Cu — Louvered Hail Guard
S = Cu/Cu - Cu/Cu — Louvered Hail Guard
Voltage
E = 460-3-60
P = 208/230-3-60
T = 575-3-60
Example:
Position:
549JP08D000A1B0AA
123456789
10 11 12 13 14 15 16 17
Factory Installed Options
0A = None
NOTE: See the 549J Price Pages for a complete
list of factory installed options.
Outdoor Air Options
A = None
B = Temperature Economizer, Barometric Relief,
Standard Leak (W7212 or W7220)
E = Temperature Economizer, Barometric Relief,
Standard Leak w/CO
2
, (W7212 or W7220)
H =
Enthalpy Economizer, Barometric Relief,
Standard Leak, (W7212 or W7220)
L =
Enthalpy Economizer,Barometric Relief,
Standard Leak w/CO
2
, (W7212 or W7220)
Q = Motorized 2 Position Damper
U = Temperature
Economizer, Barometric Relief,
Ultra Low Leak, (W7220)
W = Enthalpy Economizer, Barometric Relief,
Ultra Low Leak, (W7220)
a549J---007
Fig. 1 -- 549J 07--09 Model Number Nomenclature (Example)

4
C160144
Fig. 2 -- Unit Dimensional Drawing: 07 — 08 Size Units

5
C160145
Fig. 2 -- Unit Dimensional Drawing: 07 — 08 Size Units (cont.)

6
C10757A
Fig. 3 -- Unit Dimensional Drawing: 09 Size Units

7
C10758A
Fig. 3 -- Unit Dimensional Drawing: 09 Size Unit (cont.)

8
C
D
A
B
C11247
LOCATION DIMENSION CONDITION
A
48--- in. (1219 mm)
18--- in. (457 mm)
18--- in. (457) mm
12--- in. (305 mm)
Unit disconnect is mounted on panel
No disconnect, convenience outlet option
Recommended service clearance
Minimum clearance
B
42--- in. (1067 mm)
36--- in. (914 mm)
Special
Surface behind servicer is grounded (e.g., metal, masonry wall)
Surface behind servicer is electrically non--- conductive (e.g., wood, fiberglass)
Check sources of flue products within 10---ft of unit fresh air intake hood
C36--- in. (914 mm)
18--- in. (457 mm)
Side condensate drain is used
Minimum clearance
D42--- in. (1067 mm)
36--- in. (914 mm)
Surface behind servicer is grounded (e.g., metal, masonry wall, another unit)
Surface behind servicer is electrically non--- conductive (e.g., wood, fiberglass)
NOTE: Unit not designed to have overhead obstruction. Contact Application Engineering for guidance on any application
planning overhead obstruction or for vertical clearances.
Fig. 4 -- Service Clearance Dimensional Drawing
REFRIGERATION SYSTEM
COMPONENTS
Each heat pump refrigeration system includes a
compressor, accumulator, reversing valve, dual--function
outdoor coil with vapor header check valve, cooling liquid
line with a filter drier and a check valve, dual--function
indoor coil with a vapor header check valve, and heating
liquid line with check a valve and a strainer. Size 07 units
have a single compressor--circuit; unit sizes 08 through 09
have two compressor--circuits. See Fig. 5 for typical unit
piping schematic (unit size 09 (4--row indoor coil) with
two compressor--circuits is shown).
Dual--function outdoor and indoor coils are designed to
provide parallel coil circuits during evaporator--function
operation and converging coil circuits during the
condenser--function operation.
Reversing Valve and Check Valve Position
See Fig. 5 (on page 9) and Tables 1, 2, and 3.
Troubleshooting Refrigerant Pressure Problems and
Check Valves
Refer to Fig. 5 and the Cooling Mode and Heating Mode
tables (Tables 1 and 2).
Refrigerant System Pressure Access Ports
There are two access ports in each circuit -- on the suction
tube and the discharge tube near the compressor. These are
brass fittings with black plastic caps. The hose connection
fittings are standard 1/4--in. SAE male flare couplings.
The brass fittings are two--piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
spring--closed check valve core screwed into the base. See
Fig. 6 on page 9. This check valve is permanently
assembled into this core body and cannot be serviced
separately. Replace the entire core body if necessary.
Service tools are available from RCD that allow the
replacement of the check valve core without having to
recover the entire system refrigerant charge. Apply
compressor refrigerant oil to the check valve core’s
bottom O--ring. Install the fitting body and torque to
96 10 in--lbs (10.9 1 Nm). Do not exceed 106 in--lbs
(11.9 Nm) when tightening.
Table 1 – Cooling Mode (each circuit)
Component Status/Position
Reversing Valve Energized
Check Valve A Closed
Check Valve B Open
Check Valve C Closed
Check Valve D Open

9
Table 2 – Heating Mode (each circuit)
Component Status/Position
Reversing Valve De---energized
Check Valve A Open
Check Valve B Closed
Check Valve C Open
Check Valve D Closed
Table 3 – Defrost Mode
Component Status/Position
Defrost Thermostat Closed
Outdoor Fan(s) Off
Reversing Valve Energized
Check Valve A Closed
Check Valve B Open
Check Valve C Closed
Check Valve D Open
COMPRESSOR
ACCUMULATOR
HPS
COMPRESSOR
ACCUMULATOR
HPS
Filter
Drier 2B
1B
LPS/LOC
Acutrol DFT 1
Cooling Liquid Lines
DFT 2
2A
1A
1D
2D
Outdoor Coil
Indoor Coil
Comp 2
Comp 1
2C
1C Strainer
Heating Mode Liquid Lines
Acutrol
Reversing
Valve
Reversing
Valve
C09228
Fig. 5 -- Typical Unit Piping Schematic (with TXV valves on Indoor Coils)
5/8” HEX 0.47
30°
0.596
1/2-20 UNF RH
1/2” HEX
45°
WASHER
O-RING
7/16-20 UNF RH
DEPRESSOR PER AHRI 720
+.01/-.035
FROM FACE OF BODY
This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
SEAT CORE
(Part No. EC39EZ067)
a548J---009
Fig. 6 -- CoreMax* Access Port Assembly
* CoreMax is a registered trademark of Fastest, Inc.

10
INSTALLATION
Jobsite Survey
Complete the following checks before installation.
1. Consult local building codes and the NEC (National
Electrical Code) ANSI/NFPA 70 for special installa-
tion requirements.
2. Determine unit location (from project plans) or select
unit location.
3. Check for possible overhead obstructions which may
interfere with unit lifting or rigging.
Step 1 — Plan for Unit Location
Select a location for the unit and its support system (curb
or other) that provides for the minimum clearances
required for safety. This includes the clearance to
combustible surfaces, unit performance and service access
below, around and above unit as specified in unit
drawings. See Fig. 4.
NOTE: Consider also the effect of adjacent units.
Unit may be installed directly on wood flooring or on Class
A, B, or C roof--covering material when roof curb is used.
Do not install unit in an indoor location. Do not locate air
inlets near exhaust vents or other sources of contaminated
air.
Although unit is weatherproof, avoid locations that permit
water from higher level runoff and overhangs to fall onto
the unit.
Select a unit mounting system that provides adequate
height to allow for removal and disposal of frost and ice
that will form during the heating--defrost mode as well as
allow installation of condensate trap per requirements.
RefertoStep9—InstallExternalCondensate Trap and
Line – for required trap dimensions.
Roof Mount —
Check building codes for weight distribution
requirements. Unit operating weight is shown in Table 4.
Table 4 – Operating Weights
549J* UNITS LB (KG)
07 08 09
Base Unit 710 (322) 875 (397) 1020 (463)
Economizer
Vertical 80 (36) 80 (36) 80 (36)
Horizontal 105 (48) 105 (48) 105 (48)
Powered Outlet 32 (15) 32 (15) 32 (15)
Curb
14--- in. / 356mm 110 (50) 110 (50) 110 (50)
24--- in. / 610mm 145 (66) 145 (66) 145 (66)
Step 2 — Plan for Sequence of Unit Installation
The support method used for this unit will dictate different
sequences for the steps of unit installation. For example,
on curb--mounted units, some accessories must be
installed on the unit before the unit is placed on the curb.
Review the following for recommended sequences for
installation steps.
Curb--Mounted Installation —
Install curb
Install field--fabricated ductwork inside curb
Install accessory thru--base service connection package
(affects curb and unit) (refer to accessory installation
instructions for details)
Prepare bottom condensate drain connection to suit
planned condensate line routing (refer to Step 9 for
details)
Rig and place unit
Install outdoor air hood
Install condensate line trap and piping
Make electrical connections
Install other accessories
Pad--Mounted Installation —
Prepare pad and unit supports
Check and tighten the bottom condensate drain
connection plug
Rig and place unit
Convert unit to side duct connection arrangement
Install field--fabricated ductwork at unit duct openings
Install outdoor air hood
Install condensate line trap and piping
Make electrical connections
Install other accessories
Frame--Mounted Installation —
Frame--mounted applications generally follow the
sequence for a curb installation. Adapt as required to
suit specific installation plan.
Step 3 — Inspect unit
Inspect unit for transportation damage. File any claim
with transportation agency.
Confirm before installation of unit that voltage, amperage
and circuit protection requirements listed on unit data
plate agree with power supply provided.
On units with hinged panel option, check to be sure all
latches are snug and in closed position.
Locate the carton containing the outside air hood parts;
see Fig. 12 (on page 14). Do not remove carton until unit
has been rigged and located in final position.
Step 4 — Provide Unit Support
Roof Curb Mount —
Accessory roof curb details and dimensions are shown in
Fig. 7. Assemble and install accessory roof curb in
accordance with instructions shipped with the curb.
NOTE: The gasketing of the unit to the roof curb is
critical for a watertight seal. Install gasket supplied with
the roof curb as shown in Fig. 7. Improperly applied
gasket can also result in air leaks and poor unit
performance.

11
7/16" [11]
4 9/16"
[115.5]
1/4"
[7.0]
"A"
1 3/4" [44.5]
1 3/4" [44.4]
20-3/4" [513] INSIDE
"A"
81 3/4"
[2076.3]
53 1/2"
[1358.9]
1 3/4" [44.5]
40 3/16" [1020.8]
2 1/4" [57.2]
26"
[660.4]
4 3/16" [106.0]
6 3/64" [153.5]
32 9/16"
[827.1]
23 1/16"
[585.8]
31 17/32"
[800.9]
1 3/4" [44.5]
15 13/16"
[401.6]
11.42" [290.0]
1 3/4"
[44.4]
3"
[76.2]
2-3/8" [61]
14 3/4" [374.7]
6' 6-1/4"
[1987.5]
1-3/4" TYP [44.5]
4' 2"
[1270.0]
15 15/32 [392.9]
1.00" [25.4]
CRBTMPWR002A01
3/4" [19] NPT 1 1/4" [31.7] NPT
CRRFCURB004A01
CONNECTOR PKG. ACC. GAS CONNECTION TYPE GAS FITTING POWER WIRING
FITTING
CONTROL WIRING
FITTING
ACCESSORY CONVENIENCE
OUTLET WIRING CONNECTOR
THRU THE CURB
1/2" [12.7] NPT 1/2" [12.7] NPT
CRBTMPWR004A01 THRU THE BOTTOM
ROOF CURB
ACCESSORY # A
CRRFCURB003A01 14"
[356]
24"
[610]
ECN NO.APP'DCHK'DBYDATEREVISION RECORDREV
1067898--MMC4/22/13
6' 61/4" WAS 6' 7 1/6", 4'2' WAS 4' 2 13/16"; 18 GA WAS 16 GA.; 15 13/16" WAS 15 15/16"; NAIL FIELD SUPPLIED WAS WITH CURB
C
DRAWING RELEASE LEVEL:
PRODUCTION
THIRD ANGLE PROJECTION
UNLESS OTHERWISE SPECIFIED
DIMENSIONS ARE IN INCHES
TOLERANCES ON: THIS DOCUMENT AND THE INFORMATION CONTAINED THEREIN
IS PROPRIETARY TO CARRIER CORPORATION AND SHALL NOT BE USED OR DISCLOSED TO OTHERS, IN WHOLE OR IN PART, WITHOUT THE WRITTEN AUTHORIZATION OF CARRIER CORPORATION.
1 DEC 2 DEC 3 DEC ANG
MATERIAL
----
- - -
AUTHORIZATION NUMBER TITLE
1029120
CURB ASY, ROOF
ENGINEERING MANUFACTURING
ENGINEERING REQUIREMENTS
----
SIZE DRAWING NUMBER REV
T-005, Y-002
DRAFTER CHECKER D50HJ405012 C
WEIGHT:
-MMC 12/16/09 - -
SHEET 5 OF 5
SURFACE FINISH MFG/PURCH MODEL (INTERNAL USE ONLY) NEXT DRAWING SCALE DISTRIBUTION
- PURCH - N/A -
NOTES: 1. ROOFCURB ACCESSORY IS SHIPPED DISASSEMBLED. 2. INSULATED PANELS: 25.4 [1"] THK. POLYURETHANE FOAM, 44.5 [1-3/4] # DENSITY. 3. DIMENSIONS IN [ ] ARE IN MILLIMETERS. 4. ROOFCURB: 18 GAGE STEEL. 5. ATTACH DUCTWORK TO CURB. (FLANGES OF DUCT REST ON CURB). 6. SERVICE CLEARANCE 4 FEET ON EACH SIDE. 7. DIRECTION OF AIR FLOW. 8. CONNECTOR PACKAGE CRBTMPWR002A01 IS FOR THRU-THE-CURB GAS TYPE PACKAGE CRBTMPWR004A01 IS FOR THRU-THE-BOTTOM TYPE GAS CONNECTIONS.
TYPICAL (4) SIDES
SUPPLY AIR RETURN AIR
ROOFING MATERIAL (FIELD SUPPLIED)
CANT STRIP (FIELD SUPPLIED)
ROOFING FELT (FIELD SUPPLIED)
COUNTER FLASHING (FIELD SUPPLIED)
UNIT
GASKET
(SUPPLIED WITH CURB)
RIGID INSULATION (FIELD SUPPLIED)
DUCT
(FIELD SUPPLIED)
NAIL (FIELD SUPPLIED)
CERTIFIED DRAWING
VIEW "B"
CORNER DETAIL
SECTION THRU SIDE
SEE VIEW "B"
GAS SERVICE PLATE THRU THE CURB DRILL HOLE
2" [50.8] @ ASSEMBLY (IF REQUIRED) (SEE NOTE #8)
SEE NOTE #2
12-1/2" [317.5] WIDE
INSULATED DECK PANELS
9-15/16" [252.4] WIDE
INSULATED DECK PANEL
SUPPLY AIR
RETURN AIR
SUPPLY AIR
OPENING
RETURN AIR
OPENING
C13311
Fig. 7 -- Roof Curb Details

12
Curb should be level. This is necessary for unit drain to
function properly. Unit leveling tolerances are shown in
Fig. 8. Refer to Accessory Roof Curb Installation
Instructions for additional information as required.
A-B
0.5″ (13)
B-C
1.0″ (25)
A-C
1.0″ (25)
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
a50---9658
Fig. 8 -- Unit Leveling Tolerances
Install insulation, cant strips, roofing felt, and counter
flashing as shown. Ductwork must be attached to curb and
not to the unit. The accessory thru--the--base power package
must be installed before the unit is set on the roof curb.
If electric and control wiring is to be routed through the
basepan, attach the accessory thru--the--base service
connections to the basepan in accordance with the
accessory installation instructions.
Slab Mount (Horizontal Units Only) —
Provide a level concrete slab that extends a minimum of
6 in. (150 mm) beyond unit cabinet. Install a gravel apron
in front of condenser coil air inlet to prevent grass and
foliage from obstructing airflow.
NOTE: Horizontal units may be installed on a roof curb
if required.
Alternate Unit Support (In Lieu of Curb or Slab
Mount) —
A non--combustible sleeper rail can be used in the unit curb
support area. If sleeper rails cannot be used, support the long
sides of the unit with a minimum of 3 equally spaced 4--in. x
4--in. (102 mm x 102 mm) pads on each side.
Step 5 — Field Fabricate Ductwork
Cabinet return-air static pressure (a negative condition)
shall not exceed 0.35 in. wg (87 Pa) with economizer or
0.45 in. wg (112 Pa) without economizer.
For vertical ducted applications, secure all ducts to roof curb
and building structure. Do not connect ductwork to unit.
Fabricate supply ductwork so that the cross sectional
dimensions are equal to or greater than the unit supply
duct opening dimensions for the first 18 in. (458 mm) of
duct length from the unit basepan.
Insulate and weatherproof all external ductwork, joints,
and roof openings with counter flashing and mastic in
accordance with applicable codes.
Ducts passing through unconditioned spaces must be
insulated 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.
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in damage
to roofing materials.
Membrane roofs can be cut by sharp sheet metal
edges. Be careful when placing any sheet metal parts
on such roof.
CAUTION
!
For Units with Accessory Electric Heaters —
All installations require a minimum clearance to
combustible surfaces of 1--in. (25 mm) from duct for first
12--in. (305 mm) away from unit.
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)
code for use with electric heat.
PERSONAL INJURY HAZARD
Failure to follow this warning could cause personal
injury.
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.
!WARNING
Step 6 — Rig and Place Unit
UNIT DAMAGE HAZARD
Failure to follow this caution may result in
equipment damage.
All panels must be in place when rigging. Unit is not
designed for handling by fork truck.
CAUTION
!
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 using unit frame as a
reference. See Table 4 and Fig. 9 for additional information.
Lifting holes are provided in base rails as shown in Fig. 9.
Refer to rigging instructions on unit.
Rigging materials under unit (cardboard to prevent base
pan damage) must be removed PRIOR to placing the unit
on the roof curb.

13
DETAIL “A”
PLACE ALL SEAL STRIP IN PLACE
BEFORE PLACING UNIT ON ROOF CURB.
DUCT END
SEE DETAIL “A”
“C”
“B”
“A”
914-1371
(36"-54")
SPREADER
BARS
REQUIRED
C10410
UNIT MAX WEIGHT DIMENSIONS
A B C
LB KG IN. MM IN. MM IN. MM
549J*07A/D 1100 500 88.0 2235 40.8 1035 41.5 1055
549J*08D 1315 598 88.0 2235 41.6 1057 49.5 1257
549J*09D 1505 684 88.0 2235 40.0 1015 49.5 1257
NOTES:
1. Dimensions in ( ) are millimeters.
2. Hook rigging shackles through holes in base rail, as shown in detail “A.” Holes in base rails are centered
around the unit center of gravity. Use wooden top to prevent rigging straps from damaging unit.
Fig. 9 -- Rigging Details
When using the standard side drain connection, ensure the
red plug in the alternate bottom connection is tight. Do
this before setting the unit in place. The red drain pan
plug can be tightened with a 1/2--in. square socket drive
extension. For further details see “Step 9 -- Install External
Condensate Trap and Line” on page 15.
Before setting the unit onto the curb, recheck gasketing on
curb.
PositioningonCurb—
Position unit on roof curb so that the following clearances
are maintained: 1/4in. (6.4 mm) clearance between the
roof curb and the base rail inside the front and rear, 0.0 in.
clearance between the roof curb and the base rail inside on
the duct end of the unit. This will result in the distance
between the roof curb and the base rail inside on the
condenser end of the unit being approximately 1/4in.
(6.4 mm).
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
For size 08 and 09 units: after unit is in position, remove
the compressor access panel. Holding the blocking
between compressors with one hand, cut the strapping.
Carefully remove the blocking without damaging tubing,
wiring, or controls. Remove the strapping and replace the
access panel.
Remove all shipping materials and top skid. Recycle or
dispose of all shipping materials.
Step 7 — Convert to Horizontal and Connect
Ductwork (when required)
Unit is shipped in the vertical duct configuration. Unit
without factory--installed economizer or return air smoke
detector option may be field--converted to horizontal ducted
configuration. To convert to horizontal configuration,
remove screws from side duct opening covers and remove
covers. Using the same screws, install covers on vertical
duct openings with the insulation--side down. Seals around
duct openings must be tight. See Fig. 10.
C06108
Fig. 10 -- Horizontal Conversion Panels
Field--supplied flanges should be attached to horizontal
duct openings and all ductwork should be secured to the
flanges. Insulate and weatherproof all external ductwork,
joints, and roof or building openings with counter flashing
and mastic in accordance with applicable codes.
Do not cover or obscure visibility to the unit’s informative
data plate when insulating horizontal ductwork.

14
Step 8 — Install Outside Air Hood
Economizer and Two Position Damper Hood
Package Removal and Setup -- Factory Option
1. The hood is shipped in knock--down form and must be
field assembled. The indoor coil access panel is used as
the hood top while the hood sides, divider and filter are
packaged together, attached to a metal support tray us-
ing plastic stretch wrap, and shipped in the return air
compartment behind the indoor coil access panel. The
hood assembly’s metal tray is attached to the basepan
and also attached to the damper using two plastic tie--
wraps.
2. To gain access to the hood, remove the filter access
panel. (See Fig. 11.)
FILTER ACCESS PANEL
OUTDOOR-AIR OPENING AND
INDOOR COIL ACCESS PANEL
COMPRESSOR
ACCESS PANEL
C06023
Fig. 11 -- Typical Access Panel Locations
3. Locate the (2) screws holding the metal tray to the
basepan and remove. Locate and cut the (2) plastic
tie--wraps securing the assembly to the damper. (See
Fig. 12.) Be careful to not damage any wiring or cut
tie--wraps securing any wiring.
Hood Parts
Plastic Tie Wrap
Qty (2)
Screws for Metal Tray
Qty (2)
C08639
Fig. 12 -- Economizer and Two--Position Damper
Hood Parts Location
4. Carefully lift the hood assembly (with metal tray)
through the filter access opening and assemble per the
steps outlined in Economizer Hood and Two–Position
Hood.
Economizer Hood and Two--Position Hood —
NOTE: If the power exhaust accessory is to be installed
on the unit, the hood shipped with the unit will not be
used and must be discarded. Save the aluminum filter for
use in the power exhaust hood assembly.
1. The indoor coil access panel will be used as the top of
the hood. Remove the screws along the sides and bot-
tom of the indoor coil access panel. See Fig. 13.
TOP
PANEL
INDOOR
COIL
ACCESS
PANEL
INDOOR
COIL
ACCESS
PANEL
CAULK
HERE
TOP
PANEL
C06025
Fig. 13 -- Indoor Coil Access Panel Relocation
2. Swing out indoor coil access panel and insert the hood
sides under the panel (hood top). Use the screws
provided to attach the hood sides to the hood top. Use
screws provided to attach the hood sides to the unit. See
Fig. 14.
B
TOP
PANEL
INDOOR COIL
ACCESS PANEL
19 1/16″
SCREW
HOOD DIVIDER
LEFT
HOOD
SIDE
33 3/8″
(848mm)
(483mm)
a50---9659
Fig. 14 -- Economizer Hood Construction
3. Remove the shipping tape holding the economizer
barometric relief damper in place (economizer only).
4. Insert the hood divider between the hood sides. See
Fig. 14 and Fig. 15. Secure hood divider with 2
screws on each hood side. The hood divider is also
used as the bottom filter rack for the aluminum filter.

15
5. Open the filter clips which are located underneath the
hood top. Insert the aluminum filter into the bottom
filter rack (hood divider). Push the filter into position
past the open filter clips. Close the filter clips to lock
the filter into place. See Fig. 15.
6. Caulk the ends of the joint between the unit top panel
and the hood top.
7. Replace the filter access panel.
DIVIDER
BAROMETRIC
RELIEF
CLEANABLE
ALUMINUM
FILTER FILTER
HOOD
FILTER
CLIP
OUTSIDE
AIR
C08634
Fig. 15 -- Economizer Filter Installation
Step 9 — Install External Condensate Trap
and Line
The unit has one 3/4-in. condensate drain connection on
the end of the condensate pan and an alternate connection
on the bottom. See Fig. 16. Unit airflow configuration
does not determine which drain connection to use. Either
drain connection can be used with vertical or horizontal
applications.
To use the alternate bottom drain connection, remove the
red drain plug from the bottom connection (use a 1/2-- i n .
square socket drive extension) and install it in the side
drain connection.
DRAIN
(FACTORY-INSTALLED)
PLUG
CONDENSATE PAN (SIDE VIEW)
STANDARD
SIDE DRAIN
ALTERNATE
BOTTOM DRAIN
C08021
Fig. 16 -- Condensate Drain Pan (Side View)
The piping for the condensate drain and external trap can
be completed after the unit is in place. See Fig. 17.
NOTE: Trap should be deep enough to offset maximum unit static
difference. A 4 in. (102 mm) trap is recommended.
MINIMUM PITCH
1” (25mm) PER
10’ (3m) OF LINE
BASE RAIL
OPEN
VENT
TO ROOF
DRAIN
DRAIN PLUG
ROOF
CURB
SEE NOTE
3˝(76mm)
MIN
a50---9660
Fig. 17 -- Condensate Drain Piping Details
All units must have an external trap for condensate
drainage. Install a trap at least 4-in. (102 mm) deep and
protect against freeze-up. If drain line is installed
downstream from the external trap, pitch the line away
from the unit at 1-in. per 10 ft (25 mm in 3 m) of run. Do
not use a pipe size smaller than the unit connection
(3/4-in.).
Step 10 — Make Electrical Connections
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Do not use gas piping as an electrical ground. Unit
cabinet must have an uninterrupted, unbroken
electrical ground to minimize the possibility of
personal injury if an electrical fault should occur. This
ground may consist of electrical wire connected to
unit ground lug in control compartment, or conduit
approved for electrical ground when installed in
accordance with NEC (National Electrical Code);
ANSI/NFPA 70, latest edition (in Canada, Canadian
Electrical Code CSA [Canadian Standards
Association] C22.1), and local electrical codes.
!WARNING
NOTE: Check all factory and field electrical connections
for tightness. Field--supplied wiring shall conform with
the limitations of 63_F(33_C) rise.
Field Power Supply —
If equipped with optional Powered Convenience Outlet:
The power source leads to the convenience outlet’s
transformer primary are not factory connected. Installer
must connect these leads according to required operation
of the convenience outlet. If an always--energized
convenience outlet operation is desired, connect the
source leads to the line side of the unit--mounted
disconnect. (Check with local codes to ensure this method
is acceptable in your area.) If a de--energize via unit
disconnect switch operation of the convenience outlet is
desired, connect the source leads to the load side of the

16
unit disconnect. On a unit without a unit--mounted
disconnect, connect the source leads to compressor
contactor C and indoor fan contactor IFC pressure lugs
with unit field power leads.
Field power wires are connected to the unit at line--side
pressure lugs on compressor contactor C and indoor fan
contactor IFC or terminal board (see wiring diagram label
for control box component arrangement) or at
factory--installed option non--fused disconnect switch.
Max wire size is #2 AWG (copper only). (See Fig. 18.)
NOTE: TEST LEADS -- Unit may be equipped with
short leads (pigtails) on the field line connection points on
contactor C or optional disconnect switch. These leads are
for factory run--test purposes only; remove and discard
before connecting field power wires to unit connection
points. Make field power connections directly to line
connection pressure lugs only.
Units Without Disconnect Option
Units With Disconnect Option
2
4
6
1
3
5
L1
L2
L3
Optional
Disconnect
Switch
Disconnect factory test leads; discard.
Factory
Wiring
11 13 13
L1 L2 L3
TB
C
IFC
(3 Phase
Indoor Motor)
(1 Phase Indoor Motor
and 1 Phase Unit)
208/230-3-60
460-3-60
575-3-60
Disconnect
per
NEC
C10468
Fig. 18 -- Power Wiring Connections
!WARNING
FIRE HAZARD
Failure to follow this warning could result in
personal injury, death, or property damage.
Do not connect aluminum wire between disconnect
switch and furnace. Use only copper wire.
(See Fig. 19.)
COPPER
WIRE ONLY
ELECTRIC
DISCONNECT
SWITCH
ALUMINUM
WIRE
A93033
Fig. 19 -- Disconnect Switch and Unit
Units with Factory--Installed Non--Fused Disconnect —
The factory--installed option non--fused disconnect (NFD)
switch is located in a weatherproof enclosure located
under the main control box. The manual switch handle and
shaft are shipped in the disconnect enclosure. Assemble the
shaft and handle to the switch at this point. Discard the
factory test leads (see Fig. 18).
Connect field power supply conductors to LINE side
terminals when the switch enclosure cover is removed to
attach the handle.
C12284
Fig. 20 -- Location of Non--Fused Disconnect Enclosure
To field install the NFD shaft and handle:
1. Remove the unit front panel (see Fig. 2 or Fig. 3).
2. Remove (3) hex screws on the NFD enclosure -- (2) on
the face of the cover and (1) on the left side cover. See
Fig. 21.
3. Remove the front cover of the NFD enclosure.
4. Make sure the NFD shipped from the factory is at
OFF position (the arrow on the black handle knob is
at OFF).
5. Insert the shaft with the cross pin on the top of the shaft
in the horizontal position.
6. Measure from the tip of the shaft to the top surface of
the black pointer; the measurement should be 3.75 to
3.88 in. (95 to 99 mm).
7. Tighten the locking screw to secure the shaft to the
NFD.
8. Turn the handle to the OFF position with red arrow
pointing at OFF.
9. Install the handle on to the painted cover horizontally
with the red arrow pointing to the left.

17
10. Secure the handle to the painted cover with (2) screws
and lock washers supplied.
11. Engaging the shaft into the handle socket, re--install
(3) hex screws on the NFD enclosure.
12. Re--install the unit front panel.
C12279
Fig. 21 -- Handle and Shaft Assembly for NFD
Units Without Factory--Installed
Non--Fused Disconnect —
When installing units, provide a disconnect switch per
NEC (National Electrical Code) of adequate size.
Disconnect sizing data is provided on the unit informative
plate. Locate on unit cabinet or within sight of the unit per
national or local codes. Do not cover unit informative
plate if mounting the disconnect on the unit cabinet.
All Units --
All field wiring must comply with NEC and all local codes.
Size wire based on MCA (Minimum Circuit Amps) on the
unit informative plate. See Fig. 18 and the unit label
diagram for power wiring connections to the unit power
terminal blocks and equipment ground. Maximum wire size
is #2 ga AWG (copper only) per pole on contactors.
Provide a ground--fault and short--circuit over--current
protection device (fuse or breaker) per NEC Article 440
(or local codes). Refer to unit informative data plate for
MOCP (Maximum Over--current Protection) device size.
All field wiring must comply with the NEC and local
requirements.
All units except 208/230-v units are factory wired for the
voltage shown on the nameplate. If the 208/230-v unit is
to be connected to a 208-v power supply, the control
transformer must be rewired by moving the black wire
with the 1/4-in. female spade connector from the 230--v
connection and moving it to the 208-v 1/4-in. male
terminal on the primary side of the transformer. Refer to
unit label diagram for additional information. Field power
wires will be connected line--side pressure lugs on the
power terminal block or at factory--installed option
non--fused disconnect.
NOTE: Check all factory and field electrical connections
for tightness.
Convenience Outlets —
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Units with convenience outlet circuits may use
multiple disconnects. Check convenience outlet for
power status before opening unit for service. Locate
its disconnect switch, if appropriate, and open it.
Lock--out and tag--out this switch, if necessary.
!WARNING
Two types of convenience outlets are offered as
factory--installed options on 549J models: Non--powered
and unit--powered. Both types provide a 125--volt GFCI
(ground--fault circuit--interrupter) duplex receptacle rated at
15--A behind a hinged waterproof access cover, located on
the end panel of the unit. See Fig. 22.
A 20 amp non--powered convenience outlet is available as
a field--installed accessory.
Convenience
Outlet
GFCI
Pwd-CO
Fuse
Switch
Pwd-CO
Transformer
Control Box
Access Panel
C08128
Fig. 22 -- Convenience Outlet Location
Installing Weatherproof Cover: A weatherproof
while-in-use cover for the factory-installed convenience
outlets is now required by UL standards. This cover cannot
be factory-mounted due its depth; it must be installed at unit
installation. For shipment, the convenience outlet is covered
with a blank cover plate.
The weatherproof cover kit is shipped in the unit’s control
box. The kit includes the hinged cover, a backing plate
and gasket.
DISCONNECT ALL POWER TO UNIT AND
CONVENIENCE OUTLET. LOCK--OUT AND TAG--OUT
ALL POWER.
Remove the blank cover plate at the convenience outlet;
discard the blank cover.
Loosen the two screws at the GFCI duplex outlet, until
approximately 1/2-in. (13 mm) under screw heads are
exposed. Press the gasket over the screw heads. Slip the
backing plate over the screw heads at the keyhole slots
and align with the gasket; tighten the two screws until
snug (do not over-tighten).

18
Mount the weatherproof cover to the backing plate as
shown in Fig. 23. Remove two slot fillers in the bottom of
the cover to permit service tool cords to exit the cover.
Check for full closing and latching.
RECEPTACLE
NOT INCLUDED
COVER – WHILE-IN-USE
WEATHERPROOF
BASE PLATE FOR
GFCI RECEPTACLE
C09022
Fig. 23 -- Weatherproof Cover Installation
Non--powered type: This type requires the field
installation of a general--purpose 125--volt 15--A circuit
powered from a source elsewhere in the building. Observe
national and local codes when selecting wire size, fuse or
breaker requirements and disconnect switch size and
location. Route 125--v power supply conductors into the
bottom of the utility box containing the duplex receptacle.
Unit--powered type: A unit--mounted transformer is
factory--installed to stepdown the main power supply
voltage to the unit to 115--v at the duplex receptacle. This
option also includes a manual switch with fuse, located in
a utility box and mounted on a bracket behind the
convenience outlet; access is through the unit’s control
box access panel. See Fig. 22.
The primary leads to the convenience outlet transformer are
not factory--connected. Selection of primary power source is
a customer--option. If local codes permit, the transformer
primary leads can be connected at the line--side terminals on
the unit--mounted non--fused disconnect or HACR breaker
switch; this will provide service power to the unit when the
unit disconnect switch or HACR switch is open. Other
connection methods will result in the convenience outlet
circuit being de--energized when the unit disconnect or
HACR switch is open. See Fig. 24.
Using unit--mounted convenience outlets: Units with
unit--mounded convenience outlet circuits will often
require that two disconnects be opened to de--energize all
power to the unit. Treat all units as electrically energized
until the convenience outlet power is also checked and
de--energization is confirmed. Observe National Electrical
Code Article 210, Branch Circuits, for use of convenience
outlets.
C08283
UNIT
VOLTAGE
CONNECT
AS
PRIMARY
CONNECTIONS
TRANSFORMER
TERMINALS
208,
230 240 L1: RED +YEL L2: BLU + GRA
H1 + H3
H2 + H4
460 480
L1: RED
Splice BLU + YEL
L2: GRA
H1
H2 + H3
H4
575 600 L1: RED
L2: GRA
H1
H2
Fig. 24 -- Powered Convenience Outlet Wiring
a549J---006
Fig. 25 -- Convenience Outlet Utilization Notice Label
Test the GFCI receptacle by pressing the TEST button on
the face of the receptacle to trip and open the receptacle.
Check for proper grounding wires and power line phasing
if the GFCI receptacle does not trip as required. Press the
RESET button to clear the tripped condition.
Factory Option Thru--Base Connections —
This service connection kit consists of a 1/2--in. electrical
bulkhead connector and a 3/4--in. electrical bulkhead
connector, all factory--installed in the embossed (raised)
section of the unit basepan in the condenser section. The
1/2--in. bulkhead connector enables the low--voltage
control wires to pass through the basepan. The 3/4-- i n .
electrical bulkhead connector allows the high--voltage
power wires to pass through the basepan. See Fig. 26.

19
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR
C13412
Fig. 26 -- Thru--Base Connection Fittings
Check tightness of connector lock nuts before connecting
electrical conduits.
Field--supplied and field--installed liquid tight conduit
connectors and conduit may be attached to the connectors
on the basepan. Pull correctly rated high voltage and low
voltage through appropriate conduits. Connect the power
conduit to the internal disconnect (if unit is so equipped)
or to the external disconnect (through unit side panel). A
hole must be field cut in the main control box bottom on
the left side so the 24--v control connections can be made.
Connect the control power conduit to the unit control box
at this hole.
Units without Thru--Base Connections —
1. Install power wiring conduit through side panel open-
ings. Install conduit between disconnect and control
box.
2. Install power lines to terminal connections as shown
in Fig. 18.
All Units —
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. On
3--phase units, voltages between phases must be balanced
within 2% and the current within 10%. Use the formula
below to determine the percent of voltage imbalance.
%Voltage
Imbalance = 100 x max voltage deviation from average voltage
average voltage
Example: Supply voltage is 230-3-60
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage = (224 + 231 + 226) =681 = 227
33
Determine maximum deviation from average voltage.
(AB) 227 – 224 = 3 v
(BC) 231 – 227 = 4 v
(AC) 227 – 226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
%VoltageImbalance = 100 x 4= 1.76%
227
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.
Operation on improper line voltage or excessive phase
imbalance constitutes abuse and may cause damage to
electrical components. Such operation would invalidate
any applicable Bryant warranty.
Field Control Wiring —
The 549J unit requires an external temperature control
device. This device can be a thermostat emulation device
provided as part of a third--party Building Management
System or the RTU Open controller (RTU Open controller
is available as a factory--installed option only).
Thermostat —
Select a Bryant--approved accessory thermostat. When
electric heat is installed in the 549J unit, the thermostat must
be capable of energizing the G terminal (to energize the
Indoor Fan Contactor) whenever there is a space call for
heat (energizing the W1 terminal). Accessory thermostats
listed on the unit price pages can provide this signal but they
are not configured to enable this signal as shipped.
X
C
G
W2
C
W2
G
W1
O/B/Y2 Y2
R
W1
R
Y1 Y1
T
H
E
R
M
O
S
T
A
T
(Note 1)
(Note 2)
Note 1: Typical multi-function marking. Follow manufacturer’s configuration
instructions to select Y2. Do not configure for O output.
Note 2: W2 connection not required on units without electric heating.
Field Wiring
Central
Terminal
Board
Typical
Thermostat
Connections
C09012
Fig. 27 -- Typical Low--Voltage Control Connections
Install the accessory thermostat according to installation
instructions included with the accessory.
Locate the thermostat accessory on a solid wall in the
conditioned space to sense average temperature in
accordance with the thermostat installation instructions.
If the thermostat contains a logic circuit requiring 24--v
power, use a thermostat cable or equivalent single leads of
different colors with minimum of seven leads. If the
thermostat does not require a 24--v source (no “C”
connection required), use a thermostat cable or equivalent
with minimum of six leads. Check the thermostat
installation instructions for additional features which
might require additional conductors in the cable.

20
For wire runs up to 50 ft. (15 m), use no. 18 AWG
(American Wire Gage) insulated wire [35_C(95_F)
minimum]. For 50 to 75 ft. (15 to 23 m), use no. 16 AWG
insulated wire [35_C(95_F) minimum]. For over 75 ft.
(23 m), use no. 14 AWG insulated wire [35_C(95_F)
minimum]. All wire sizes larger than no. 18 AWG cannot
be directly connected to the thermostat and will require a
junction box and splice at the thermostat.
Central Terminal Board
The Central Terminal Board (CTB) is a pass through
connection point. The CTB provides the capability to add
factory--installed options and field--installed accessories to
the units by cutting jumper wires without having to change
or reroute wires through the structure of the unit. The CTB
does not provide any microprocessor control; it is simply a
basic multifunction wiring terminal configuration.
Commercial Defrost Control
The Commercial Defrost Control Board (DFB)
coordinates thermostat demands for supply fan control, 1
or 2 stage cooling, 2 stage heating, emergency heating and
defrost control with unit operating sequences. The DFB
also provides an indoor fan off delay feature (user
selectable). See Fig. 28 for board arrangement.
The DFB is located in the 549J’s main control box (see
Fig. 29). All connections are factory--made through
harnesses to the unit’s CTB, to IFC (belt--drive motor) or
to ECM (direct--drive motor), reversing valve solenoids
and to defrost thermostats. Refer to Table 5 for details of
DFB Inputs and Outputs.
Reversing valve control — The DFB has two outputs for
unit reversing valve control. Operation of the reversing
valves is based on internal logic; this application does not
use an “O” or “B” signal to determine reversing valve
position. Reversing valves are energized during the
cooling stages and the defrost cycle and de--energized
during heating cycles. Once energized at the start of a
cooling stage, the reversing valve will remain energized
until the next heating cycle demand is received. Once
de--energized at the start of a Heating cycle, the reversing
valves will remain de--energized until the next cooling
stage is initiated.
DIP
Switches
Speed-Up
Jumpers
C09275
Fig. 28 -- Defrost Control Board Arrangement
Compressor control — The DFB receives inputs
indicating Stage 1 Cooling, Stage 2 Cooling and Stage 1
Heating from the space thermostat or unit control system
(RTU Open controller); it generates commands to start
compressors with or without reversing valve operation to
produce Stage 1 Cooling (one compressor on 08--09
systems, compressor unloaded on 07 2--stage system),
Stage 2 Cooling (both compressors run on 08--09 systems,
compressor full load on 07 2--stage system) or Stage 1
Heating (both compressors run on 08--09 systems; the 07
systems have only one compressor).
Auxiliary (Electric) Heat control — The 549J unit can be
equipped with one or two auxiliary electric heaters, to
provide a second stage of heating. The DFB will energize
this Heating System for a Stage 2 Heating Command
(heaters operate concurrently with compressor(s) in the Stage
1 Heating cycle), for an Emergency Heating sequence
(compressors are off and only the electric heaters are
energized) and also during the Defrost cycle (to eliminate a
“cold blow” condition in the space).
C09276
Fig. 29 -- Defrost Control Board Location