Suntherm MSVT Series User manual

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 1
Multi-Position DX and Chilled Water-Cooling with Electric Heating
MODELS: MSVT Series With Single-Stage Cooling/Heat Pump Air-Flow
MSVE Series With Single or Two-Stage Cooling/Heat Pump Air-Flow
INSTALLATION MANUAL
SAVE THIS MANUAL FOR FUTURE REFERENCE
8 – Field Installed Electric Heater Kits .....................................................16
9 – Thermostat Wiring and Connections ..............................................17
10 – Blower Performance ..............................................................................21
11 – Motor Speed Selection and Air Handler Startup.........................22
12 – Final System Checkout..........................................................................23
13 – Wiring Diagrams......................................................................................24
19 – Low Voltage Connections: 1-Stage Heat & 1-Stage Cooling..........18
20 – Low Voltage Connections: 1-Stage Heat & 1-Stage HP ....................18
21 – Low Voltage Connections: 2-Stage Heat & 1-Stage Cooling..........19
22 – Low Voltage Connections: 2-Stage Heat & 1-Stage HP ....................19
23 – Constant Torque Motor Terminals ..............................................................22
24 – ECM Control Board Layout.............................................................................22
25 – ECM Motor Control Plug Pin Positions .....................................................22
26 – Wiring Diagram:MSVE 18-72; ECM Mtr; No Electric Htr ...................24
27 – Wiring Diagram:MSVE 18-72; ECM Mtr; 5 kW Electric Htr...............24
28 – Wiring Diagram:MSVE 25-72; ECM Mtr; 10 kW Electric Htr ............25
29 – Wiring Diagram:MSVE 37-72; ECM Mtr; 15 kW Electric Htr ............25
30 – Wiring Diagram:MSVE 42-72; ECM Mtr; 20 kW Electric Htr ............26
31 – Wiring Diagram:MSVT 18-72; C.T. Motor; No Electric Htr................26
32 – Wiring Diagram:MSVT 18-72; C.T. Motor; 5kW Electric Htr.............27
33 – Wiring Diagram:MSVT 18-72; C.T. Mtr; 10kW Electric Htr................27
34 – Wiring Diagram:MSVT 36-72; C.T. Mtr; 15kW Electric Htr ...............28
35 – Wiring Diagram:MSVT 37-72; C.T. Mtr; 20kW Electric Htr................28
11 – Electric Heater Kit Model Numbers .................................................. 16
12 – Accessory Heater Kit Model Number Nomenclature................. 17
13 – Low Voltage Wire Gauge and Maximum Lengths....................... 17
14 – Typ Heat/Cool T-stat Wire Colors & Low Voltage Connections.. 19
15 – Typ Heat PumpT-stat Wire Colors & Low Voltage Connections ..... 19
16 – Blower Performance – Constant Torque Motors.......................... 21
17 – Blower Performance – ECM Motors.................................................. 21
18 – Constant Torque Motor Terminal Connections............................ 22
19 – ECM Motor Control Connector Terminal Descriptions.............. 23
1 – General...........................................................................................................1
2 – Safety..............................................................................................................2
3 – Location, Clearances and Return Air Requirements......................7
4 – Air Handler Orientation, Supply Air Duct, & Return Air Filters...8
5 – Installing the Air Handler...................................................................... 10
6 – Refrigerant Piping, TXV, and Condensate Piping......................... 10
7 – Line Voltage Wiring.................................................................................12
1. Air handler is rated for 208/240 VAC at 60 Hertz.
2. Air handler size varies by model.
3. Air handler is designed for A/C or heat pump operation.
4. Air handler is designed for upow, downow and
horizontal applications.
5. Air handler must not be operated with the access
panels removed.
6. Air handler is listed by ETL in the United States and Canada.
1 – Dimensional Data DX Cool With & Without Electric Heat ............5
2 – Dimensional Data Chilled Water With & Without Electric Heat 6
3 – Clearance – Access for Service...............................................................7
4 – Closet Clearances .......................................................................................7
5 – Air Filter Base Accessory for 1”or 2” Air Filters .................................8
6 – Indoor Coil Disassembly When Converting to Downow...........9
7 – Indoor Coil Assembly When Converting to Downow.................9
8 – Combustible Floor Base Installation....................................................9
9 – Indoor Coil Below Outdoor Unit Piping.......................................... 10
10 – Typical TXV Connections...................................................................... 10
11 – TXV Sensing Bulb Location.................................................................. 11
12 – TXV Bulb Placement............................................................................... 11
13 – Typical Condensate Trap....................................................................... 12
14 – Component Locations – Electric Heat Control Box .................... 15
15 – Component Locations – No Heat Control Box ............................. 15
16 – Control Box Circuit Breaker Locations............................................. 15
17 – Circuit Breaker Location on Front Panel ......................................... 15
18 – Cabinet Wiring Entrances ...............................................................................17
1 – Air Handler Model Specications.........................................................3
2 – Air Handler Model Number Nomenclature.......................................4
3 – Dimensional Data DX Cooling With or Without Electric Heat ....5
4 – Dimensional Data Chilled Water With or Without Electric Heat 6
5 – Clearances to Combustibles...................................................................7
6 – Electrical Data: 18-36 kBTU–Single Branch Circuit...................... 13
7 – Electrical Data: 37-72 kBTU–Single Branch Circuit...................... 13
8 – Electrical Data: 25-36 kBTU–Dual Branch Circuit ......................... 14
9 – Electrical Data: 37-72 kBTU–Dual Branch Circuit ......................... 14
10 – Electric Heater Heating Capacities ................................................... 14
The following list includes important facts and information regarding the air handler models covered in this manual.
LIST OF SECTIONS
LIST OF FIGURES
LIST OF TABLES
SECTION 1: GENERAL

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 2
This is a safety alert symbol. When this symbol is seen 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.
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 qualied 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 re 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.
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.
MS Series Multi-Position Air Handler
Safety Requirements
This appliance should be installed in accordance with all
national and local building/safety codes and requirements,
local plumbing or 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 unit rating plate for the air handler model
number, and then see the dimensions page of this
instruction for return air plenum dimensions in Figures 1
and 2. The plenum must be installed according to the above
listed codes or the instructions in this manual.
2. Refer to the dimensions page of this instruction and the duct
connector and combustible oor base dimensions shown in
Figure 9 for the proper duct connector or combustible oor
base for downow applications. The duct connector and
combustible oor base must be installed according to the
instructions in this manual.
3. These models are not ETL listed or approved for
installation into a Manufactured (Mobile) Home.
4. Provide clearances from combustible materials as listed
under Clearances to Combustibles.
5. Provide clearances for servicing ensuring service access is
allowed for the control box, electric elements, hot water
coil and the blower.
6. Check the rating plate and the power supply to be sure the
electrical characteristics match.
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 air handler shall 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
SECTION 2: SAFETY

Always shut o electricity at the disconnect switch or turn
o the circuit breakers in the main electrical panel before
performing any service on this air handler.
Models MS**18,24 MS**25,30,36 MS**37,42,48,60 MS**72
Available Electric Heat kW 5,10 5,10,15 5,10,15,20 5,10,15,20
Blower Size (D x W) 9 x 6 (MSVE)
10 x 7 (MSVT)
10 x 7 (MSVE)
10 x 8 (MSVT)
12 x 9
(MSVE & MSVT)
12 x 10
(MSVE & MSVT)
Unit Voltage 208/240V, 60 HZ, 1 PH
Max. External SP (Duct), In. W.C. 0.50
Thermostat Circuit 24 VAC,60 Hz, 40VA
Available Blower Motors
1. 5 SPD CONSTANT TORQUE MOTOR
2. VARIABLE SPEED ECM MOTOR
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 3
service heating/cooling equipment. Untrained service
personnel can perform basic maintenance functions such as
cleaning of exterior surfaces and replacing the air lters.
Observe all precautions in the manuals and on the attached
labels when working on this appliance.
11. These instructions cover minimum requirements and
conform to existing national standards and safety codes. In
some instances, these instructions exceed certain local
codes and ordinances, especially those who have not
kept up with changing home and/ or HUD construction
practices. These instructions are to be followed and are the
minimum requirement for a safe installation.
12. The size of the unit should be based on an acceptable heat
loss calculation for the structure. ACCA, Manual J or other
approved methods may be used.
13. Check the rating plate and power supply to be sure that the
electrical characteristics match. This air handler must be
connected to a nominal 208/240 VAC, 1 Phase, 60-Hertz
power supply. DO NOT CONNECT THIS AIR HANDLER TO A
50 HZ POWER SUPPLY OR A VOLTAGE ABOVE 250 VOLTS.
14. Ground connections must be securely fastened to the
control box and ground wires must be secure.
GENERAL INFORMATION
This single piece air handler provides the exibility for
installation in any upow, downow, or horizontal application.
The versatile models may be used with or without electric heat
or hot water heat. The direct-drive variable speed ECM and
5-speed constant torque motors provide a selection of
air-ow volume to match any application. The air handler can
be positioned for bottom air return in the upow position, top
air return in the downow position, or air return through the
end of the air handler in the horizontal position.
NOTE: Refer to the instructions in this manual for the proper
downow conversion kit and instructions on the proper
conversion to downow.
Inspection
As soon as the air handler is received, it should be inspected for
possible damage during transit. If damage is evident, 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, you should
check the cabinet for screws or bolts which may have loosened
in transit. There are no shipping or spacer brackets which need
to be removed before startup.
See local distributor for more information. Mortex Products, Inc
assumes no liability for freight damage.
Also check to be sure all accessories such as heater kits, and
coils are available. Installation of these accessories should
be accomplished before the air handler is set in place or the
connecting of the wiring, electric heat, ducts or piping.
Table 1: Air Handler Model Specications

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 4
MODEL NUMBER NOMENCLATURE
MS VT 36 15 B 862T AA
I II III IV V VI VII
ISeries
MS = Multi-Position Single-Piece
II
Motor Type
VT = Variable Constant Torque
VE = Variable Speed ECM
III
Unit Size (Capacity in MBTUH)
12 through 24 - Small Cabinet
25 through 36 - Medium Cabinet
37 through 72 - Large Cabinet
OS = No Cooling Small Cabinet
OM = No Cooling Medium Cabinet
OL = No Cooling Large Cabinet
IV
Heating Conguration
00 = Cooling Only
05 = 5 kW Electric Heating Capacity
10 = 10 kW Electric Heating Capacity
15 = 15 kW Electric Heating Capacity
20 = 20 kW Electric Heating Capacity
VAir Handler Voltage
B = 208/240
VI
SUMMIT Evaporator Coil Conguration
862T = DX Coil Geometry And Metering Device
8K2N = CW Coil Geometry, No Metering Device
VII Option Code
AA = Standard Factory Options
Table 2: Electric Heat Air Handler Model Number Nomenclature

DIMENSIONAL DATA MULTI-POSITION AIR HANDLER COOL ONLY OR ELECTRIC HEAT
Model A B C D E F G H J K L M N P R S T
MS**18, 24 17.50 43.00 21.00 15.63 12.50 13.50 11.00 6.75 16.75 14.00 11.00 10.75 2.00 1.50 5.00 16.10 20.20
MS**25, 30, 36, 38, 46 21.00 48.00 21.00 19.00 12.50 14.50 13.00 6.75 20.00 17.00 12.75 10.30 2.30 4.35 5.00 19.90 20.80
MS**37, 42, 48, 60, 72 24.50 58.88 21.75 22.25 14.25 19.75 17.25 6.75 26.00 23.00 16.75 14.35 2.30 4.35 4.50 23.50 20.70
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 5
Figure 1: Dimensional Data DX Cooling With Or Without Electric Heat
Table 3: Dimension Data - DX Cooling With & Without Electric Heat

DIMENSIONAL DATA MULTI-POSITION AIR HANDLER COOL ONLY OR ELECTRIC HEAT
Model A B C D E F G H J K L M N P R S T
MS**18, 24 17.50 43.00 21.00 15.63 12.50 13.50 11.00 6.75 16.75 14.00 11.00 10.75 2.00 1.50 5.00 16.10 20.20
MS**25, 30, 36, 38, 46 21.00 48.00 21.00 19.00 12.50 14.50 13.00 6.75 20.00 17.00 12.75 10.30 2.30 4.35 5.00 19.90 20.80
MS**37, 42, 48, 60, 72 24.50 58.88 21.75 22.25 14.25 19.75 17.25 6.75 26.00 23.00 16.75 14.35 2.30 4.35 4.50 23.50 20.70
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 6
Table 4: Dimensional Data - Chilled Water With And Without Electric Heat
Figure 2: Dimensional Data Chilled Water With And Without Electric Heat

MODEL TOP (in) BACK (in) SIDES (in) FRONT OF FURNACE DUCT (in)
ALCOVE (in) CLOSET (in)
ELECTRIC 0 0 0 30 6 1
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 7
LOCATION
Access for servicing is an important factor in the location of
any air handler. Provide a minimum of 30 inches in front of the
appliance for access to the control box, heating elements, water
pump, blower and air lters. This access may be provided by a
closet door or by locating the appliance so that a wall or partition
is not less than 30 inches from the front access panel. As the
location is usually predetermined, check with owner’s or dealer’s
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, clearance for return and supply duct connections.
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. It is best to locate the air handler so that supply air ducts are
about the same length and the return air ducts are about the
same length to provide even air distribution of supply and
return air to and from the living spaces.
4. Locate appliance where electrical supply wiring can be easily
routed to main electrical panel and where electrical wiring will
not be damaged.
5. Locate appliance where thermostat wiring can be easily routed
to the thermostat and where the wiring will not be damaged.
6. Locate appliance where refrigerant lines can be easily routed
from the indoor coil to the outdoor unit.
7. Locate the appliance where condensate lines can be easily
routed to an available drain or outside. Be sure to route
condensate drain piping so as not to obstruct access to the air
lter.
8. When the coil is installed in a draw-through conguration as in
this air handler, a negative pressure is created in the condensate
drain system. To assure proper condensate drainage and to
prevent condensate from being drawn into the blower, it is
recommended that a trap be installed in the primary (main) and
secondary (overow) drain lines. Refer to the CONDENSATE
DRAIN PIPING section and Figure 13 in this manual. If the
secondary drain is not used, it must be capped.
9. The draw-through design can also cause exterior surface
of cabinet to sweat when air handler is installed in a non
conditioned space such as an attic or garage. The installer must
provide protection such as full-size auxiliary drain pan under
all air handlers installed in a non-conditioned space to prevent
damage from condensation runo. Some states, cities and
counties require additional insulation to be installed on the
exterior casing of the air handler to prevent sweating. Refer to
the state, city, county or local code for insulation requirement
to be sure the installation is in compliance. In the absence of
a local code, it is recommended that air handlers installed in
non-conditioned spaces be insulated on the exterior of the
entire cabinet including the front access panel with one (1) inch
thick berglass that has a vapor barrier on the outside.
SECTION 3: LOCATION, CLEARANCES AND RETURN AIR
REQUIREMENTS
CLEARANCES
This air handler is approved for zero (0) inches clearance to
combustible material on any part of the air handler exterior
casing. Refer to Table 5 and Figures 3 and 4 for clearance to
combustibles and for service access clearances.
Table 5: Clearances to Combustibles
Figure 3: Clearance – Access for Service
Figure 4: Closet Clearances

MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 8
RETURN AIR REQUIREMENTS
Provisions shall be made to permit the air in all rooms in the
living space to return to the air handler. Failure to comply may
cause a reduction in the amount of return air available to the
blower, causing reduced air ow resulting in improper heating
of the living space. The reduced air ow may cause the air
handler to cycle on the electric heater’s over-temperature limit
causing premature heating element failure.
The return air opening can be located in the oor, on a closet
front door, or in a side wall above the air handler cabinet. If the
opening for the return air is located in the oor, side walls, or
closet door anywhere below the appliance cabinet, a 6-inch
minimum clearance between the air handler and the wall or
door must be provided on the side where the return is located
to provide for proper air ow. The 6-inch minimum clearance
is not required if there is a return grille installed above the air
handler casing providing the grille has a sucient return air
opening.
For the air handler to work properly, a closet or alcove must
have a certain total free area opening for the return air.
For A/C and HP Air Handlers 1/3 HP Blower Motor On
(MSVE, MSVT18 & 24)
• Minimum 200 in free area opening
• Use Return Grille or Coil Cabinet
For A/C and HP Air Handlers 1/2 HP Blower Motors On
(MSVE, MSVT25, 30, & 36)
• Minimum 250 in² free area opening
• Use Return Grille, A/C Coil Cabinet, or any return grille with a
minimum 250 in² free area opening.
For A/C and HP Air Handlers with Electric Heat use 3/4 HP
Blower Motor On (MSVE, MSVT 37, 42, 48, & 60)
• Minimum 390 in² free area opening
• Use Return Grille, or A/C Coil Cabinet, or any return grille with
a minimum 390 in² free area opening.
For A/C and HP Air Handlers use 1.0 HP Blower Motor On
(MSVE, MSVT72)
• Minimum 430 in² free area opening
• Use Return Grille, or A/C Coil Cabinet, or any return grille with
a minimum 430 in² free area opening.
SECTION 4: AIR HANDLER ORIENTATION, SUPPLY AIR
DUCT, AND RETURN AIR FILTERS
The air handler is shipped from the factory congured to be
installed in an upow or horizontal right- to-left air-ow position.
Horizontal right-to-left means when facing the front of the air
handler and when it is laid on its side, the supply air opening is on
the left and the return opening is on the right. This air handler is
eld convertible to a horizontal left-to-right air-ow position.
UPFLOW APPLICATIONS
In an upow installation the discharge outlet is at the top. Care
should be taken to ensure air handler is level to permit proper
condensate drainage. Normal upow installation will be in a
closet or basement. If installed in a closet, the closet should have
a platform framed in that measures at least 12 inches in height
with an opening cut in the top of the platform for the return air
to enter the bottom of the air handler. A lter frame and lter
can be used that covers the opening and is sealed to prevent air
by-passing the lter. A lter grille can be used that is located as
described in RETURN AIR REQUIREMENTS.
The minimum lter size is shown as follows:
Standard Throw Away Air Filter @ 300 ft/min or Less
800 CFM = 20 x 20 x 1
1000 CFM = 20 x 25 x 1
1200 CFM = 20 x 30 x 1
1400 CFM = 25 x 30 x 1
1600 CFM = 25 x 30 x 1
1800 CFM = 30 x 30 x 1
2000 CFM = 30 x 40 x 1 or two 30 x 20 x 1
2400 CFM = 30 x 40 x 1 or two 30 x 20 x 1
Pleated Air Filter @ 500 ft/min or Less
800 CFM = 16 x 16 x 1
1000 CFM = 18 x 20 x 1
1400 CFM = 20 x 20 x 1
1200 CFM = 20 x 20 x 1
1600 CFM = 20 x 25 x 1
1800 CFM = 20 x 30 x 1 or two 20 x 15 x 1
2000 CFM = 20 x 30 x 1 or two 20 x 15 x 1
2400 CFM = 25 x 30 x 1 or two 14 x 30 x 1
Another option is to use a SunTherm Air Filter Base Accessory Kit
which can be used on the return air end of the air handler when
congured in the upow position (See Figure 5). The lter base
is placed over the return plenum in the oor and sealed to the
plenum using sealant or caulking material and/or tape. The air
handler is placed on top of the return lter base and the return
opening sealed to prevent leaks.
FILTER BASE ASSEMBLY KIT – FIELD INSTALLED
86ET0002 – 16”X 20” X 2”Small Cabinet 86ET0001 and
20”X 20” X 2” Medium Cabinet
86ET0003 – 20” X 24”X 2”Large Cabinet
Figure 5: Air Filter Base Accessory for 1” or 2” Air Filters.
Notes for Air Filter Base Accessory
• The lter size adjustment knobs are located on both sides of
the base.
• Make sure the ow arrow on the air lter is pointing towards
the coil.
• The Air Filter Base Accessory can also be used on the return
air end of the air handler when congured in the downow
position in place of a wall, door or ceiling mounted return
lter grille.
After the air handler has been secured to the return platform,
connect the supply air outlet to a plenum to the top of the air
handler and secure it with screws. Use a non-tape sealant such
as mastic or an aerosol sealant to seal duct leakage. If the air
handler is installed in a basement, run the supply and return
duct work in accordance with local codes. Use a non-tape
sealant such as mastic or an aerosol sealant to seal duct leakage.

AIR HANDLER
COIL ACCESS DOOR
INDOOR COIL
COIL SUPPORT RAILS
AIR HANDLER
COIL ACCESS DOOR
INDOOR COIL
COIL SUPPORT RAILS
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 9
HORIZONTAL APPLICATION
Horizontal applications will normally be used in an attic or crawl
space. This type of installation requires supply air plenum or duct
to be connected to the supply collar and a return air plenum or
duct be attached to the air handler inlet collar. The supply ducts
will be connected to the supply air plenum and routed through
the attic to a register in each room. Use a non-tape sealant such as
mastic or an aerosol sealant to prevent leaks in the ducts and the
plenum.
NOTE: The same return air ltration requirements apply to
horizontal applications as upow applications. Refer to the upow
orientation section for return air lter requirements on this page.
The opposite end of the return air duct is attached to a return
lter grille housing. The lter grille is usually located in a wall,
just below the ceiling or the ceiling in a hallway. Use a non-tape
sealant such as mastic or an aerosol sealant to prevent leaks in the
ducts and the plenum.
The air handler is shipped to be installed without modication in
a right-to-left conguration.
To convert the air handler for left-to-right applications:
1. Remove the air handler access panels.
2. Remove the cooling coil.
3. Move the condensate drain pan to the right side.
4. Reinstall the cooling coil.
5. Connect the condensate drains and refrigerant lines.
6. Reinstall air handler access panels.
DOWNFLOW APPLICATIONS
This air handler may be converted to a downow conguration
using a required downow conversion kit by following the
instructions below (See Figures 6 and 7).
NOTE: The same return air ltration requirements apply to
downow applications as upow applications. Refer to the upow
orientation section on page 8 of this manual for return air lter
requirements.
1. Remove the blower and control box access panel.
2. Remove indoor coil access panel and discard it. The indoor coil
access panel will not be re-used.
3. Remove indoor coil assembly with drain pan by sliding out the
front of the air handler as shown in the Figure
4. Remove 6 screws (3 on each side of air handler), securing
indoor coil support rails. Refer to Figure 6.
5. Flip the air handler so the discharge is on the bottom.
6. Re-install the indoor coil support rails in the holes provided in
the air handler casing as shown in Figure 7. Use the six (6)
screws that were removed in step 4 to secure the indoor coil
support rails to the air handler casing.
7. Re-install the cooling coil in the upright position as shown in
Figure 7.
8. Remove the new indoor coil access panel from the conversion
kit and install over the indoor coil section as shown in Figure 7.
9. Re-install the blower and control box access panel in the
upside-down position and secure with the screws that were
removed in step 1.
Figure 6: Indoor Coil Disassembly
When Converting to Downow
Figure 7: Indoor Coil Assembly
When Converting to Downow Operation.
Figure 8: Combustible Floor Base Installation

OUTDOOR UNIT
LIQUID LINE
SUCTION LINE
INDOOR COIL
MORTEX PRODUCTS INC. 501 TERMINAL RD FORT WORTH, TX 76106 Page 10
DX Refrigerant Piping:
Air handlers with DX type indoor coils require liquid and suction
piping sized in accordance with outdoor unit manufacturer’s
instructions. Indoor coils have sweat copper connections.
Refrigerant lines should be soldered with silver solder or high
temperature brazing alloy. Suction line must be insulated to
avoid condensate from forming and dropping o. Armaex
pipe insulation (or equivalent) with 3/8”(1 cm) minimum wall
thickness is recommended. In severe conditions such as hot or
high humidity areas require 1/2”(1.3 cm) minimum wall thickness
may be required. If outdoor unit is installed above indoor coil,
then oil traps are required at equal intervals along suction line
(see Figure 9). Horizontal suction lines should slope downward
Prior to installing the air handler, make sure the holes are cut into
the oor for the refrigerant tubing, the drain line, the electrical
wiring, the thermostat wiring and the outdoor unit control wiring.
1. Remove the top shipping cover and corner posts.
2. Remove the bottom shipping cover.
3. Remove the blower and control box access panel.
4. Remove the coil compartment access panel.
5. Place the air handler into position using one of the
following choices:
(a) If the Combustible Floor Base is used, slide the
air handler onto the combustible oor base until the
air handler touching the anges on the back of the
oor base.
(b) If the Combustible Floor Base is not used, slide the
air handler over the duct opening until the opening
in the air handler lines up with the duct opening in
the oor.
6. Secure the air handler by one of the two choices:
(a) If the Combustible Floor Base is used, secure the air
handler to the oor by drilling two holes through the air
handler base and the oor base at the right and left front
inside corners of the cabinet. Use two screws to secure
the air handler to the oor.
(b) If the Combustible Floor Base is not used, secure the air
handler to the oor by drilling two holes through the
air handler base at the left and right front inside corners
of the cabinet. Use two screws to secure the air handler
to the oor.
7. Use calking, sealers, and/or tape to seal between the
combustible oor base and the opening on the air handler
or between the opening on the air handler and the duct in
the oor.
8. Connect the electrical supply wires and the thermostat
control wires in the control box.
9. Connect the refrigerant lines to the coil.
10. Re-install the coil compartment access panel and secure
with the screws that were removed in step 3.
11. Re-install the blower and control box access panel and secure
with the screws that were removed in step 2.
12. Turn the power on to the air handler by following the
procedure in the Users Information Manual.
13. Set the thermostat to the desired temperature.
• Install 1 oil trap for a height dierence of 15 ft to 25 ft
(4.6 m to 7.6 m) between indoor and outdoor units.
• Install 2 oil traps for a height dierence of 26 ft to 50 ft
(7.9 m to 15.2 m) between indoor and outdoor units.
• Install 3 oil traps for a height dierence of 51 ft to 100 ft
(15.5 m to 30.5 m) between indoor and outdoor units.
• Install 4 oil traps for a height dierence of 101 ft to 150 ft
(30.8 m to 45.7 m) between indoor and outdoor units.
Thermal Expansion Valves (TXV)
SunTherm air handlers can have a factory installed thermal
expansion valve (TXV) or a TXV may be eld installed. The factory
and eld installed TXV’s for this air handler have an internal check
valve making them compatible for both cooling only and heat
pump applications. The TXV has an external pressure equalizer,
non-adjustable superheat, and a 15% bleed rate. A hard start
capacitor on the outdoor unit is normally not required when
a 15% bleed TXV is used, but may be necessary if compressor
starting issues are encountered.
Field Installed TXV Kit Information
R72DB0053HX: R-410A, 1.5 – 2.5 Ton, 15% Bleed,
Inlet: Male Rotolock, Outlet: Female Swivel Nut
R72DB0054HX: R-410A, 3.0 – 5.0 Ton, 15% Bleed,
Inlet: Male Rotolock, Outlet: Female Swivel Nut
Figure 10: Indoor Coil Below Outdoor Unit Piping
SECTION 5: INSTALLING THE AIR HANDLER
SECTION 6: REFRIGERANT PIPING, TXV,
AND CONDENSATE PIPING
1 inch for every 20 feet toward outdoor unit. The manufacturer
recommends that dry nitrogen be owed through refrigerant
lines during soldering operation.