DURASTAR DRAH1T User manual

AIR HANDLERS
FEATURING INDUSTRY STANDARD R-410A REFRIGERANT:
DRAH1T
INSTALLATIONINSTRUCTIONS
92-20521-124-00
service personnel for proper installation, adjustment and
operation of this unit. Read these instructions thoroughly before
attempting installation or operation. Failure to follow these
instructions may result in improper installation, adjustment,
service or maintenance possibly resulting in fire, electrical
shock, property damage, personal injury or death.
ACCREDITED
WARNING
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2
TABLE OF CONTENTS
1.0 SAFETY INFORMATION ................................................................................. 4
2.0 GENERAL INFORMATION ............................................................................. 6
2.1 Important Information About Efciency & Indoor Air Quality ........................ 6
2.2 Checking Product Received ......................................................................... 7
2.3 Model Number Nomenclature ...................................................................... 7
2.4 Available Models .......................................................................................... 8
2.5 Dimensions & Weight ................................................................................... 9
2.5.1 DRAH1T Models .......................................................................... 9
2.6 Importance of Proper Indoor/Outdoor Match-Ups ........................................ 10
2.7 Importance Of Quality Installation ................................................................ 10
3.0 INSTALLATION ............................................................................................... 11
3.1 Tools and Refrigerant ................................................................................... 11
3.1.1 Tools Required For Installation and Servicing R-410A Models .............. 11
3.1.2 Specications of R-410A ....................................................................... 11
3.1.3 Quick-Reference Guide for R-410A ....................................................... 11
3.2 Applications and Orientation ........................................................................ 12
3.2.1 Vertical Upow & Horizontal Left Discharge .......................................... 12
3.2.2 Vertical Downow & Horizontal Right Discharge ................................... 12
3.2.3 Installation in an Unconditioned Space ................................................. 14
3.2.4 Installation in Mobile/Manufactured Homes ........................................... 15
3.2.5 Installation in Corrosive Environments .................................................. 16
3.2.6 Supporting Air-Handler in Horizontal Applications ................................. 16
3.3 Auxiliary Overow Pan ................................................................................. 16
3.4 Clearances ................................................................................................... 16
3.5 Duct Flanges ................................................................................................ 17
3.6 Ductwork ...................................................................................................... 17
3.7 Return Air Filter ............................................................................................ 18
3.8 Orice Size ................................................................................................... 18
3.9 Refrigerant Line Connections & Charging ................................................... 18
3.9.1 Preparation ............................................................................................ 18
3.9.2 Liquid Line Filter Drier ........................................................................... 18
3.9.3 Brazing .................................................................................................. 19
3.9.4 Leak Testing .......................................................................................... 19
3.9.5 Evacuation ............................................................................................. 19
3.9.6 Refrigerant Charging ............................................................................. 19
3.10 TXV Sensing Bulb Attachment ................................................................... 19
3.11 Condensate Drain ...................................................................................... 20
3.12 Thermostat ................................................................................................. 21
3.13 Electrical Wiring ......................................................................................... 21
3.13.1 Conguring Unit for 208 Volt Power .................................................... 22
3.13.2 Grounding ............................................................................................ 22
3.13.3 Power Wiring ....................................................................................... 22
3.13.4 Cooper Wire Size - AWG. (3% Voltage Drop) ..................................... 22
3.13.5. Electrical Data - Blower Motor Only - Without Electrical Heat ............ 22
3.13.5.1 DRAH1T ......................................................................................... 22
3.13.6 Electrical Data - With Electric Heat ...................................................... 23
3.13.6.1 DRAH1T ......................................................................................... 26
3.13.7 Electric Heater Kit Supplemental Information ...................................... 27
3.13.8 Control Wiring ...................................................................................... 27
3.13.9 Thermostat & Control Wiring Connections .......................................... 27
3.14 Airow ......................................................................................................... 27

3
TABLE OF CONTENTS (continued)
3.14.1 General Airflow Operating Limits ......................................................... 28
3.14.2 Selecting Indoor Blower Motor Speed ................................................. 28
3.14.2.1 DRAH1T Models (Constant Torque ECM Motor) ............................ 28
3.14.3 Airow Performance Data .................................................................... 29
3.14.3.1 DRAH1T (Constant Torque Motor) - 115/208/240/480V ................. 29
4.0 START-UP ....................................................................................................... 33
4.1 Pre-Start Checklist ....................................................................................... 33
4.2 System Start-Up and Operational Check-Out .............................................. 33
4.3 Sequence of Operation ................................................................................ 33
4.3.1 Cooling Mode ........................................................................................ 33
4.3.2 Electrical Heat Mode ............................................................................. 34
4.3.3 Heat Pump Heating Mode ..................................................................... 34
4.3.4 Supplemental Electric Heat During Defrost ........................................... 34
4.3.5 Emergency Heat (Heat Pump) .............................................................. 34
4.3.6 Thermostat Fan Setting ......................................................................... 34
4.4 Correcting Electric Heat kW for Voltage ....................................................... 35
4.5 Calculating Electric Heat Capacity in BTUH ................................................ 35
4.6 Checking Indoor Air-Flow ............................................................................. 35
4.6.1 Estimating CFM Using External Static Pressure ................................... 35
4.6.2 Estimating CFM Using Electric HEat Temperature Rise ....................... 35
4.7 Checking Refrigerant Charge ....................................................................... 36
5.0 COMPONENTS & CONTROLS ...................................................................... 36
5.1 Blower Motor ................................................................................................ 36
5.2 Motor Run Capacitor .................................................................................... 36
5.3 Blower Control .............................................................................................. 37
5.4 Blower .......................................................................................................... 37
5.5 Transformer .................................................................................................. 37
5.6 Indoor Coil Assembly ................................................................................... 37
6.0 ACCESSORIES & KITS .................................................................................. 38
6.1 Electric Resistance Heart Kits ...................................................................... 38
6.2 Jumper Bar Kits ............................................................................................ 38
6.3 Auxiliary Horizontal Overow Pans .............................................................. 38
6.4 External Filter Bases .................................................................................... 38
6.5 Combustible Floor Bases ............................................................................. 39
6.6 Horizontal Adapter Kits ................................................................................ 39
7.0 MAINTENANCE .............................................................................................. 39
7.1 Air Filter ........................................................................................................ 39
7.2 Indoor Coil, Drain Pan, Drain Line ............................................................... 40
7.3 Blower Motor and Wheel .............................................................................. 40
7.4 Motor Lubrication ......................................................................................... 40
7.5 Blower Assembly Removal & Replacement ................................................. 40
7.6 Motor Replacement ...................................................................................... 41
7.7 Blower Wheel Replacement ......................................................................... 41
7.8 Replacement Parts ....................................................................................... 41
8.0 DIAGNOSTICS ................................................................................................ 42
9.0 WIRING DIAGRAMS ....................................................................................... 43
9.1 DRAH1T - 208-240V ..................................................................... 43

4
WARNING (SEE SECTION 3.2.2: VERTICAL DOWNFLOW)
The RXHB-17, RXHB-21 or RXHB-24 combustible oor base is required when
some units with electric heat are applied downow on combustible ooring.
Failure to use the base can cause a re resulting in property damage, personal
injury or death. See CLEARANCES for units requiring a combustible oor base.
See the accessory section in this manual for combustible oor base RXHB.
WARNING
These instructions are intended as an aid to qualied, licensed service per-
sonnel for proper installation, adjustment and operation of this unit. Read
these instructions thoroughly before attempting installation or operation.
Failure to follow these instructions may result in improper installation, adjust-
ment, service or maintenance possibly resulting in re, electrical shock, prop-
erty damage, personal injury or death.
WARNING
Duct leaks can create an unbalanced system and draw pollutants such as
dirt, dust, fumes and odors into the home causing property damage. Fumes
and odors from toxic, volatile or ammable chemicals, as well as automo-
bile exhaust and carbon monoxide (CO), can be drawn into the living space
through leaking ducts and unbalanced duct systems causing personal injury
or death (see Figure 1).
• If air-moving equipment or ductwork is located in garages or off-garage stor-
age areas - all joints, seams, and openings in the equipment and duct must
be sealed to limit the migration of toxic fumes and odors including carbon
monoxide from migrating into the living space.
• If air-moving equipment or ductwork is located in spaces containing fuel
burning appliances such as water heaters or boilers - all joints, seams, and
openings in the equipment and duct must also be sealed to prevent depres-
surization of the space and possible migration of combustion byproducts
including carbon monoxide into the living space.
WARNING (SEE SECTION 3.6: DUCTWORK)
Do not, under any circumstances, connect return ductwork to any other heat
producing device such as replace insert, stove, etc. Unauthorized use of
such devices may result in re, carbon monoxide poisoning, explosion, per-
sonal injury or property damage.
WARNING (SEE SECTION 7.0: MAINTENANCE)
Units with circuit breaker(s) meet requirements as a service disconnect
switch, however, if access is required to the line side (covered) of the circuit
breaker, this side of the breaker(s) will be energized with the breaker(s) de-en-
ergized. Contact with the line side can cause electrical shock resulting in per-
sonal injury or death.
WARNING (SEE SECTION 3.13.2: GROUNDING)
The unit must be permanently grounded. Failure to do so can result in electri-
cal shock causing personal injury or death.
WARNING
Because of possible damage to
equipment or personal injury,
installation, service, and mainte-
nance should be performed by a
trained, qualied service person-
nel. Consumer service is recom-
mended only for lter cleaning/re-
placement. Never operate the unit
with the access panels removed.
WARNING
If removal of the blower assembly
is required, all disconnect switch-
es supplying power to the equip-
ment must be de-energized and
locked (if not in sight of unit) so
the eld power wires can be safely
removed from the blower assembly.
Failure to do so can cause electrical
shock resulting in personal injury
or death.
WARNING
Disconnect all power to unit
before installing or servicing.
More than one disconnect switch
may be required to de-energize
the equipment. Hazardous volt-
age can cause severe personal
injury or death.
(SEE SECTION 3.13:
ELECTRICAL WIRING)
(SEE SECTION 7.5: BLOWER
ASSEMBLY REMOVAL &
REPLACEMENT)
Continued on next page ❯
1.0 SAFETY INFORMATION
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CAUTION (SEE SECTION 3.2.2: VERTICAL DOWNFLOW & HORIZONTAL RIGHT DISCHARGE)
Unit must be recongured for vertical down or horizontal right supply air dis-
charge applications. The coil must be repositioned so the vertical drainpan is
on the bottom for vertical down discharge applications or the horizontal drip
pan is below coil for horizontal right discharge applications. Failure to recon-
gure the unit for these applications can result in property damage and poor
system performance.
CAUTION (SEE SECTION 3.3: AUXILIARY OVERFLOW PAN)
In compliance with recognized codes, an auxiliary drain pan must be
installed under all equipment containing evaporator coils that are located in
any area of a structure where damage to the building or building contents
may occur as a result of an overow of the coil drain pan or a stoppage in
the primary condensate drain piping. See Section 6.3 of this manual for
auxiliary horizontal overow pan accessory information (model RXBM).
NOTICE
When used in cooling applications, excessive sweating may occur when unit
is installed in an unconditioned space. This can result in property damage.
WARNING (SEE SECTION 3.7: AIR FILTER)
Do not operate the system without lters. A portion of the dust entrained in
the air may temporarily lodge in the duct runs and at the supply registers. Any
circulated dust particles could be heated and charred by contact with the heat-
ing elements. This residue could soil ceilings, walls, drapes, carpets and other
articles in the house.
Soot damage may occur even with lters in place when certain types of can-
dles, oil lamps or standing pilots are burned.
WARNING
The rst 36 inches of supply air plenum and ductwork must be constructed
of sheet metal as required by NFPA 90B. The supply air plenum or duct must
have a solid sheet metal bottom directly under the unit with no openings, reg-
isters or exible air ducts located in it. If exible supply air ducts are used they
may be located only in the vertical walls of a rectangular plenum, a minimum
of 6 inches from the solid bottom. Metal plenum or duct may be connected
to the combustible oor base, if not, it must be connected to the unit supply
duct anges such that combustible oor or other combustible material is not
exposed to the supply air opening from the downow unit. Exposing combus-
tible (non-metal) material to the supply opening of a downow unit can cause
a re resulting in property damage, personal injury or death.
Exceptions to downow warnings:
• Installations on concrete oor slab with supply air plenum and ductwork
completely encased in not less than 2 inches of concrete (See NFPA 90B).
NOTICE
Improper installation, or installation not made in accordance with the Underwriters
Laboratory (UL) certication or these instructions, can result in unsatisfactory
operation and/or dangerous conditions and are not covered by the unit warranty.
WARNING
PROPOSITION 65: This appliance
contains berglass insulation.
Respirable particles of berglass
are known to the State of California
to cause cancer.
All manufacturer products meet
current Federal OSHA Guidelines for
safety. California Proposition 65
warnings are required for certain
products, which are not covered by
the OSHA standards.
California’s Proposition 65 requires
warnings for products sold in
California that contain or produce
any of over 600 listed chemicals
known to the State of California to
cause cancer or birth defects such
as berglass insulation, lead in
brass, and combustion products
from natural gas.
All “new equipment” shipped for
sale in California will have labels
stating that the product contains
and/or produces Proposition 65
chemicals. Although we have not
changed our processes, having the
same label on all our products facil-
itates manufacturing and shipping.
We cannot always know “when,
or if” products will be sold in the
California market.
You may receive inquiries from cus-
tomers about chemicals found in, or
produced by, some of our heating
and air-conditioning equipment, or
found in natural gas used with some
of our products. Listed below are
those chemicals and substances
commonly associated with similar
equipment in our industry and other
manufacturers.
• Glass Wool (Fiberglass) Insulation
• Carbon Monoxide (CO).
• Formaldehyde
• Benzene
More details are available at the
websites for OSHA (Occupational
Safety and Health Administration),
at www.osha.gov and the State of
California’s OEHHA (Ofce of
Environmental Health Hazard
Assessment), at www.oehha.org.
Consumer education is important
since the chemicals and substanc-
es on the list are found in our daily
lives. Most consumers are aware
that products present safety and
health risks, when improperly used,
handled and maintained.
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NOTICE
Improper installation, or installation not made in accordance with the Underwriters
Laboratory (UL) certication or these instructions, can result in unsatisfactory
operation and/or dangerous conditions and are not covered by the unit warranty.
WARNING
Duct leaks can create an unbalanced system and draw pollutants such as
dirt, dust, fumes and odors into the home causing property damage. Fumes
and odors from toxic, volatile or ammable chemicals, as well as automo-
bile exhaust and carbon monoxide (CO), can be drawn into the living space
through leaking ducts and unbalanced duct systems causing personal injury
or death (see Figure 1).
• If air-moving equipment or ductwork is located in garages or off-garage stor-
age areas - all joints, seams, and openings in the equipment and duct must
be sealed to limit the migration of toxic fumes and odors including carbon
monoxide from migrating into the living space.
• If air-moving equipment or ductwork is located in spaces containing fuel
burning appliances such as water heaters or boilers - all joints, seams, and
openings in the equipment and duct must also be sealed to prevent depres-
surization of the space and possible migration of combustion byproducts
including carbon monoxide into the living space.
NOTICE
Use of this air-handler during construction is not recommended. If oper-
ation during construction is absolutely required, the following temporary
installation requirements must be followed:
Installation must comply with all Installation Instructions in this manual
including the following items:
• Properly sized power supply and circuit breaker/fuse
• Air-handler operating under thermostatic control;
• Return air duct sealed to the air-handler;
• Air lters must be in place;
• Correct air-ow setting for application
• Removing the coil and storing it in a clean safe place is highly recom-
mended until construction is completed and the outdoor unit is installed.
• Clean air-handler, duct work, and components including coil upon com-
pletion of the construction process and verify proper air-handler operat-
ing conditions according as stated in this instruction manual.
• NOTE: Electric strip heater elements tend to emit a burning odor for a few
days if dust has accumulated during construction. Heater elements are
easily damaged. Take great care when cleaning them. Low pressure com-
pressed air is recommended for cleaning elements.
2.0 GENERAL INFORMATION
2.1 IMPORTANT INFORMATION ABOUT EFFICIENCY & INDOOR
AIR QUALITY
Central cooling and heating equipment is only as efcient as the duct system that car-
ries the cooled or heated air. To maintain efciency, comfort and good indoor air quality,
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FIGURE 1
MIGRATION OF DANGEROUS SUBSTANCES, FUMES, AND ODORS INTO LIVING SPACES
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WARNING
Carbon Monoxide (CO) Poisoning
Can Cause Severe Injury or Death.
Carbon Monoxide from the exhaust of motor vehicles
and other fuel burning devices can be drawn into the
living space by the operation of the central heating
and air conditioning system.
Exhaust from motor vehicles, generators, garden tractors,
mowers, portable heaters, charcoal and gas grills, gasoline
powered tools, and outdoor camping equipment contains
carbon monoxide, a poisonous gas that can kill you.
You cannot see it, smell it, or taste it.
• Do NOT operate an automobile or any engine in a
garage for more than the few seconds it takes to
enter or exit the garage.
• Do NOT operate any fuel-burning device in an
enclosed or partly enclosed space, or near
building windows, doors or air intakes.
The U.S. Consumer Product Safety Commission (CPSC)
and Health Canada recommend the installation of UL or CSA
certied Carbon Monoxide Alarm(s) in every home.

7
it is important to have the proper balance between the air being supplied to each room
and the air returning to the cooling and heating equipment.
Proper balance and sealing of the duct system improves the efciency of the heating
and air conditioning system and improves the indoor air quality of the home by reducing
the amount of airborne pollutants that enter homes from spaces where the ductwork
and/or equipment is located. The manufacturer and the U.S. Environmental Protection
Agency’s Energy Star Program recommend that central duct systems be checked by a
qualied contractor for proper balance and sealing.
2.2 CHECKING PRODUCT RECEIVED
Immediately upon receipt, all cartons and contents should be inspected for transit dam-
age. Units with damaged cartons should be opened immediately. If damage is found, it
should be noted on the delivery documents and a damage claim led with the delivering
carrier.
After unit has been delivered to the job site, remove the unit from the carton taking care
not to damage the unit. Check the unit rating plate for unit model number, unit size, coil
model, voltage, phase, etc. to assure the unit matches the job specications.
'5$+ $$7   6 7  1  - $
0,1256(5,(6
$ ),567
92/7$*(
$ 
' 
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027257<3(
3 36&
7 &2167$1772548(
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FIGURE 2
MODEL NUMBER NOMENCLATURE
2.3 MODEL NUMBER NOMENCLATURE

8
AVAILABLE 208/240V MODELS
2.4 AVAILABLE MODELS
Notes:
• J Voltage (208/240V) single phase air handler is designed to be used with single or
three phase 208/240V power. When connecting 3-phase power to the air handler ter-
minal block, bring only two leads to the terminal block. Cap, insulate and fully secure
the third lead.
• The air handlers are shipped from the factory with the proper indoor coil installed, and
cannot be ordered without a coil.
• These air handlers do not have an internal lter rack. An external lter rack or other
means of ltration of return air is required.
• Electric resistance heaters are eld installed items. (See Section 6.1)
DRAH1TA2417ASTNJA
DRAH1TA3617ASTNJA
DRAH1TA3621AHTNJA
DRAH1TA3621AMTNJA
DRAH1TA4821AMTNJA
DRAH1TA4821ASTNJA
DRAH1TA6021ASTNJA
DRAH1TA6024ASTNJA

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2.5.1 DIMENSIONS & WEIGHTS: DRAH1T MODELS
UPFLOW UNIT SHOWN;
UNIT MAY BE INSTALLED UPFLOW, DOWNFLOW. HORIZONTAL RIGHT, OR LEFT AIR SUPPLY.
Return Air Return Air Opening
Model Opening Width Depth/Length
Cabinet Size (Inches) (Inches)
17 157⁄8193⁄4
21 193⁄8193⁄4
24 227⁄8193⁄4
Return Air Opening Dimensions
FIGURE 3A
DIMENSIONS AND WEIGHTS
A-1038-01
NOTE: 24” CLEARANCE REQUIRED
IN FRONT OF UNIT FOR FILTER
AND COIL MAINTENANCE.
ELECTRICAL CONNECTIONS MAY
EXIT TOP OR EITHER SIDE
HIGH VOLTAGE CONNECTION 7/8”,
1 3/32”, 1 31/32” DIA. KNOCK OUTS.
LOW VOLTAGE CONNECTION
5/8” AND 7/8” KNOCK OUT
(OUTSIDE OF CABINET)
FLANGES ARE PROVIDED
FOR FIELD INSTALLATION
AUXILIARY DRAIN CONNECTION
3/4” FEMALE PIPE THREAD (NPT)
HORIZONTAL APPLICATION ONLY
PRIMARY DRAIN CONNECTION
3/4” FEMALE PIPE THREAD (NPT)
AUXILIARY DRAIN CONNECTION
3/4” FEMALE PIPE THREAD (NPT)
UPFLOW/DOWNFLOW APPLICATION
ONLY
LIQUID LINE CONNECTION
COPPER (SWEAT)
VAPOR LINE CONNECTION
COPPER (SWEAT)
2111/16
105/16
SUPPLY AIR
W
A
H
191/2
RETURN AIR
OPENING
(SEE DUCT FLANGES, SECTION 3.5,
FOR INSTRUCTIONS)
DIMENSIONAL DATA
MODEL
SIZE
REFRIGERANT CONNECTIONS
UNIT
HEIGHT
IN. [mm]
UNIT
WIDTH
“W” IN.
[mm]
SUPPLY
DUCT
“A” IN.
[mm]
NOMINAL CFM
[L/s]
UNIT WEIGHT / SHIPPING
WEIGHT (LBS.) [kg]
SWEAT (IN.) [mm] ID LO HI UNIT WITH
COIL (MAX. kW.)
DRAH1T LIQUID VAPOR
2717AS 3/8” [9.53] 3/4” [19.05] 421/2” [1080] 171/2” [445] 16” [409] 600 [283] 800 [378] 92/106 [42/48]
3617AS 3/8” [9.53] 3/4” [19.05] 421/2” [1080] 171/2” [445] 16” [409] 1000 [472] 1200 [566] 96/110 [44/50]
3621AM 3/8” [9.53] 7/8” [22.23] 501/2” [1282] 21” [533] 191/2” [495] 1000 [472] 1200 [566] 126/142 [57/64]
3621AH 3/8” [9.53] 7/8” [22.23] 57 [1448] 21” [533] 191/2” [495] 1000 [472] 1200 [566] 137/149 [62/68]
4821AS 3/8” [9.53] 7/8” [22.23] 501/2” [1282] 21” [533] 191/2” [495] 1400 [661] 1600 [755] 128/144 [56/65]
4821AM 3/8” [9.53] 7/8” [22.23] 57 [1448] 21” [533] 191/2” [495] 1400 [661] 1600 [755] 139/151 [63/68]
6021AS 3/8” [9.53] 7/8” [22.23] 57 [1448] 21” [533] 191/2” [495] 1600 [755] 1725 [814] 139/151 [63/68]
6024AS 3/8” [9.53] 7/8” [22.23] 551/2” [1410] 241/2” [622] 23” [585] — 1800 [850] 159/176 [72/80]

10
2.6 IMPORTANCE OF PROPER INDOOR/OUTDOOR MATCH-UPS
To assure many years of reliable operation and optimum customer comfort and to
assure the outdoor unit warranty remains valid, an air-handler model should be selected
that is properly matched to the outdoor unit. This is especially critical for heat pump
systems to assure proper refrigerant charge balance between the cooling and heating
modes. The recommended approach is to select an air-handler model that has an
AHRI match with the outdoor unit. Refer to the AHRI directory at www.ahridirectory.
org to conrm the air-handler and outdoor unit are a certied combination in the AHRI
Directory.
2.7 IMPORTANCE OF QUALITY INSTALLATION
A quality installation is critical to assure safety, reliability, comfort, and customer satis-
faction. Strict adherence to applicable codes, the information in this installation manual,
the outdoor unit installation manual, and the thermostat installation manual are key to a
quality installation. Read the entire instruction manuals before starting the installation.
IMPORTANT: This product has been designed and manufactured to meet certied
AHRI capacity and efciency ratings with the appropriate outdoor units. However, prop-
er refrigerant charge, proper airow, and refrigerant line sizing are critical to achieve
optimum capacity and efciency and to assure reliable operation. Installation of this
product should follow the manufacturer’s refrigerant charging and airow instructions
located in the outdoor unit installation instructions and the charging chart label afxed to
the outdoor unit. Failure to conrm proper charge and airow may reduce energy ef-
ciency and shorten equipment life.
The equipment has been evaluated in accordance with the Code of Federal
Regulations, Chapter XX, Part 3280.
Install the unit in accordance with applicable national, state, and local codes. Latest edi-
tions are available from: “National Fire Protection Association, Inc., Batterymarch Park,
Quincy, MA 02269.” These publications are:
• ANSI/NFPA No. 70-(Latest Edition) National Electrical Code.
• NFPA90A Installation of Air Conditioning and Ventilating Systems.
• NFPA90B Installation of warm air heating and air conditioning systems.
Install the unit in such a way as to allow necessary access to the coil/lter rack and
blower/control compartment.

11
3.0 INSTALLATION
3.1 TOOLS & REFRIGERANT
3.1.1 TOOLS REQUIRED FOR INSTALLING AND SERVICING R-410A MODELS
Manifold Sets:
• Up to 800 PSIG High-Side
• Up to 250 PSIG Low-Side
• 550 PSIG Low-Side Retard
Manifold Hoses:
• Service Pressure Rating of
800 PSIG
Recovery Cylinders:
• 400 PSIG Pressure Rating
• Dept. of Transportation
4BA400 or BW400
3.1.2 SPECIFICATIONS OF R-410A
Application: R-410A is not a drop-in replacement for R-22. Equipment designs must
accommodate its higher pressures. It cannot be retrotted into R-22 heat pumps.
Physical Properties: R-410A has an atmospheric boiling point of -62.9°F [-52.7°C] and
its saturation pressure at 77°F [25°C] is 224.5 psig.
Composition: R-410A is a near-azeotropic mixture of 50% by weight diuoromethane
(HFC-32) and 50% by weight pentauoroethane (HFC-125).
Pressure: The pressure of R-410A is approximately 60% (1.6 times) greater than
R-22. Recovery and recycle equipment, pumps, hoses, and the like must have design
pressure ratings appropriate for R-410A. Manifold sets need to range up to 800 psig
high-side and 250 psig low-side with a 550 psig low-side retard. Hoses need to have a
service pressure rating of 800 psig. Recovery cylinders need to have a 400 psig service
pressure rating, DOT 4BA400 or DOT BW400.
Combustibility: At pressures above 1 atmosphere, a mixture of R-410A and air can
become combustible. R-410A and air should never be mixed in tanks or supply
lines or be allowed to accumulate in storage tanks. Leak checking should never
be done with a mixture of R-410A and air. Leak-checking can be performed safely
with nitrogen or a mixture of R-410A and nitrogen.
3.1.3 QUICK-REFERENCE GUIDE FOR R-410A
• R-410A refrigerant operates at approximately 60% higher pressure (1.6 times) than
R-22. Ensure that servicing equipment is designed to operate with R-410A.
• R-410A refrigerant cylinders are light rose in color.
• R-410A, as with other HFCs, is only compatible with POE oils.
• Vacuum pumps will not remove moisture from POE oil used in R-410A systems.
• R-410A systems are to be charged with liquid refrigerants. Prior to March 1999,
R-410A refrigerant cylinders had a dip tube. These cylinders should be kept upright
for equipment charging. Post-March 1999 cylinders do not have a dip tube and should
be inverted to ensure liquid charging of the equipment.
• Do not install a suction line lter drier in the liquid line.
• A factory-approved outdoor liquid line lter drier is shipped with every unit and must
be installed in the liquid line at the time of installation. If only the air-handler is being
replaced on an existing system, the existing lter drier must be replaced at the time
of installation with a eld supplied lter drier. IMPORTANT: A bi-ow lter drier must
be used for heat pump applications. Filter driers must be rated for minimum working
pressure of 600 psig. The lter drier will only have adequate moisture-holding capaci-
ty if the system is properly evacuated.
• Desiccant (drying agent) must be compatible for POE oils and R-410A refrigerant.
Ambient and Tube
Thermometers
Manifold
Gauge
Set
Brazing
Rods
Torch Nitrogen
Reclaimer
Recovery
Cylinders
Allen Wrench
Crescent Wrench
NOTICE
R-410A systems oper-
ate at higher pressures
than R-22 systems. Do
not use R-22 service
equipment or compo-
nents on R-410A equip-
ment.
!

12
3.2 APPLICATIONS AND ORIENTATION
3.2.1 VERTICAL UPFLOW & HORIZONTAL LEFT DISCHARGE
• Vertical Upow & Horizontal Left Discharge is the factory conguration for all models
(see Figure 4).
• The return air plenum must be large enough to supply unit and strong enough to sup-
port unit weight.
• If return air is to be ducted through the oor, install duct ush with oor. Use reproof
resilient gasket 1/8 to 1/4 in. thick between duct, unit and oor. Set unit on oor over
opening.
IMPORTANT: Do not cut the side out of air-handler cabinet for a side return duct as this
will result in the return air bypassing the coil. Instead, install air-handler on top of a eld
supplied sheet metal or wooden box and run the side return duct into the side of the box.
3.2.2 VERTICAL DOWNFLOW & HORIZONTAL RIGHT DISCHARGE
The unit as shipped from the factory is not congured for vertical down or horizontal right
discharge applications and must be converted in the eld to work in those applications.
To make this conversion, remove the coil door and slide the indoor coil out of the cabinet.
When converting the air-handler for vertical down and horizontal right discharge appli-
cations, an additional set of 2 coil support rails must be installed before the coil can be
reinstalled. These additional rails are supplied with the air-handler and are packaged
with the duct anges. Six screws are also provided for mounting the rails and can be
found in the installation hardware bag. Clearance holes must be drilled in the sides of
the cabinet for the mounting screws using the provided dimples as guides. Note that the
shorter coil support rail with no notch must be mounted on the left-hand side to provide
clearance for the drainpan condensate connection boss.
The vertical down/horizontal right coil support rails were not installed at the factory so the
insulation under them would not be compressed which could result in exterior cabinet
sweating in humid environments due to that location being in the cold downstream side
of the indoor coil in vertical up and horizontal left discharge applications. The coil support
rails installed at the factory should be left in place to help retain the cabinet insulation.
They will be located on the warmer return side of the air-handler for down and horizontal
right discharge applications and will therefore not pose a risk for cabinet sweating.
Once the additional coils support rails are installed, slide the coil back into the cabinet 180º
from its original position, ensuring the retaining channel is fully engaged with the coil rail.
(See Figure 6, Detail A.) Leave the coil door off until after the refrigerant tubing is brazed
to the refrigerant stubs to allow TXV to be wrapped with a wet rag or heat sink compound
during the brazing process. If the air-handler is not already in position, it can now be posi-
tioned so the blower discharge is either down or to the right depending on the application.
FIGURE 4
DIMENSIONS FOR REFRIGERANT-TUBING & DRAIN CONNECTIONS
515/16
41/8
31/16
13/16 11/8
11/16
1
3/8
213/16
51/4
53/8
VERTICAL
AUXILIARY DRAIN
CONNECTION
HORIZONTAL
AUXILIARY DRAIN
CONNECTION
MAIN DRAIN
CONNECTION
SUCTION LINE
CONNECTION
LIQUID LINE
CONNECTION

13
DRIP LOOP NOTE: When installing the unit in down or horizontal right discharge appli-
cations, make sure the wires going to the blower motor form a proper drip loop to force
any condensate that might form on the wires to drip off the lowest point of the wiring
instead of entering the motor or motor control. This may require cutting the wire-tie and
installing a new wire-tie to form a new drip loop.
IMPORTANT: To comply with certication agencies and the National Electric Code for
down discharge applications, the circuit breaker(s) on eld-installed electric heater kits
must be re-installed per procedure below so that the breaker switch “on” position and
marking is up and the “off” position and marking is down.
- To turn breaker(s): Rotate one breaker pair (circuit) at a time starting with the one
on the right. Loosen both lugs on the load side of the breaker. Wires are bundles
with wire ties, one bundle going to the right lug and one bundle going to the left lug.
- Using a screwdriver or pencil, lift white plastic tab with hole away from breaker until
breaker releases from mounting opening (see Figure 5).
- With breaker held in hand, rotate breaker so that “on” position is up and the “off”
position is down with unit in the vertical mounting position. Insert right wire bundle
into top right breaker lug, ensuring all strands of all wires are inserted fully into lug,
and no wire insulation is caught in lug.
- Tighten lug as tight as possible while holding circuit breaker. Check wires and
make sure each wire is secure and none are loose. Repeat for left wire bundle in
left top circuit breaker lug.
IMPORTANT: Failure to securely hold the breaker will result in the plastic mounting
boss on the breaker to be broken off when the lug is tightened.
- Replace breaker by inserting breaker mounting tab opposite white pull tab in open-
ing, hook mounting tab over edge in opening.
- With screwdriver or pencil, pull white tab with hole away from breaker while setting
that side of breaker into opening. When breaker is in place, release tab, locking
circuit breaker into location in opening.
- Repeat above operation for remaining breaker(s) (if more than one is provided).
- If one is used, replace the single point wiring jumper bar on line side of breaker
and tighten securely.
- Double check wires and lugs to make sure all are secure and tight. Check to
make sure unit wiring to circuit breaker load lugs match that shown on the unit wir-
ing diagram.
IMPORTANT: Units cannot be installed horizontally laying on or suspended from the
back of the unit.
WARNING
The RXHB-17, RXHB-21 or RXHB-24 combustible oor base is required
when some units with electric heat are applied downow on combustible
ooring. Failure to use the base can cause a re resulting in property
damage, personal injury or death. See CLEARANCES (Section 3.4) for
units requiring a combustible oor base. See the accessory section in this
manual for combustible oor base RXHB.
!
FIGURE 5
ROTATING CIRCUIT BREAKER

14
CAUTION
Auxiliary horizontal overow pan kits RXBM- (or equivalent) are required
when the unit is congured for the horizontal position over a nished ceil-
ing and/or living space. (See Sections 3.3 and 6.3.) Failure to install over-
ow plan can result in property damage.
3.2.3 INSTALLATION IN AN UNCONDITIONED SPACE
The exterior cabinet of an air handler has a greater risk of sweating when installed in an
unconditioned space than when it is installed in the conditioned space. This is primarily
due to the temperature of the conditioned air moving through the air handler and the
air circulating around the unit where it is installed. For this reason, the following is rec-
ommended for all air handler applications, but special attention should be paid to those
installed in unconditioned spaces:
• Duct sizing and airow are critical and must be based on the equipment selected.
• Supply and return duct attachment: If other than the factory anges are used, the
attachment of ducting must be insulated and tight to prevent sweating.
!
FIGURE 6
VERTICAL DOWNFLOW & HORIZONTAL RIGHT APPLICATIONS
FIGURE 7
INDOOR COIL AND DRAIN PAN DETAILS
ST-A1213-01
HORIZONTAL DRIP PAN
KIT TOP AIR STOP
STRAPS
VAPOR LINE
CONNECTION
PRIMARY
DRAIN
CONNECTION
LIQUID LINE
CONNECTION
VERTICAL
DRAIN PAN
AUXILIARY
HORIZONTAL
DRAIN
CONNECTION
AUXILIARY
UPFLOW/DOWNFLOW
DRAIN CONNECTION
DETAIL A
ENSURE THE RETAIN-
ING CHANNEL IS FULLY
ENGAGED WITH THE
COIL RAIL.
ADDITIONAL
COIL RAILS
FACTORY COIL RAIL LOCATION ST-A1213-02
FACTORY COIL
RAIL LOCATION
ADDITIONAL
COIL RAILS

15
• No perimeter supply anges are provided. If a full perimeter supply duct is used, it is
the responsibility of the installer to provide duct anges as needed, to secure and seal
the supply duct to prevent air leakage and the sweating that will result.
• Apply caulking around all cabinet penetrations such as power wires, control wires,
refrigerant tubing and condensate line where they enter the cabinet. Seal the power
wires on the inside where they exit conduit opening. Sealing is required to prevent air
leakage into the unit which can result in condensate forming inside the unit, control
box, and on electrical controls. Take care not to damage, remove or compress insula-
tion when applying the caulk.
• In some cases, the entire air handler can be wrapped with insulation. This can be
done as long as the unit is completely enclosed in insulation, sealed and service
access is provided to prevent accumulation of moisture inside the insulation wrap.
• An auxiliary overow pan is recommended to protect the structure from excessive
cabinet sweating or a restricted coil drain line. (See Section 3.3)
• If an electric heater kit is installed, be sure the breaker or disconnect cover is sealed
tightly to the door panel.
3.2.4 INSTALLATION IN MOBILE/MANUFACTURED HOMES
1. Air handler must be secured to the structure using “L” brackets or pipe strap.
2. Allow a minimum of 24 inches (610 mm) front clearance required to access doors.
3. Recommended method for securing air handler:
A. If air handler is against the wall, secure top of air handler to wall stud using two
16ga thick angle brackets one on each side. Attach brackets with No. 10 self-tap-
ping 1⁄2( long screws to air handler and use 5⁄16( lag screws 11⁄2( long to wall stud.
Secure bottom of unit with two 16ga “L” brackets with No. 10 self-tapping 1⁄2( long
screws to air handler and use 5⁄16( lag screws 11⁄2( long to oor.
B. If air handler is away from wall attach pipe strap to top of air handler using No. 10
1⁄2( long self-tapping screws on both sides. Angle strap down and away from back
of air handler, remove all slack, and fasten to wall stud of structure using 5⁄16( lag
screws 11⁄2( long. Secure bottom of unit with two 16ga “L” brackets with No. 10
self-tapping screws to air handler and use 5⁄16( lag screws 11⁄2( long to oor.
FIGURE 8
ST-A-1193-01

16
3.2.5 INSTALLATION IN CORROSIVE ENVIRONMENTS
The metal parts of this unit may be subject to rust or deterioration if exposed to a cor-
rosive environment which can shorten its life. In addition to exposure to the exterior of
the cabinet, chemical contaminants inside the building that can be drawn into the unit
from the return air grille and attack structural metal parts, electrical components and the
indoor coil, causing premature failure of the unit. If the unit is to be installed in an area
where contaminants are likely to be a problem, special attention should be given to iso-
late the unit and return grille from contaminants.
3.2.6 SUPPORTING AIR-HANDLER IN HORIZONTAL APPLICATIONS
The air-handler must be adequately supported underneath if it is installed in the hori-
zontal position to prevent it from sagging in the middle which can cause issues remov-
ing and re-installing the access panels. Position the unit on adequate supports or on
support angles or channels (See Figure 9) before connecting ductwork to the unit. If
an auxiliary overow pan is required (See Section 3.3), the overow pan will need to be
adequately supported with the air-handler being supported underneath within the auxilia-
ry overow pan by angles and/or channels.
3.3 AUXILIARY OVERFLOW PAN
In compliance with recognized codes, an auxiliary overow pan must installed under all
equipment containing evaporator coils that are located in any area of a structure where
damage to the building or building contents may occur as a result of an overow of the
coil drain pan or a stoppage in the primary condensate drain piping. See Section 6.3 of
this manual for information regarding the recommended auxiliary horizontal overow pan
(model RXBM) for this air-handler.
3.4 CLEARANCES
• All units are designed for “0” inches clearance to combustible material on all cabinet
surfaces except for downow application with higher kW electric heat as noted below.
• Some units require a combustible oor base depending on the heating kW if installed
in the downow conguration on a combustible surface. The following table should be
used to determine these requirements.
• Units with electric heating kW equal to or less than the values listed in the table do
not require a combustible floor base. See Section 6.5 for Combustible Floor Base
RXHB-XX.
• Units with electric heat require a one inch clearance to combustible material for the
first three feet of supply plenum and ductwork.
Model Cabinet Size 17 21 24
Maximum Model Designation kW 15 18 20
SUPPORTING HORIZONTAL AIR-HANDLERS IN AUXILIARY
OVERFLOW PANS OR AIR-HANDLERS THAT ARE NOT SUSPENDED.
NOTE:
DO NOT BLOCK AIR-HANDLER ACCESS
WITH SUPPORT RODS, ALLOW SPACE
FOR PROPER SERVICE MAINTENANCE
OR REPLACEMENT OF THE COIL AND
BLOWER ASSEMBLY.
NOTE:
HORIZONTAL LEFT ORIENTATION
DEPICTED IN ILLUSTRATION.
HORIZONTAL RIGHT ORIENTATION
IS SIMILAR IN INSTALLATION.
SUSPENDED HORIZONTAL AIR-HANDLER.
AIR FLOW
ST-A1298-01
FIGURE 9

17
electrical connections. Refrigerant and condensate drain connections are made on
the front of the unit.
• All units require 24 inches minimum access to the front of the unit for service.
• These units may be installed in either ventilated or nonventilated spaces.
3.5 DUCT FLANGES
Duct anges (4 pieces) are shipped with the unit and are to be eld installed on the top
of the air-handler using the following procedure and referring to Figure 10.
1. Loosen the screws attaching the heat barrier to the cabinet.
2. Form a 90° bend with the short leg length at approximately 9.9” from the end where
the slot is cut in the ange to facilitate bending. The duct anges are shipped sized
for the 24.5” wide cabinet. For the 17.5” and 21” wide cabinets, cut the long leg as
shown in Figure 10 to match the cabinet width.
3. Side the duct anges onto the screws loosened in step one above. Tighten the
screws to secure the anges.
3.6 DUCTWORK
Field ductwork must comply with the National Fire Protection Association NFPA 90A,
NFPA 90B and any applicable local ordinance.
Sheet metal ductwork run in unconditioned spaces must be insulated and covered with a
vapor barrier. Fibrous ductwork may be used if constructed and installed in accordance
with SMACNA Construction Standard on Fibrous Glass Ducts. Ductwork must comply
with National Fire Protection Association as tested by U/L Standard 181 for Class I Air
Ducts. Check local codes for requirements on ductwork and insulation.
• Duct system must be designed within the range of external static pressure the unit is
designed to operate against. It is important that the system airow be adequate. Make
sure supply and return ductwork, grills, lters, accessories, etc. are accounted for in
total resistance. Refer to the airow performance tables in this manual to determine the
available external static pressure for the particular air-handler model being installed.
• Design the duct system in accordance with “ACCA” Manual “D” Design for Residential
Winter and Summer Air Conditioning and Equipment Selection. Latest editions are
available from: “ACCA” Air Conditioning Contractors of America, 1513 16th Street,
N.W., Washington, D.C. 20036. If duct system incorporates exible air duct, be sure
pressure drop information (straight length plus all turns) shown in “ACCA” Manual
“D” is accounted for in system.
• Supply plenum is attached to the duct anges supplied with the unit. See Section 3.5.
•IMPORTANT: If an elbow is included in the plenum close to the unit, it must not be
smaller than the dimensions of the supply duct ange on the unit.
•IMPORTANT: The front ange on the return duct if connected to the blower casing
must not be screwed into the area where the power wiring is located. Drills or sharp
screw points can damage insulation on wires located inside unit.
• Secure the supply and return ductwork to the unit anges, using proper fasteners for the
type of duct used and tape or caulk the duct-to-unit joint as required to prevent air leaks.
!WARNING
Do not, under any circumstances, connect return ductwork to any other
heat producing device such as replace insert, stove, etc. Unauthorized
use of such devices may result in re, carbon monoxide poisoning, explo-
sion, personal injury or property damage.
´&$%,1(7 &87 +(5(
+($7 %$55,(5
´&$%,1(7 &87 +(5(
'8&7 )/$1*(
5(48,5('
%(1'
FIGURE 10
DUCT FLANGE INSTALLATION
• Vertical downflow applications require clearance on at least one side of the unit for

18
3.7 RETURN AIR FILTER
An internal lter rack is not provided with this air-handler. Therefore, an external means
of ltering the return air is required. External lters should be sized for a maximum of
300 feet/min air velocity or the maximum velocity recommended by the type of lter
installed. One or more return air lter grilles, a lter rack attached to unit return air
intake, or a lter rack installed between a sealed return air platform and the return duct
are all acceptable means of ltration. All return ducts must be ltered, either at each
return grille or at a common lter near the unit.
Important: Do not install a return air lter grille and a lter rack at the unit and do not
install a lter in the supply duct system.
Filter type, sizing, and placement are critical to heating and cooling system performance.
Reduced air-ow can shorten the life of system components such as the compressor,
indoor coil, heater elements, over temperature limits, and relays. As lters near the end
of their useful life, the pressure drop through them increases. Therefore, it is important
to factor the “end of life” (dirty) pressure drop of lters into the external static pressure
of the duct system when selecting blower speeds and designing ductwork to assure
the system is operating at the design CFM and system reliability is not compromised.
Always verify that the system’s air-ow is within specications by performing a tempera-
ture rise (heating mode) and/or temperature drop (cooling mode) with all lters in place.
Important: High efciency pleated lters and electronic air cleaners typically have
signicantly higher pressure drop than standard efciency berglass lters, especially
when they get dirty. Do not use high efciency lters or electronic air cleaners unless
adequate lter area is provided to lower the lter pressure drop to an acceptable level.
3.8 ORIFICE SIZE
The piston model air handler comes standard with a ow check piston installed. The pis-
ton may need to be changed to a different orice size depending upon the outdoor unit.
The following table lists the recommended orice size for various outdoor units.
*Piston size installed at factory. Correct piston for other tonnages will be included with
the matching outdoor unit.
3.9 REFRIGERANT LINE CONNECTIONS & CHARGING
3.9.1 PREPARATION
The coil is shipped with a low pressure (5-10 psig) charge of dry nitrogen which will be
released when the rubber plugs are removed. Leave the rubber plugs in the refrigerant con-
nection stubs on the air-handler until the refrigerant lines are ready to be brazed to the refrig-
erant connection stubs to prevent contaminants from entering the coil. Clean the ends of the
tubing and coil connection stubs (inside and outside) with an alcohol wipe before inserting
the line set tubes into the coil connection stubs to assure a quality leak-free braze joint.
Refer to the outdoor unit installation instructions for details on refrigerant line sizing and
installation. Be sure to follow long line length guidelines if they apply.
Route the refrigerant tubing in a manner than does not block service access to the front
of the air-handler.
3.9.2 LIQUID LINE FILTER DRIER
A new liquid lter drier must be installed every time any part of the system has been
open to the atmosphere, even if it’s for a short period of time. The lter drier should be
installed close to the air-handler for a system started up in the cooling mode and near
the outdoor unit for a heat pump system started up in the heating mode. This allows the
lter drier to catch any contaminants in the liquid line before they can enter the indoor or
outdoor TXV inlet screen.
2417 11⁄2Ton R-410A .049
2 Ton .057*
3617 21⁄2Ton R-410A .062
3 Ton .067*
4821 31⁄2Ton R-410A .074
4 Ton .078*
Indoor Nominal Tons Refrigerant Piston
!WARNING
Do not operate the system without lters. A portion of the dust entrained in
the air may temporarily lodge in the duct runs and at the supply registers.
Any circulated dust particles could be heated and charred by contact with the
heating elements. This residue could soil ceilings, walls, drapes, carpets and
other articles in the house. Operating the system without a lter will also allow
lint and dirt particles to accumulate on the indoor coil n and restrict air-ow
through the coil. Soot damage may occur even with lters in place when cer-
tain types of candles, oil lamps or standing pilots are burned.

19
3.9.3 BRAZING
Air inside the tubing and coil should be displaced with dry nitrogen prior to the brazing
process to prevent the formation of harmful copper oxide inside the tubing. It is very
important not to pressurize the system with nitrogen while brazing or pin-hole leaks will
form in the braze joint. This is accomplished by removing the gauge port valve core on
one of the outdoor unit service valves to allow the pressure to be relieved as the heat-
ed nitrogen expands. Fill the system with dry nitrogen through the other service valve
gauge port and then turn the nitrogen ow off just before brazing is begun.
Protect the TXV, copper to aluminum suction header joint, and outdoor unit service
valves from overheating using a wet rag or heat sink compound. Leave the wet rag or
heat sink material in place until the joint and surrounding tubing cools down to a safe
temperature. Double tip torches can help minimize brazing time and heat conduction
to the heat sensitive components if the ame is turned down and held on the joint just
long enough to make the braze joint. With both single and double tip torches, turning
the ame up too much and keeping the ame on the joint too long will damage the heat
sensitive components even when a wet rag or heat sink compound is used.
Use a sheet metal shield to protect the cabinet’s paint from the torch ames during the braz-
ing process. The vapor line insulation should be pushed back on the line about 12 inches
from the joint and retained to prevent it from igniting or melting during the brazing process.
After the refrigerant brazed connections are made at the air-handler and the tubing has
cooled down sufciently, replace the coil section access panel if it has been removed
and seal the air gap around the connection stubs with the foam rubber gasket included
in the air-handler parts bag. Peel the self-adhesive backing off of the foam gasket and
position it around the stubs with the adhesive side toward the cabinet, then press it rm-
ly against the cabinet. The gasket is split to allow it to go over the stubs after the refrig-
erant tubes are brazed to the stubs. (See Figure 12 in Section 3.10)
After the foam gasket has been installed, the vapor line insulation should be pulled back
in place so it contacts the air-handler cabinet to prevent condensate from forming on the
cold tube and dripping off. A loosely tting zip-tie placed around the insulation ½” from
the end can be used to hold it in place so it doesn’t move away from the cabinet. For
air-handlers with TXV’s, a section of the insulation will need to be cut out to make room
for the externally mounted TXV bulb. (See Section 3.10) Once the bulb is mounted,
insulate the bulb with the foam insulation included in the air-handler parts bag, making
sure none of the vapor line is uninsulated.
3.9.4 LEAK TESTING
After all braze joints are completed, replace the valve core removed when purging with
nitrogen and then leak test the system by pressurizing to 150 psig with dry nitrogen and
allow the system to sit for at least 15 minutes (longer if possible) to assure the pressure
does not drop.
3.9.5 EVACUATION
If no leaks are detected, evacuate the system down to 500 microns or below before
charging the system or opening the service valves on the outdoor unit which will release
the charge stored in the outdoor unit into the line set and air-handler coil. Failure to
reach 500 microns of vacuum is a sign of a leak or excessive moisture inside the system.
3.9.6 REFRIGERANT CHARGING
Once the evacuation process is completed, break the vacuum with the refrigerant from a
refrigerant cylinder or with refrigerant stored in the outdoor unit by opening the outdoor
unit service valves. The charging process cannot be completed until the remaining
steps in the installation process are completed and the indoor air-ow is adjusted to the
proper level. See Section 4.7 for further details.
3.10 TXV SENSING BULB ATTACHMENT
IMPORTANT: DO NOT perform any brazing with the TXV bulb attached to the vapor
line. After brazing operations have been completed and the tubing has cooled to the
touch, clamp the TXV bulb securely on the vapor line at the 10 to 2 o’clock position (see
Figures 11 and 12) with the strap provided in the parts bag. Insulate the TXV sensing
bulb and suction line with the provided pressure sensitive insulation (size 4” × 7”) and
secure with provided wire ties.
IMPORTANT: TXV sensing bulb should be located on a horizontal section of suc-
tion line, just outside of coil box. The copper sensing bulb must never be placed
on any aluminum tube as this will result in galvanic corrosion and eventual failure
of the aluminum tube.

20
3.11 CONDENSATE DRAIN
Consult local codes or ordinances for specic requirements.
IMPORTANT: When making drain tting connections to the drain pan, use a thin layer of
Teon paste, silicone or Teon tape and install hand tight.
IMPORTANT: When making drain tting connections to drain pan, do not overtighten.
Overtightening ttings can split pipe connections on the drain pan.
• Install drain lines so they do not block service access to front of the unit. Minimum
clearance of 24 inches is required for lter, coil or blower removal and service access.
• Although the condensate drain pan is designed is designed to be self draining, it is
recommended that the air-handler cabinet be pitched slightly downward toward the
primary drain connection to assure the condensate drains completely from the drain
pan. The downward pitch should be approximately 1/8” per foot and in both axes.
FIGURE 12
TXV BULB & FOAM GASKET LOCATION
ST-A1278-01
TXV BULB
FOAM GASKET
FIGURE 11
BULB LOCATION
10 O’CLOCK 2 O’CLOCK
TXV
BULB
VAPOR LINE
TXV
BULB