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.

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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

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diaphragm. It’s purpose is to regulate the rate at which
refrigerant flows into the evaporator.
Figure 12: The TXV Bulb Best Placement
The bulb is best mounted on a horizontal suction line tube and
in a position corresponding to between 1 o'clock and 4 o'clock.
The location depends on the outside diameter of the tube.
(Figure 6) .
Note: The bulb must never be located at the bottom of the
suction line due to the possibility of oil laying in the bottom of
the pipe causing false signals.
The 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.
Be sure that the expansion valve provided is the proper size and
type required to achieve rating. If a non-bleed type valve is to be
used, the outdoor unit must be equipped with a hard start kit
allowing the outdoor unit to start under load. Check with our
factory if necessary.
How the TXV Controls Superheat
The thermostatic expansion valve (TXV) is a precision device
designed to regulate the rate at which liquid refrigerant flows
into the evaporator. This controlled flow is necessary to prevent
the return of liquid refrigerant to the compressor.
The TXV separates the high pressure and low-pressure sides of
a refrigeration or air conditioning system. Liquid refrigerant
enters the valve under high pressure, but its pressure is reduced
when the TXV limits the amount of refrigerant entering the
evaporator.
Remember: the TXV controls only one thing: the rate of flow of
liquid refrigerant into the evaporator. The TXV is not designed
to control air temperature, head pressure, capacity, suction
pressure, or humidity. Attempts to use the TXV to control any
of these system variables will lead to poor system performance
and possible compressor failure.
The TXV responds to the temperature of refrigerant gas as it
leaves the evaporator. This temperature is detected by the
sensing bulb, which is located near the evaporator outlet. The
TXV also responds to the refrigerant pressure within the
evaporator, which is transmitted to the TXV by an equalizer
line. By responding to these variables, the TXV maintains a
predetermined superheat within the evaporator. This is how the
TXV keeps the system in balance and operating properly. To
understand how this works, we must have a clear understanding
of superheat.
The TXV controls superheat by controlling the flow of liquid
refrigerant. As it does this, it also reduces refrigerant pressure.
Liquid refrigerant enters the TXV under high pressure. As the
flow of liquid refrigerant is reduced, its pressure drops. The
refrigerant leaving the TXV is now a combination of low-
pressure liquid and vapor.
As the flow is restricted, several things happen:
The pressure on the liquid refrigerant drops;
A small amount of the liquid refrigerant is converted
to gas, in response to the drop in pressure;
This "flash gas" represents a high degree of energy
transfer, as the sensible heat of the refrigerant is
converted to latent heat;
The low-pressure liquid and vapor combination moves
into the evaporator, where the rest of the liquid
refrigerant "boils off" into its gaseous state as it
absorbs heat from its surroundings.
Changes in gas temperature at the evaporator outlet are detected
by the sensing bulb, which then causes the valve pin to move in
or out, regulating the flow of refrigerant through the TXV. In
this way, the valve allows just enough refrigerant into the
evaporator, to maintain the correct level of superheat in the
suction line.
The TXV controls superheat by varying the size of the orifice
through which the refrigerant flows. The pin angle, the size of
the stroke (typically 0.015- to 0.035-in.) and the diameter of the
orifice itself all affect how much refrigerant can pass through
the valve. In addition, all valves have some leakage around the
valve pin, although this is normally kept within acceptable
limits.
It's important to remember that valve capacity is a function of
the orifice diameter, pin angle, and stroke. Adjusting the
superheat spring doesn't change valve capacity.
Trouble Shooting:
The thermostatic expansion valve (TXV) is like the carburetor
in your car's engine. It opens and closes to allow the correct
amount of refrigerant into your system. When the TXV isn't
working properly, the efficiency of your unit is crippled. If you
suspect you have a faulty TXV, perform these tests:
First, connect your gauges to the system and check that the
refrigerant pressures, subcooling and superheat are where they
should be (for pressures settings, refer to unit's pressure chart;
for subcooling (usually around 10°F) and superheat (between
8°F-12°F) follow manufacturer's specification sheet.
Check to see if airflow through the system is good . There
should be no dirty coils or air filters. Also check for proper
CFMs readings across the system.
Make sure there's the right amount of refrigerant charge in the
system (this step may require weighing out the refrigerant in the
system). Once you've added or removed charge as necessary,
check the pressures, subcooling and superheat again. If there is
no change then it is probably the TXV.

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Check the evaporator coil and remove the TXV's sensing bulb
from the suction line.
Check the subcooling, superheat and pressures again. If there's
no change, that's a further indication of a TXV problem.
Another test is to put the sensing bulb in ice water and checking
the pressures, superheat, and subcooling again. If they don't
change, it's a bad TXV.
When a non-bleed expansion valve (TXV) is specified in a
Summit AC or HP Rating, the following assumptions are made:
a) The TXV is a field or factory installed accessory to be field
or factory installed in accordance with recommended TXV
practice.
b) The combination of this non-bleed valve and the
compressor in the outdoor unit results in a system that
operates with a loaded condition on startup.
c) The outdoor unit is capable of starting against this loaded
condition or a hard start kit is to be field installed.
APPLICATION DATA:
R72DB0005 (R-22) 15% Bleed Non-Adjustable - 1.5-3.0 Ton
“T” Valve Letter Code
R72DB0003 (R-410A) 15%-Bleed Non-Adjustable-1.5–2.5 Ton
“D” Valve Letter Code
R72DB0004 (R-410A) 15%-Bleed Non-Adjustable-3.0–5.0 Ton
“Y” Valve Letter Code
Inlet Fitting Male Rotalock / Outlet Fitting Female swivel nut.
R72DB0006 (R-22) 15% Bleed Non-Adjustable - 3.0-5.0 Ton
“X” Valve Letter Code
R72DB0044 (R-410A) Non-Bleed Adjustable - 3.0-6.0 Ton
“Z” Valve Letter Code
Inlet Fitting Male Rotalock / Outlet Fitting Female swivel nut.
TXV TROUBLE SHOOTING:
Changing parts might be the first reaction, BUT…
1. May not be necessary and…
2. Does not always solve the problem.
SUPERHEAT AND SUCTION PRESSURE
LOW SUCTION PRESSURE – HIGH SUPERHEAT
POSSIBLE CAUSES:
1. Undersized valve
2. High superheat adjustment
3. Evaporator pressure drop – no external equalizer
4. External equalizer location – needs to be located on suction
line after the last feeder tube.
5. Restricted or capped external equalizer
6. Low refrigerant charge
7. Plugged dryer or strainer
8. Low pressure drop across valve:
a. Plugged dryer or strainer
b. Low condensing temperature
HIGH SUCTION PRESSURE – LOW SUPERHEAT
POSSIBLE CAUSES:
1. Oversized valve
2. TXV seat leak
3. Low superheat adjustment
4. Bulb installation:
a. Poor thermal contact
b. Warm location
5. Bad compressor – low capacity
6. Incorrectly located external equalizer line – needs to be
located on suction line after the last feeder tube.
LOW SUCTION PRESSURE – LOW SUPERHEAT
POSSIBLE CAUSES:
1. Low load:
a. Not enough air
b. Dirty air filters
c. Air too cold
d. Coil icing or frosting
2. Poor air distribution
3. Improper compressor evaporator balance – coil too big or
small or incorrect balance on heat pump systems.
4. Oil is trapped in the evaporator
Check these things before removing the TXV
1. Remove the sensing bulb and hold in your hand. The high
side pressure should drop and low side pressure should
increase as the TXV opens.
2. Loosen the flare nut on the TXV external equalizer tube
that is connected with a flare nut on the suction line. If you
get a lot of pressure when the nut has been loosened then
tighten the nut. If you get a slight pressure or no pressure;
the Schrader valve stem is not being depressed. Install a
anti blow back fitting to the external equalizer line of the
TXV to depress the Schrader valve stem and check for
proper operation of the TXV.
Figure 13: TXV Sensing Bulb Location
INSTALLATION NOTES:
With reference to the Figure 7, the TXV assembly is to be
installed between the distributor and the existing liquid line

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Field Installed :
1. After coil pressure has been relieved, turn the female swivel
nut counter-clockwise to remove.
2. If Flowrator Distributor Assembly is being replaced by a
TXV, remove the piston orifice from the flowrator
distributor assembly using a small diameter wire or paper
clip.
3. Attach the TXV by connecting the female swivel nut on
TXV outlet to the flowrator distributor (aligning Teflon seal
first) and torque swivel nut to 10-30 ft. lbs.
4. Attach liquid line with female swivel nut to male rotalock
fitting on TXV inlet (Aligning Teflon seal first) and torque
swivel nut to 10-30 ft. lbs.
5. Remove the cap on Schrader valve port on coil manifold.
Attach equalizer tubing with 1/4” female flare nut that
includes depressor to this male Schrader port. Torque nut
to 10-30 ft. lb
6. Install the TXV bulb to the suction manifold of coil or the
suction line using the two bulb clamps furnished with kit.
a. Bulb should be installed on a horizontal run of the
manifold if possible. On line less than 7/8” OD the
bulb may be installed on top of the line. With 7/8” OD
and over, the bulb should be installed in a position at
about 4 or 8 o’clock.
b. If bulb installation is made on a vertical run, the bulb
should be located at least 6 inches from any bend, and
on the tubing side opposite the plane of the bend. On
vertical bulb installations, the bulb should be
positioned with the bulb capillary tube at the top.
c. The bulb should be insulated using thermal insulation
to protect it from the effect of the surrounding ambient
temperature.
7. After completing installation of TXV (including equalizer
tube), it will be necessary to leak check the coil and
evacuate the coil through the service access fittings of
liquid and suction line valves.
Figure 14 Typical TXV Connections
SPECIAL INSTRUCTIONS FOR COILS WITH
FLOWRATOR DISTRIBUTOR ASSEMBLIES
The sizing of the orifice piston should be based strictly on the
rated capacity of the outdoor unit and coil match.
Summit provides capacity performance ratings that match both
same size and upsized coils with specific manufacturer’s
outdoor units. At the Summit distributor’s request, the orifice
piston is selected and installed in each coil for the specific range
of cooling capacities likely to be encountered. The factory
installed orifice piston size is marked on the flowrator
distributor assembly and on the front of the coil carton.
When using this coil with an outdoor unit of another capacity,
select an orifice piston from the table below if the capacity
range for the coil and outdoor unit to be used differs.
Failure to install the proper orifice piston can lead to poor
system performance and possible compressor damage. A
variation of one piston size is not normally critical. Summit
reserves the right to substitute a factory installed piston one size
smaller or greater if the piston size ordered is out of stock.
A selection of replacement orifice pistons is available from your
Summit supplier.
FLOWRATOR TO TXV CONVERSION:
While thermal expansion valves can be factory installed, they
are normally available in kit form for field installation. For kit
version, follow the installation instructions provided with the
kit. Normally these can be field installed before system is
charges without requiring cutting and brazing. BE SURE
FLOWRATER PISTON HAS BEEN REMOVED FROM
THE FLOWRATER DISTRIBUTOR BODY PRIOR TO
INSTALLATION OF EXPANSION VALVE.
ORIFICE PISTON REPLACEMENT:
If the flowrator distributor assembly is being used the piston is
to be installed as shown in Figure 9 in the distributor body then
the existing liquid line attached to the flowrator distributor.
1. After coil pressure has been relieved, turn the female swivel
nut counter-clockwise to remove.
2. Remove the piston from the flowrator distributor fitting
using a small diameter wire or paper clip. ALWAYS
REMOVE PISTON FROM DISTRIBUTOR BODY
WHEN TXV IS INSTALLED).
3. Replace the orifice piston with the correct piston for the coil
you are using. Make sure the tapered end of the piston is
facing the feeder tubes on the distributor body.
4. Turn the female swivel nut on clockwise the flowrator
distributor (aligning Teflon seal first) and torque swivel
nut to 10-30 ft. lbs.
5. After completing the replacement of the orifice piston, it
will be necessary to leak check the coil and evacuate the
coil through the service access fittings of liquid and suction
line valves.
Coil is pressurized with nitrogen. Relieve pressure before
installing TXV by depressing Schrader valve on coil
manifold.

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Figure 15: Flowrator Distributor
CONDENSATE DRAIN PIPING:
The air handler “A” coil drain pan has two ¾” NPT female
primary and two secondary connections (left or right hand).
Horizontal pan has two ¾” NPT female, one primary and one
secondary. Piping from each fitting used is to have 1-1/2
minimum trap and each run in such a manner as to provide
enough slope for adequate drainage to a visible area. Do not
pipe these two fittings together into a common drain. Cap
unused connection.
Figure 14: Typical Condensate Traps
SECTION VII: LINE VOLTAGE WIRING
Power Supply Wiring
The unit internal wiring is complete except for the power supply
and the thermostat wires. See wiring diagram and/or Tables 6-9
for wire size, fuse/circuit breaker size, and ground wire sizes.
The use of cable connectors on incoming power supply wires to
relieve any strain on wiring is recommended. Follow the steps
below to connect the power supply wires.
Single Circuit Line Wiring Connections
1. Remove the blower and control box access panel (door).
2. Remove the control box cover.
3. Install the cable connectors on the 7/8” dia holes on the
right side of the control box.
4. Strip ½” of the insulation on the end of each wire.
5. Insert the wires through the holes in the casing and through
the cable connectors.
6. Insert the black wire into the L1 screw terminal on the first
circuit breaker from the top and tighten the set screw to
clamp down on the wire.
7. Insert the white or red wire into the L2 screw terminal on
the first circuit breaker down from the top and tighten the
set screw to clamp down on the wire.
8. If you are using a single circuit for a 5 kW, 10kW, 15kW or
20kW model you will need to install a black jumper wire
from the L1 terminal on circuit breaker #1 to the L1
terminal on circuit breaker #2 and a white or red jumper
wire from the L2 terminal on circuit breaker #1 to the L2
terminal on circuit breaker #2. Refer to Figures 13, 14, 15,
16 and 17 for circuit breaker locations.
Note: The 100 amp 4 Pole Jumper Bar Assembly part
number 68BAE001 can be used in place of the jumper
wires.
9. Insert the green wire into the ground lug and tighten the
set screw.
Dual Circuit Line Wiring Connections: 15kW or 20kW
Models
10. You will need to insert the black wire from the second
power supply into the L1 screw terminal on the second
circuit breaker down from the top and tighten the set screw
to clamp down on the wire.
11. You will need to insert the white or red wire from the
second power supply into the L2 screw terminal on the
second circuit breaker down from the top and tighten the set
screw to clamp down on the wire.
12. You will need to insert both green wires into the ground lug
and tighten the set screw.
13. Tighten the screws on the cable connectors until the power
supply wires are securely fastened to the connector.
NOTE: The furnaces are equipped with either one or two circuit
breakers. These circuit breakers protect the wiring inside of the
furnace in the event of a short circuit. Additionally, these
breakers provide a means of disconnecting the power to the unit.
The circuit breakers in the furnace are not meant to protect the
branch circuit wiring between the furnace and the home's
breaker panel. General wire and breaker sizes are shown in
Tables 6-9. If sheathed cable is used, refer to NEC National
Electrical Code (NFPA 70) or the Canadian Electrical Code,
Part I (CSA C22.1) and local codes for additional requirements
concerning supply circuit wiring. Electrical data can be found in
Tables 6-9.
IMPORTANT - All installation on field wiring must be rated at
60ºC or higher. Please refer to the wiring diagrams on the
furnace or the tables this manual for more information.
Air handler must be located so that if any connections
should leak, water will not cause damage to the adjacent
area. When such locations can’t be avoided, a suitable drain
pan should be installed under the air handler, not over 1-
1/2” deep, with minimum length and width at least 2”
greater than the air handler dimensions and connected to an
adequate drain. Under no circumstances is the
manufacturer to be held liable for any water damage in
connection with this air handler.

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The 15kW and 20kW models may be connected to a single or
dual branch circuit.
IMPORTANT - Refer to the NEC National Electrical Code
(NFPA 70) or the Canadian Electrical Code, Part I (CSA C22.1)
and local codes for wiring material requirements.
5kWHeaterAmps‐208/230VAC
10kWHeaterAmps‐208/230VAC
15kWHeaterAmps‐208/230VAC
IndoorBlowerType
IndoorBlowerAmps
Heater‐kW 5 10 5 10 5 10 5 10 15 5 10 15 5 10 15
CircuitLoad‐FLA‐230VAC 21.66 42.44 21.60 42.38 22.88 43.66 22.91 43.69 64.53 22.54 43.32 64.16 23.88 44.66 65.50
Min.WireSize(90°C) #10 #6 #10 #6 #10 #6 #10 #6 #3 #10 #6 #4 #10 #6 #3
MinimumWireSize(75°C) #10 #6 #10 #6 #10 #6 #10 #6 #3 #10 #6 #4 #10 #6 #3
MinimumWireSize(60°C) #10 #4 #10 #4 #10 #4 #10 #4 #2 #10 #4 #3 #10 #4 #2
GroundWireSize * * * * * **********
MaxFuseAmps 30 60 30 60 30 60 30 60 90 30 60 80 30 60 90
18.0/20.88
36.1/41.66
AIRHANDLERMODELS
**VE18,24 **PS18,24 **VT25,30,36**VE25,30,36 **PS25,30,36**VT18,24
18.0/20.88
36.1/41.66 36.1/41.66 36.1/41.66
3.00
54.1/62.5N/AN/AN/A 54.1/62.5 54.1/62.5
ECM X‐13(CTM)
0.78 0.72 2.00 2.03 1.66
PSC ECM X‐13(CTM) PSC
18.0/20.88 18.0/20.88 18.0/20.88
36.1/41.66
18.0/20.88
36.1/41.66
Table 6: Wiring Requirements – 208/230 VAC Electric Heat 18-36 kBTU Models - Single Branch Circuit
15kW, and 20kW Two Stage models may have a dual or single power supply.
Single power supply will require circuit breaker jumper bar or a jumper wire.
+ Refer to the National Electrical Code Table 250-95 for Non-Sheathed Conductor Ground Wire.
* Ground conductor must be the same size and temperature rating as the other conductors listed in Tables 6.
** Model Series – MS, MM, US or UM
5kWHeaterAmps‐ 208/230VAC
10kWHeaterAmps‐208/230VAC
15kWHeaterAmps‐208/230VAC
20kWHeaterAmps‐208/230VAC
IndoorBlowerType
IndoorBlowerAmps
Heater‐kW 5 101520 5 101520 5 101520 5 101520 5 101520
CircuitLoad‐FLA‐230VAC 23.3 44.2 65.0 85.8 24.6 45.4 66.3 87.1 27.6 48.5 69.3 90.1 26.6 47.4 68.2 89.1 24.4 45.3 66.1 86.9
Min.WireSize(9
0
°C) #1
0
#6 #3 #3 #
8
#
6
#3 #2 #10 #4 #3 #2 #1
0
#6 #3 #2 #1
0
#6 #3 #2
Mini mumWireSize(75°C) #10 #6 #3 #2 #8 #6 #3 #1 #10 #4 #3 #1 #10 #6 #3 #1 #10 #6 #3 #1
Mini mumWireSize(60°C) #10 #4 #2 N/A #8 #4 #2 N/A #10 #4 #2 N/A #10 #4 #2 N/A #10 #4 #2 N/A
GroundWireSize ********************
MaxFuseAmps 30 60 90 110 35 60 90 125 35 70 90 125 35 60 90 125 35 60 90 125
54.1/62.5
3.60
**VE72 **VT37,42,48,60
18.0/20.8
8
36.1/41.6
6
18.0/20.8
8
36.1/41.6
6
18.0/20.88
36.1/41.66
54.1/62.5
PSC
72.2/83.33
2.50
36.1/41.66
3.75 6.8
0
5.72
54.1/62.5
72.2/83.33
54.1/62.5 54.1/62.5
ECM ECM X‐13(CTM) X‐13(CTM)
72.2/83.33 72.2/83.33 72.2/83.33
18.0/20.88
**VE37,42,48,60
36.1/41.66
18.0/20.88
AIRHANDLERMODELS
**VT72 **PS37,42,48,60
Table 7: Wiring Requirements – 208/230 VAC Electric Heat 37-60 kBTU Models - Single Branch Circuit
15kW, and 20kW Two Stage models may have a dual or single power supply. - Single power supply may require jumper bar or a jumper wire.
+ Refer to the National Electrical Code Table 250-95 for Non-Sheathed Conductor Ground Wire.
* Ground conductor must be the same size and temperature rating as the other conductors listed in Table 7.
** Model Series – MS, MM, US or UM
5kWHeaterAmps‐208/230VAC
10kWHeaterAmps‐208/230VAC
15kWHeaterAmps‐208/230VAC
20kWHeaterAmps‐208/230VAC
IndoorBlowerType
IndoorBlowerAmps
Heater‐kW 510 510 510 510
Circuit111211121112111212
CircuitLoad‐FLA 22.9 43.7 43.7 20.8 22.5 43.3 43.3 20.8 23.9 44.7 44.7 20.8 23.3 44.2 44.2 20.8 44.2 41.7
Min.WireSize(9
0
°C) #10 #6 #6 #10 #1
0
#6 #6 #1
0
#10 #6 #6 #10 #1
0
#6 #6 #1
0
#6 #6
MinimumWireSize(75°C) #10 #6 #6 #10 #10 #6 #6 #10 #10 #6 #6 #10 #10 #6 #6 #10 #6 #6
MinimumWireSize(60°C) #10 #4 #4 #10 #10 #4 #4 #10 #10 #4 #4 #10 #10 #4 #4 #10 #4 #4
GroundWireSize ******************
MaxFuseAmps 30 60 60 30 30 60 60 30 30 60 60 30 30 60 60 30 60 60
**VE37,42,48,60,72
AIRHANDLERMODELS
15 20
18.0/20.88
ECM
2.50
36.1/41.66
15 15 15
PSC
2.03 1.66 3.00
ECM X‐13(CTM)
36.1/41.66 36.1/41.66 36.1/41.66
**VE25,30,36 **VT25,30,36 **PS25,30,36
18.0/20.88 18.0/20.8
8
18.0/20.88
38.1/41.718/20.
8
36.1/41.7 36.1/41.7N/A N/A N/A
18/20.8 38.1/41.7 18/20.
8
38.1/41.7 18/20.8 38.1/41.7

MORTEXPRODUCTSINC.501TERMINALRDFORTWORTH,TEXAS76106Page16
Table 8: Wiring Requirements – 208/230 VAC Electric Heat 25-60 kBTU Models – Dual Branch Circuit
15kW, and 20kW Two Stage models may have a dual or single power supply. - Single power supply may require jumper bar or a jumper wire.
+ Refer to the National Electrical Code Table 250-95 for Non-Sheathed Conductor Ground Wire.
* Ground conductor must be the same size and temperature rating as the other conductors listed in Table 8.
** Model Series – MS, MM, US or UM
5kWHeaterAmps‐208/230VAC
10kWHeaterAmps‐208/230VAC
CircuitNumber
15kWHeaterAmps‐208/230VAC
20kWHeaterAmps‐208/230VAC
IndoorBlowerType
IndoorBlowerAmps
Heater‐kW 510 510 510 510
Circuit 111212111212111212111212
CircuitLoad‐FLA‐230VAC 24.645.445.420.845.441.727.648.548.520.848.541.726.647.447.420.847.441.724.445.345.320.845.341.7
Min.WireSize(90
°C)
#8#6#6#10#6#6#8#4#6#1
0
#6 #6 #10 #6 #6 #10 #6 #6 #8 #6 #6 #10 #6 #6
MinimumWireSize(75°C) #8 #6 #6 #10 #6 #6 #8 #4 #4 #10 #4 #6 #10 #6 #6 #10 #6 #6 #8 #6 #6 #10 #6 #6
MinimumWireSize(60°C) #8 #4 #4 #10 #4 #4 #8 #4 #4 #10 #4 #4 #10 #4 #4 #10 #4 #4 #8 #4 #4 #10 #4 #4
GroundWireSize *** ********************
MaxFuseAmps 35 60 60 30 60 60 35 70 70 30 70 60 35 60 60 30 60 60 35 60 60 30 60 60
**VE72 **VT37,42,48,60 **PS37,42,48,60
12121212
**VT72
36.1/41.66
2015
36.1/41.66
18.0/20.8
36.1/41.7
38.1/41.7
36.1/41.7
18.0/20.8
36.1/41.7
38.1/41.7
36.1/41.7
36.1/41.66
ECM X‐13(CTM)
36.1/41.66
18.0/20.8
36.1/41.7
38.1/41.7
36.1/41.7
18.0/20.8
36.1/41.7
38.1/41.7
36.1/41.7
15
5.72 3.6
0
2
0
AIRHANDLERMODELS
X‐13(CTM) PSC
3.75 6.8
0
18.0/20.8
8
18.0/20.88 18.0/20.88 18.0/20.88
2
0
15 15 20
Table 9: Wiring Requirements – 208/240 VAC Electric Heat 37-72 kBTU Models – Dual Branch Circuit
15kW, and 20kW Two Stage models may have a dual or single power supply. - Single power supply may require jumper bar or a jumper wire.
+ Refer to the National Electrical Code Table 250-95 for Non-Sheathed Conductor Ground Wire.
* Ground conductor must be the same size and temperature rating as the other conductors listed in Table 9.
** Model Series – MS, MM, US or UM
5kW 10kW
BRANCH
CIRCUIT 111212
BTU 17,033 34,067 34,067 17,033 34,067 34,067
kW 4.99 10 10 4.99 10 10
BTU 15,876 33,686 33,686 15,876 33,686 33,686
kW 4.65 9.78 9.78 4.65 9.78 9.78
BTU 14,736 30,222 30,222 14,736 30,222 30,222
kW 4.3186 8.8572 8.8572 4.3186 8.8572 8.8572
BTU 17,033 34,067
kW 4.99 9.9984
ELECTRICHEATERSIZES
19.9968HeatingElementCapacity
51,149 68,232
14.9904
230VAC,60HZ,1PH
220VAC,60HZ,1PH
240VAC,60HZ,1PH
15kW 20kW
Table 10: Electric Heater Electrical Data

Figure 15: Component Locations – Electric Heat Control Box
Casing or cabinet must be permanently grounded in accordance with the National Electrical Code or other applicable codes.

MORTEXPRODUCTSINC.501TERMINALRDFORTWORTH,TEXAS76106Page17
Figure 16: Component Locations – No Heat Control Box
Figure 17: Control Box Circuit Breaker Location.
Figure 18: Circuit Breaker Front Panel Location
SECTION VIII: FIELD INSTALLED ELECTRIC
HEATER KITS
This instruction covers the physical installation of the
following electric heat kits on the MS,MM,US,UM series
models. Refer to Tables 6 – 9 for electrical specifications.
ModelNo CabinetSize Voltage Phase Hertz HeaterkW Motor
BSPHK05B Smal l 208/240 1 60 5 PSC
BSPHK10B Small 208/240 1 60 10 PSC
BMPHK05B Me dium 208/240 1 60 5 PSC
BMPHK10B Medium 208/240 1 60 10 PSC
BMPHK15B Medium 208/240 1 60 15 PSC
BLPHK05B Large 208/240 1 60 5 PSC
BLPHK10B Large 208/240 1 60 10 PSC
BLPHK15B Large 208/240 1 60 15 PSC
BLPHK20B Large 208/240 1 60 20 PSC
BSXHK05B Small 208/240 1 60 5 X‐13
BSXHK10B Small 208/240 1 60 10 X‐13
BMXHK05B Medium 208/240 1 60 5 X‐13
BMXHK10B Medium 208/240 1 60 10 X‐13
BMXHK15B Medium 208/240 1 60 15 X‐13
BLXHK05B Large 208/240 1 60 5 X‐13
BLXHK10B Large 208/240 1 60 10 X‐13
BLXHK15B Large 208/240 1 60 15 X‐13
BLXHK20B Large 208/240 1 60 20 X‐13
BSEHK05B Small 208/240 1 60 5 ECM
BSEHK10B Small 208/240 1 60 10 ECM
BMEHK05B Medium 208/240 1 60 5 ECM
BMEHK10B Medium 208/240 1 60 10 ECM
BMEHK15B Medium 208/240 1 60 15 ECM
BLEHK05B Large 208/240 1 60 5 ECM
BLEHK10B Large 208/240 1 60 10 ECM
BLEHK15B Large 208/240 1 60 15 ECM
BLEHK20B Large 208/240 1 60 20 ECM
Modelsequippedwithcircuitbreakers
Table 11: Electric Heater Kit Model Numbers.
NOTE: All models have factory installed circuit breakers and
electric heater kits have field installed circuit breakers.
The models are MS, MM, US, UM are configured as follows:
Small cabinet **VE18,24 - **VT 18, 24 - **PS 18, 24
Medium cabinet **VE25, 30, 36 - **VT25, 30, 36 - **PS25,
30, 36.
For personal safety be sure to turn the electrical power
“OFF” at the main entrance (Home Circuit Breaker Box)
and at the unit control box circuit breakers before
attempting any service or maintenance operations.
Homeowners should never attempt to perform any
maintenance which requires opening the air handler control
box door. Refer to Figure 16.
This air handler is not equipped with a shield that covers the
line voltage electrical supply wires and the circuit breaker
connections. Take precautions to prevent accidental
electrical shock. Be sure to turn the electrical power “OFF”
at the main entrance (Home Circuit Breaker Box) and at the
control box circuit breakers before removing the front
panel. Refer to Figure 19 for drawing of the front panel
circuit breaker location.

MORTEXPRODUCTSINC.501TERMINALRDFORTWORTH,TEXAS76106Page18
Large cabinet **VE37, 42, 48, 60, 72 - **VT37, 42, 48, 60, 72 -
**PS37, 42, 48, 60, 72.
The field installed electric heat accessories are used on cooling
or heat pump models that were not purchased with electric heat
from the factory. Each air handler model is approved for use
with the field installed accessory electric heat kit.
INSTALLING THE HEATERS
1. Follow the instructions in the USERS INFORMATION
MANUAL to properly shut down the air handler.
2. Remove the block off plate shown in Figure 14 and discard.
Retain the screws, they will be used to secure the electric
heater mount plate.
3. Insert electric heat kit into the opening where the block off
plate was removed. Secure the mounting plate with the
screws that were removed from the block off plate.
4. Connect the six pin male plug on the electric heater
assembly to the six pin female plug mounted on the side of
the low voltage control box divider panel.
5. Remove the wiring diagram from the kit, remove the paper
that covers the adhesive back and place the electric heat
wiring diagram over the wiring diagram located on the
blower housing.
6. Follow the instructions in the USERS INFORMATION
MANUAL to properly start up the air handler.
POWER SUPPLY CONNECTIONS
If the air handler has been installed prior to installing the electric
heaters or if an older unit is being replaced, the supply power
wires must be checked to make sure the wires are the proper
sizes to handle the current load for the heaters Refer to Tables 6
thru 9 for correct wire size. If the supply power wire size is
incorrect, new wires will need to be installed. Follow the
instructions “Power Supply Wiring” on page 18 and 21 of these
instructions for proper installation.
For circuit breaker models only - After the supply wiring has
been connected to the circuit breakers you must remove the
transformer and indoor blower motor wires from the terminal
block as shown in Figure 14 and connect them to load side of
circuit breaker #1.
LOW VOLTAGE CONNECTIONS
If the air handler was previously installed, nothing will need to
change on the low voltage wiring. If this is a new installation
refer to SECTION VII of these instructions.
Type Series Accessory HeatingCapacity Voltage@ 240 Volts 1PH
B = Breaker
SE = Small Cabinet ECM Motor
ME= MediumCabinetECM Motor
LE = Large Cabinet ECM Motor
SX = SmallCabinetX-13Motor
MX= MediumCabinetX-13Motor
LX= LargeCabinetX-13Motor
SP = Small Cabinet PSCMotor
MP= MediumCabinetPSCMotor
LP = Large Cabinet PSC Motor
B = 208/240VAC, 1PH, 50/60 HZ
05 = 5 kW
10 = 10 kW
15 = 15 kW
20 = 20 kW
HK = ElectricHeatKit
Table 12: Accessory Heater kit Nomenclature
SECTION IX: THERMOSTAT WIRING AND
CONNECTIONS
Thermostat Wiring
Thermostat wires connect through side of furnace and should be
no smaller than 22 gauge. Refer to Table 13 for recommended
wire gauge, lengths and maximum current for each wire gauge.
Max.Thermostat
WireLength
ThermostatWire
Gauge
ThermostatWire
MaximumCurrent
0‐100Feet 22 3.0Amps
0‐125Feet 20 3.0amps
0‐250Feet 18 3.0amps
Table 13: Low Voltage Wire Gauge and Max Lengths
Thermostat wires can enter through the side or top of the unit.
When bringing wiring through the top or side of the furnace,
cable connectors must be installed to hold wiring in place and to
relieve any strain on the wiring.
The use of a five-conductor cable from the thermostat to the
furnace is recommended for typical heating or heating/cooling
installations with a two or three-conductor cable from the
furnace to the condenser. The thermostat wire colors and the
typical heating/cooling connections are listed in Tables 14 and
15.
A seven-conductor cable from the thermostat to the furnace is
recommended for a typical heat pump installation with a five-
conductor cable from the furnace to the condenser.
The thermostat wire colors and the typical heat pump
heating/cooling connections are listed in Tables 14 and 15.
To prevent damage, carefully insert the electric heating
assembly through the rectangular opening in the front of the
discharge opening so the heat element support rod is seated
into the hole on the back side of the discharge opening.
After installing the electric heater, a one inch clearance
must be maintained on all sides of the supply air duct
and/or plenum for a minimum of thirty six inches from the
air handler discharge opening.

MORTEXPRODUCTSINC.501TERMINALRDFORTWORTH,TEXAS76106Page19

Figure 19: No Heat and Factory Installed Electric Heat
Control Box
Thermostat Installation
The thermostat heat anticipator must be-set at 0.4 Amps if the
thermostat has a manual heat anticipator adjustment. This
setting should be checked at the time of installation.
The thermostat may be a “self-setting" type in which case no
heat anticipator setting will be found on the thermostat,
eliminating the need for any field adjustment.
Thermostat should be located on an inside wall in an open area
to more closely regulate average room air, preferably, where
there is air movement back to furnace. Locating height of
thermostat is important. Thermostat should be located
preferably in a hall way upstream from the furnace return
airflow, not within three feet of from any windows and 52 to 66
inches above the floor.
DO NOT place the thermostat within three feet of any of the
furnace supply air registers
DO NOT place the thermostat within three feet of any of the air
conditioner supply air registers
Maintenance, operating and/or programming instructions are in
the envelope accompanying the thermostat. Give the envelope to
the home owner.
Separate Heating and Cooling System; Same Thermostat
If the furnace and the cooling unit have separate transformers be
sure to use a thermostat with isolated heating and cooling
contacts “RC” and “RH” to prevent interconnection of Class II
24 Volt Systems. Cycle furnace and the air conditioner
separately to make sure it will operate correctly.
Most new thermostats have separate heating and cooling
contacts for use with homes that have a air handler and air
conditioner that are completely separate and each have a 24
VAC transformer for system control. These thermostats have a
“RC” terminal for cooling and a “RH” terminal for heating.
Connect the cooling unit red wire from the “R” terminal on the
outdoor unit to the “RC” terminal on the thermostat and the
RED air handler pigtail wire to the “RH” terminal on the
thermostat. Refer to Figures 18 and 25 for typical low voltage
wire connections.
If you have separate furnace and air conditioner with separate
transformers and your thermostat does not have the “RC” and
“RH” terminals it is recommended that you purchase a new
thermostat. If the furnace and air conditioner are both connected
to the thermostat “R” terminal it can cause transformer burnout
or it can cause either the furnace or air conditioner control
system to go into lockout.
Separate Heating and Cooling Units, Separate Thermostats
If the heating/cooling system in your house is a central heating
and cooling system but, the furnace and the cooling unit are
controlled by separate thermostats, then the use of a thermostat
interlock switch is required in order to prevent the furnace and
the air conditioner from operating at the same time.
Do not locate thermostat within three feet of any of the following
items:
1Furnace supply air registers
2Cooling unit supply air registers
3Lights or heat lamps
4Aquariums
5Televisions, stereo, amplifiers, surround sound systems
6Stoves or any cooking appliance
7Refrigerator
8Washer and/or dryer
9Hot water tank
10 Sink or near any hot water
11 Within 15 feet of any electric space heater
12
Within two feet of any sunlight
When using separate thermostats a thermostat interlock
system must be provided to prevent simultaneous operation
of the furnace and air conditioner. Simultaneous operation
can result in equipment overheating, equipment damage,
and wasted energy.
Do Not connect the Yellow wire to the thermostat unless an
outdoor unit is installed.

MORTEXPRODUCTSINC.501TERMINALRDFORTWORTH,TEXAS76106Page20
RH
G
Y
C
R
G
W1
C
C
Thermostat
AH ECM
Cooling Unit
W/E
Y
Outdoor Section
RC Air Handler
24VAC
24VAC
Y1
Y2
W2
O
EM
Transformer
Jumper
Common
Figure 20: Typical Single Stage Heat with Single Stage
Split System Cooling
RH
G
Y
C
R
G
W1
C
C
Thermostat
AH ECM
Cooling Unit
W/E
Y
Outdoor Section
RC Air Handler
24 VAC
Y1
Y2
W2
O
EM
BOARD
Transformer
24VAC
RC
24VAC
Common
Transformer
24VAC
Common
Figure 21 Typical Single Stage Heat with Single Stage
Package Cooling Unit
RH
G
Y
C
R
R
G
W1
C
C
Thermostat
AH ECM
Heat Pump Unit
W/E
Y
Outdoor Section
RC Air Handler
24VAC
24VAC
Common
Y1
Y2
W2
O
EM
O
O
BOARD
Transformer W/E
Jumper
W2
Follow
Manufacturers
Instructions
Figure 22: Typical Single Stage Heat with Single Stage
Split System Heat Pump
RH
G
Y
C
R
R
G
W1
C
C
Thermostat
AH ECM
Heat Pump Unit
W/E
Y
Outdoor Section
RC Air Handler
24VAC
24VAC
Common
Y1
Y2
W2
O
EM
O
O
BOARD
Transformer W/E
W2
Follow
Manufacturers
Instructions
24VAC
24 VAC
Transformer
24VAC
Common
Figure 23: Typical Single Stage Heat with Single Stage
Package Heat Pump Unit