Suntherm MS Series User manual

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INSTALLATION MANUAL
Multi-position, Upflow, and Horizontal DX and Chilled Water Cooling with Electric Heating
MODELS: MS, MM, US, UM SERIES
LIST OF SECTIONS
1 – General 1 7 – Line Voltage Wiring 13
2 – Safety 2 8 – Field Installed Electric Heater Kits 16
3 – Clearance and Return Air Requirements 6 9 – Thermostat Wiring and Connections 17
4 – Furnace and Supply Air Duct Installation 8 10 – Motor, Blower and Furnace Startup 23
5 – Furnace Installation 10 11 – Final System Checkout 25
6 – Hydronic Heating / Cooling / Refrigerant Piping 10 12 – Wiring Diagrams 26
LIST OF FIGURES
1 – Dimensional Data DX Cool With or Without Electric Heat 4 24 – 2 Stage Heat w/ 2 Stage Split System Cooling Wiring Diagram 19
2 – Dimensional Data Chilled Water With or Without Electric Heat 5 25 – 1 Stage Heat w/ 2 Stage Package Cooling Wiring Diagram 19
3 – Clearance – Access for Service 7 26 – 2 Stage Heat w/ 2 Stage Split System HP Wiring Diagram 20
4 – Closet Clearances 7 27 – 2 Stage Heat w/ 2 Stage Package HP Wiring Diagram 20
5 – Typical Closet Installations 8 28 – X-13 Motor Terminals 22
6 – Accessory Air Filter Box for 1” or 2” Air Filters 8 29 – Blower Assembly and Blower Deck Drawing 22
7 – Evaporator Coil Disassembly for Conversion to Downflow 9 30 – ECM Motor Control Plug Pin out 22
8 – Evaporator Coil Assembly to Convert to Downflow 9 31 – ECM Control Board Diagram 23
9 – Combustible Floor Base – Downflow Operation 10 32 – MSVE 18-72 – ECM – No Electric Heater Wiring Diagram 24
10 – Installing Evaporator Below Condenser – Piping 10 33 – MSVE 18-72 – ECM – 5 kW Electric Heater Wiring Diagram 25
11 – TXV Trouble Shooting Guide 11 34 – MSVE 25-72 – ECM – 10 kW Electric Heater Wiring Diagram 25
12 – Typical TXV Connections 12 35 – MSVE 37-72 – ECM – 15 kW Electric Heater Wiring Diagram 26
13 – Flowrator Distributor 12 36 – MSVE 42-72 – ECM – 20 kW Electric Heater Wiring Diagram 26
14 – Typical Condensate Trap 13 37 – MSVT 18-72 – X-13 – No Electric Heater Wiring Diagram 27
15 – Component Locations – Electric Heat Control Box 15 38 – MSVT 18-72 – X-13 – 5 kW Electric Heater Wiring Diagram 27
16 – Component Locations – No Heat Control Box 15 39 – MSVT 18-72 – X-13 – 10 kW Electric Heater Wiring Diagram 28
17 – Control Box Circuit Breaker Locations 16 40 – MSVT 36-72 – X-13 – 15 kW Electric Heater Wiring Diagram 28
18 – Circuit Breaker Location on Front Panel 16 41 – MSVT 37-72 – X-13 – 20 kW Electric Heater Wiring Diagram 29
19 – No Heat and Factory Installed Electric Heat Control Box 17 42 – MSPS 18-60 – PSC – No Electric Heater Wiring Diagram 29
20 – 1 Stage Heat w/ 1 Stage Split System Cooling Wiring Diagram 18 43 – MSPS 18-60 – PSC – 5 kW Electric Heater Wiring Diagram 30
21 – 1 Stage Heat w/ 1 Stage Package Cooling Wiring Diagram 18 44 – MSPS 18-60 – PSC – 10 kW Electric Heater Wiring Diagram 30
22 – 1 Stage Heat w/ 1 Stage Split System HP Wiring Diagram 19 45 – MSPS 30-60 – PSC – 15 kW Electric Heater Wiring Diagram 31
23 – 1 Stage Heat w/ 1 Stage Package HP Wiring Diagram 19 46 – MSPS 37-60 – PSC – 20 kW Electric Heater Wiring Diagram 31
LIST OF TABLES
1 – Air Handler Model Specifications 3 10 – Electrical Data 15
2 – Dimensional Data DX Cooling With or Without Electric Heat 4 11 – Field Installed Electric Heater Kit Model Numbers 16
3 – Dimensional Data Chilled Water With or Without Electric Heat 5 12 – Field Installed Accessory Heater Kit Nomenclature 17
4 – Air Handler Model Nomenclature 6 13 – Low Voltage Wire gauge and Maximum Lengths 17
5 – Clearances to Combustibles 7 14 – Recommended Heating / Cooling Thermostat Wire Colors 20
6 – Wiring Requirements – 18-36 kBTU – Single Branch Circuit 14 15 – Recommended Heating / Cooling / HP Thermostat Wire Colors 20
7 – Wiring Requirements – 37-60 kBTU – Single Branch Circuit 14 16 – X-13 Motor Terminal Connections 21
8 – Wiring Requirements – 25-60 kBTU – Duel Branch Circuit 14 17 – ECM Motor Control Connector Terminal Descriptions 22
9 – Wiring Requirements – 37-72 kBTU – Duel Branch Circuit 15
SECTION I: GENERAL
The following list includes important facts and information
regarding the electric furnace and its inclusions.
1. Air handler is rated at either 120 volts AC or 240 volts
AC at 60 Hertz
2. Air handler size varies by model
3. Four-wire thermostat operation for heating and cooling
4. Seven wire thermostat for heat pump operation.
5. Air Handlers equipped with blower for A/C or Heat Pump
operation
6. This air handler is designed for multi position, upflow and
horizontal application
7. This air handler must not be operated without the door
installed
NOTE: This air handler and its components listed on the A/C
and Heat Pump equipment sticker were listed in combination as
a system by ETL for the United States and Canada.
SAVE THIS MANUAL FOR FUTURE REFERENCE

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SECTION II: SAFETY
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: indicated 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.
IMPORTANT
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 floor base dimensions shown in
Figure 9 for the proper duct connector or combustible floor
base for downflow applications. The duct connector and
combustible floor 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.
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.
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
Hot water from a boiler used to satisfy heating requirements
can be heated to temperatures of 180°F. Parts containing
water this hot can scald very quickly. Use extreme caution
when servicing or performing maintenance on any parts
containing hot water.
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.

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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 qualified personnel should install repair or
service heating/cooling equipment. Untrained service
personnel can perform basic maintenance functions such as
cleaning of exterior surfaces and replacing the air filters.
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. The 115 VAC models use
nominal 115 VAC, 1 Phase, 60-Hertz power supply. DO
NOT CONNECT THIS APPLIANCE TO A 50 HZ
POWER SUPPLY OR A VOLTAGE ABOVE 130
VOLTS.
14. The 208/230 VAC models use nominal 208 or 230 VAC, 1
Phase, 60-Hertz power supply. DO NOT CONNECT THIS
APPLIANCE TO A 50 HZ POWER SUPPLY OR A
VOLTAGE ABOVE 250 VOLTS.
15. Ground connections MUST BE securely fastened to the
control box and ground wires MUST BE secured to the
ground lugs control box with terminals.
GENERAL INFORMATION
This single piece air handler provides the flexibility for
installation in any upflow, downflow, or horizontal application.
The versatile models may be used with or without electric heat
or hot water heat. The direct drive variable speed ECM motor,
optional (3) speed PSC motor, or the (5) five speed X-13 motors
provide a selection of air volume to match any application.
The unit can be positioned for bottom air return in the upflow
position, top air return in the downflow position, or air return
through the end of the unit in the horizontal position.
NOTE: Refer to the instructions in this manual for the proper
downflow conversion kit and instructions on the proper
conversion to downflow.
Inspection
As soon as the furnace 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.
Models MS**18,24 MS**25,30,36 MS**37,42,48,60 MS**72
Input, kW 5,10 5,10,15 5,10,15,20 5,10,15,20
Blower Size-Heat (D x W) 9 X6 10 X7 12 X9 12 X10
Unit Voltage
Max. External SP (Duct), In. W.C.
Thermostat Circuit 0.50 24 VAC, 60 Hz, 40VA
CoolingOnly&CoolingW/ElectricHeat
240V, 60 HZ, 1 PH
Table 1 Air Handler Model Specifications
Available Blower Motors
1. Standard Blower Motor - – VAR SPD ECM MOTOR
2. Optional Blower Motor - 3 SPD PSC MOTOR
3. Optional Blower Motor – 5 SPD X-13 MOTOR
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
A
PPLIANCE.

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Figure 1: DIMENSIONALDATADXCOOLINGWITHORWITHOUT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
DIMENSIONALDATAMULTI‐POSITIONAIRHANDLERCOOLONLYORELECTRICHEAT
Table 2: DIMENSIONALDATADXCOOLINGWITHORWITHOUTELECTRICHEAT
S
T

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Figure 2: DIMENSIONALDATACHILLEDWATERWITHANDWITHOUTELECTRICHEAT
Model A B C D E F G H I J K L M N O P Q R S T
MS**18,24 17.50 43.00 21.00 15.50 12.50 13.50 11.00 6.75 16.75 16.25 13.50 10.75 8.25 4.75 2.00 4.00 8.75 2.00 16.10 20.20
MS**25,30,36 21.00 48.00 21.00 19.00 12.50 15.50 13.00 6.75 20.25 19.75 14.25 12.75 10.25 7.50 2.25 4.25 10.50 2.50 19.90 20.80
MS**37,42,48,60,72 24.50 58.75 21.75 19.50 16.25 19.75 17.25 6.75 28.25 27.75 19.75 16.00 13.50 10.25 2.25 4.25 12.50 2.25 23.50 20.70
Table 3: DIMENSIONALDATACHILLEDWATERWITHANDWITHOUTELECTRICHEAT
S
T

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AA =
XX =
XX =
XX =
XX =
862T= DX Coil Geometry andMetering
Device. (Refer to Coil Nomenclature)
8K2N CW Coil Gepmetry
(Refer to Coil Nomenclature)
Small Cabinet 18, 24, OS
Medium Cabinet 25, 30, 36, OM A = 120 VAC, 1 PH, 50/60 HZ
Large Cabinet 37, 42, 48 B = 208/230 VAC, 1 PH, 50/60 HZ
60, OL Contact factory ForOther Voltage
Availibility
MotorTypeSeries Evaporator
Coil
Confi
g
uratio
n
Option CodeVoltage
Heating
Configuration
Unit Size
Capacity in
MBTU/H
3N = 3 RowHW Coil No Pump
4N = 4 RowHW Coil No Pump
Pre-Painted Grey Top &
Front Embossed Galvanized
MotorProgramCode
10 = 10kW Electric Heat
15 = 15kW Electric Heat
20 = 20kW Electric Heat
2P = 2 RowHWCoil with Pump
3P = 3 RowHWCoil with Pump
MM =Multi-positionModular
US = UpflowSingle Piece
UM = Upflow Modular
PS = Standard PSC
VT = Variable Speed X-13
VE = Variable Speed ECM
00 = No Heat Models
05 = 5kWElectric Heat
Standard Configuration
Standard Coil
1" Insulation
4P = 4 RowHWCoil with Pump
2N = 2 RowHW Coil No Pump
MS = Multi-position Single Piece
Table 4: Air Handler Model Nomenclature
NOTES: OS = No Cooling Coil – Small Cabinet Model.
OM = No Cooling Coil – Medium Cabinet Model.
OL = No Cooling Coil – Large Cabinet Model.
MS = Multiposition Single Piece Cabinet – DX or Chilled Water Cooling – Electric or Hot Water (HW) Heating.
MM = Multiposition Modular “Heating Only”.
US = Upflow Single Piece Cabinet – DX or Chilled Water Cooling – Electric or Hot Water Heating.
UM = Upflow Modular “Heating Only”.
FILTER BASE ASSEMBLY KIT – FIELD INSTALLED
86ET0002 – 16”X 20” X 2” Small Cabinet
86ET0001 – 20” X 20” X 2” Medium Cabinet
86ET0003 – 20” X 24” X 2” Large Cabinet
SECTION IlI: CLEARANCE AND RETURN
AIR REQUIREMENTS
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 filters. 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
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. Caution should be taken to locate the unit so that supply
and return air ducts are about the same length causing 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 evaporator coil to the condenser.
7. Locate the appliance where condensate lines can be easily
routed to an available drain. Be sure to route condensate
drain piping so as not to obstruct access to the air filter.
8. When the coil is installed in a draw-thru application it will
create a negative pressure situation in the condensate drain
system. To prevent condensate from being drawn into the
blower it is recommended to trap the primary (Main) and
secondary (Overflow) drain line. Refer to CONDENSATE
DRAIN SYSTEM and Figure 12 in these instructions.
If the secondary drain is not used, it must be capped.
9. The draw-thru design will cause exterior surface of cabinet
to sweat when units is installed in a non-conditioned space

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such as an attic or garage. Installer must provide protection
such as full size auxiliary drain pan on all units installed in
a non-conditioned space to prevent damage from
condensation runoff.
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.
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 fiberglass with the vapor barrier on the outside.
Appliance Clearances
This appliance is approved for zero (0) inches clearance to
combustible material on any part of the air handler exterior
casing and the inlet or outlet ducts providing NO electric heater
is being used. There is a one (1) inch clearance on the supply
plenum and supply air duct when an electric heater is installed
in the appliance. Refer to Table 5 for clearance to combustibles
information.
Figure 3: Clearance – Access for Service
ALCOVE(in) CLOSET(in)
Electric000 30 6 1
FRONTOFFURNACE
MODEL TOP(in) BACK(in) SIDES(in) DUCT(in)
Table 5: Clearances to Combustibles
Figure 4: Closet Clearances
Return Air
In order 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, MSVT, MSPS18 & 24)
Minimum 200 in² free area opening
Use Return Grille or Coil Cabinet
For A/C and HP Air Handlers 1/2 HP Blower Motors On
(MSVE, MSVT, MSPS25, 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, MSPS 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
Bottom Return Only – Recommended Grille Size
800 CFM – 20 X 20 Grille – 324 in²
1000 CFM – 20 X 25 Grille - 414 in²
1200 CFM – 25 X 25 Grille - 414 in²
1400 CFM – 25 X 30 Grille - 644 in²
1600 CFM – 25 X 30 Grille - 644 in²
1800 CFM – 30 X 30 Grille - 784 in²
2000 CFM – 30 X 35 Grille - 924 in²
2400 CFM – 30 X 40 Grille - 1064 in²
The return air opening can be located in in the floor, on a closet
front door or in a side wall above the furnace casing. If opening
for the return air is located in the floor, side walls, or closet door
anywhere below the appliance casing, a 6 inch minimum
clearance between the appliance and the wall or door must be
provided on the side where the return is located to provide for
proper air flow. The 6 inch minimum clearance is not required if
there is a return grille installed above the appliance casing,
providing the grille has a sufficient return air opening.

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Figure 5: Typical Closet Installations
Provisions shall be made to permit the air in the rooms and the
living spaces to return to the furnace. Failure to comply may
cause a reduction in the amount of return air available to the
blower, causing reduced air flow resulting in improper heating
of the living space. The reduced air flow may cause the furnace
to cycle on the limit causing premature heating element failure.
Upflow Accessory Filter Box Kit
Accessory filter box kit can be used on the return air end of the
air handler when configured in the upflow position. The filter kit
is placed over the return plenum in the floor and sealed to the
plenum using sealant or caulking material and/or tape. The Air
Handler is placed on top of the return filter box and the return
opening sealed to prevent leaks.
Accessory filter box kit can be used on the return air end of the
air handler when configured in the downflow position in place
of a wall, door or ceiling mounted return filter grille.
NOTE: Make sure the flow arrow on the air filter is pointing
towards the coil.
Figure 6: Accessory Air Filter Box for 1” or 2” Air
Filters. Filter Size Adjustment knob is on both sides.
SECTION IV: FURNACE & SUPPLY AIR
DUCT INSTALLATION
ARRANGEMENT:
Unit is shipped from the factory arranged to be installed in an
upflow or horizontal right to left air flow position. Horizontal
right to left means, when facing the front of the unit, when the
unit is laid on its side, the supply air opening is to the left and
the return opening is to the right. These models are field
convertible to a horizontal left to right air flow position
UPFLOW APPLICATION:
In an upflow installation the discharge outlet is at the top. Care
should be taken to insure unit is level to permit proper
condensate drainage. Normal upflow installation will be in a
closet or basement. If installed in a closet, the closet should have
a platform framed in, that with an opening at the top of the
platform centered in the closet that measure at least 12 inches in
height. A filter frame and filter can be used that covers the
opening and is sealed to prevent air by-passing the filter. A filter
grille can be used that is located as described in RETURN AIR
REQUIREMENTS. The minimum filter size is shown in the
table below.
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
1200 CFM = 20 x 20 x 1
1400 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
Pleated filters are not recommended for use with PSC Motors.
Another option is to use the SunTherm Filter Base Accessory
Kit. This filter base is placed on the closet floor and secured
with screws. The unit is placed on top of the filter base and
secured to the base with screws. Use seal strip, tape or calking
to seal between the unit and the base.
Connect the supply air outlet to a plenum to the top of the unit
and secure it with screws. Use a Non-tape sealant such as mastic
or an aerosol sealant to seal duct leakage.
If installed in a basement, run 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.
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 unit inlet collar. The supply
ducts will be connected to the supply air plenum and routed thru

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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.
The opposite end of the return air duct is attached to a return
filter grille housing. The filter 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 unit is shipped to be installed without modification in a
right to left configuration. See ARRANGEMENT for details.
For left to right applications
1. Remove the unit 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 unit access panels.
DOWNFLOW APPLICATION:
The unit is designed to be converted to a downflow
configuration. You must use the downflow conversion kit and
follow the instructions below. Refer to Figures 7 and 8.
1. Remove the blower and control box access door.
2. Remove evaporator coil access door and discard it. The
evaporator access door will not be re-used.
3. Remove evaporator coil assembly with drain pan by
sliding out the front of the unit as shown in the Figure
7.
4. Remove 6 screws (3 on each side of unit), securing
evaporator coil support rails. Refer to Figure 7.
5. Flip the unit so the top is not the bottom.
6. Re-install the evaporator coil support rails in the holes
provided in the unit casing as shown in Figure 8. Use
the six (6) screws that were removed in step 4 to
secure the evaporator coil support rails to the unit
casing.
7. Re-install the cooling coil in the upright position as
shown in Figure 8.
8. Remove the new evaporator coil access door from the
kit and install over the evaporator section as shown in
Figure 8.
9. Re-install the blower and control box access door in the
upside down position and secure with the screws that
were removed in step 1.
Hydronic heat units cannot be used in the down flow position.
DOWNFLOW CONVERSION KIT:
DISASSEMBLY INSTRUCTIONS
1. Remove evaporator coil door and discard. The door
cannot be used in the downflow configuration. Remove
the new evaporator coil door from the conversion kit
box.
2. Remove the evaporator coil assembly with the drain
pan by sliding it out of the front of the unit as shown in
Figure 8.
3. Remove the 6 screws (3 on each side of the unit)
securing the evaporator coil rails. Unit is ready to be
reassembled in the downflow configuration.
Figure 7: Evaporator Coil Disassembly for conversion to
downflow. ASSEMBLY INSTRUCTIONS
1. Invert the air handler 180°and reinstall the coil support
rails, just above the blower. Use the six (6) screws that
were removed in the disassembly instructions.
2. Slide the evaporator assembly back into the coil
section. Evaporator must be installed so it is configured
in the “A” position.
3. Install the new evaporator coil door that was removed
from the kit..
Figure 8: Evaporator Coil Assembly Converting to
downflow operation.
INSTALLATION ON COMBUSTIBLE FLOORING
Combustible Floor Base MUST BE USED when the unit is
being installed on combustible flooring. The unit cannot be
installed on carpeting.
Failure to use the combustible floor base combustible
flooring or installing the unit on carpeting could result in a
fire causing personnel injury, property damage or loss of
life.

MORTEXPRODUCTSINC.501TERMINALRDFORTWORTH,TEXAS76106Page10
Before installing the combustible floor base make sure that there
is a minimum of R-2.1 insulation between the sheet metal and
any wood or combustible flooring. Refer to Figure 9 for typical
combustible floor base installation.
Figure 9: Combustible Floor Base Installation
SECTION V: FURNACE INSTALLATION
Installing the Air Handler
Closet Installation
Prior to installing the furnace make sure the holes are cut into
the floor for the refrigerant tubing, the drain line, the electrical
wiring, the thermostat wiring and the condenser 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 (door).
4. Remove the coil compartment access panel (door).
5. Place the unit into position using one of the following
choices:
A. If the Combustible Floor Base is used you slide the unit on
to the combustible floor base until the unit is touching the
flanges on the back of the floor base.
B. If the Combustible Floor Base is not used you slide the unit
over the duct opening until the opening in the unit lines up
with the duct opening in the floor.
6. Secure the unit by one of the two choices:
A. If the Combustible Floor Base is used you secure the
furnace to the floor by drilling two holes through the
furnace base and the floor base at the right and left front
inside corners of the cabinet. Use two screws to secure the
furnace to the floor.
B. If the Combustible Floor Base is not used you secure the
unit to the floor by drilling two holes through the furnace
base at the left and right front inside corners of the cabinet.
Use two screws to secure the unit to the floor.
7. Use calking, sealers, and/or tape to seal between the
combustible floor base and the opening on the unit or
between the opening on the unit and the duct in the floor.
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 (door) and
secure with the screws that were removed in step 3.
11. Re-install the blower and control box access panel (door)
and secure with the screws that were removed in step 2
12. Turn the power on to the unit by following the procedure in
the Users Information Manual.
13. Set the thermostat to the desired temperature.
SECTION VI: COOLING AND REFRIGERANT
PIPING
DX Refrigerant Piping:
Air Handlers with DX type evaporator coils require liquid and
suction piping sized in accordance with condensing unit
manufacturer’s instructions. The evaporator 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 off. Armaflex (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 condensing unit is
installed above evaporator coil then oil traps are required at
equal intervals along suction line (see Figure 5). Horizontal
suction lines should slope 1 inch for every 20 feet toward
condensing unit. Manufacturer recommends that dry nitrogen be
flowed through refrigerant lines during soldering operation.
Figure 11 Evaporator Below Condenser Piping
SPECIAL INSTRUCTIONS FOR COILS WITH
THERMAL EXPANSION VALVES (TXV)
Thermal expansion valve (TXV) have a built in check valve
making them A/C and heat pump capable. Hard start kit may be
required on non-bleed TXV’s. 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
provided on coils.
A thermostatic expansion valve (TXV) is built around a
thermostatic element separated from the valve body by a