Bryant 598A Series D Instructions and recipes

NOTE: Read the entire instruction manual before starting the
installation.
This symbol →indicates a change since the last issue.
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service, maintenance,
or use can cause explosion, fire, electrical shock, or other
conditions which may cause death, 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, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have fire extinguisher available. Read these instructions thor-
oughly and follow all warnings or cautions included in literature
and attached to the unit. Consult local building codes and National
Electrical Code (NEC) for special requirements.
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 these signal words; DANGER, WARNING, and
CAUTION. 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 would result in minor personal
injury or product and property damage.
WARNING: Before installing, modifying, or servicing
system, main electrical disconnect switch must be in the
OFF position. There may be more than 1 disconnect
switch. Lock out and tag switch with a suitable warning
label. Electrical shock can cause personal injury or death.
INSTALLATION RECOMMENDATIONS
NOTE: In some cases noise in the living area has been traced to
gas pulsations from improper installation of equipment.
1. Locate unit away from windows, patios, decks, etc. where
unit operation sound may disturb customer.
2. Ensure that vapor and liquid tube diameters are appropriate
to capacity of unit.
3. Run refrigerant tubes as directly as possible by avoiding
unnecessary turns and bends.
4. Leave some slack between structure and unit to absorb
vibration.
5. When passing refrigerant tubes through the wall, seal
opening with RTV or other pliable silicon-based caulk. (See
Fig. 2.)
6. Avoid direct tubing contact with water pipes, duct work,
floor joists, wall studs, floors, and walls.
7. Do not suspend refrigerant tubing from joists and studs with
a rigid wire or strap which comes in direct contact with
tubing. (See Fig. 2.)
8. Ensure that tubing insulation is pliable and completely
surrounds vapor tube.
9. When necessary, use hanger straps which are 1 in. wide and
conform to shape of tubing insulation. (See Fig. 2.)
10. Isolate hanger straps from insulation by using metal sleeves
bent to conform to shape of insulation.
When outdoor unit is connected to factory-approved indoor unit,
outdoor unit contains system refrigerant charge for operation with
indoor unit of the same size when connected by 15 ft of
field-supplied or factory accessory tubing. For proper unit opera-
tion, check refrigerant charge using charging information located
on control box cover.
IMPORTANT: Maximum liquid-line size is 3/8-in. O.D. for all
residential applications.
IMPORTANT: Always install a liquid-line filter drier. Refer to
Product Data Sheet for appropriate part number. Obtain filter
driers from your local dealer or branch.
INSTALLATION
I. CHECK EQUIPMENT AND JOB SITE
A. Unpack Unit
Move to final location. Remove carton taking care not to damage
unit.
B. Inspect Equipment
File claim with shipping company prior to installation if shipment
is damaged or incomplete. Locate unit rating plate on unit corner
panel. It contains information needed to properly install unit.
Check rating plate to be sure unit matches job specifications.
Fig. 1—Model 598A A98538
installation and
start-up instructions
TWO-SPEED
SPLIT-SYSTEM
AIR CONDITIONER
Cancels: II 598A-36-6 II 598A-36-7
10-98
598A
Series D
—1—
→

II. INSTALL ON A SOLID, LEVEL MOUNTING PAD
If conditions or local codes require the unit be attached to pad, tie
down bolts should be used and fastened through knockouts
provided in unit base pan. Refer to unit mounting pattern in Fig. 3
to determine base pan size and knockout hole location.
On rooftop applications, mount on level platform or frame. Place
unit above a load-bearing wall and isolate unit and tubing set from
structure. Arrange supporting members to adequately support unit
and minimize transmission of vibration to building. Consult local
codes governing rooftop applications.
Roof mounted units exposed to winds above 5 mph may require
wind baffles. Consult Low-Ambient Guideline for wind baffle
construction.
NOTE: Unit must be level to within ±2° (±3/8 in./ft) per
compressor manufacturer specifications.
III. CLEARANCE REQUIREMENTS
When installing, allow sufficient space for airflow clearance,
wiring, refrigerant piping, and service. Allow 30-in. clearance to
service end of unit and 48 in. above unit. For proper airflow, a 6-in.
clearance on 1 side of unit and 12 in. on all remaining sides must
be maintained. Maintain a distance of 24 in. between units.
Position so water, snow, or ice from roof or eaves cannot fall
directly on unit.
On rooftop applications, locate unit at least 6 in. above roof
surface.
IV. OPERATING AMBIENTS
The minimum outdoor operating ambient in cooling mode is 55°F,
and the maximum outdoor operating ambient in cooling mode is
125°F.
V. REMOVE INDOOR CHECK-FLO-RATER® PISTON
AND REPLACE WITH TXV
CAUTION: For proper unit operation and reliability, the
outdoor unit must be installed with the factory-supplied
balance port, hard shutoff TXV. Do not install with
evaporator coils having capillary tube metering devices.
After removing existing Check-Flo-Rater from indoor coil, install
factory-supplied thermostatic expansion valve (TXV) kit. (See Fig.
4.) The kit is shipped inside the unit’s compressor compartment. If
unit is installed with an FK4 or FC4 fan coil, no TXV change is
necessary since these fan coils are factory-equipped with proper
TXV.
Install TXV kit to indoor coil as follows:
1. Install suction tube adapter.
2. Install liquid flare-to-sweat adapter.
3. Install TXV on liquid flare-to-sweat adapter.
4. Connect external equalizer tube to fitting on suction tube
adapter.
5. Position sensing bulb on horizontal portion of suction tube
adapter. Secure using supplied hardware. Insulate bulb after
installation. (See Fig. 5.)
6. Check all connections for leaks.
Fig. 2—Connecting Tubing Installation A94028
INSULATION
VAPOR TUBE
LIQUID TUBE
OUTDOOR WALL INDOOR WALL
LIQUID TUBE
VAPOR TUBE
INSULATION
CAULK
Avoid contact between tubing and structureNOTE:
THROUGH THE WALL
HANGER STRAP
(AROUND VAPOR
TUBE ONLY)
JOIST
1″MIN.
SUSPENSION
Fig. 3—Mounting Unit to Pad
DIMENSIONS (IN.)
UNIT
SIZE
MINIMUM
MOUNTING PAD
DIMENSIONS
TIEDOWN KNOCKOUT LOCATIONS
AB
036, 048, 060 26 X 32 5-1/16 9-11/16
A97375
B
A
L
C
8 3⁄16″
3⁄8 IN. DIA TIEDOWN
KNOCKOUTS
(2) PLACES
IN BASEPAN Fig. 4—TXV Installed A91277
THERMOSTATIC
EXPANSION
VALVE
EQUALIZER
TUBE
SENSING
BULB
COIL
—2—

VI. MAKE PIPING CONNECTIONS
WARNING: Relieve pressure and recover all refrigerant
before system repair or final unit disposal to avoid
personal injury or death. Use all service ports and open all
flow-control devices, including solenoid valves.
CAUTION: If ANY refrigerant tubing is buried, provide
6-in. vertical rise at service valve. Refrigerant tubing
lengths up to 36 in. may be buried without further special
consideration. For lengths above 36 in., consult your local
distributor.
CAUTION: To prevent damage to unit or service valves
observe the following:
• Use a brazing shield.
• Wrap service valves with wet cloth or use a heat sink
material.
Outdoor units may be connected to indoor section using accessory
tubing package or field-supplied refrigerant grade tubing of correct
size and condition. Tubing diameters listed in Table 1 are adequate
for equivalent lengths up to 100 ft. DO NOT INSTALL EQUIVA-
LENT INTERCONNECTING TUBING LENGTHS GREATER
THAN 100 FT. Do not increase or decrease interconnecting tubing
diameters.
If refrigerant tubes or indoor coil are exposed to atmosphere, they
must be evacuated to 500 microns to eliminate contamination and
moisture in the system.
A. Outdoor Unit Connected to Factory-Approved
Indoor Unit
See Product Data Sheet for factory-approved indoor units.
Outdoor unit contains correct system refrigerant charge for opera-
tion with indoor unit of same size when connected by 15 ft of
field-supplied or factory-accessory tubing. Check refrigerant
charge for maximum efficiency.
B. Refrigerant Tubing
Connect tubing to fittings on outdoor unit vapor and liquid service
valves. (See Table 1.) Use refrigerant grade tubing.
C. Sweat Connection
CAUTION: To avoid valve damage while brazing, ser-
vice valves must be wrapped in a heat-sinking material
such as a wet cloth.
Service valves are closed from factory and ready for brazing. After
wrapping service valve with a wet cloth, tubing set can be brazed
to service valve using either silver bearing or non-silver bearing
brazing material. Consult local code requirements. Refrigerant
tubing and indoor coil are now ready for leak testing. This check
should include all field and factory joints.
VII. MAKE ELECTRICAL CONNECTIONS
WARNING: To avoid personal injury or death, do not
supply power to unit with compressor terminal box cover
removed.
Be sure field wiring complies with local and national fire, safety,
and electrical codes, and voltage to system is within limits shown
on unit rating plate. Contact local power company for correction of
improper voltage. See unit rating plate for recommended circuit
protection device.
NOTE: Operation of unit on improper line voltage constitutes
abuse and could affect unit reliability. See unit rating plate. Do not
install unit in system where voltage may fluctuate above or below
permissible limits.
NOTE: Use copper wire only between disconnect switch and
unit.
NOTE: Install branch circuit disconnect of adequate size per
NEC to handle unit starting current. Locate disconnect within sight
from and readily accessible from unit, per Section 440-14 of NEC.
A. Route Ground and Power Wires
Remove access panel to gain access to unit wiring. Extend wires
from disconnect through power wiring hole provided and into unit
control box. Size wires per NEC but not smaller than minimum
wire size shown in Product Data Sheet.
WARNING: The unit cabinet must have an uninter-
rupted or unbroken ground to minimize personal injury if
an electrical fault should occur. The ground may consist
of electrical wire or metal conduit when installed in
accordance with existing electrical codes. Failure to
follow this warning can result in an electric shock, fire, or
death.
B. Connect Ground and Power Wires
Connect ground wire to ground connection in control box for
safety. Connect power wiring to leads provided as shown in Fig. 6.
C. Connect Control Wiring
Route 24-v control wires through control wiring grommet and
connect to leads provided in control box. (See Table 2 and Fig. 7.)
Use No. 18 AWG color-coded, insulated (35°C minimum) wire. If
thermostat is located more than 100 ft from unit, as measured
along the control voltage wires, use No. 16 AWG color-coded wire
to avoid excessive voltage drop.
All wiring must be NEC Class 1 and must be separated from
incoming power leads.
The outdoor unit requires a minimum of 27-va, 24-vac control
power.
Fig. 5—Positioning of Sensing Bulb A81032
2 O'CLOCK
10 O'CLOCK
SENSING BULB
STRAP
SUCTION TUBE
8 O'CLOCK 4 O'CLOCK
7⁄8IN. OD & SMALLER LARGER THAN 7⁄8IN. OD
TABLE 1—REFRIGERANT CONNECTIONS AND
RECOMMENDED LIQUID AND VAPOR TUBE
DIAMETERS (IN.)
UNIT
SIZE
LIQUID VAPOR
Connection
Diameter Tube Diameter Connection Diameter Tube Diameter
036, 048 3/8 3/8 7/8 7/8
060 3/8 3/8 7/8 1-1/8
NOTES:
1. Tube diameters are for lengths up to 100 equivalent ft.
2. Do not increase or decrease tubing sizes.
—3—
→

IMPORTANT: Check factory wiring and wire connections to
ensure terminations are secured properly. Check wire routing to
ensure wires are not in contact with tubing, sheet metal, etc.
VIII. INSTALL ELECTRICAL ACCESSORIES
A. General
Refer to the individual instructions packaged with kits or acces-
sories when installing.
CAUTION: Low-ambient kits are not available for
2-speed units. Do not attempt to operate below 55°F or
modify control system for low-ambient operation. Com-
pressor damage may occur.
Available electrical accessories include latent capacity control. See
Table 2 and Fig. 7 for typical accessory wiring diagrams.
B. Latent Capacity Control (LCC)
The purpose of an LCC is to provide a dehumidification mode to
assure a 75 percent or less system sensible heat ratio. If indoor unit
installed contains an ICM blower (such as an FK4C fan coil or a
333(B,J)AV or 355MAV gas furnace), no LCC is required. Indoor
products with ICM blowers have enough CFM range to provide
proper airflow for low-speed cooling. If indoor unit installed has a
standard PSC blower motor, the low-speed airflow available is too
great to assure 75 percent or less system sensible heat ratio. The
LCC for standard blower products consists of a standard humidis-
tat which opens contacts on humidity rise and a pilot duty relay
with 24-v coil.
NOTE: If an LCC is desired, low-speed airflow must be main-
tained so that a minimum of 300 CFM/ton can be supplied during
high-speed LCC operation.
LCC OPERATION FOR TYPICAL PSC FAN COILS
The standard blower operation for systems with typical PSC fan
coils is covered in Fig. 7A, B, and D. The blower runs in high
speed regardless if compressor operation is high or low speed.
When the LCC is wired according to Fig. 7A, B, or D and humidity
rises, the humidistat contacts open and de-energize the relay. If
relay is de-energized, the system operates on high-speed compres-
sor and high-speed airflow until humidistat closes. Fig. 7C shows
the wiring with a Bryant Thermidistat which controls temperature
and humidity level without the need for an additional humidistat
and relay.
LCC OPERATION FOR TYPICAL PSC FURNACES
The standard blower operation of systems with typical PSC
furnaces is covered in Fig. 7J, K, M, N, P, or R. The blower runs
in high or low speed in conjunction with compressor high- or
low-speed operation. When the LCC is wired according to Fig. 7K,
M, N, P, or R and humidity rises, the humidistat contacts open and
de-energize the relay. If relay is de-energized, the system operates
on high-speed compressor and low-speed airflow until humidistat
closes. Fig. 7L and 7Q shows the wiring with a Bryant Thermi-
distat which controls temperature and humidity level without the
need for an additional humidistat and relay.
Fig. 6—Line Power Connections A91306
CONTACTOR
DISCONNECT
PER N. E. C. AND/ OR
LOCAL CODES
FIELD POWER
WIRING
FIELD GROUND
WIRING GROUND
LUG
TABLE 2—WIRING DIAGRAM REFERENCE
INDOOR PRODUCT THERMOSTAT CONTROLS DIAGRAM LETTER
IN FIG. 7
Standard Fan Coil
Bryant Programmable (Model 2S) Latent Capacity A
Bryant Non-Programmable (Model 2S) Latent Capacity B
Bryant Thermidistat™ Control Humidifier and Outdoor Sensor C
Other Brand Models Latent Capacity D
FK4C Fan Coil
Bryant Programmable (Model 2S) — E
Bryant Non-Programmable (Model 2S) — F
Bryant Thermidistat™ Control Humidifier and Outdoor Sensor G
Other Brand Models — H
Single-Stage Furnace
Bryant Programmable (Model 2S) Latent Capacity J
Bryant Non-Programmable (Model 2S) Latent Capacity K
Bryant Thermidistat™ Control Humidifier and Outdoor Sensor L
Other Brand Models Latent Capacity M
Two-Stage Furnace with PSC Blower Motor
Bryant Programmable (Model 2S) Latent Capacity N
Bryant Non-Programmable (Model 2S) Latent Capacity P
Bryant Thermidistat™ Control Humidifier and Outdoor Sensor Q
Other Brand Models Latent Capacity R
Two-Stage Furnace with ICM Blower Motor Bryant Programmable (Model 2S) — S Bryant Non-Programmable (Model 2S) — T
Other Brand Models — U
Variable-Speed 80% Non-Condensing Furnace Bryant Thermidistat™ Control Humidifier and Outdoor Sensor V
Variable-Speed Condensing Furnace Bryant Thermidistat™ Control Humidifier and Outdoor Sensor W
—4—

Fig. 7—Typical 24-v Circuit Connections
CA97464
O/W2
Y1/W2
W/W1
G
R
E
W3
BRYANT
THERMIDISTAT
CONTROL

TYPICAL
FAN COIL TWO-SPEED
AIR CONDITIONER
W2
G
C
Y2
R
Y1
C
DHUM
HUM
B
S1
S2
Y
R
C
HEAT STAGE 2
HEAT STAGE 1
COOL STAGE 2
COOL STAGE 1
FAN
24 VAC HOT
24 VAC COMM
N/A
HUMIDIFY
N/A

OUTDOOR
SENSOR
CONNECTION
Y/Y2


HUMIDIFIER
(24 VAC)
OUTDOOR 
SENSOR
See notes 8, 11, 12, and 16
AA97448
24 VAC HOT
FAN
HEAT STAGE 1
COOL STAGE 2
HEAT STAGE 2
COOL STAGE 1
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM
N/A
OUTDOOR
SENSOR
CONNECTION
C
B
S1
S2
C
Y2
C
BRYANT
PROGRAMMABLE
THERMOSTAT
MODEL 2S

TYPICAL
FAN COIL TWO-SPEED AIR CONDITIONER
See notes 6 and 8
W2
Y
E
R
W3
Y1
L
H
R1
DA97458
R
CC
Y1
TYPICAL
FAN COIL TWO-SPEED
AIR CONDITIONER
See note 8
Y
G
W2
R
Y2
E
W3
L
H
R1
24 VAC HOT
24 VAC COM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W
Y2
Y1
OTHER BRAND
TWO-SPEED
THERMOSTATS

COOL STAGE 1

BA97453
24 VAC HOT
24 VAC COMM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W/W1
Y/Y2
R
C
HEAT STAGE 2
COOL STAGE 1
N/A
OUTDOOR
SENSOR
CONNECTION
Y1
B
S1
S2
C
Y1
BRYANT
NON-PROGRAMMABLE
THERMOSTAT
MODEL 2S TYPICAL
FAN COIL TWO-SPEED
AIR CONDITIONER
See notes 8, 9, and 16
Y
G
O/W2
W2
R
Y2
E
W3
L
H
R1
—5—

Fig. 7—Typical 24-v Circuit Connections (Continued)
GA97465
O/W2
W/W1
Y1/W2
G
R
W2
W1
BRYANT
THERMIDISTAT
CONTROL

FK4C
FAN COIL TWO-SPEED
AIR CONDITIONER
Y1
G
C
Y2
R
Y1
C
DHUM
HUM
B
S1
S2
Y/Y2
R
O
C
DH
HEAT STAGE 2
HEAT STAGE 1
COOL STAGE 1
COOL STAGE 2
FAN
24 VAC HOT
24 VAC COMM
DEHUMIDIFY
HUMIDIFY
N/A

OUTDOOR
SENSOR
CONNECTION
Y/Y2


HUMIDIFIER
(24 VAC)
OUTDOOR 
SENSOR
See notes 8, 10, 11, 12, 16, and 19



REMOVE J2 JUMPER
FOR HEAT STAGING
REMOVE 
J1 JUMPER
EA97449
24 VAC HOT
FAN
COOL STAGE 1
COOL STAGE 2
HEAT STAGE 1
HEAT STAGE 2
R
G
R
G
24 VAC COMM
N/A
OUTDOOR
SENSOR
CONNECTION
C
B
S1
S2
C C
L
R
BRYANT
PROGRAMMABLE
THERMOSTAT
MODEL 2S FK4C
FAN COIL
J1
JUMPER
REMOVE
J2 JUMPER
FOR HEAT
STAGING
TWO-SPEED
AIR CONDITIONER
See notes 6, 8, and 19
DH
Y1
Y1
W/W1
O/W2
Y1/W2
W1
Y/Y2 Y2Y/Y2
O
W2
HA97459
R
Y2
R
Y2
CCC
R
L
Y1
OTHER BRAND
TWO-SPEED
THERMOSTATS FK4C
FAN COIL TWO-SPEED
AIR CONDITIONER
J1 JUMPER
REMOVE
J2 JUMPER
FOR HEAT
STAGING

GG
Y/Y2
DH
WW1
Y1
W2
Y1
O
W2
24 VAC HOT
24 VAC COM
FAN
COOL STAGE 2
HEAT STAGE 1
HEAT STAGE 2
COOL STAGE 1

See notes 8 and 19
FA97454
R
Y/Y2
R
Y2
CCC
R
L
Y1
BRYANT
NON-PROGRAMMABLE
THERMOSTAT
MODEL 2S FK4C
FAN COIL TWO-SPEED AIR CONDITIONER
J1 JUMPER
REMOVE
J2 JUMPER
FOR HEAT
STAGING
See notes 8, 9, 16, and 19
GG
Y/Y2
DH
W/W1 W1
Y1
O/W2
Y1
O
W2
B
S1
S2
24 VAC HOT
24 VAC COMM
FAN
COOL STAGE 2
HEAT STAGE 1
HEAT STAGE 2
COOL STAGE 1

N/A
OUTDOOR
SENSOR
CONNECTION
—6—

Fig. 7—Typical 24-v Circuit Connections (Continued)
LA97460
O/W2
W/W1
Y1/W2
G
R
BRYANT
THERMIDISTAT
CONTROL

SINGLE-STAGE
FURNACE TWO-SPEED
AIR CONDITIONER
W
G
Y
C
Y2
R
Y1
C
DHUM
HUM
B
S1
S2
R
C
HEAT STAGE 1
COOL STAGE 2
COOL STAGE 1
N/A
FAN
24 VAC HOT
24 VAC COMM
N/A
HUMIDIFY
See notes 11 and 12
N/A

OUTDOOR
SENSOR
CONNECTION
Y/Y2


HUMIDIFIER
(24 VAC)
OUTDOOR 
SENSOR



JA97445
COOL STAGE 1
FAN
HEAT STAGE 1
COOL STAGE 2
N/A
24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
G
24 VAC COMM
N/A
OUTDOOR
SENSOR
CONNECTION
C
B

S1
S2
C
Y2
C
BRYANT
PROGRAMMABLE
THERMOSTAT
MODEL 2S SINGLE-STAGE
FURNACE TWO-SPEED AIR CONDITIONER
See note 6
W
R
Y1
R
G
L
Y
H
R1
MA97455
24 VAC HOT
24 VAC COM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W
Y2
R
C
Y1
C
OTHER BRAND
TWO-SPEED
THERMOSTATS

SINGLE-STAGE
FURNACE TWO-SPEED
AIR CONDITIONER
G
W
R
YY2
L
Y1
H
R1
COOL STAGE 1

KA97450
24 VAC HOT
24 VAC COMM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W/W1
Y/Y2
R
C
N/A
COOL STAGE 1
N/A
OUTDOOR
SENSOR
CONNECTION
Y1
B
S1
S2
C
BRYANT
NON-PROGRAMMABLE
THERMOSTAT
MODEL 2S SINGLE-STAGE
FURNACE TWO-SPEED
AIR CONDITIONER
See note 9
G
O/W2
W
R
YY2
L
Y1
H
R1
—7—

Fig. 7—Typical 24-v Circuit Connections (Continued)
QA97461
O/W2
W/W1
Y1/W2
G
R
BRYANT
THERMIDISTAT
CONTROL

TWO-STAGE
FURNACE
WITH PSC
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
W/W1
G
Y/Y2
C
Y2
R
Y1
C
DHUM
HUM
B
S1
S2
W2
R
C
HEAT STAGE 1

COOL STAGE 1
COOL STAGE 2
HEAT STAGE 2
FAN
24 VAC HOT
24 VAC COMM
N/A
HUMIDIFY
N/A
OUTDOOR
SENSOR
CONNECTION
Y/Y2
HUMIDIFIER
(24 VAC)
OUTDOOR 
SENSOR
See notes 11, 12, 16, and 17
NA97447
G
C
Y2
C
TWO-STAGE 
FURNACE WITH PSC
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
See notes 6, 16, and 17
R
Y1
R
L
W/W1
Y/Y2
W2
Y1 *
COOL STAGE 1
FAN
HEAT STAGE 1
COOL STAGE 2
HEAT STAGE 2
24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
24 VAC COMM
N/A
OUTDOOR
SENSOR
CONNECTION
C
B
S1
S2
BRYANT
PROGRAMMABLE
THERMOSTAT
MODEL 2S
G
H
R1
A97457
24 VAC HOT
24 VAC COM 
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W
Y2
R
C
Y1
C
OTHER BRAND
TWO-SPEED
THERMOSTATS
TWO-STAGE 
FURNACE WITH PSC
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
See notes 7 and 17
G
R
Y2
L
W/W1
Y/Y2
W2
Y1
Y1 *
H
R1
COOL STAGE 1

A97452
24 VAC HOT
24 VAC COMM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W/W1
Y/Y2
R
C
HEAT STAGE 2
COOL STAGE 1
N/A
OUTDOOR
SENSOR
CONNECTION
Y1
B
S1
S2
C
BRYANT
NON-PROGRAMMABLE
THERMOSTAT
MODEL 2S
TWO-STAGE 
FURNACE WITH PSC
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
See notes 7, 9, 16, and 17
G
O/W2
R
Y2
L
W/W1
Y/Y2
W2
Y1
Y1 *
H
R1 P
R
—8—

Fig. 7—Typical 24-v Circuit Connections (Continued)
UA97456
R
CC
TWO-STAGE 
VARIABLE-SPEED
FURNACE WITH ICM
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
See notes 7 and 17
G
R
Y2
L
W/W1
Y/Y2
W2
Y1
Y1 *
24 VAC HOT
24 VAC COM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W
Y2
Y1
OTHER BRAND
TWO-SPEED
THERMOSTATS

COOL STAGE 1

SA97446
COOL STAGE 1
FAN
HEAT STAGE 1
COOL STAGE 2
HEAT STAGE 2
24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
G
24 VAC COMM
N/A
OUTDOOR
SENSOR
CONNECTION
C
B
S1
S2
C
Y2
C
BRYANT
PROGRAMMABLE
THERMOSTAT
MODEL 2S

TWO-STAGE 
VARIABLE-SPEED
FURNACE WITH ICM
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
See notes 6, 7, 16, and 17
R
Y1
R
G
L
W/W1
Y/Y2
W2
Y1 *24 VAC HOT
24 VAC COMM
HEAT STAGE 1
COOL STAGE 2
FAN
R
C
G
W/W1
Y/Y2
R
C
HEAT STAGE 2
COOL STAGE 1
N/A
OUTDOOR
SENSOR
CONNECTION
Y1
B
S1
S2
C
BRYANT
NON-PROGRAMMABLE
THERMOSTAT
MODEL 2S
TWO-STAGE 
VARIABLE-SPEED
FURNACE WITH ICM
BLOWER MOTOR TWO-SPEED
AIR CONDITIONER
See notes 7, 9, 16, and 17
G
O/W2
R
Y2
L
W/W1
Y/Y2
W2
Y1
Y1 *
A97451
T
—9—

Fig. 7—Typical 24-v Circuit Connections (Continued)
VA97463
O/W2
W/W1
Y1/W2
G
R
BRYANT
THERMIDISTAT
CONTROL
FURNACE
BOARD

AFS
BOARD

TWO-SPEED
AIR CONDITIONER
VARIABLE SPEED 
80% NON-CONDENSING FURNACE
W/W1
G
Y/Y2
C
Y2
Y1
C
DHUM
HUM
B
S1
S2
R
W2
O
Y1
R
COM
HUM
PL9-10
DEHUM
HEAT STAGE 1
COOL STAGE 2
COOL STAGE 1
HEAT STAGE 2
FAN
24 VAC HOT
24 VAC COM
DEHUMIDIFY
HUMIDIFY
N/A
OUTDOOR
SENSOR
CONNECTIONS
Y/Y2
HUMIDIFIER
(24 VAC)
OUTDOOR 
SENSOR
See notes 11, 12, 13, 15, 16, and 17
O/W2
W/W1
Y1/W2
G
R
BRYANT
THERMIDISTAT
CONTROL

VARIABLE-SPEED
CONDENSING
FURNACE TWO-SPEED
AIR CONDITIONER
W/W1
G
Y/Y2
C
Y2
R
Y1
C
DHUM
HUM
B
S1
S2
W2
R
C
HEAT STAGE 1
COOL STAGE 1
COOL STAGE 2
HEAT STAGE 2
FAN
24 VAC HOT
24 VAC COMM
DEHUMIDIFY
HUMIDIFY
N/A
OUTDOOR
SENSOR
CONNECTION
Y/Y2
HUMIDIFIER
(24 VAC)

OUTDOOR 
SENSOR
See notes 11, 12, 13, 14, 16, and 18
DH
HUM
A97462
W
—10—

WIRING DIAGRAM NOTES:
1. BRYANT THERMOSTAT WIRING DIAGRAMS ARE ONLY ACCURATE FOR MODEL NUMBERS BEGINNING
WITH TSTAT_______.
2. WIRING MUST CONFORM TO NEC OR LOCAL CODES.
3. CONNECT 24-V FIELD WIRING TO FACTORY-PROVIDED STRIPPED LEADS.
4. THERMOSTATS ARE FACTORY CONFIGURED WITH 5-MINUTE COMPRESSOR CYCLE PROTECTION AND 4
CYCLES PER HR LIMIT. SEE THERMOSTAT INSTALLATION INSTRUCTIONS FOR DETAILS.
5. TO STAGE ELECTRIC RESISTANCE HEAT, CONSULT OUTDOOR THERMOSTAT INSTALLATION INSTRUC-
TIONS.
6. WHEN USED IN TWO-SPEED AIR CONDITIONER INSTALLATIONS THERMOSTAT DIP SWITCH C SHOULD BE
IN THE "ON" POSITION. IN THIS CONFIGURATION, O/W2 IS USED TO CONTROL SECOND-STAGE HEAT.
7. TERMINALS MARKED WITH AN * MAY NOT BE PRESENT ON EQUIPMENT.
8. REFER TO FAN COIL INSTALLATION INSTRUCTIONS FOR FEATURES AND ADDITIONAL WIRING INFORMA-
TION.
9. CUT AND REMOVE R19 JUMPER AT THERMOSTAT TO CONVERT TO AIR CONDITIONER OPERATION.
10. TO ACTIVATE DEHUMIDIFY FUNCTION ON FK4C, REMOVE J1 JUMPER AT FAN COIL CONTROL BOARD.
11. THERMIDISTAT DIP SWITCH 1 SHOULD BE SET IN THE "OFF" POSITION FOR AIR CONDITIONER INSTALLA-
TIONS. THIS IS THE FACTORY DEFAULT.
12. THERMIDISTAT DIP SWITCH 2 SHOULD BE SET IN THE "ON" POSITION FOR 2-SPEED COMPRESSOR
OPERATION.
13. REFER TO INDOOR EQUIPMENT INSTALLATION INSTRUCTIONS FOR PROPER SETUP.
14. TO ACTIVATE DEHUMIDIFY FEATURE ON CURRENT STYLE VARIABLE-SPEED FURNACES (355MAV), A
PILOT DUTY, 24-V RELAY MUST BE USED.
15. TO ACTIVATE DEHUMIDIFY FEATURE ON CURRENT STYLE VARIABLE-SPEED 80% NON-CONDENSING
FURNACES (333(B,J)AV), DISCONNECT GREEN (DEHUM) WIRE FROM G ON FURNACE CONTROL BOARD AND
CONNECT TO DEHUMIDIFY TERMINAL DHU ON THERMIDISTAT.
16. AS AN OPTION, O/W2 CAN CONTROL SECOND-STAGE HEAT.
17. SEE TABLE 3—AIRFLOW SELECTION FOR 333(B,J)AV FURNACES.
18. SEE TABLE 4—AIRFLOW SELECTION FOR 355MAV FURNACES.
19. SEE TABLE 5—AIRFLOW SELECTION FOR FK4C FAN COILS.
LEGEND
24-V FACTORY WIRING
24-V FIELD WIRING
FIELD SPLICE CONNECTION
RELAY SPDT, PILOT DUTY
24-V COIL (HN61KK324)
OR EQUIVALENT
HUMIDISTAT, OPENS ON
HUMIDITY RISE (HL38MG026)
AIRFLOW SELECTOR

R1
H
AFS
A97466
—11—

IX. MAKE AIRFLOW SELECTIONS
A. Airflow Selection for 333(B,J)AV Furnaces
The 333(B,J)AV Non-Condensing Variable-Speed Furnaces pro-
vide high- and low-speed blower operation to match the capacities
of compressor high and low speeds. To select recommended
airflow, refer to Table 3 and the 333(B,J)AV Installation Instruc-
tions. These settings are made on the furnace airflow selector
board by moving the appropriate color-coded jumper wires. The
ORANGE jumper wire should be set to the AC position for
cooling only. The YELLOW COOL SIZE jumper is used to select
airflow to match the needed tons of cooling. The BLUE
CFM/TON jumper wire is used to select slight adjustments to
airflow of 400, 350, or 315 CFM per ton. (See Table 3.)
B. Airflow Selection for 355MAV Furnaces
The 355MAV Condensing Variable-Speed Furnaces provide high-
and low-speed blower operation to match the capacities of com-
pressor at high and low speeds. To select recommended airflow,
refer to Table 4 and the 355MAV Installation Instructions. The
355MAV utilizes a control center that allows the installing
technician to select proper airflows.
For adjustments to the manual switches labeled A/C and CF and
recommended switch positions, refer to Table 4. High-speed
airflow is determined by the position of the A/C switches, and
low-speed airflow is determined by the position of the CF
switches. This furnace has a built-in, non-adjustable 90 sec off
delay for cooling mode blower operation.
C. Airflow Selection for FK4C Fan Coils
The FK4C provides high- and low-speed blower operation to
match the capacities of compressor at high and low speeds. To
select recommended airflow, refer to Table 5 and the FK4C
Installation Instructions. The FK4C utilizes an EASY SELECT
control board that allows the installing technician to select proper
airflows. For adjustments to control board and recommended A/C
SIZE and CFM ADJUST selections, refer to Table 5. This fan coil
has an adjustable blower off delay factory set at 90 sec for high-
and low-speed blower operation.
TABLE 3—AIRFLOW SELECTION FOR 333(B,J)AV FURNACES (CFM)
598A
UNIT
SIZE
FURNACE
MODEL/HEATING
SIZE
FURNACE AIRFLOW SELECTION BOARD SETTINGS
AC/HP
Jumper
Position
Cool Size
Jumper
Position
Cool CFM Per Ton Jumper Position
400 350 315
High Low High Low High Low
036
060 AC HI 1260 780 1100 680 990 585
080 AC M-LO 1260 790 1100 700 990 625
100 AC LO 1260 780 1090 775 990 700
120 AC LO 1195 865 1085 785 985 785
048 080 AC HI 1635 1040 1470 915 1325 820 100 AC M-HI 1680 1040 1465 915 1325 820
120 AC M-HI 1650 1070 1465 975 1315 930
060 100 AC HI 1085 1300 1840 1150 1655 1025
120 AC HI 2110 1300 1865 1140 1640 1080
TABLE 4—AIRFLOW SELECTION FOR 355MAV FURNACES (CFM)
598A
UNIT
SIZE
HIGH-SPEED
A/C SETUP
SWITCH POSITION
FURNACE MODEL/HEATING SIZE LOW-SPEED
CF SETUP
SWITCH POSITION
060 080 100
A/C-1 A/C-2 A/C-3 High Low High Low High Low CF-1 CF-2 CF-3
036 OFF OFF ON 1200 800 1200 800 1200 800 OFF ON OFF
048 OFFONON————1600 1000 ON ON OFF
060 OFFONON————1600* 1000 ON ON OFF
* Efficiency rating obtained at 1600 CFM. If 2000 CFM is desired, adjust airflow per 355MAV Installation Instructions.
TABLE 5—AIRFLOW SELECTION FOR FK4C FAN COILS (CFM)
598A
UNIT
SIZE FK4C EASY SELECT CONTROL BOARD CFM*
SYSTEM TYPE
(Orange Wire) A/C SIZE (Blue Wire) AC/HP CFM ADJUST (Black Wire) High Low
036
001 AC 036 NOM 1100 680
002 AC 036 NOM 1100 680
003 AC 036 NOM 1100 680
005 AC 036 NOM 1100 680
006 AC 036 NOM 1100 745
048 005 AC 048 NOM 1470 910
006 AC 048 NOM 1470 995
060 006 AC 060 NOM 1835 1240
* Airflow CFMs are given with AC/HP CFM ADJUST jumper set at NOM. Airflow can be adjusted +15% or -10% by selecting HI or LO respectively.
—12—

X. START-UP
CAUTION: To prevent compressor damage or personal
injury, observe the following:
• Do not overcharge system with refrigerant.
• Do not operate unit in a vacuum or at negative pressure.
• Do not disable low-pressure switch.
In scroll compressor applications:
• Dome temperatures may be hot.
• In 3-phase application, incorrect phasing will cause
reverse rotation, resulting in elevated noise levels, equal-
ized pressures, and reduced current draw. Correct by
reversing power connection L1 and L2 on contactor.
CAUTION: To prevent personal injury wear safety
glasses, protective clothing, and gloves when handling
refrigerant and observe the following:
• Back seating service valves are not equipped with
Schrader valves. Fully back seat (counter clockwise)
valve stem before removing gage port cap.
• Front seating service valves are equipped with Schrader
valves.
CAUTION: Do not vent refrigerant to atmosphere. Re-
cover during system repair or final unit disposal.
1. The outdoor unit is equipped with a crankcase heater which
operates at temperatures less than 75°F. If outdoor tempera-
ture is less than 75°F, energize crankcase heater 24 hr
before starting unit. To energize heater only, set indoor
thermostat to OFF position and close power disconnect to
unit.
2. Fully back seat (open) liquid and vapor tube service valves.
3. Unit is shipped with valve stem(s) front seated and caps
installed. Replace stem caps after system is opened to
refrigerant flow (back seated). Replace caps finger tight and
tighten additional 1/12 turn (20 ft-lb torque) with wrench.
4. Close electrical disconnects to energize system.
5. Set room thermostat at desired temperature. Be sure set
point is below indoor ambient and is set low enough to
energize desired speed.
NOTE: Bryant electronic thermostats are equipped with a 15-
minute staging timer. This timer prevents the 2-speed system from
operating at high speed until unit has been operating in low speed
for 15 minutes unless there is at least a 5°F difference between
room temperature and thermostat set point. To force high speed
(after a minimum of 2 minutes in low speed), adjust the set point
at least 5° below room ambient.
6. Set room thermostat to COOL and fan control to AUTO or
ON as desired. Wait for appropriate time delay(s) and
2-minute minimum low-speed run time. Operate unit for 15
minutes. Check refrigerant charge.
XI. CHECK CHARGE
WARNING: Service valve gage ports are not equipped
with Schrader valves. To prevent personal injury, make
sure gage manifold is connected to the valve gage ports
before moving valves off fully back seated position. Wear
safety glasses and gloves when handling refrigerant.
A. Unit Charge
Factory charge is shown on unit rating plate.
NOTE: When 2-speed unit is operating at low speed, system
vapor (suction) pressure will be higher than a standard single-
speed system or high-speed operation. This normal operation is
due to the reduced capacity operating with typically larger indoor
and outdoor coils.
Adjust charge by following procedure shown on charging tables
located on unit.
NOTE: If superheat or subcooling charging conditions are not
favorable, charge must be weighed in accordance with unit rating
plate ±0.6 oz/ft of 3/8-in. liquid line above or below 15 ft
respectively.
EXAMPLE:
25 ft - 15 ft = 10 ft X 0.6 oz/ft=6ozofadditional charge
B. Cooling Only Procedure
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure liquid service valve pressure by attaching an
accurate gage to service port.
3. Measure liquid line temperature by attaching an accurate
thermistor type or electronic thermometer to liquid line near
outdoor coil.
4. Refer to unit rating plate for required subcooling tempera-
ture.
5. Refer to Table 6. Find the point where required subcooling
temperature intersects measured liquid service valve pres-
sure.
6. To obtain required subcooling temperature at a specific
liquid line pressure, add refrigerant if liquid line tempera-
ture is higher than indicated or reclaim refrigerant if
temperature is lower. Allow a tolerance of ±3°F.
TABLE 6—REQUIRED LIQUID-LINE TEMPERATURE (°F)
LIQUID
PRESSURE AT
SERVICE VALVE
(PSIG)
REQUIRED SUBCOOLING
TEMPERATURE
(°F)
5 101520
134 71 66 61 56
141 74 69 64 59
148 77 72 67 62
156 80 75 70 65
163 83 78 73 68
171 86 81 76 71
179 89 84 79 74
187 92 87 82 77
196 95 90 85 80
205 98 93 88 83
214 101 96 91 86
223 104 99 94 89
233 107 102 97 92
243 110 105 100 95
253 113 108 103 98
264 116 111 106 101
274 119 114 109 104
285 122 117 112 107
297 125 120 115 110
309 128 123 118 113
321 131 126 121 116
331 134 129 124 119
346 137 132 127 122
359 140 135 130 125
—13—

XII. SYSTEM FUNCTIONS AND SEQUENCE OF
OPERATION
The outdoor unit control system has special functions. The
following is an overview of the 2-speed control functions:
A. Cooling Operation
This product utilizes a 2-stage cooling indoor thermostat. With a
call for first stage cooling (Y1), the outdoor fan and low-speed
compressor are energized. If low speed cannot satisfy cooling
demand, high speed is energized (Y1 and Y2) by the second stage
of indoor thermostat. After second stage is satisfied, the unit
returns to low-speed operation until first stage is satisfied or until
second stage is required again.
B. LED Function Lights
System control function LED indicator lights are available at the
outdoor unit 2-speed control board. The indoor thermostat pro-
vides indicator signals for high- and low-speed operation and
system malfunction (if equipped to do so). The 2-speed control
board has an LED which provides signals for several system
operations. See Table 7 for LED functions and definitions. Table
7 also provides the order of signal importance if more than 1 signal
should occur. If equipped and properly wired, a signal to indoor
thermostat is supplied by the low-voltage L lead.
NOTE: A signal (code) is sent through the L lead to thermostat
unless a failure has occurred.
C. 3-Sec Time Delay
Any time the control receives a 24-v input, such as Y1 or Y2, there
is a 3-sec time delay before control function is initiated. This helps
prevent nuisance trips from thermostat jiggling.
D. 1-Minute Speed Change Time Delay
When compressor changes speeds from high to low or low to high,
there is a 1-minute time delay before compressor restarts. The
outdoor fan motor remains running.
E. 5-Minute Time Delay
The 2-speed control logic contains a 5-minute time delay that
prevents unit from short cycling after a thermostat off cycle or
power interruption. The unit can be forced to operate immediately
by momentarily touching a jumper between speed-up terminals of
control board. (See Fig. 8.) The speed-up feature does not bypass
any other function or time delay.
F. 2-Minute Low-Speed Minimum
If unit has not operated within the past 30 minutes, upon the next
thermostat high- or low-speed demand, unit operates for a mini-
mum of 2 minutes in low speed.
G. Crankcase Heater Operation
The 2-speed control energizes crankcase heater during unit off
cycle when outdoor ambient is below 75°F.
H. Outdoor Fan Motor Operation
The 2-speed control energizes outdoor fan anytime compressor is
operating. The outdoor fan remains energized during the 1-minute
speed change time delay and if a pressure switch or compressor
PTC overload should trip.
I. Second-Stage Latching
Mechanical thermostats operate with a staging differential of 2°F
(droop). Bryant electronic thermostats are droopless, meaning that
they maintain room temperature at set point without latching
second stage. If system is installed with a mechanical thermostat or
second stage latching is desired, the following information applies.
During normal operation, the compressor operates at low speed to
satisfy first stage of indoor thermostat. If indoor thermostat
temperature increases 2 degrees, the compressor shifts into high-
speed operation. When indoor thermostat temperature is satisfied,
the compressor returns to low-speed, first-stage operation.
The installing technician can select high-speed compressor opera-
tion until first stage of indoor thermostat is satisfied. This
eliminates the temperature droop of indoor thermostat between
first- and second-stage operation and holds room temperature
closer to set point when load requirements are high. To select this
option, rotate the STAGE 2 LATCH potentiometer (pot) to desired
temperature. (See Fig. 9). The pot is factory set at OFF; however,
a temperature of 85°, 90°, 95°, 100°, or 105°F can be selected. The
selected temperature is the outdoor temperature at which the
structure’s cooling load requires high-speed operation.
The unit’s capacities should be plotted versus cooling load (heat
gain) of structure to accurately determine the STAGE 2 LATCH
temperature to be selected. The unit’s capacities versus outdoor
temperature can be found in presale literature. The cooling load
must be taken from structure’s heat gain/loss calculations. The
selected temperature is the point at which high-speed capacity is
needed and is just above the low-speed balance point. (See Fig.
10.)
After the temperature is selected, unit operates in high speed
during first-stage demand at any temperature at or above the
setting.
TABLE 7—CONTROL FUNCTION LED CODE
CODE DEFINITION SIGNAL
IMPORTANCE*
Constant flash
No pause No demand Stand by 9
1 flash
w/pause Low-speed operation 8
2 flashes
w/pause High-speed operation 7
3 flashes
w/pause Outdoor thermistor failure 6
4 flashes
w/pause Used for heat pump only Outdoor coil thermistor failure 5
3 flashes
pause
4 flashes
Used for heat pump only
Thermistor out of range 4
5 flashes
w/pause Pressure switch trip (LM1/LM2) 3
6 flashes
w/pause Compressor PTC’s out of limit 2
Constant light
No Pause
No Flash Board failure 1
* Function light signal order of importance in case of multiple signal request; 1
is most important.
Fig. 8—Two-Speed Control Board A91504
LM1 LM2 DFT1 DFT2 T1 T2 S2 S1 PW2 PW1
P1118
SPEED-UP
STAGE 2
LATCH DEFROST TIME BALANCE POINT
K7
ZONE
OFF105
100
95
90
85
—14—

J. Compressor PTC Overload Protection
The control senses the resistance of the compressor internal
positive temperature coefficient (PTC) overloads. If PTC resis-
tance is out of range, control shuts off the unit until resistance
range is acceptable. See Table 8 for compressor PTC ranges.
When the control turns outdoor unit off due to out of range PTCs,
the unit remains off for 15 minutes with outdoor fan running. After
15 minutes, the control checks resistance every 5 minutes until it
reaches the reset range. During this time, a malfunction signal
appears at control board. If a PTC trip occurs 3 times, the control
locks out outdoor unit operation and provides a malfunction signal
at control and indoor thermostat.
K. Pressure Switch Protection
The outdoor unit is equipped with high- and low-pressure
switches, wired in series. If the control senses the opening of a
pressure switch, it provides a 5-minute time delay in outdoor unit
operation with outdoor fan running. A malfunction signal appears
on control when pressure switch opens. If pressure switch remains
open for 1 hr or longer, a malfunction signal is provided at L
terminal on indoor thermostat.
WARNING: Interlocked contactor coils are 240v, high
voltage. Electrical shock can cause personal injury or
death.
CAUTION: Do not bypass interlocks of contactors, as
compressor damage will occur.
L. Major Components
2-SPEED CONTROL
The 2-speed control board controls the following functions:
- High- and low-compressor contactor operation
- Outdoor fan motor operation
- Crankcase heater operation
- Compressor protection
- Pressure switch monitoring
- Second-stage latching
- Time delays
- 5-minute time delay speed-up (bypass)
Refer to the System Functions section for individual function
information.
HEADER PIN HOUSING
The header pin housing is the plastic assembly which holds the
stripped lead ends for field connections. The 2-speed control
receives 24-vac low-voltage control system inputs through the
housing/pins. The housing also contains jumpers which the control
uses for system configuration, such as heat pump versus air
conditioner. Refer to Fig. 11 for header pin housing configuration.
2-SPEED COMPRESSOR
The 2-speed compressor contains motor windings that provide
low-speed, 4 pole (1750 RPM) and high-speed, 2-pole (3500
RPM) operation. Refer to Table 9 for appropriate winding resis-
tances. Refer to unit wiring label for winding configurations.
The 2-speed compressor is protected by an internal pressure relief
(IPR) which relieves discharge gas into compressor shell when
differential between suction and discharge pressures exceeds 500
psi.
The compressor is also protected by 3 PTC devices attached to
motor windings. The PTC resistance is sensed by the 2-speed
control. See Table 8 for resistance ranges.
Fig. 9—LED and Potentiometer Location A91503
HIGH VOLTAGE LOW VOLTAGE
L2 LO HI CCH ODF OC LM1 LM2 DFT1 DFT2 T1 T2 S2 S1 PW2 PW1
P1118
SPEED-UP
STAGE 2
LATCH DEFROST TIME BALANCE POINT
K7K6K5K4K3K2K1
LED 1
Fig. 10—Typical Cooling Balance Points A91282
10
20
30
40
50
60
70
50 60 70 80 90 100 110 120
BTU (1000'S)
HIGH SPEED CAPACITY
HIGH SPEED
BALANCE POINT
LOW SPEED
BALANCE POINT
LOW SPEED CAPACITY
TEMPERATURE (°F)
STRUCTURE
BALANCE POINT
TABLE 8—COMPRESSOR PTC RANGES
COMPRESSOR INTERNAL PTC RESISTANCE
Safe range (77°F) 1.5k to 7.8k ohms
To trip 26k to 34k ohms
To reset 8.4k to 10k ohms
Fig. 11—Header Pin Housing Configuration A93565
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
C - TRANSFORMER COMMON
R - TRANSFORMER LINE
Y2 - SECOND STAGE COOLING
L - MALFUNCTION LIGHT
Y1 - FIRST STAGE COOLING
—15—

MECHANICALLY INTERLOCKED CONTACTORS
The 2-speed products are equipped with mechanically interlocked
contactors. Each contactor has interconnecting linkage, providing
independent interlocks.
The 2-speed control provides the electrical interlock. The contac-
tors are supplied with 240-v coils, which reduce the va require-
ments of low-voltage (24-vac) control system.
TEMPERATURE THERMISTORS
Thermistors are electronic devices which sense temperature. As
the temperature increases, the resistance decreases. A thermistor is
used to sense outdoor ambient. Refer to Fig. 12 for resistance
values versus temperature.
If the outdoor ambient thermistor should fail, a malfunction signal
appears on indoor thermostat and 2-speed control. The control
does not initiate second-stage latching, and crankcase heater is
turned on during all off cycles.
XIII. FINAL CHECKS
IMPORTANT: Before leaving job, be sure to do the following:
1. Securely fasten all panels and covers.
2. Tighten service valve stem caps to 1/12-turn past finger
tight.
3. Leave User’s Manual with owner. Explain system operation
and periodic maintenance requirements outlined in manual.
4. Fill out Dealer Installation Checklist and place in customer
file.
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equip-
ment failure, periodic maintenance must be performed on this
equipment.
Frequency of maintenance may vary depending upon geographic
areas, such as coastal applications.
TABLE 9—TWO-SPEED COMPRESSOR
(WINDING RESISTANCE AT 70°F ±20°)
WINDING 3 TON 4 TON 5 TON
T1-T2 0.80 0.70 0.60
T1-T3 3.20 2.20 1.80
T1-T7 1.30 1.00 1.00
T1-T8 3.10 2.20 2.00
Fig. 12—Resistance Values Versus Temperature
A91431
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80 100 120
TEMPERATURE (DEG. F)
RESISTANCE (KOHMS)
THERMISTOR CURVE
A94328
SERVICE TRAINING
Packaged Service Training programs are an excellent way to increase your
knowledge of the equipment discussed in this manual, including:
 • Unit Familiarization • Maintenance
 • Installation Overview • Operating Sequence
A large selection of product, theory, and skills programs is available, using popular
video-based formats and materials. All include video and/or slides, plus companion
book.
Classroom Service Training plus "hands-on" the products in our labs can mean
increased confidence that really pays dividends in faster troubleshooting, fewer
callbacks. Course descriptions and schedules are in our catalog.
CALL FOR FREE CATALOG 1-800-962-9212
[ ] Packaged Service Training [ ] Classroom Service Training
© 1998 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231 —16— Printed in U.S.A. 598a367 Catalog No. 5359-803