Suntherm SEHX Series User manual

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 1
INSTALLATION MANUAL
LIST OF SECTIONS
LIST OF FIGURES
LIST OF TABLES
SECTION 1: GENERAL
8 – Line Voltage Wiring................................................................................................21
9 – Thermostat Wiring and Connections ..............................................................23
10 – Blower Performance .............................................................................................28
11 – Blower Motor Speed Selection .........................................................................30
12 – Final System Checkout and Startup................................................................31
13 – Wiring Diagrams.....................................................................................................30
17 – Components and Water Connections ............................................................15
18 – Proper Wiring of the SHL Temperature Switch............................................23
19 – Component Locations – No Heat Control Box ........................................... 23
20 – Component Locations - Hydronic Heat Control Box................................ 23
21 – Heat/Cool Tstat Connections - Separate Tstats & Single Tfmr................24
22 – Heat/Cool Tstat Connections-Separate Tstats & Separate Tfmrs...........24
23 – Heat/Cool Tstat Connections - Single Tstat & Separate Tfmrs................25
24 – Heat/Cool Tstat Connections - Single Tstat & Single Tfmr.......................25
25 – Heat Pump Tstat Connections - Single Tstat & Single Tfmr.....................25
26 – Constant Torque Motor Control Module Terminals ..................................30
27 – Constant Torque Blower Assembly .................................................................30
28 – Wiring Diagram - No Heat; C.T. Motor ............................................................30
29 – Wiring Diagram 3kW-10kW Electric Ht; C.T. Motor w/ Lockout.............32
30 – Wiring Diagram Hydronic Heat; C.T. Motor; No Water Pump.................33
31 – Wiring Diagram Hydronic Heat; C.T. Motor and Water Pump ................33
12 – Electrical Data – Electric and Hot Water Heat ............................................ 22
13 – Electric Heater Heating Capacity .................................................................... 22
14 – Low Voltage Wire Gauge and Maximum Lengths..................................... 23
15 – Thermostat Terminal Designations................................................................. 25
16 – Air Handler Low Voltage Pigtail Wire Colors & Connections ................. 26
17 – Typical Heating/Cooling Tstat Wire Colors & Connections..................... 26
18 – Typical Heat Pump Tstat Wire Colors & Connections ............................... 26
19 – 28 – Blower Performance..............................................................................28-29
29 – Constant Torque Motor Terminals - Electric Heat Models...................... 30
30 – Constant Torque Motor Terminals - Hydronic Heat Models .................. 30
1 – General............................................................................................................................1
2 – Safety, General, Dimensional & Model Number Nomenclature ................2
3 – Location and Clearances...........................................................................................6
4 – Return and Supply Air Requirements ..................................................................7
5 – Air Handler Installation..............................................................................................8
6 – Refrigerant Piping, TXV, Flowrator & Condensate Drain ........................... 10
7 – Hot Water and Chilled Water........................................................................................ 14
1. This air handler is rated at 208/240 VAC (electric heat) or 115 VAC
(hydronic heat), 60 Hertz, Single-Phase
2. This air handler is not designed to operate at 50 Hertz.
3. Air handler size varies by model.
4. This air handler is designed for both A/C and heat pump applications
5. Use 4-wire thermostat cable for heating/cooling
applications and 7-wire thermostat cable for heat pump applications.
6. This air handler is designed for horizontal applications only.
7. This air handler must not be operated without the access
panels installed.
8. This air handler and its components listed are listed by ETL for the
United States and Canada.
9. This air handler is for use at elevations of 10,000 ft (3,048m) or less.
10. This appliance is not to be used by persons (including children) with
reduced physical, sensory or mental capabilities, or lack of experience
and knowledge, unless they have been given supervision or instruction
concerning use of this appliance by a person responsible for their safety.
1 – CEHX/CCWE Dimensions........................................................................................4
2 – SEHX/SCWE Dimensions.........................................................................................5
3 – Clearance For Service Access ................................................................................7
5 – Return & Supply Duct Transitions........................................................................8
6 – Cased Air Handler Mounting ................................................................................9
7 – Piping for Air Handler Below Outdoor Unit ................................................. 10
8 – TXV Sensing Bulb Placement ............................................................................. 10
9 – TXV Sensing Bulb Location................................................................................. 10
10 – Typical TXV Connections ................................................................................... 12
11 – Flowrator Distributor Assembly....................................................................... 13
12 – SHL Temperature Sensor Location ................................................................. 13
13 – SHL Temperature Sensor Mounting............................................................... 13
14 – SHL Temperature Switch Wiring ...................................................................... 13
15 – Typical Condensate Trap..................................................................................... 14
16 – Condensate Drain Pan......................................................................................... 14
1 – CEHX/CCWE/CDXW/CCWW Dimensional Data..............................................4
2 – SEHX/SCWE/SDXW/SCWW Dimensional Data................................................5
3 – SEHX/CEHX/SCWE/CCWE Model Nomenclature ...........................................6
4 – Clearance to Combustibles....................................................................................6
5 – Optional Ceiling Access Panels.............................................................................8
6 – SCWW/CCWW Chilled Water Capacity 4&5 Row Coil – C.T .................... 16
7 – SCWE/CCWE Hot Water Capacity 4&5 Row Coil – C.T............................... 17
8 – SCWW/CCWW Chilled Water Capacity 4&5 Row Coil – C.T .................... 18
9 – SCWW/CCWW Hot Water Capacity 4 & 5 Row Coil – C.T......................... 19
10 – SCWW/CCWW Hot Water Capacity 2 Row HW Coil – C.T........................ 20
11 – SDXW/CDXW Hot Water Capacity 2 Row HW Coil – C.T.......................... 20
The following list includes important facts and information regarding this air handler.
Horizontal Air Handler Models:
SEHX - DX Cooling w/ Electric Heat, Uncased SDXW - DX Cooling w/ Hot Water Heat, Uncased
CEHX – DX Cooling w/ Electric Heat, Cased CDXW – DX Cooling w/ Hot Water Heat, Cased
SCWE – Chilled Water Cooling w/Electric Heat, Uncased-2P SCWW – Chilled Water Cooling w/Hot Water Heat, Uncased-4P
CCWE – Chilled Water Cooling w/Electric Heat, Cased-2P CCWW – Chilled Water Cooling w/Hot Water Heat, Cased-4P
9700771

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 2
Improper installation may create a condition where the
operation of the product could cause personal injury or
property damage.
Improper installation, adjustment, alteration, service or
maintenance can cause injury or property damage. Refer
to this manual for assistance; or for additional information
consult a qualified contractor, installer, or service agency.
FIRE OR ELECTRICAL HAZARD
Failure to follow the safety warnings exactly could result
in serious injury, death, or property damage.
A fire or electrical hazard may result causing property
damage, personal injury or loss of life.
This product must be installed in strict compliance with the
installation instructions and any applicable local, state, and
national codes including, but not limited to; building,
electrical, and mechanical codes.
Safety Requirements
This air handler must be installed in accordance with all national
and local building/safety codes and requirements, local plumbing
and waste water codes, and other applicable codes. In the
absence of local codes, install in accordance with the following
codes.
• Standard for the Installation of Air Conditioning and
Ventilating Systems (NFPA 90A)
• Standard for the Installation of Warm Air heating and Air
Conditioning Systems (NFPA 90B)
• National Electrical Code (NFPA 70)
• Canadian Electrical Code, Part I (CSA C22.2) or ANSI/NFPA
No. 70
• All local codes (State, City, and Township)
NOTE: All applicable codes take precedence over any
recommendation made in these instructions. SunTherm
assumes no responsibility for units installed in violation of any
code or regulation.
1. Refer to the air handler rating plate for the air handler model
number and refer to the dimensions page of this manual
for return air plenum dimensions for the applicable model
(see Figures 2 and 3 and Tables 9 and 10). The return air
plenum must be installed according to the above listed codes
or the instructions in this manual.
2. Refer to the dimensions page of these instructions to
determine the proper location to install the air handler.
3. This air handler is not ETL listed or approved for installation in
a manufactured (mobile) home.
4. Provide clearances from combustible materials as listed in the
LOCATION AND CLEARANCES section.
5. Provide clearances for service access panel to allow access
to the control box, electric heater elements, hot water coil,
and blower.
6. Power supply wiring and circuit breakers/fuses must be sized
for the electrical characteristics listed on the air handler rating
plate.
7. Failure to carefully read and follow all instructions in this
manual can result in malfunction of the air handler, death,
personal injury, and/or property damage.
8. Electric heat air handlers must be installed so the electrical
components are protected from water.
9. Installing and servicing heating/cooling equipment can be
hazardous due to electrical components.
10. Only trained and qualied personnel should install, repair, or
service heating/cooling equipment. Untrained service
personnel only perform basic maintenance functions such as
cleaning of exterior surfaces and replacing the air lters.
11. Observe all precautions shown in the manuals and on
labels attached to the air handler when servicing or
conducting maintenance tasks.
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFC’s and HFC’s) as of July 1, 1992. Approved
methods of reclaiming must be followed. Fines and/or
incarceration may be levied for non-compliance
This is a safety alert symbol. When you see this symbol on
labels or in manuals, be alert to the potential for personal
injury. Understand and pay particular attention to the signal
words DANGER, WARNING, or CAUTION.
DANGER: Indicates an imminently hazardous situation, which
if not avoided, will result in death or serious injury.
WARNING: Indicates a potentially hazardous situation, which
if not avoided, could result in death or serious injury.
CAUTION: Indicates a potentially hazardous situation, which
if not avoided, may result in minor or moderate injury.
It is also used to alert against unsafe practices and hazards
involving property damage.
SECTION 2: SAFETY, GENERAL, DIMENSIONAL & MODEL NUMBER NOMENCLATURE

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 3
12. These instructions cover minimum requirements and conform
to existing national standards and safety codes. In some cases,
these instructions exceed certain local codes and ordinances,
especially those who have not kept up with changing home
construction practices. These instructions are to be followed
and are the minimum requirement for a safe installation.
13. The capacity of the air handler should be based on an
acceptable heat loss calculation for the structure such as
ACCA Manual J or other approved methods.
14. 115 VAC models must be connected to a nominal 115 VAC,
Single-Phase, 60-Hertz power supply. DO NOT CONNECT
THIS APPLIANCE TO A 50 HZ POWER SUPPLY OR VOLTAGE
ABOVE 132 VOLTS OR BELOW 98 VOLTS.
15. 208/240 VAC models must be connected to a nominal 208
or 240 VAC, Single-Phase, 60-Hertz power supply. DO NOT
CONNECT THIS APPLIANCE TO A 50 HZ POWER SUPPLY OR
VOLTAGE ABOVE 253 VOLTS OR BELOW 187 VOLTS.
16. Ground wire connections must be securely fastened to the
ground lugs inside the control box.
17. Ductwork must be installed in accordance with the standards
of the National Fire Protection Association (NFPA) Warm Air
Heating and Ventilation Systems (NFPA Standards 90A and
90B). The air distribution duct should be sized for 0.2 inches
of static pressure. See Air Conditioning Contractors of America
(ACCA) Manual D for duct sizing.
18. The safety testing label appearing on this air handler covers
the air handler and the factory installed coil only. It does not
cover any other equipment.
19. Exterior surface of the cabinet may sweat when installed in a
non-conditioned space such as an attic or garage. Installer
must provide protection for the building structure such as
a full size auxiliary drain pan under all air handlers installed in
the non-conditioned space. The auxiliary drain pan is needed
to prevent building damage from condensation runo from
the unit casing.
20. Cabinet insulation used in this air handler is rated for R-2.1
(standard) and is ½”thick. Some jurisdictions require R-4.2 or
R-6.0 on installations in a non-conditioned spaces. Add 1”thick
insulation to the exterior casing of the air handler to comply in
these jurisdictions and add a vapor barrier on the outside of
the added insulation.
ALWAYS SHUT OFF ELECTRICITY AT THE DISCONNECT
SWITCH OR TURN OFF THE CIRCUIT BREAKERS IN THE MAIN
ELECTRICAL ENTRANCE BEFORE PREFORMING ANY SERVICE
ON THE APPLIANCE.
GENERAL INFORMATION
This air handler provides the flexibility for installation in any
horizontal application and may be used with or without electric
heat or hydronic heat. The direct-drive three 3-speed PSC motor
or 5-speed constant torque motor is capable of providing
sufficient air flow for most applications. Return air may enter the
bottom or end of a cased air handler.
Inspection
As soon as the air handler is received, it should be inspected
for damage that may have occurred during transit. If shipping
damage is found, the extent of the damage should be noted
on the carrier’s freight bill. A separate request for inspection by
the carrier’s agent should be made in writing. Before installing
the air handler, check the cabinet for screws or bolts which may
have become loose during transit. Some air handler models
have shipping supports for the blower motor shaft. Remove this
support before operating the air handler unit.
See the local wholesale distributor for more information. Mortex
Products, Inc assumes no liability for freight damage.

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 4
Figure 1: CEHX/ CCWE/ CDXW/ CCWW Dimensions - DX or Chilled Water Cooling With or Without Electric Heat
Table 1: CEHX/ CCWE/ CDXW/ CCWW Dimensional Data
Model Number Physical Dimensions
A B C D E F G H
CEHX / CCWE / CDXW / CCWW - 18 41 2.625 7.125 4 3 5.25 2.625 3.75
CEHX / CCWE / CDXW / CCWW - 19 41 2.625 7.125 4 3 5.25 2.625 3.75
CEHX / CCWE / CDXW / CCWW - 24 41 2.625 7.125 4 3 5.25 2.625 3.75
CEHX / CCWE / CDXW / CCWW - 25 47 2 10.5 2.5 1.5 4.625 2 2.6875
CEHX / CCWE / CDXW / CCWW - 30 47 2 10.5 2.5 1.5 4.625 2 2.6875
CEHX / CCWE / CDXW / CCWW - 31 47 2 10.5 2.5 1.5 5.875 2 2.6875
CEHX / CCWE / CDXW / CCWW - 34 53.5 3.25 13.75 3.25 2.75 5.875 3.25 3.9375
CEHX / CCWE / CDXW / CCWW - 35 53.5 3.25 13.75 3.25 2.75 5.875 3.25 3.9375
CEHX / CCWE / CDXW / CCWW - 36 60.5 3.25 17.5 3.25 2.75 5.875 3.25 3.9375
CEHX / CCWE / CDXW / CCWW - 37 60.5 3.25 17.5 3.25 2.75 5.875 3.25 3.9375

Model Number Physical Dimensions
Liquid Line Suction
Line
Evap. Rows A B C Ship
Weight
SEHX / SCWE / SDXW / SCWW - 18 3/8 3/4 3 37 34.25 30 60
SEHX / SCWE / SDXW / SCWW - 19 3/8 3/4 4 37 34.25 30 65
SEHX / SCWE / SDXW / SCWW - 24 3/8 3/4 3 37 34.25 30 60
SEHX / SCWE / SDXW / SCWW - 25 3/8 3/4 4 45 42.25 38 75
SEHX / SCWE / SDXW / SCWW - 30 3/8 3/4 3 45 42.25 38 70
SEHX / SCWE / SDXW / SCWW - 31 3/8 3/4 4 45 42.25 38 75
SEHX / SCWE / SDXW / SCWW - 34 3/8 3/4 3 49 46.25 42 74
SEHX / SCWE / SDXW / SCWW - 35 3/8 3/4 4 49 46.25 42 80
SEHX / SCWE / SDXW / SCWW - 36 3/8 3/4 3 56 53.25 49 85
SEHX / SCWE / SDXW / SCWW - 37 3/8 3/4 4 56 53.25 49 90
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 5
Figure 2: SEHX/ SCWE/ SDXW/ SCWW Dimensions - DX or Chilled Water Cooling With or Without Electric Heat
Table 2: SEHX/ SCWE/ SDXW/ SCWW Dimensional Data

MOTOR & BLOWER CODE
80 - 1/3 HP, 208/240V, Constant Torque Mtr; (2) 7.00” x 8.00” Blowers (High EFF.)
81 - 1/2 HP, 208/240V, Constant Torque Mtr; (2) 7.00” x 9.00” Blowers (High EFF.)
82 - 1/3 HP, 115V, Constant Torque Mtr; (2) 7.00” x 8.00” Blowers (High EFF.)
83 - 1/2 HP, 115V, Constant Torque Mtr; (2) 7.00” x 9.00” Blowers (High EFF.)
UNIT VOLTAGE
A - 115/1/60
C - 208/240/1/60
TIME DELAY RELAY
0 - No TDR (not required, blower time delay
built into constant torque motor)
ORIFICE OR EXPANSION VALVE NUMBER
D - TXV4-A (E410A 1.5 to 2.5 Ton)
Y - TXV4-A (R410A 3.0 Ton)
4 - 4 Row Chilled Water Coil (CW)
5 - 5 Row Chilled Water Coil (CW)
HEATING CAPACITY
03 - Electric Heat Capacity in kW
26 - Hot Water Heat Capacity in M/BTUH
TONS
Nominal Cooling BTUH
TYPE
EHX - DX Coil and Electric Heat
CWE - Chilled Water Coil and Electric Heat
DXW - DX Coil and Hot Water Heat
CWW - Chilled Water Coil and Hot Water Heat
SERIEC
S - Horizontal Firdown Unit Uncased
C - Horizontal Firdown Unit Cased
S E D 0 C 7924 03EHX
Expansion Device Code
E = Expansion Valve (DX)
2 = 2 Pipe Chilled Water (CW)
4 = 4 Pipe Chilled Water (CW)
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 6
Table 3: SEHX/CEHX/SCWE/CCWE/SDXW/CDXW/SCWW/CCWW Model Number Nomenclature
Location
Access for servicing is an important factor when selecting the
location of an air handler. Provide a minimum of 30 inches under
the air handler for access to the control box, heating elements,
water pump, blower, and air filters. The air handler can be serviced
entirely from the bottom, including replacing the air filter on
models equipped with a louvered ceiling access panel with an
integrated filter rack.
NOTE: The air handler is designed for horizontal applications only
and is therefore not designed to be installed in a closet or flush
mounted in a wall in an upflow vertical position.
Location is usually predetermined. Check with the homeowner
or general contractor for predetermined installation plans. If
location has not been decided, consider the following in choosing
a suitable location.
1. Select a location with adequate structural support, space for
service access, and clearance for return and supply duct
connections. The air handler is designed to fit in a 12” high drop
down space (furred-in area).
2. Normal operating sound levels may be objectionable if the air
handler is placed directly over or under some rooms such as
bedrooms, study, etc.
3. Locate the air handler where the supply and return air ducts can
provide even air distribution to and from the living spaces.
4. Locate the air handler where the electrical supply wiring can
be easily routed from main electrical panel to the air handler
and where electrical wiring will not be damaged.
5. Supply power wiring may be installed in a flexible conduit
or armored cable. The installer must refer to National Electrical
Code (NFPA 70), Canadian Electrical Code, Part I (CSA C22.2),
ANSI/NFPA No. 70 and/or any local codes to ensure supply
wiring complies with all applicable codes.
6. Locate appliance where thermostat wiring can be easily
routed from the thermostat to the air handler and where the
wiring will not be damaged. Make sure the wiring has enough
length so it will not to block access to any components that
may need to be replaced or serviced.
7. Locate the air handler where refrigerant lines can be easily
routed from the air handler to the outdoor unit.
8. Primary and secondary drain lines must be routed so air filter
replacement is not obstructed.
9. The blow-thru design of this air handler will cause the exterior surface
of cabinet to sweat when installed in a non-conditioned space such
as an attic or garage. The installer must provide protection such
as a full size auxiliary drain pan under any unit installed in a non
conditioned space to prevent damage to the building structure from
condensation runoff.
Clearances
This air handler is approved for 0 inches of clearance to
combustible material on any part of the air handler exterior
casing and the inlet or outlet ducts (See Table 12). A clearance
of 30 inches below the air handler is required for the service
access panel to swing open (See Figure 3).
SECTION 3: LOCATION AND CLEARANCES
Top
(inches)
Back
(inches)
Sides
(inches)
Supply Duct
(inches)
0 0 0 0
Table 4: Clearance to Combustibles

NON-METALLIC RETURN DUCTS MAY NOT BE ALLOWED IN
SOME STATES, COUNTIES, OR CITIES.
CHECK ALL STATE, LOCAL AND FIRE CODES TO DETERMINE
IF NON-METTALIC RETURN DUCTS ARE ALLOWED.
FIRE HAZARD:
NON-METALIC DUCTS CAN COLLECT DUST AND DEBRIS
WHICH CAN RESULT IN A FIRE HAZARD. BE SURE TO
THOROUGHLY CLEAN THE DUCT SYSTEM ANNUALLY TO
REMOVE ALL DUST AND DEBRIS.
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 7
SECTION 4: RETURN AND SUPPLY AIR REQUIREMENTS
RETURN AIR REQUIREMENTS
Provisions shall be made to permit air in the conditioned space to
return to the air handler. Failure to provide means for adequate
return air will result in reduced airflow through the air handler
causing improper heating and cooling of the living space.
Reduced airflow may also cause the cooling coil to freeze up and
the electric heat limit(s) to cycle, resulting in premature heating
element failure.
Uncased Air Handler – Return Air
If a louvered service access panel with an integral filter (See Figure
4) is not used, a return air duct should be routed between the
ceiling joists from the furred-in area around the air handler to a
return air filter grille located in the ceiling. The return air grille
must never be located in a closet.
NOTE: The return air must be filtered to prevent a buildup of lint,
dust, and debris on the coil surface.
Cased Air Handler – Return Air
A cased air handler can utilize a louvered ceiling access panel
with an integral filter (See Figure 4) as a means of returning the
conditioned air from the conditioned space to the air handler.
A cased air handler may also utilize a non-louvered ceiling access
panel with a return air duct attached to the return air opening in
the air handler. If a return air duct is used, the return air opening
knock-out must be removed to allow the return air to enter the
air handler through the return air opening. The return air duct
may consist of an elbow that drops directly into a return air filter
grille in the ceiling or the return duct may be routed between the
ceiling joists to a return air filter grille located in the ceiling away
from the air handler.
NOTE: The return air must be filtered to prevent a buildup of lint,
dust, and debris on the coil surface.
Return Air Filter Location
Horizontal air handlers are not factory equipped with an air filter.
The air filter can be installed in the filter rack of the louvered
ceiling access panel (See Figure 4 and Table 13) or it may be
located remotely in a ceiling mounted return air filter grille. If
a return duct and return air filter grille is used, a non-louvered
ceiling access panel will be required.
The louvered ceiling panel air filter size for the SEHX, CEHX, SCWE
and the CCWE models is 20”x 20” x 1”.
The recommended minimum filter sizes for a return air filter grille
is shown below.
Standard Throw-Away Air Filter @ 300 ft/min or Less
600 CFM = 16”x 20”x 1”
700 CFM = 20”x 20”x 1”
800 CFM = 20”x 20”x 1”
900 CFM = 20”x 24”x 1”
1000 CFM = 20”x 24”x 1”
NOTE: Pleated filters are not recommended due to their higher
pressure drop.
Figure 3: Clearance for Service Access
Figure 4: Ceiling Access Panel

Extreme caution must be taken that no internal damage will
result if screws or holes are drilled into the cabinet.
The air handler and enclosure must be covered during the
drywall installation, texturing, and painting process to
prevent spray and debris from collecting on and entering
the air handler and enclosure.
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 8
IMPACT HAZARD
Use extreme caution when removing the ceiling
access panel screws. The panel is secured to the
frame assembly with the thumb screws. Once the
thumb screws have been removed, the ceiling
access panel will swing down rapidly and can
injure anyone standing underneath the panel. The
panel must be supported from underneath as it
swings downward to prevent injury.
The louvers can also have sharp edges which can
cut hands or fingers. Wearing gloves is recommended
when servicing the horizontal air handler.
Table 5: Optional Ceiling Access Panels
Figure 5: Supply and Return Duct Transitions
USING A DUCTED RETURN WILL RESULT IN QUIETER
OPERATION THAN USING A LOUVERED CEILING ACCESS
PANEL USED FOR RETURN AIR.
Part
Number
Overall
Frame
Dimensions
Type SunTherm Horizontal Fan Coil Models Ship
Weight
CPL1 27.5 x 43 Louvered SCWE/CCWE/SDXW/CDXW/CCWW-12,
SCWE/CCWE/SDXW/CDXW/CCWW-18
SCWE/CCWE/SDXW/CDXW/CCWW-19,
SCWE/CCWE/SDXW/CDXW/CCWW-24,
SCWE/CCWE/CCWW-25
18
CPNL1 27.5 x 43 Non-Louvered 18
CPL2 27.5 x 49 Louvered SCWE/CCWE/SDXW-25
SCWE/CCWE/SDXW/CDXW/CCWW-30,
SCWE/CCWE/SDXW/CDXW/CCWW-31
20
CPNL2 27.5 x 49 Non-Louvered 20
CPL3 27.5 x 55.5 Louvered SCWE/CCWE/SDXW/CDXW/CCWW-34,
SCWE/CCWE/SDXW/CDXW/CCWW-35
21
CPNL3 27.5 x 55.5 Non-Louvered 21
CPL4 27.5 x 62.5 Louvered SCWE/CCWE/SDXW/CDXW/CCWW-36,
SCWE/CCWE/SDXW/CDXW/CCWW-37
22
CPNL4 27.5 x 62.5 Non-Louvered 22
SUPPLY AIR REQUIREMENTS
The horizontal air handler can be mounted into the ceiling to
allow horizontal left supply air flow or horizontal right supply air
flow. The supply air plenum is attached and secured to the air
handler duct flanges using screws. Use a non-tape sealant such
as mastic or an aerosol sealant to seal the plenum to the air
handler to prevent air leakage. The supply plenum must be the
same size as the supply air opening.
The entire supply duct system must be designed for a total of
0.20”W.C. static pressure drop or less and each individual duct
must be sized to deliver the proper amount of air to each room
of the conditioned space. Holes cut in the supply plenum for
ducts must be the same size as the supply ducts. Use a duct
starting collar to attach the ducts to the plenum. Use a non-tape
sealant such as mastic or an aerosol sealant to seal the ducts to
the plenum to prevent air leakage.
If the supply duct system is installed in an non-conditioned space,
the duct system must be insulated and installed in accordance
with local codes.
SECTION 5: AIR HANDLER INSTALLATION
Ceiling Installation
The area in the ceiling where the air handler is to be located
should have a framed in structure so the air handler can be
properly mounted and secured. The inside height of the area
must be 12 inches. Prior to installing the air handler, holes must
be cut into the frame for the refrigerant tubing, drain line(s),
electrical wiring, thermostat wiring, and outdoor unit control
wiring to enter the air handler. The air handler must be level in
both directions to allow proper condensate drainage.
NOTE: Cased air handlers require return and supply
transition ducts to assure proper airflow. Uncased air
handlers only require a supply duct transition. See Figure 5
below for factory recommendations.

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 9
Cased Air Handler
The following steps are required to properly install a cased
air handler.
1. Remove the top shipping cover and corner posts.
2. Remove the bottom shipping cover.
3. Use screws to secure the 4 straps to the ceiling joists where
the air handler will be installed (See Figure 6). The straps must
be located so the hooks in the straps line up with the slots in
the base of the air handler.
4. Raise the air handler into place and place the hooks into the
slots in the base. Bend the hooks back to keep the hooks from
slipping out of the slots in the base.
5. Connect the supply air plenum to the air handler supply air
duct flanges as described in SUPPLY DUCT REQUIREMENTS
found in SECTION 3 of these instructions.
6. New Installations Only:
a. If a non-louvered ceiling access panel is being used, connect
the return air duct to the air handler as described in
RETURN AIR REQUIREMENTS / Cased Air Handler found in
SECTION 3 of these instructions.
b. After the air handler is mounted, a 2x2 or 2x4 frame must be
installed around the base of the air handler to create an air
tight seal and support the ceiling access panel frame.
c. Install the ceiling access panel.
NOTE: The ceiling access panel is sold separately. It is not
included with the air handler.
7. Remove the thumb screws that secure the ceiling access panel
and slowly swing the panel down.
8. Remove the control box cover.
9. Connect the electrical supply wires and the thermostat control
wires to the appropriate terminal block and pigtails in the
control box as described in SECTIONS 8 and 9 of these
instructions.
NOTE: An ON/OFF switch must be installed in the supply
circuit to disconnect the power to the air handler during
servicing. The switch must be easily accessible and clearly
identified.
10. Connect the refrigerant lines or chilled water lines to the coil
as described in SECTIONS 6 and 7 of these instructions.
Figure 6: Cased Air Handler Mounting
11. Make the necessary blower motor speed changes as described
in SECTION 10 of these instructions.
12. Install the control box cover.
13. Raise the ceiling access panel into place and secure with the
thumbscrews.
14. Turn the power on to the unit by following the procedure
found in SECTION 11 of these instructions and in the Users
Information Manual to place the air-handler into service.
15. Set the thermostat to the desired operating mode and
temperature.
Uncased Air Handler
The following steps are required to properly install an uncased
air handler.
1. Remove the top shipping cover and corner posts.
2. Remove the screws from the control box cover and remove
the cover.
3. Remove the bottom shipping cover.
4. Raise the air handler into place and install the lag bolts with
washers through the slots in the top cover. Tighten the lag
bolts until the air handler is securely fastened to the ceiling.
5. Connect the supply air plenum to the air handler supply air
duct flanges as described in SUPPLY DUCT REQUIREMENTS
found in SECTION 3 of these instructions.
6. New Installations Only:
a. If a non-louvered ceiling access panel is being used,
install the return air duct as described in RETURN AIR
REQUIREMENTS / Uncased Air Handler found in SECTION 3
of these instructions.
b. After the air handler is mounted, a 2x2 or 2x4 frame must
be installed around the base of the air handler to create an
air-tight seal and support the ceiling access panel frame.
c. Install the ceiling access panel.
NOTE: The ceiling access panel is sold separately. It is not
included with the air handler.
7. Remove the thumb screws that secure the ceiling access
panel and slowly swing the panel down.
8. Remove the control box cover.
9. Connect the electrical supply wires and the thermostat
control wires to the appropriate terminal block and pigtails
in the control box as described in SECTIONS 8 and 9 of
these instructions.
NOTE: An ON/OFF switch must be installed in the supply
circuit to disconnect the power to the air handler during
servicing.

CONDENSING UNIT
LIQUID LINE
SUCTION LINE
EVAPORATOR COIL
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 10
SECTION 6: REFRIGERANT PIPING, TXV,
FLOWRATOR, CONDENSATE DRAIN
DX Cooling / Chilled Water Cooling
DX Refrigerant Piping:
Air handlers with DX type evaporator coils require liquid and
suction piping sized in accordance with the outdoor unit
manufacturer’s instructions. The DX coil has sweat copper
connections. Refrigerant lines should be soldered with silver
solder or high temperature brazing alloy. The suction line must
be insulated to prevent condensate from forming and dripping
off. Armaflex (or equivalent) with 3/8” (1 cm) minimum wall
thickness is recommended. In severe conditions, such as hot
or high humidity areas, insulation with 1/2”(1.3 cm) minimum
wall thickness may be required. If the outdoor unit is installed
above air handler, oil traps are required at equal intervals along
suction line (See Figure 7). Horizontal suction lines should slope
downward 1 inch for every 20 feet toward the outdoor unit.
Flow dry nitrogen through refrigerant lines during the soldering
operation to prevent oxidation of the inside surface of the
copper tubing which can result in debris plugging the TXV or
orifice screen.
• Install 1 oil trap for a height difference of 15 ft to 25 ft
(4.6 m to 7.6 m) between indoor and outdoor units.
• Install 2 oil trap for a height difference of 26 ft to 50 ft
(7.9 m to 15.2 m) between indoor and outdoor units.
• Install 3 oil trap for a height difference of 51 ft to 100 ft
(15.5 m to 39.5 m) between indoor and outdoor units.
• Install 4 oil trap for a height difference of 101 ft to 150 ft
(30.8 m to 45.7 m) between indoor and outdoor units.
Figure 7: Piping for Air Handler Below Outdoor Unit
Figure 8: TXV Sensing Bulb Placement
SPECIAL INSTRUCTIONS FOR COILS WITH
THERMAL EXPANSION VALVES (TXV)
The thermal expansion valve (TXV) used in this air handler has a
built-in check valve making it heat pump capable. The external
equalizer line attached to the TXV has a female flare nut with built
in Schrader valve depressor that attaches to the Schrader valve
port located on the coil suction manifold.
Figure 9: TXV Sensing Bulb Location
The best location for the TXV sensing bulb is on a horizontal
section of the suction line tube and positioned between 10
o’clock and 2 o’clock on the tube. (See Figures 8 and 9).
NOTE: The sensing bulb must never be located at the bottom of
the suction line due to the possibility of oil and refrigerant laying
in the bottom of the pipe causing false signals.
The sensing bulb must be able to sense the temperature of the
superheated suction vapor and must therefore not be located in
a position that will expose it to extraneous heat/cold. The sensing
bulb must be insulated to isolate it from the surrounding air. The
TXV must be the proper size and type to achieve the performance
ratings of the system.
NOTE: If a non-bleed type TXV is used, the outdoor unit may
require a hard start kit to allow the compressor to start under load.
How the TXV Controls Superheat
The TXV is a precision device designed to regulate the rate at
A TXV has a thermostatic element separated from the valve body
by a diaphragm designed to regulate the rate at which refrigerant
flows into the evaporator.