Bryant 637G 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 the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety-alert symbol. DAN-
GER 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. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
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.
CAUTION: Puron® (R-410A) systems operate at higher
pressures than standard R-22 systems. Be certain that
service equipment is rated for Puron®. Some R-22
service equipment may not be acceptable. Check with
your distributor.
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 same size when connected by 15 ft of field-supplied
or factory accessory tubing. Add (or subtract) 0.6 oz/ft of 3/8
liquid line for lengths greater (or less) than 15 ft. For proper unit
operation, check refrigerant charge using charging information
located on control box cover and/or in the Check Charge section of
this instruction.
IMPORTANT: Maximum liquid-line size is 3/8-in. O.D. for all
residential applications including long line.
IMPORTANT: Always install the factory-supplied Puron® heat
pump (bi-flow) liquid-line filter drier. If replacing the filter drier,
refer to Product Data Sheet for appropriate part number. Obtain
replacement filter driers from your distributor or branch.
Fig. 1—Model 637G
A98524
installation and
start-up instructions
14 SEER ENERGY STAR
SPLIT-SYSTEM HEAT PUMP
WITH PURON®
Cancels: New II 637G-18-1
11-02
637G
—1—

INSTALLATION
IMPORTANT: Specifications for this unit in residential new
construction market require using the outdoor unit, indoor unit,
refrigerant tubing sets, metering device, and filter drier listed in
presale literature. There can be no deviation. Consult the Appli-
cation Guideline and Service Manual for Residential Split-System
Air Conditioners and Heat Pumps using Puron® Refrigerant to
obtain required unit changes for specific applications and for R-22
retrofit.
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.
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.
CAUTION: Do not allow POE lubricant to come into
contact with roofing material. POE may deteriorate cer-
tain types of synthetic roofing.
Roof mounted units exposed to winds above 5 mph may require
wind baffles. Consult the Application Guideline and Service
Manual for Residential Split-System Air Conditioners and Heat
Pumps using Puron® Refrigerant 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 AMBIENT
The minimum outdoor operating ambient in cooling mode without
additional accessories is 55°F, and the maximum outdoor operat-
ing ambient in cooling mode is 125°F. The maximum outdoor
operating ambient in heating mode is 66°F.
V. ELEVATE UNIT
CAUTION: Accumulation of water and ice in base pan
may cause equipment damage.
Elevate unit per local climate and code requirements to provide
clearance above estimated snowfall level and ensure adequate
drainage of unit.
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
ABC
018–060 30 X 30 6-1/2 23-1/2 20
A94199
C
B
A
3⁄8″D. (9.53) TIEDOWN
KNOCKOUTS (2) PLACES
—2—

VI. CHECK INDOOR EXPANSION DEVICE
CAUTION: For proper unit operation and reliability,
units must be installed with hard shutoff TXV specifically
designed to operate with Puron®. Do not use R-22 TXV.
Do not install with evaporator coils having capillary tube
metering devices or pistons.
For TXV kit part number and charging instructions, refer to TXV
label in outdoor unit.
A. Furnace Coils
If indoor unit (furnace coil) comes factory equipped with a bi-flow
hard shutoff TXV specifically designed for Puron®, no TXV
change is required. If TXV installation is required, remove existing
Check-Flo-Rater® from indoor coil. Refer to Fig. 4 and 5 and
install TXV kit (specifically designed for Puron®) as follows:
1. Install suction tube adapter.
2. Install liquid flare-to-sweat adapter.
3. Connect external equalizer tube to fitting on suction tube
adapter.
4. Position sensing bulb on horizontal portion of suction tube
adapter. Secure using supplied hardware.
5. Insulate bulb after installation. (See Fig. 5.)
6. Leak check all connections.
B. Fan Coils
If indoor unit (fan coil) comes factory equipped with a bi-flow
hard shutoff TXV specifically designed for Puron®, no TXV
change is required.
If fan coil is not designed for Puron®, a Puron® TXV installation
is required. Refer to TXV kit Installation Instructions for details.
VII. CHECK DEFROST THERMOSTAT
Check defrost thermostat to ensure it is properly located and
securely attached. There is a liquid header with a brass distributor
and feeder tube going into outdoor coil. At the end of 1 of the
feeder tubes, there is a 3/8-in. OD stub tube approximately 3 in.
long. (See Fig. 6.) The defrost thermostat should be located on stub
tube. Note that there is only 1 stub tube used with liquid header,
and on most units it is the bottom circuit.
VIII. IN LONG-LINE APPLICATIONS, INSTALL LIQUID-
LINE SOLENOID VALVE (LSV)
For refrigerant piping arrangements with equivalent lengths
greater than 50 ft or when elevation difference between indoor and
outdoor unit is greater than ± 20 ft, follow all requirements of the
Long-Line Guideline section in the Application Guideline and
Service Manual for Residential Split-System Air Conditioners and
Heat Pumps Using Puron® Refrigerant.
If required by Long-Line Application Guideline, install LSV kit
part No. KHALS0401LLS specifically designed for Puron® Heat
Pump. LSV should be installed within 2 ft of the outdoor unit with
arrow pointing toward outdoor unit, as close as possible to filter
drier. Follow the Installation Instructions included with accessory
kit.
IX. MAKING 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: Do not leave system open to atmosphere
any longer than minimum required for installation. POE
oil in compressor is extremely susceptible to moisture
absorption. Always keep ends of tubing sealed during
installation.
CAUTION: If ANY refrigerant tubing is buried, provide
a 6 in. vertical rise at service valve. Refrigerant tubing
lengths up to 36 in. may be buried.
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. For tubing requirements beyond 50 ft, substan-
tial capacity and performance losses can occur. Follow the
recommendations in the Application Guideline and Service
Manual for Residential Split-System Air Conditioners and Heat
Pumps using Puron® Refrigerant to minimize losses. Refer to
Table 1 for field tubing diameters. Refer to Table 2 for accessory
requirements.
Refrigerant tubes and indoor coil must be evacuated to 500
microns to minimize contamination and moisture in the system.
Fig. 4—Typical TXV Installation
A91277
THERMOSTATIC
EXPANSION
VALVE
EQUALIZER
TUBE
SENSING
BULB
COIL
Fig. 5—Positioning of Sensing Bulb
A00399
SENSING BULB
STRAP
8 O'CLOCK 4 O'CLOCK
—3—

A. Outdoor Unit Connected To Factory-Approved In-
door Unit
These outdoor units are carefully evaluated and listed with specific
indoor coils for proper system performance.
IMPORTANT: Do not apply indoor coils which are not factory
approved to these units.
B. Install Adapter Tube
1. Remove plastic retainer holding outdoor piston in liquid
service valve.
2. Check outdoor piston size with matching number listed on
unit rating plate.
3. Locate plastic bag taped to unit containing adapter tube.
4. Remove teflon washer from bag and install on open end of
liquid service valve. (See Fig. 7.)
5. Remove adapter tube from bag and connect threaded nut to
liquid service valve. Tighten nut finger tight and then with
wrench an additional 1/12 turn (15 ft-lb). DO NOT OVER-
TIGHTEN.
C. Refrigerant Tubing And Filter Drier
CAUTION: Installation of filter drier in liquid line is
required to avoid performance loss due to plugged
circuits or plugged expansion devices, and to avoid
compressor failure.
Connect vapor tubing to fittings on outdoor unit vapor service
valve. Connect liquid tubing to filter drier. (See Table 1 and Fig.
8.) Use refrigerant grade tubing. Connect other end of filter drier
to adapter tube on liquid service valve.
D. Sweat Connection
CAUTION: To avoid valve damage while brazing, ser-
vice valves must be wrapped in a heat-sink material such
as a wet cloth.
Wrap service valves and filter drier with a wet cloth or heat-
sinking material. Braze connections using either silver bearing or
non-silver bearing brazing material. Do not use soft solder
(materials which melt below 800° F.) Consult local code require-
ments.
E. Leak Checking
Leak test all joints in indoor, outdoor, and refrigerant tubing.
F. Evacuate Refrigerant Tubing And Indoor Coil
CAUTION: To avoid compressor damage, never use the
system compressor as a vacuum pump.
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum method of 500 microns. The alternate
triple evacuation method may be used if the procedure outlined
below is followed.
IMPORTANT: Never open system under vacuum to atmosphere
without first breaking it open with nitrogen.
DEEP VACUUM METHOD
The deep vacuum method requires a vacuum pump capable of
pulling a vacuum of 500 microns and a vacuum gage capable of
accurately measuring this vacuum depth. The deep vacuum
method is the most positive way of assuring a system is free of air
and liquid water. (See Fig. 9.)
TRIPLE EVACUATION METHOD
The triple evacuation method should only be used when vacuum
pump is only capable of pumping down to 28 in. of mercury
vacuum and system does not contain any liquid water. Refer to
Fig. 10 and proceed as follows:
1. Pump system down to 28 in. of mercury and allow pump to
continue operating for an additional 15 minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system and
open until system pressure is 2 psig.
4. Close service valve and allow system to stand for 1 hr.
During this time, dry nitrogen will be able to diffuse
throughout the system absorbing moisture.
5. Repeat this procedure as indicated in Fig. 10. System will
then contain minimal amounts of contaminants and water
vapor.
G. Final Tubing Check
IMPORTANT: Check to be certain factory tubing on both indoor
and outdoor unit has not shifted during shipment. Ensure tubes are
not rubbing against each other or any sheet metal. Pay close
attention to feeder tubes, making sure wire ties on feeder tubes are
secure and tight.
Fig. 6—Defrost Thermostat Location
A97517
FEEDER TUBE
DEFROST
THERMOSTAT
STUB TUBE
Fig. 7—Liquid Service Valve with Sweat Adapter Tube
A99441
SWEAT/FLARE
ADAPTER
TEFLON
SEAL
PISTON BODY
LIQUID SERVICE VALVE
PISTON
—4—

X. 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 to correct
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 or phase imbalance (3-phase)
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.
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.
TABLE 1—REFRIGERANT CONNECTIONS AND RECOMMENDED LIQUID LINE AND VAPOR TUBE DIAMETERS (IN.)
UNIT
SIZE CONNECTION DIAMETER TUBE DIAMETER
Liquid Vapor Liquid Vapor
018, 024 3/8 5/8 3/8 5/8
030 3/8 3/4 3/8 3/4
036 3/8 3/4 3/8 3/4
042, 048 3/8 7/8 3/8 7/8
060 3/8 7/8 3/8 1-1/8
NOTES:
1. Tube diameters are for lengths up to 50 ft. For alternate tube diameters and for tubing lengths greater than 50 ft horizontal or 20 ft vertical differential, consult the
Application Guideline and Service Manual — Residential Split System Air Conditioners and Heat Pumps Using Puron® Refrigerant.
2. Refrigerant tubes and indoor coils must be evacuated to 500 microns to minimize contamination and moisture in the system.
TABLE 2—ACCESSORY USAGE
ACCESSORY REQUIRED FOR LOW-AMBIENT APPLICATIONS
(BELOW 55°F)
REQUIRED FOR LONG-LINE
APPLICATIONS*
(OVER 50 FT)
Crankcase Heater Yes Yes
Evaporator Freeze Thermostat Yes No
Compressor Start Assist—Capacitor and Relay Yes Yes
Puron® Low-Ambient Pressure Switch Yes No
Wind Baffle See Low-Ambient Instructions No
Support Feet Recommended No
Hard Shutoff TXV Yes† Yes†
Puron® Liquid-Line Solenoid Valve for Heating No See Long-Line
Application Guideline
* For tubing line sets between 50 and 175 ft, refer to Application Guideline and Service Manual — Residential Split System Air Conditioners and Heat Pumps Using Puron®
Refrigerant.
† Required for all applications.
Fig. 8—Filter Drier with Sweat Adapter Tube and
Liquid Tube
A00431
LIQUID
SERVICE
VALVE
LIQUID-LINE
FILTER-DRIER
Fig. 9—Deep Vacuum Graph
A95424
500
MINUTES
01234567
1000
1500
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
2000
MICRONS
2500
3000
3500
4000
4500
5000
A95424
—5—

B. Connect Ground And Power Wires
Connect ground wire to ground connection in control box for
safety. Connect power wiring to contactor as shown in Fig. 11.
C. Connect Control Wiring
Route 24v control wires through control wiring grommet and
connect leads to control wiring. (See Fig. 12.)
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.
Use furnace transformer, fan coil transformer, or accessory trans-
former for control power, 24v/40va minimum.
NOTE: Use of available 24v accessories may exceed the mini-
mum 40va power requirement. Determine total transformer load-
ing and increase the transformer capacity or split the load with an
accessory transformer as required.
D. Final Wiring Check
IMPORTANT: Check factory wiring and field wire connections
to ensure terminations are secured properly. Check wire routing to
ensure wires are not in contact with tubing, sheet metal, etc.
XI. COMPRESSOR CRANKCASE HEATER
When equipped with a crankcase heater, furnish power to heater a
minimum of 24 hr before starting unit. To furnish power to heater
only, set thermostat to OFF and close electrical disconnect to
outdoor unit.
A crankcase heater is required in long-line applications (tubing
greater than 50 ft. or elevation greater than 20 ft. between indoor
and outdoor units). Refer to Application Guideline and Service
Manual for Residential Split System Air Conditioners and Heat
Pumps Using Puron® Refrigerant.
XII. INSTALL ELECTRICAL ACCESSORIES
Refer to the individual instructions packaged with kits or acces-
sories when installing.
XIII. 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
Fig. 10—Triple Evacuation Method
A95425
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
EVACUATE
BREAK VACUUM WITH DRY NITROGEN
WAIT
EVACUATE
CHARGE SYSTEM
BREAK VACUUM WITH DRY NITROGEN
EVACUATE
WAIT
Fig. 11—Line Power Connections
A91056
DISCONNECT
PER N. E. C. AND/OR
LOCAL CODES CONTACTOR
GROUND
LUG
FIELD GROUND
WIRING
FIELD POWER
WIRING
24 VAC HOT R
C
W2
Y
G
R
C
RVS COOLING
C
W2
HP THERMOSTAT TYPICAL
FAN COIL HEAT
PUMP
G
O
E
W2
E
W3
R
Y
24 VAC COM
HEAT STAGE 2
COOL/HEAT
STAGE 1
INDOOR FAN
EMERGENCY
HEAT
O
*
*
*
IF AVAILABLE
*
A02325
Fig. 12—Generic Wiring Diagram
(See Thermostat Installation Instructions for
wiring specific unit combinations)
A97413
LEGEND
24-V FACTORY WIRING
24-V FIELD WIRING
FIELD SPLICE CONNECTION
OUTDOOR THERMOSTAT
EMERGENCY HEAT RELAY
SUPPLEMENTAL HEAT RELAY
SHR
EHR
ODT
—6—

CAUTION: To prevent personal injury wear safety
glasses, protective clothing, and gloves when handling
refrigerant.
CAUTION: Back seating service valves are not
equipped with Schrader valves. Fully back seat (counter
clockwise) valve stem before removing gage port cap.
CAUTION: Federal regulations require that you do not
vent refrigerant to atmosphere. Recover during system
repair or final unit disposal.
Follow these steps to properly start up the system:
1. Fully back seat (open) liquid and vapor service valves.
2. Unit is shipped with valve stem(s) front seated (closed) and
caps installed. Replace stem caps after system is opened to
refrigerant flow (back seated). Replace caps finger-tight and
tighten with wrench an additional 1/12 turn. Use a backup
wrench on valve body flats to prevent distortion of sheet
metal.
3. Close electrical disconnects to energize system.
4. Set room thermostat at desired temperature. Be sure set
point is below indoor ambient temperature.
5. Set room thermostat to HEAT or COOL and fan control to
ON or AUTO mode, as desired. Operate unit for 15
minutes. Check system refrigerant charge.
CAUTION:
• 3–phase scroll compressors are rotation sensitive.
• A flashing LED on phase monitor indicates reverse
rotation. (See Fig. 13 and Table 3.)
• This will not allow contactor to be energized.
• Disconnect power to unit and interchange 2 field wiring
leads on unit contactor.
A. Sequence Of Operation
NOTE: Defrost control board is equipped with a 5-minute lock-
out timer which may be initiated upon an interruption of power.
With power supplied to indoor and outdoor units, transformer is
energized.
COOLING
On a call for cooling, thermostat makes circuits R-O, R-Y, and
R-G. Circuit R-O energizes reversing valve, switching it to cooling
position. On three phase models with scroll compressors, the units
are equipped with a phase monitor to detect if the incoming power
is correctly phased for compressor operation. If the phasing is
correct, circuit R-Y energizes contactor, starting outdoor fan motor
and compressor circuit. R-G energizes indoor unit blower relay,
starting indoor blower motor on high speed.
NOTE: If the phasing is incorrect, the contactor will not be
energized. To correct the phasing interchange any two of the three
power connections on the field side.
When thermostat is satisfied, contacts open, de-energizing the
contactor and blower relay. Compressor and motors should stop.
NOTE: If indoor unit is equipped with a time-delay relay circuit,
the blower runs an additional 90 sec to increase system efficiency.
HEATING
On a call for heating, thermostat makes circuits R-Y and R-G. If
phasing is correct, circuit R-Y energizes contactor, starting out-
door fan motor and compressor. Circuit R-G energizes indoor
blower relay, starting blower motor on high speed.
Should temperature continue to fall, R-W2 is made through
sec-stage room thermostat bulb. Circuit R-W2 energizes a se-
quencer, bringing on first bank of supplemental electric heat and
providing electrical potential to sec heater relay (if used). If
outdoor temperature falls below setting of outdoor thermostat
(field-installed option), contacts close to complete circuit and bring
on sec bank of supplemental electric heat.
When thermostat is satisfied, its contactors open, de-energizing
contactor and sequencer. All heaters and motors should stop.
QUIET SHIFT
Quiet Shift is a field-selectable defrost mode, which will eliminate
occasional noise that could be heard at the start of the defrost cycle
and restarting of heating cycle. It is selected by placing DIP switch
3 (on defrost board) in ON position.
When Quiet Shift switch is placed in ON position, and a defrost is
initiated, the following sequence of operation will occur. Revers-
ing valve will energize, compressor will turn off for 30 sec, then
turn back on to complete defrost. At the start of heating cycle after
conclusion of defrost mode, reversing valve will de-energize, the
compressor will turn off for another 30 sec, and the fan will turn
off for 40 sec, before starting in the heating mode.
DEFROST
The defrost control is a time/temperature control which includes a
field-selectable time period (DIP switch 1 and 2 on the board)
between defrost cycles of 30, 60, 90, or 120 minutes (factory set at
90 minutes).
To initiate a forced defrost, two options are available depending on
the status of the defrost thermostat.
If defrost thermostat is closed, speedup pins (J1) must be shorted
by placing a flat head screw driver in between for 5 sec and
releasing, to observe a complete defrost cycle. When the Quiet
Shift switch is selected, compressor will be turned off for two 30
sec intervals during this complete defrost cycle as explained
previously. When Quiet Shift switch is in factory default OFF
position, a normal and complete defrost cycle will be observed.
If defrost thermostat is in open position, and speedup pins are
shorted (with a flat head screw driver) for 5 sec and released, a
short defrost cycle will be observed (actual length is dependent
upon the selected Quiet Shift position). When Quiet Shift switch is
in ON position, the length of defrost is 1 minute (30 sec
compressor off period followed by 30 sec of defrost with com-
pressor operation). On return to heating operation, compressor will
again turn off for an additional 30 sec and the fan for 40 sec. When
the Quiet Shift is in OFF position, only a brief 30 sec cycle will be
observed.
If it is desirable to observe a complete defrost in warmer weather,
the thermostat must be closed as follows:
1. Turn off power to outdoor unit.
2. Disconnect outdoor fan motor lead from OF2 on control
board (See Fig. 13.) Tape to prevent grounding.
3. Restart unit in heating mode, allowing frost to accumulate
on outdoor coil.
4. After a few minutes in heating mode, liquid line tempera-
ture should drop below closing point of defrost thermostat
(approximately 30°F).
NOTE: Unit will remain in defrost until defrost thermostat
reopens at approximately 80°F coil temperature at liquid line or
remainder of defrost cycle time.
5. Turn off power to outdoor and reconnect fan motor lead to
OF2 on control board after above forced defrost cycle.
—7—

XIV. CHECK CHARGE
A. Unit Charge
Factory charge is shown on unit rating plate. To check charge in
cooling mode, refer to Cooling Only Procedure. To check charge
in heating mode, refer to Heating Check Chart Procedure.
With unit operating, charge Puron® units with liquid using a
commercial-type metering device in manifold hose. Charge refrig-
erant into suction line. Some refrigerant cylinders may contain a
dip tube that allows liquid refrigerant to flow from cylinder in
upright position. Check cylinder label for correct position to allow
liquid flow.
B. Cooling Only Procedure
NOTE: If 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:
To calculate additional charge required for a 25-ft line set:
25 ft - 15 ft = 10 ft X 0.6 oz/ft=6ozofadditional charge
Units installed with cooling mode TXV require charging by the
subcooling method.
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 near
outdoor coil.
4. Refer to Heat Pump Charging Instructions label on outdoor
unit for required subcooling temperature.
5. Refer to Table 4. 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.
C. HEATING CHECK CHART PROCEDURE
To check system operation during heating cycle, refer to the Heat
Pump Charging Instructions label on outdoor unit. This chart
indicates whether a correct relationship exists between system
operating pressure and air temperature entering indoor and outdoor
units. If pressure and temperature do not match on chart, system
refrigerant charge my not be correct. Do not use chart to adjust
refrigerant charge.
NOTE: In heating mode, check refrigerant charge only when
pressures are stable. If operating conditions cause Pressure Guard
switch to open and outdoor fan to cycle, check refrigerant charge
in cooling or lower indoor dry bulb temperature. If in doubt,
remove charge and weigh in correct refrigerant charge.
NOTE: When charging is necessary during heating season,
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:
To calculate additional charge required for a 25-ft line set:
25 ft - 15 ft = 10 ft X 0.6 oz/ft=6ozofadditional charge
XV. 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.n
Fig. 13—Defrost Control
A99442
OF2
CESO130076–00
OF1
ON
QUIET SHIFT
120
30 60
60 30
90
INTERVAL TIMER OFF
P3
DFT
O R W2Y C
T2 C C O
DFT
T1 Y P1 J1
SPEEDUP
Speedup
Pins Defrost interval DIP switches
Quiet
Shift
—8—

TABLE 3—REQUIRED LIQUID-LINE TEMPERATURE (°F)
LIQUID PRESSURE
AT SERVICE VALVE
REQUIRED SUBCOOLING TEMPERATURE
(°F) LIQUID PRESSURE
AT SERVICE VALVE
REQUIRED SUBCOOLING TEMPERATURE
(°F)
5 10 15 20 5 10 15 20
174 56 51 46 41 398 112 107 102 97
181 58 53 48 43 405 113 108 103 98
188 61 56 51 46 412 114 109 104 99
195 63 58 53 48 419 115 110 105 100
202 65 60 55 50 426 117 112 107 102
209 67 62 57 52 433 118 113 108 103
216 69 64 59 54 440 119 114 109 104
223 71 66 61 56 447 120 115 110 105
230 73 68 63 58 454 122 117 112 107
237 75 70 65 60 461 123 118 113 108
244 77 72 67 62 468 124 119 114 109
251 79 74 69 64 475 125 120 115 110
258 81 76 71 66 482 126 121 116 111
265 82 77 72 67 489 127 122 117 112
272 84 79 74 69 496 129 124 119 114
279 86 81 76 71 503 130 125 120 115
286 88 83 78 73 510 131 126 121 116
293 89 84 79 74 517 132 127 122 117
300 91 86 81 76 524 133 128 123 118
307 93 88 83 78 531 134 129 124 119
314 94 89 84 79 538 135 130 125 120
321 96 91 86 81 545 136 131 126 121
328 97 92 87 82 552 137 132 127 122
335 99 94 89 84 559 138 133 128 123
342 100 95 90 85 566 139 134 129 124
349 102 97 92 87 573 140 135 130 125
356 103 98 93 88 580 141 136 131 126
363 105 100 95 90 587 142 137 132 127
370 106 101 96 91 594 143 138 133 128
377 107 102 97 92 601 144 139 134 129
384 109 104 99 94 608 145 140 135 130
391 110 105 100 95 —————
—9—

—10—

—11—

PURON® (R-410A) QUICK REFERENCE GUIDE
• Puron® refrigerant operates at 50-70 percent higher pressures than R-22. Be sure that servicing equipment and replacement
components are designed to operate with Puron®.
• Puron® refrigerant cylinders are rose colored.
• Recovery cylinder service pressure rating must be 400 psig. DOT 4BA400 or DOT BW400.
• Puron® systems should be charged with liquid refrigerant. Use a commercial type metering device in the manifold hose when
charging into suction line with compressor operating.
• Manifold sets should be at least 700 psig high side and 180 psig low side with 550 psig low-side retard.
• Use hoses with 700 psig service pressure rating.
• Leak detectors should be designed to detect HFC refrigerant.
• Puron®, as with other HFCs, is only compatible with POE oils.
• Vacuum pumps will not remove moisture from oil.
• Do not leave Puron® suction line filter driers in line longer than 72 hrs.
• Do not use liquid-line filter driers with rated working pressures less than 600 psig.
• Do not install a suction-line filter drier in liquid line.
• POE oils absorb moisture rapidly. Do not expose oil to atmosphere.
• Poe oils may cause damage to certain plastics and roofing materials.
• Wrap all filter driers and service valves with wet cloth when brazing.
• A factory-approved liquid-line filter drier is required on every unit.
• Do not use an R-22 TXV.
• If indoor unit is equipped with an R-22 TXV, it must be changed to an Puron® TXV.
• All Puron® Heat Pumps must have indoor Puron® TXV.
• Never open system to atmosphere while it is under a vacuum.
• When system must be opened for service, recover refrigerant, break vacuum with dry nitrogen prior to opening to atmosphere.
Evacuate to 500 microns prior to recharging.
• Always replace filter drier after opening system for service.
• Do not vent Puron® into the atmosphere.
• Do not use capillary tube coils.
• Observe all warnings, cautions, and bold text.
© 2002 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231 —12— Printed in U.S.A. ii637g181 Catalog No. 5363-700