Intertherm MG2S Installation Instruction

MG2S Series Downflow Condensing Gas Furnace :R410A and A2L Compatible 96+ % AFUE
INSTALLATION INSTRUCTIONS
Two-Stage, Direct Vent (Sealed Combustion)
Forced Air
For Installation in:
• Manufactured Homes
• Park Models, & Manufactured
Buildings
WARNING
FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could
result in serious injury or property damage.
• Installation and service must be performed
by a qualified installer, service agency or the
gas supplier.
• Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a
neighbors phone. Follow the gas suppliers
instructions.
• If you cannot reach your gas supplier, call
the fire department.
CAUTION
HUD Manufactured Home Construction and
Safety Standards (3280.714) prohibit the use
of non-certified air conditioning or heat pump
equipment with this furnace. It is strongly
recommended that manufactured housing
air conditioning components from Nortek
Global HVAC be selected to provide a matched
system specifically designed to meet these
requirements.
The cutting, splicing or modifying of any
internal electrical wiring may void product
warranties and create a hazardous condition.
Failure to comply with these standards could
also provide inadequate heating or cooling
performance and cause structural damage to
a manufactured home.
Reference: HUD Manufactured Home
Construction and Safety Standards 3280.714.
AVERTISSEMENT
RISQUE D’INCENDIE OU D’EXPLOSION
• Le non-respect des avertissements de sécurité
pourrait entraîner des blessures graves ou des
dommages matériels.
• L’installation et l’entretien doivent être effectués
par un installateur qualifié, un organisme de
service ou le fournisseur de gaz.
• Ne pas entreposer ni utiliser de l’essence ni
d’autres vapeurs ou liquides inflammables
dans le voisinage de cet appareil, ni de tout
autre appareil.
QUE FAIRE S’IL Y A UNE ODEUR DE GAZ
• Ne tenter d’allumer aucun appareil.
• Ne toucher à aucun interrupteur électrique;
n’utiliser aucun téléphone dans le bâtiment.
• Évacuer l’immeuble immédiatement.
• Appeler immédiatement le fournisseur de gaz en
employant le téléphone d’un voisin. Respecter
les instructions du fournisseur de gaz.
• Si personne ne répond, appeler le service des
incendies.
DO NOT DESTROY. PLEASE READ CAREFULLY & KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.
NE PAS DÉTRUIRE. VEUILLEZ LIRE ATTENTIVEMENT ET CONSERVER EN UN LIEU SÛR POUR RÉFÉRENCE ULTÉRIEURE.
TABLE OF CONTENTS
IMPORTANT SAFETY INFORMATION...................... 3
GENERAL INFORMATION......................................... 4
Requirements & Codes........................................... 4
Clearances to Combustible Materials...................... 5
Combustion Air Quality............................................ 6
Heating Load........................................................... 6
COMBUSTION AIR & VENTING REQUIREMENTS.. 7
Important Information.............................................. 8
Category IV Appliances........................................... 8
Direct Vent Installation............................................. 8
Vent Pipe Length & Diameter.............................. 8
Vent Pipe Material............................................... 9
Vent Pipe Installation.......................................... 9
Outdoor Terminations - Horizontal Venting......... 9
Outdoor Terminations - Vertical Venting............. 11
Vent Freezing Protection..................................... 11
Existing Installations............................................ 11
Ventilaire III or IV Air Quality Package.................... 11
A2L Coil................................................................... 12
C85 Loose Coils.................................................. 12
Coils from other Manufacturers........................... 12
CIRCULATING AIR REQUIREMENTS.............. 12
Plenums & Air Ducts................................................ 12
Supply Air Connections........................................... 12
Return Air Connections........................................... 12
Closet & Alcove Installations................................... 12
Furnace Filter.......................................................... 12
Dampers.................................................................. 13
FURNACE INSTALLATION........................................ 15
About The Furnace.................................................. 15
Before You Install this Furnace............................... 15
Locating the Unit...................................................... 15
Locating & Cutting Floor Openings..................... 16
Locating & Cutting Ceiling Openings................ 17
Installing Finger Tabbed Duct Connectors....... 17
Narrow Duct Attachment - Option 1.................. 17
Narrow Duct Attachment - Option 2.................. 17
Installing Screw-Down Duct Connectors.......... 17
Round Duct Connector Installation................... 17
Installing the Furnace....................................... 18
Condensate Drainage.............................................. 18
GAS SUPPLY & PIPING............................................. 19
Leak Check.............................................................. 20
High Altitude Application.......................................... 21
Converting to LP/Propane Gas at Altitudes
between 0 & 10,000 FT........................................... 21
ELECTRICAL WIRING........................................... 22
Line Voltage Wiring................................................. 22
Grounding................................................................ 23
Thermostat / Low Voltage Connections................... 23
Single Stage AC & Single Stage Thermostat.......... 23
Single Stage AC & Two Stage Thermostat........ 23
Autostaging for Single Stage Thermostats........ 23
2
Autostaging for Two-Stage Thermostats........... 24
Fixed Speed Blower Applications...................... 23
START-UP & ADJUSTMENTS................................... 23
Pre-Start Check List................................................ 23
Start-up Procedures................................................ 23
Verifying & Adjusting Input Rate.............................. 23
Verifying & Adjusting Temperature Rise.................. 24
Verifying Burner Operation...................................... 24
Verifying Operation of the Supply Air Limit Switch.. 25
OPERATING SEQUENCE.......................................... 25
Heating Cycle.......................................................... 25
Cooling Cycle.......................................................... 25
Fan Mode................................................................ 26
MAINTENANCE.......................................................... 26
TROUBLESHOOTING................................................ 27
FURNACE COMPONENTS........................................ 28
FIGURES & TABLES.................................................. 30
Figure 24. Front Return Model Dimensions........ 30
Figure 25. Top Return Model Dimensions......... 31
Airflow Data............................................................. 32
Table 7. Blower Performance - Front Return........... 32
Table 8. Blower Performance - Top Return............. 33
Electircal Diagrams & Data...................................... 34
Table 9. Wire Length & Voltage Specifications... 34
Figure 26. Line Voltage Field Wiring................... 34
Figure 27. MG2S Motor Control Board............... 34
Figure 28. Two-Stage Furnace Control Board.... 34
Figure 29. MG2S Wiring Diagram....................... 35
Gas Information....................................................... 36
Table 10. Gas Flow Rates................................... 36
Table 11. Gas Pipe Capacities............................ 36
Table 12. Liquid Propane Conversion Chart....... 37
Table 13. Natural Gas Heating Values................ 37
Table 14. Orifices for Natural Gas High
Heating Value........................................ 37
Table 15. High Altitude Deration Chart for
Natural Gas - Low heating Value........... 37
Venting Information............................................. 38
Table 16. Vent Termination Clearances.............. 38
Figure 30. Horizontal / Vertical Venting &
Clearances from Soffit....................... 39
INSTALLATION CHECKLIST.......................... 40
MODEL IDENTIFICATION CODE
M
G
2
S
B
045
Manufactured Housing
F
2
A
B
M
1
Revision
Gas Furnace
Cabinet Width
M = Manufactured Housing
B = 17.5"
C = 21.0"
Series
A = No Evap Coil Cabinet
B = Cabinet fits 18' nominal coil heights
Efficiency (AFUE)
R = 95.0%
S = 96.0%
R410A and A2L(454B)
Indoor coil compatible
A = 115V, 1 Phase, 60 Hz
Input Heating Capacity (BTU)
045 = 45,000
060 = 60,000
072 = 72,000
F = Front Return Downflow
T = Top Return Downflow
IMPORTANT SAFETY INFORMATION
INSTALLER: Please read all instructions before servicing
this equipment. Pay attention to all safety warnings and
any other special notes highlighted in the manual. Safety
markings are used frequently throughout this manual to
designate a degree or level of seriousness and should
not be ignored.
WARNING indicates a potentially hazardous situation that
if not avoided, could result in personal injury or death.
CAUTION indicates a potentially hazardous situation that
if not avoided, may result in minor or moderate injury or
property damage.
• To minimize equipment failure or personal injury, it is
essential that only qualified individuals install, service,
or maintain this equipment. If you do not posses
mechanical skills or tools, call your local dealer for
assistance.
• Follow all precautions in the literature, on tags, and
on labels provided with the equipment. Read and
thoroughly understand the instructions provided with
the equipment prior to performing the installation and
operational checkout of the equipment.
• Use caution when handling this appliance or removing
components. Personal injury can occur from sharp
metal edges present in all sheet metal constructed
equipment.
• Do not store any of the following on, or in contact with,
the unit: Rags, brooms, vacuum cleaners, or other
cleaning tools, spray or aerosol cans, soap powders,
bleaches, waxes, cleaning compounds, plastics or
plastic containers, paper bags or other paper products,
gasoline, kerosene, cigarette lighter fluid, dry cleaning
fluids, paint thinners, or other volatile fluids.
• Installation of equipment may require brazing
operations. Installer must comply with safety codes
1 = Single Stage
2 = Two Stage
and wear appropriate safety equipment (safety glasses,
work gloves, fire extinguisher, etc.) when performing
brazing operations.
• The installer should become familiar with the units
wiring diagram before making any electrical connections
to the unit. See the unit wiring label or Figure 29
(page 35).
• Always reinstall the doors on the indoor blower after
servicing or cleaning/changing the filters. Do not operate
the indoor blower without all doors and covers in place.
WARNING:
The safety information listed in this manual must
be followed during the installation, service, and
operation of this unit. Unqualified individuals
should not attempt to interpret these instructions
or install this equipment. Failure to follow safety
recommendations could result in possible
damage to the equipment, serious personal
injury or death.
3
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
WARNING:
FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could
result in serious injury or property damage.
• Installation and service must be performed
by a qualified installer, service agency or the
gas supplier.
• Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
WARNING:
Improper installation, service, adjustment, or
maintenance may cause explosion, fire, electrical
shock or other hazardous conditions which may
result in personal injury or property damage.
Unless otherwise noted in these instructions,
only factory authorized kits or accessories may
be used with this product.
4
GENERAL INFORMATION
Requirements & Codes
WARNING:
This unit must be installed in accordance
with instructions outlined in this manual
during the installation, service, and operation
of this unit. Unqualified individuals should
not attempt to interpret these instructions or
install this equipment. Failure to follow safety
recommendations could result in possible
damage to the equipment, serious personal
injury or death..
• The installer must comply with all local codes and
regulations which govern the installation of this type
of equipment. Local codes and regulations take
precedence over any recommendations contained in
these instructions. Consult local building codes and
the National Electrical Code (NFPA 70) for special
installation requirements.
• All electrical wiring must be completed in accordance
with local, state and national codes and regulations and
with the National Electric Code (NFPA 70) or in Canada
the Canadian Electric Code Part 1 CSA C.22.1.
• This furnace must be installed in accordance with
these instructions, all applicable local building codes
and the current revision of the National Fuel Gas Code
(NFPA54/ANSI Z223.1) or the Natural Gas and Propane
Installation Code, CAN/CGA B149.1.
• Use only with type of gas approved for this furnace.
Refer to the furnace rating plate.
• Install this furnace only in a location and position as
specified on page 5.
• Provide adequate combustion and ventilation air to the
furnace space as specified on page 7.
• Provide adequate clearances around the vent air
intake terminal as specified in Figure 1 (page 4),
Figure 2 (page 10), Figure 3 (page 10) &
Figure 4 (page 10).
• Combustion products must be discharged outdoors.
Connect this furnace to an approved vent system only,
as specified on page 8, page 9, page 10, &
page 11.
• Never test for gas leaks with an open flame. Use
a commercially available soap solution to check all
connections. See page 20.
• This furnace is designed to operate with a maximum
external pressure rise of 0.3 inches of water column.
Consult Table 8, (page 33) and the rating plate for the
proper circulating air flow and temperature rise. It is
important that the duct system be designed to provide
the correct flow rates and external pressure rise. An
improperly designed duct system can result in nuisance
shutdowns, and comfort or noise issues.
• This furnace must not be used for temporary heating
of buildings or structures under construction.
• The Commonwealth of Massachusetts requires
compliance with regulation 248 CMR 4.00 and 5.00 for
installation of through – the – wall vented gas appliances
as follows:
1. For direct-vent appliances, mechanical-vent heating
appliances or domestic hot water equipment, where the
bottom of the vent terminal and the air intake is installed
below four feet above grade the following requirements
must be satisfied:
a.) A carbon monoxide (CO) detector and alarm shall
be placed on each floor level where there are
bedrooms. The detector shall comply with NFPA
720 (2005 Edition) and be mounted in the living
area outside the bedroom(s).
b.) A (CO) detector shall be located in the room that
houses the appliance or equipment and shall:
• Be powered by the same electrical circuit as the
appliance or equipment. Only one service switch
shall power the appliance and the (CO) detector;
• Have battery back-up power;
• Meet ANSI/UL 2034 Standards and comply with
NFPA 720 (2005 Edition); and Approved and listed
by a Nationally Recognized Testing Laboratory as
recognized under 527 CMR.
c.) A Product-approved vent terminal must be used,
and if applicable, a product-approved air intake must
be used. Installation shall be in strict compliance
with the manufacturer’s instructions. A copy of
the installation instructions shall remain with the
appliance or equipment at the completion of the
installation.
d.) A metal or plastic identification plate shall be mounted
at the exterior of the building, 4 feet directly above
the location of vent terminal. The plate shall be of
sufficient size, easily read from a distance of eight
feet away, and read “Gas Vent Directly Below”.
2. For direct-vent appliances, mechanical vent heating
appliances or domestic hot water equipment where the
bottom of the vent terminal and the air intake is installed
above four feet above grade the following requirements
must be satisfied:
a.) A (CO) detector and alarm shall be placed on each
floor level where there are bedrooms. The detector
shall comply with NFPA 720 (2005 Edition) and be
mounted in the living area outside the bedroom(s).
b.) The (CO) detector shall:
• Be located in the room that houses the appliance
or equipment;
• Be hard-wired, battery powered or both.
• Shall comply with NFPA 720 (2005 Edition).
c.) A product-approved vent terminal must be used,
and if applicable, a product-approved air intake must
be used. Installation shall be in strict compliance
with the manufacturer’s instructions. A copy of
the installation instructions shall remain with the
appliance or equipment at the completion of the
installation.
Clearances to Combustible Materials
This furnace is Design Certified in the U.S. and Canada
for the minimum clearances to combustible materials.
NOTE: The furnace is listed for installation on combustible
or non-combustible flooring. However, wood is the only
combustible flooring allowed for installation. To obtain
furnace base model number and specific clearance
information, refer to the furnace rating plate, located inside
of the furnace cabinet.
Access for positioning and servicing the unit must be
considered when locating unit. The need to provide
clearance for access to panels or doors may require
clearance distances over and above the requirements.
Allow 18 inches minimum clearance from the front of
the unit. However 36 inches is strongly recommended.
See Table 1 for minimum clearance requirements.
INSTALLATION CLEARANCES
REAR
LEFT
SIDE
REAR
LEFT
SIDE
RIGHT
SIDE
FRONT
VENT
VENT
FRONT
FRONT AIR RETURN
Front *
Rear
Sides
Top
Duct w/in 3ft of furnace
Vent
Plenum Without Coil Box
Plenum With Coil Box
RIGHT
SIDE
TOP AIR RETURN
CLOSET
ALCOVE
1"
0"
0"
6"
1/4"
0”
1"
0”
1"
0"
0"
6"
1/4"
0”
1"
0”
NOTES:
Alcove Installations - Allow 18 in. minimum clearance
from front of unit to nearest wall or partition for servicing.
Closet installations - Require a return air grill installed
in the door or a partially louvered door across the
opening for proper air circulation. For clearances 6”
or greater, the closet must have an open free area of
235 in2 minimum. For special clearances between 1” &
6”, requirements are a louvered door with a minimum
of 250 in2 (1613 cm2) free area. For 1” clearance from
furnace, use a fully louvered door with at least 400
in2 of free airflow area. A fully louvered closet door is
strongly recommended for all installation types.
Table 1. Minimum Clearance Requirements
5
The ductwork should be appropriately sized to the capacity
of the furnace to ensure its proper airflow rating. For
installations above 2,000 ft., the furnace should have a
sea level input rating large enough that it will meet the
heating load after deration for altitude.
Combustion Air Quality
CAUTION:
Combustion air must not be drawn from a
corrosive atmosphere.
To maximize heat exchanger life, the combustion air
must be free of chemicals that can form corrosive acidic
compounds in the combustion gases. The required source
of combustion air is to use outdoor air.
If outside air is used as return air to the furnace for
ventilation or to improve indoor air quality, the system must
be designed so that the return air is not less than 60° F
(15° C) during operation. If a combination of indoor and
outdoor air is used, the ducts and damper system must
be designed so that the return air supply to the furnace is
equal to the return air supply under normal, indoor return
air applications.
Exposure to the following substances in the combustion
air supply will result in safety and performance related
problems. The list below contains examples of chemical
containments found in a wide variety of common
commercial household products:
• Permanent wave solutions
• Chlorinated waxes and cleaners
• Chlorine based swimming pool chemicals
• Water softening chemicals
• De-icing salts or chemicals
• Carbon Tetrachloride
• Halogen type refrigerants
• Cleaning solvents (perchloroethylene)
• Printing inks, paint removers, varnishes, etc.
• Hydrochloric Acid
• Cements and glues
• Antistatic fabric softeners
• Masonry acid washing materials
Heating Load
This furnace should be sized to provide the design heating
load requirement. Heating load estimates can be made
using approved methods available from Air Conditioning
Contractors of America (Manual J); American Society of
Heating, Refrigerating, and Air Conditioning Engineers;
or other approved engineering methods. Excessive
oversizing of the furnace could cause the furnace
and/or vent to fail prematurely.
6
COMBUSTION AIR & VENTING REQUIREMENTS
WARNING:
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below
for each appliance connected to the venting
system being placed into operation could result
in carbon monoxide poisoning or death. The
following steps shall be followed with each
individual appliance connected to the venting
system being placed in operation, while all other
appliances connected to the venting system
are not in operation:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 or the CSA
B149.1, Natural Gas and Propane Installation
Codes and these instructions. Determine that
there is no blockage or restriction, leakage,
corrosion and other deficiencies which could
cause an unsafe condition.
3. As far as practical, close all building doors and
windows and all doors between the space in which
the appliance(s) connected to the venting system
are located and other spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not
connected to the venting system. Turn on any
exhaust fans, such as range hoods and bathroom
exhausts, so they are operating at maximum
speed. Do not operate a summer exhaust fan.
6. Follow the lighting instructions. Place the
appliance being inspected into operation.
Adjust the thermostat so appliance is operating
continuously.
7. Test for spillage from draft hood equipped
appliances at the draft hood relief opening after 5
minutes of main burner operation. Use the flame
of a match or candle.
8. If improper venting is observed during any of the
above tests, the venting system must be corrected
in accordance with the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 and/or CSA B149.1, Natural
Gas and Propane Installation Codes.
9. After it has been determined that each appliance
connected to the venting system properly vents
when tested as outlined above, return doors,
windows, exhaust fans, fireplace dampers and
any other gas-fired burning appliance to their
previous conditions of use.
7
AVERTISSEMENT:
RISQUE D’EMPOISONNEMENT AU
MONOXYDE DE CARBONED
Le non-respect des consignes suivantes portant
sur chacun des appareils raccordés au système
d’évacuation mis en service pourrait entraîner
l’empoisennement au monoxyde de carbone ou
la mort. Les consignes suivantes doivent être
observées pour chaque appareil raccordé au
système d’évacuation mis en service si les autres
appareils raccordés au système ne sont pas en
service:
1. Sceller toute ouverture non utilisée de la systéme
d’évacuation;
2. S’assurer que la systéme d’évacuation présente
des dimensions et une pente horizontale
conformes à la norme ANSI Z223.1/NFPA
54, intitulée National Fuel Gas Code ou aux
codes d’installation CSA-B149.1, ainsi qu’aux
présentes instructions. S’assurer que la systéme
d’évacuation n’est pas bloquée, restreinte,
corrodée, qu’elle ne fuit pas et qu’elle ne présente
aucun autre défaut potentiellement dangereux;
3. Dans la mesure du possible, fermer toutes les
portes et fenêtres du bâtiment, et toutes les portes
entre la pièce où se trouve l’appareil raccordé à
la systéme d’évacuation et les autres pièces du
bâtiment.
4. Fermer les registres des foyers;
5. Mettre en service les sécheuses et tout autre
appareil qui n’est pas raccordé à la systéme
d’évacuation. Faire fonctionner à régime maximal
tout ventilateur d’évacuation, tel que les hottes de
cuisinière et les ventilateurs de salles de bains.
Ne pas mettre en service les ventilateurs d’été.
6. Respecter les instructions d’allumage. Mettre en
service l’appareil à l’essai. Régler le thermostat
de manière à ce que l’appareil fonctionne sans
interruption;
7. Vérifier s’il y a débordement à l’orifice
d’évacuation du coupe tirage des appareils dotés
d’un coupe tirage 5 minutes après l’allumage
du brûleur principal. Utiliser la flamme d’une
allumette ou d’une chandelle.
8. Si l’on constate, au cours de l’un des essais
qui précèdent, que l’évacuation est déficiente,
corriger le système d’évacuation conformément
à la norm ANSI Z223.1/NFPA 54, National Fuel
Gas Code, et (ou) aux codes d’installation CSA
B149.1.
9. Après avoir déterminé que tous les appareils
raccordés à la systéme d’évacuation évacuent
correctement tel que prescrit ci-dessus,
rouvrir les portes et les fenêtres et remettre les
ventilateurs d’évacuation, les registres de foyers
et tout autre appareil fonctionnant au gaz à leur
état de fonctionnement initial.
Important Information
WARNING:
Furnace installation using methods other than
those described in the following sections must
comply with the National Fuel Gas Code (NFGC)
and all applicable local codes.
WARNING:
Upon completion of the furnace installation,
carefully inspect the entire flue system both
inside and outside the furnace to assure it is
properly sealed. Leaks in the flue system can
result in serious personal injury or death due
to exposure of flue products, including carbon
monoxide.
WARNING:
This furnace must not be vented with other
appliances, even if that appliance is of the
condensing type. This includes water heaters
of any efficiency. Common venting can result
in severe corrosion of other appliances or their
venting and can allow combustion gases to
escape through such appliances or vents. Do
not vent the furnace to a fireplace chimney or
building chase.
• This furnace must be vented in compliance with
the current revision of the National Fuel Gas Code
(ANSI-Z223.1/NFPA54). Instructions for determining
the adequacy of combustion air for an installation
can be found in the current revision of the NFGC
(ANSI Z223.1 / NFPA54). Consult local codes for
special requirements. These requirements are for
US installations as found in the NFGC.
• The requirements in Canada (B149.1) are structured
differently. In Canada, venting shall conform to the
requirements of the current (CAN/CGA B149.1 or .2)
installation codes. Consult local codes for special
requirements.
Category IV Appliances
This furnace is classified as a Category IV appliance,
which requires special venting materials and installation
procedures. Category IV appliances operate with positive
vent pressure and requires thoroughly sealed vent
systems. They also produce liquid condensate, which is
slightly acidic and can cause severe corrosion of ordinary
venting materials. Furnace operation can be adversely
affected by restrictive vent and combustion air piping.
Direct Vent Installation
This condensing furnace is certified for installation as a
direct vent (2-pipe) appliance. Direct vent (2-pipe) furnaces
draw combustion air directly from the outdoors and then
vent the combustion products back outside, isolating the
entire system from the indoor space. It is important to make
sure that the whole system is sealed and clearances to
combustibles are maintained regardless of the installation
being in a confined or unconfined space. This section
specifies installation requirements for direct vent (2-pipe)
piping. Table 2, (page 9) contains the length of vent
and combustion air piping for this type of installation.
Provisions must be made during the installation of this
furnace that provide an adequate supply of fresh air for
combustion and ventilation. The combustion air from the
outside needs to be clear of chemicals that can cause
corrosion. The inlet pipe should not be placed near
corrosive chemicals such as those listed on page 5.
Air openings on top of the furnace and openings in closet
doors or walls must never be restricted. If the furnace is
operated without adequate air for combustion, the flame
roll-out switch will open, turning off the gas supply to the
burners. This safety device is a manually reset switch.
DO NOT install jumper wires across these switches
to defeat their function or reset a switch without
identifying and correcting the fault condition. If a
switch must be replaced, use only the correct sized part
specified in the Replacement Parts List provided online.
Vent Pipe Length & Diameter
For proper furnace operation, the combustion air and vent
piping must not be excessively restrictive.
• The venting system should be designed to have the
minimum number of elbows or turns.
• All horizontal runs must slope upwards from the furnace
at 1/4 inch minimum per running foot of vent.
• Transition to the final vent diameter should be done
as close to the furnace outlet as practical.
• Always use the same size or a larger pipe for combustion
air that is used for the exhaust vent.
Table 2, (page 9) indicates the maximum allowable pipe
length for a furnace of known input rate, when installed
with piping of selected diameter and number of elbows. To
use the table, the furnace input rate, the centerline length
and the number of elbows on each pipe must be known.
When estimating the length of vent runs, consideration
must be made to the effect of elbows and other fittings.
This is conveniently handled using the idea of “equivalent
length”. This means the fittings are assigned a linear length
that accounts for the pressure drop they will cause. For
example: a 3” diameter, long radius elbow is worth the
equivalent of 3.5 feet of linear run.
The equivalent lengths of tees and various elbows are
listed in Table 2. Measure the linear length of your vent run
and then add in the equivalent length of each fitting. The
total length, including the equivalent fitting lengths, must
be less than the maximum length specified in the table.
Condensing furnace combustion products have very little
buoyancy, so Table 2 is to be used without consideration
of any vertical rise in the piping.
8
MAXIMUM DIRECT VENT, DUAL PIPE LENGTH (FT.)
MG2S INPUTS
(BTU)
INLET / OUTLET
2” DIAMETER
INLET / OUTLET
3” DIAMETER
45,000
30
60
60,000
30
60*
30
60
72,000
†
NOTES:
1. Subtract 2.5 ft. for each additional 2 inch long radius elbow, subtract
5 ft. for each additional 2” short radius elbow, subtract 3.5 ft. for each
additional 3 inch long radius elbow, and 7 ft. for each additional 3
inch short radius elbow.
2. Two 45 degree elbows are equivalent to one 90 degree elbow.
3. This table applies for elevations from sea level to 2,000 ft. For higher
elevations, decrease pipe lengths by 8% per 1,000 ft of altitude.
*. For the 60,000 BTU top return furnace, the length of the 3 inch
diameter pipe must not be longer than 30 feet.
Table 2. Vent Pipe Lengths
Vent Pipe Material
Vent and combustion air pipe and fittings must be one
of the following materials in the list and must conform to
the indicated ANSI/ASTM standards.
APPROVED VENT PIPE MATERIALS
HEAT DEFLECTION
TEMPERATURE
Materials
PVC
°F
158°
°C
Product Description/Standard
70°
DWV per ASTM D2665 or
CSA B181.2. Schedule 40, 80,
or 120 per ASTM D1785 or CSA
B137.3, or SDR Series per ASTM
D2241 or CSA D137.3
CPVC
212°
100°
CPVC 41 per ASTM D2846/
D2846M or CSA B137.6.
Schedule 40 or 80 per ASTM
F441/F441M or CSA B137.6
SDR Series per ASTM F442/
F442M
ABS
180°
82°
Schedule 40 or DWV per ASTM
D2661 or CSA B181.1
Table 3. Approved Vent Pipe Materials
NOTES:
° Based on HDT in accordance with ASTM D648 (HDT at 264 psi
(1.82 Mpa)).
Cellular Core PVC (ASTM F891), cellular core ABS, Radel® (polyphenysulfone)
and Utem, shall not be used in non-metallic venting systems.
In Canada, all plastic vent pipes and fittings including cement, cleaners, or primers
must be certified as a system to ULCS636. However this requirement does not
apply to the finish flanges or piping internal to the furnace.
When joining PVC to PVC, use cement that conforms to ASTM standard D2564.
PVC primer must meet standard ASTM F656. When joining ABS to ABS, use
cement that conforms to ASTM standard D2235. When joining PVC to ABS, use
cement as specified in procedure from ASTM standard D3138.
When using PolyPro® or Innoflue®, all venting and fittings must be from the same
manufacturer with no interchanging of other materials. Refer to specific instructions
supplied with the PolyPro or Innoflue vent kits.
Materials not identified in Table 3. Approved Vent Pipe Materials are tested to
ASTM D648.
9
Vent Pipe Installation
CAUTION:
Combustion air must not be drawn from a
corrosive atmosphere.
This furnace has been certified for installation with zero
clearance between vent piping and combustible surfaces.
However, it is good practice to allow space for convenience
in installation and service.
• In the absence of local codes, the location of any
combustion air inlet relative to any vent terminal must
be at least 8 inches. This includes installations involving
more than one furnace.
• The quality of outdoor air must also be considered. Be
sure that the combustion air intake is not located near
a source of solvent fumes or other chemicals which
can cause corrosion of the furnace combustion system.
See page 6 for a sample list of substances.
• Route piping as direct as possible between the furnace
and the outdoors. Longer vent runs require larger
diameters. Vent piping must be sloped upwards 1/4”
per foot in the direction from the furnace to the terminal.
This ensures that any condensate flows back to the
condensate disposal system.
• The combustion air intake and the vent exhaust must
be located in the same atmospheric pressure zone.
This means both pipes must exit the building through
the same portion of exterior wall or roof as shown in
Figure 1, Figure 2, Figure 4, and Figure 30 (page 39).
• Piping must be mechanically supported so that its
weight does not bear on the furnace. Pipe supports
must be installed a minimum of every five feet along the
vent run to ensure no displacement after installation.
Supports may be at shorter intervals if necessary to
ensure that there are no sagging sections that can trap
condensate. It is recommended to install couplings
(Figure 30) along the vent pipe, on either side of the
exterior wall. Couplings may be required by local code.
• If breakable connections are required in the combustion
air inlet pipe (if present) and exhaust vent piping, then
straight neoprene couplings with hose clamps can be
used. These couplings can be ordered through your
local furnace distributor. To install a coupling:
1. Slide the rubber coupling over the end of the pipe
that is attached to the furnace and secure it with
one of the hose clamps.
2. Slide the other end of the rubber coupling onto the
other pipe from the vent.
3. Secure the coupling with the second hose clamp,
ensuring that the connection is tight and leak free.
Outdoor Terminations - Horizontal Venting
• Vent and combustion air intake terminations shall be
installed as shown in Figure 1, Figure 2, Figure 3, and
Figure 4 in accordance with these instructions:
• Vent termination clearances must be consistent with the
NFGC, ANSI 2223.1/NFPA 54 and/or the CSA B149.1,
Natural Gas and Propane Installation Code. Table 15,
(page 37) lists the necessary distances from the vent
in.
18” M
ax.
36” M
t
st ven
Exhauon C
opti
t
st ven
Exhauon A
ti
p
o
building materials from degradation by moisture content
in flue gases. When wall venting on surfaces that could
be affected by this moisture, it is recommended that a
corrosion resistant shield be used behind the vent terminal.
Adequately seal or caulk all joints, cracks, and seams
around the vent terminal. (Figure 1 (page 10))
t
st ven
Exhauon B
ti
op
90
.
8” Minx.
a
M
”
6
3
ions)
ll posit
ustion
Combinlet
air
(a
um
maxim vel
in. to
le
12” mcted snow
expe oth pipes)
(b
Figure 1. Inlet & Exhaust Pipe Clearances
Dir
ec
50 term t ven
,00 ina t
or 0 Bt l
les uh
s
Me
dra chan
ter ft venical
min t
al
9 in
.
No
te
4f
t
2
Mechanical draft
vent terminal
4 ft
No
te
l
ica
an
ch nt
Meaft veal
dr min
ter
12
in.
.
3 ft
ss
Lean
th ft.
10
2
n.
2i
NOTES:
1. All dimensions shown are
minimum requirements.
2. Exterior vent terminations must
be located at least 12” above the
maximum expected snow level.
1
te
No
2
Forced air inlet
Direct vent
terminal - more
than 50,000 Btuh
Figure 2. Vent Locations
19" Max.
(See Note)
Support
Outside
Wall
12" Above
Maximum
Expected
Snow Level
1/2"
Armaflex
Insulation or
Equivalent
(if required)
NOTE: Vent Configuration to Provide
12" Minimum height above Snow Level.
Figure 3. Alternate Horizontal Vent Installation
• For optimal performance, vent the furnace through
a wall that experiences the least exposure to winter
winds.
• The vent termination shall be located at least 3 ft.
horizontally from any electric meter, gas meter, regulator
and any relief equipment. These distances apply ONLY
to U.S. installations. In Canada, CSA B149.1 takes
precedence over these instructions.
• Do not install the vent terminal such that exhaust is
directed into window wells, stairwells, under decks
or into alcoves or similar recessed areas, and do not
terminate above any public walkways.
• If venting horizontally, side wall vent kits are available
according to the pipe diameter size of the installation.
Faceplate kits are also available for 3 inch horizontal
venting. Please follow the instructions provided
with the kits.
• Concentric vent kits are available for both 2” and 3”
applications. Each size has one that meets UL 1738
and one that meets ULC S636. Refer to the technical
sales literature for kit numbers.
• When the vent pipe must exit an exterior wall close
to the grade or expected snow level where it is not
possible to obtain clearances shown in Figure 1, a riser
may be provided as shown in Figure 3. Insulation is
required to prevent freezing of this section of pipe. See
Table 4, (page 11) for vent freezing protection.
• The vent shall not terminate near soffit vents or crawl
space vents or other areas where condensate or vapor
could create a nuisance or hazard or cause property
damage (see Figure 30 (page 39)); nor shall the vent
terminate where condensate vapor could cause damage
Elbows on the combustion air
inlet must be positioned pointing
away from the exhaust vent.
12” Above Maximum
Expected Snow Level
(Both pipes)
Plumbing Vent Roof Boot
(Both Pipes)
Exhaust Vent
w
° Elbo
Combustion Air
te
faceplarews
c
ng kit
Mountito wall with s
)
d
secure (both pipes
termination to windows and building air intakes.
• Vent and combustion air intake terminations must
be located to ensure proper furnace operation and
conformance to applicable codes. A vent terminal
must be located at least 3 feet above any forced air
inlet located within 10 feet. This does not apply to the
combustion air inlet of a direct vent (two pipe) appliance.
In Canada, CSA B149.1 takes precedence over these
instructions. See Table 16, (page 38).
• All minimum clearances must be maintained to protect
in.
8" M ax.
M
36"
Figure 4. Vertical Vent Termination
10
or could be detrimental to the operation of regulators,
relief valves, or other equipment.
• For installations in a manufactured (mobile) home,
vent and air intake pipes vented through the exterior
wall shall not project more than 3” beyond the outer
surface of the wall.
to freezing, but must not be excessively restrictive.
• To prevent debris or creatures from entering the
combustion system, a protective screen may be
installed over the combustion air intake opening. The
screens hole size must be large enough to prevent air
restriction.
Outdoor Terminations - Vertical Venting
Existing Installations
Termination spacing requirements from the roof and from
each other are shown in Figure 4. The roof penetration
must be properly flashed and waterproofed with a plumbing
roof boot or equivalent flashing. Vent and combustion air
piping may be installed in an existing chimney which is
not in use provided that:
• Both the exhaust vent and air intake run the length of
the chimney.
• The top of the chimney is sealed and weatherproofed.
• The termination clearances shown in Figure 4 are
maintained.
• No other gas fired or fuel-burning equipment is vented
through the chimney.
Vent Freezing Protection
CAUTION:
When the vent pipe is exposed to temperatures
below freezing (i.e., when it passes through
unheated spaces, chimneys, etc.) the pipe
must be insulated with 1/2 inch thick sponge
rubber insulation, Armaflex-type insulation or
equivalent. Insulating pipe is important to avoid
condensate icing.
When an existing furnace is removed from a vent system
serving other appliances, the existing vent system may
not be sized properly to vent the remaining appliances
(example: water heater). An improperly sized venting
system can result in the formation of condensate, leakage,
or spillage. The existing vent system should be checked
to make sure it is in compliance with NFGC and must be
brought into compliance before installing the furnace.
NOTE: If replacing an existing furnace, it is possible you
will encounter an existing plastic venting system that is
subject to a Consumer Product Safety Commission recall.
The pipes involved in the recall are High Temperature
Plastic Vent (HTPV). If your venting system contains
these pipes DO NOT reuse this venting system! This
recall does not apply to other plastic vent pipes, such
as white PVC or CPVC. Check for details on the CPSC
website or call their toll-free number (800) 758-3688.
Ventilaire III or IV Air Quality Package
The Ventilaire air quality accessory packages are available
to meet the ventilation requirements as outlined in H.U.D.
Standard Part 3280.103 (b) (2). These packages introduce
outdoor air into the living space during furnace blower
operation. The VentilAire IV also serves to exhaust moist
and/or hot air from the attic space. See Figure 5 for typical
installation. Complete installation instructions are supplied
with each air quality package.
• Table 4 lists the maximum length of flue pipe that can
travel through an unconditioned space or an exterior
space. The total vent length must not exceed the
lengths noted in the table. For Canadian installations,
please refer to the Canadian Installation Code (CAN/
CGA-B149.1 or 2) and/or local codes.
• For extremely cold climates or for conditions of short
furnace cycles (i.e. set back thermostat conditions)
the last 18 inches of vent pipe can be reduced. It is
acceptable to reduce from 3” to 2-1/2” or, 3” to 2” if
the total vent length is at least 15 feet in length, and
the vent length is within the parameters specified in
Table 2, (page 9). The restriction should be counted as 3
equivalent feet. Smaller vent pipes are less susceptible
Winter Design
Temperature
Maximum Flue Pipe Length (FEET)
in Unconditioned & Exterior Spaces
Without Insulation
With Insulation*
20
45
60
0
20
60
-20
10
60
*NOTE: Insulation thickness greater than 3/8 inch, based on an
R value of 3.5 (ft x F x hr) / (BTU x in.)
Table 4. Vent Protection
11
VentilAire III
VentilAire IV
Figure 5. VentilAire III & IV
A2L Indoor Coil
C85 Loose Coils
C85 Loose Coils have been evaluated for the safe use
of A2L refrigerants, to meet requirements by Nortek and
the standards in UL 60335-2-40. Due to the nature of
the flammability of A2L refrigerants, modifications have
been made to mitigate refrigerant leaks from a C85 coil
in an MG2 furnace. Nortek has added an A2L sensor on
all C85 coils located in the front plate. See Figure 6. See
the C85 wiring diagrams and installation instructions for
the installation of an C85 coil in an MG2 furnace.
Coils from other Manufacturers
If coils are used by other manufacturers, follow the coil
manufacturer guidelines for installation and wiring.
duct and must be installed in accordance with the
standards of the National Fire Protection Association
Standard for Installation of Air Conditioning Systems
(NFPA 90A), Standard for Installation of Residence Type
Warm Air Heating and Air Conditioning Systems (NFPA
90B), and all applicable local codes. NFPA publications
are available by writing to: National Fire Protection
Association, Batterymarch Park, Quincy, ME 02269 or go to
www.NFPA.org on the web.
• Design the air ducts according to methods described
by the Air Conditioning Contractors of America (ACCA).
• Gas piping must not run in or through any of the air
duct system.
• Air conditioning systems may require more duct register
and open louver area to obtain necessary airflow.
• Noncombustible pans having one inch upturned flanges
are located beneath openings in a floor return duct
system.
Supply Air Connections
A2L Sensor
Figure 6. A2L Sensor Location
CIRCULATING AIR REQUIREMENTS
WARNING:
Do not allow combustion products to enter the
circulating air supply. Failure to prevent the
circulation of combustion products into the
living space can create potentially hazardous
conditions including carbon monoxide poisoning
that could result in personal injury or death.
All supply ducts must be secured to the furnace
with sheet metal screws and adequately sealed.
When supply air is provided through the bottom
of the unit, the joint between the furnace and the
plenum must be air tight.
The surface that the furnace is mounted on must
provide sound physical support of the furnace
with no gaps, cracks or sagging between the
furnace and the floor or platform.
Supply air ducts must not be connected to any
other heat producing device such as a fireplace
insert, stove, etc. This may result in fire, explosion,
carbon monoxide poisoning, personal injury, or
property damage.
Plenums & Air Ducts
This unit is designed only for use with a bottom supply
• For proper air distribution, the supply duct system must
be designed so that the static pressure measured
external to the furnace does not exceed the listed static
pressure shown on the furnace rating plate. The supply
air must be delivered to the heated space by duct(s)
secured to the furnace casing, running full length and
without interruption.
• Duct system must be designed so that no supply
registers are located in duct system directly below the
furnace.
Return Air Connections
• Front return furnaces are factory configured for the
return air to flow through the front louvered door. The
return air may also be attached to either side of the
furnace cabinet using a field installed kit. The location
and size of the side and top return air connections
are shown in Figure 24 (page 30) & Figure 25
–. The filter size for the side return air is 20” x 20” x 1”.
• Top return furnaces are factory configured for the
return air to enter the top of the furnace. See Figure 25
(page 31).
NOTE: For top return installations, an external or inwall filter mount can be used. The factory installed
filter should be removed and the return duct should
be sized to provide adequate airflow.
• For floor return systems, the manufactured housing
manufacturer or installer shall affix a prominent marking
on or near the appliance where it is easily read when
the closet door is open. The marking shall read:
CAUTION, HAZARD OF ASPHYXIATION. DO NOT
COVER OR RESTRICT FLOOR RETURN AIR
OPENING.
• Return air openings should not be located to draw air
directly from a bathroom.
• Materials located in the return duct system shall have
a flame spread classification of 200 or less.
• The total free area of the openings in the floor or the
ceiling registers serving the return air duct system must
not be not less than 352 in2 (2,270 cm2).
12
A Single trunk duct
1” clearance from furnace, use a fully louvered door
with at least 400 in2 (2,580 cm2) of free airflow area.
Furnace Filter
WARNING:
Dual trunk duct
B w/crossover connector
C
Transition duct
w/branches
Figure 7. Typical Supply Duct Systems
Closet & Alcove Installations
WARNING:
Failure to comply with the the following
instructions may result in fire, asphyxiation or
carbon monoxide poisoning.
For proper air circulation, closet installations require
a return air grill installed in the door or side wall that
exchanges with the living area of the home. A partially
louvered door may also be used across the opening. Grilles
placed in a side wall require a 6” clearance from the wall
to the furnace so that the air may enter the front grille
of the furnace. All return air systems, including the floor
and ceiling systems, must meet the following conditions:
• The return air opening, regardless of its location in the
closet, must not be smaller than size specified on unit
data label. If located in the floor, the opening must be
provided with a means of preventing its inadvertent
closure by flat object(s) placed over the opening.
• The cross-sectional area of the return duct system (in
floor or ceiling) leading into the closet must not be less
than 235 in2 (1,516 cm2).
CAUTION:
HAZARD OF ASPHYXIATION: Negative pressure
inside the closet, with closet door closed and
the furnace blower operating on high speed,
shall be no more negative than minus 0.05 inch
water column.
• Test the negative pressure in the closet with the aircirculating fan operating at high speed and the closet
closed. The negative pressure in the closet must not
be less than minus 0.05 inches water column with the
closet door closed and the fan operating at high speed.
The negative pressure is to be no more negative than
minus 0.05” water column as this indicates a dirty filter
or a restricted return air system.
• For closet installation with less than 6” front clearance,
but not less than 1”, a louvered door must be used
having a minimum 250 in2 (1,613 cm2) free area opening
directly in line with openings in the furnace door. For
13
Never operate the furnace without a filter in place.
Accumulating dust in the return air can build
up on internal components, resulting in loss of
efficiency, equipment damage, and possible fire.
• Front return furnaces are supplied with a single reusable
air filter when shipped from the factory. Accessing the
filter does not require tools and can be easily removed
from the inside of the access door. The filter is secured
to the door with a retaining bracket.
• Top return furnaces are shipped with a non-reusable
single 18” x 18” x 1” air filter from the factory. Accessing
the filter does not require tools and can be easily
removed from inside the blower compartment. The
filter is secured with a U-shaped retaining bracket. It
is recommended that the filter be cleaned or replaced
monthly. Newly built or recently renovated homes may
require more frequent changing until the construction
dust has minimized.
1. Slide the standard 18” x 18” x 1” filter into the space
between the combustion air pipe and the blower
assembly. See Figure 8 (page 14). NOTE: Make
sure the airflow arrows on the filter point towards
the blower assembly.
2. Push the filter to the rear of the furnace cabinet and
angle it up over the blower. Make sure the filter is
pushed back as far as possible.
3. Position the filter retainer under the filter and insert
the stepped ends into the 0.25 holes in the rear of
the furnace. NOTE: The stepped ends should be
facing upwards in the holes.
4. Evenly align the filter over the opening in the top of
the furnace cabinet and position the other end of
filter retainer up over the flange in the furnace’s top
panel. NOTE: To properly secure the filter, make
sure the filter retainer is properly positioned in the
top panel of the furnace. There should be no visible
air gaps. The retainer may slide left or right slightly,
but must not have any movement between the front
and rear. See Figure 5.
• Replacement filters are available at most local retailers.
Inspect filters frequently and replace when necessary
with filter of same dimensional size. Filters designed to
remove smaller particles such as pollen, may require
additional maintenance.
Dampers
An automated shut off damper is required when the home
is air conditioned by a self-contained unit. A damper
is required to prevent chilled air from flowing over the
furnace heat exchanger. This damper is designed to fit
in the feeder duct cavity, directly under the furnace. For
proper installation, refer to the instructions provided with
the damper. See replacement parts list provided online.
Insert filter between
blower assembly &
combustion air pipe
Blower
Assembly
Angle the filter into place
above the blower assembly
Filt
er
Blower
Assembly
Combustion Air Pipe
Filter
Combustion Air Pipe
Blower
Assembly
Combustion Air Pipe
Align the filter
over the opening and
secure with filter retainer
Figure 8. Filter Installation
14
FURNACE INSTALLATION
NOTE: These Installation procedures are suggested for
typical furnace installations. Since each installation is
different, the sequence of instructions may differ from
the actual installation. Only qualified HVAC technicians
should install this furnace.
The installer must be familiar with and comply with all
codes and regulations applicable to the installation of
these heating appliances and related equipment. In
the absence of local codes, the installation must be in
accordance with the current provisions of one or more of
the following standards.
• Federal Manufactured Home Constructions & Safety
Standard (H.U.D. Title 24, Part 3280.707[a][2]), or
when this Standard is not applicable, the Standard for
Manufactured Home Installations (ANSI/NCS A225.1)
and/or MH Series Mobile Homes (CAN/CSA Z240
• American National Standard (ANSI-119.2/NFPA-501C)
for all recreational vehicle installations.
• American National Standard (ANSI-Z223.1/NFPA-54)
and/or CAN/CSA B149 for all gas-fired furnace models.
• American National Standard (ANSI-Z95.1/NFPA-31)
and/or CSA B139 for all oil-fired furnace models.
• American National Standard (NFPA-70) and/or CSA
22.1 Canadian Electric Code Part 1 for all electrical
field wiring.
• Units have been researched under standards UL 307A
& B, UL727-1999, ANSI Z21.47b/CSA 2.3b, and CSA
B140.10.
About The Furnace
The MG2S furnace is designed only for indoor installations
and can be readily connected to the high static duct system
of a home. Units are approved for mobile/manufactured
structures in freestanding/closet/alcove downflow only
configurations.
This appliance will provide many years of safe and
dependable comfort, providing it is properly installed
and maintained. Abuse, improper use, and/or improper
maintenance can shorten the life of the appliance and
create unsafe hazards. Please read all instructions before
installing the unit.
Approved installation, operation, and maintenance of
this appliance must be in accordance with the listed
specifications contained in these instructions and other
documents supplied with the furnace and/or optional air
conditioning equipment. Unless it is noted differently in this
manual, only use factory authorized kits and accessories on
this appliance. Refer to local authorities having jurisdiction
for further information.
Before You Install this Furnace
√ This equipment is securely packaged at the time of
shipment and upon arrival should be carefully inspected
for damage prior to installing the equipment at the job
site. Claims for damage (apparent or concealed) should
be filed immediately with the carrier.
√ Check the electrical supply and verify the power supply
is adequate for unit operation. The system must be wired
and provided with circuit protection in accordance with
15
local building codes. If there is any question concerning
the power supply, contact the local power company.
√ Verify the air delivery of the furnace is adequate to
handle the static pressure drop of the coil, filter, and
duct work.
Locating the Unit
• The dimensions of the room or alcove must be able to
accommodate the overall size of the unit and required
clearances to combustible materials listed in Table 1,
(page 5). Access for positioning and servicing must
also be considered when locating the unit. To determine
the required clearances needed for installation and
combustible materials, refer to Figure 24 (page 30) &
Figure 25 (page 31) for overall dimensions.
• The furnace must be installed on a solid surface
and must be level front-to-back and side-to-side at
installation. The surface that the furnace is mounted
on must provide sound physical support of the unit.
• The furnace should be installed as close to the center
of the air distribution system as possible and attached
to a properly installed duct system. Do not use the
back of the furnace for return air. See page 12
for circulating requirements.
• The furnace must be installed so that all electrical
components are protected from water.
• The plenum attached to the A/C coil box and ductwork
within 3 ft. of the furnace must be installed so that
surfaces are at least 1/4” from combustible construction.
• When installed in a residential garage, the furnace must
be positioned so the burners and the source of the
ignition are located no less than 18 inches above the
floor and protected from physical damage by vehicles.
• This furnace is certified for use on wood flooring
or supports, but must not be installed directly on
carpeting, tile, or any combustible material other than
wood flooring. NOTE: The furnace may be installed on
combustible flooring when installed on a manufacturer’s
approved duct connector (Figure 9). This factory
supplied accessory must be installed in the floor cavity
and attached to the supply air duct before the downflow
furnace is installed.
• The furnace must be installed upstream from a
refrigeration system.
REDUCER
(See Notes)
FELT-SEAL
FIBERGLASS
INSULATION
SPACERS
DUCT CONNECTOR TABS
NOTES:
With reducer installed: Opening to duct is 10-1/4” x 13-1/4”.
With reducer removed: Opening to duct is 13-1/4” x 13-1/4”.
Figure 9. Duct Connector
Locating & Cutting Floor Openings
FLOOR OPENING
“X”
SUPPLY AIR DUCT
FLOOR
CAVITY
Duct Connector
Type & Part Number
If Floor Cavity
(“X”) is:
Finger Tab
Screw Down
7/8” (22)
901987A
904008
2” (51)
901988A
904009
4-1/4” (108)
901989A
904010
6-1/4” (159)
901990A
904011
8-1/4” (210)
901991A
904012
10-1/4” (260)
901992A
904013
12-1/4” (311)
901993A
904014
NOTE: Dimensions shown as Inches (Millimeter)
Table 5. Duct Connector Sizes
20"
2 1/4
2 3/4
16 3/4
21 5/8
TYP.
14 1/2”
CL
1 1/2 TYP.
1/2 TYP.
Furnace Door
Optional floor cutouts for gas,
condensate, or AC linesets
(3 1/2 x 1 1/2 - 2 places)
Figure 10. Floor Cutout Dimensions
20"
CEILING CUT-OUTS FOR
VENT & COMBUSTION AIR
23 3/4"
FURNACE OUTLINE
21 7/8
REAR WALL OF CLOSET OR ALCOVE
EXHAUST
VENT
COMBUSTION
AIR INLET
CL
CL
2 1/2
Locating & Cutting Ceiling Openings
IMPORTANT NOTE: Cut-outs in the ceiling and roof
must be carefully located to avoid misalignment of
the furnace, combustion air piping, and vent piping.
See Figure 10.
1. Measure from the rear wall or alcove and mark the
centerlines of both cut-outs in the ceiling.
2. Using the centerlines as a starting point, draw the rest
of the cut-outs to the dimensions shown in Figure 11.
3. Cut out the ceiling openings.
Installing Finger Tabbed Duct Connectors
Floor Cut-Out for
Duct Connector
14 1/2”
FURNACE CABINET OUTLINE
REAR WALL OF CLOSET OR ALCOVE
IMPORTANT NOTE: Cut-outs in the floor, must be
carefully located to avoid misalignment of the furnace.
1. Measure from the rear wall or alcove and mark the
centerline of the cut-out on the floor. Using the centerline
as a starting point, draw the rest of the duct cut-out to
the dimensions shown in Figure 10.
2. Cut out the floor opening to within 1” of the actual cutout
drawn.
3. Measure from the top of the floor down to the top of the
supply air duct to obtain the depth of the floor cavity.
NOTE: The depth of the floor cavity shown as “X” in
Table 5 will determine the correct duct connector.
4. Determine which duct connector to use from the table.
6. Measure and drill gas hole and cut out for cooling coil
(if applicable).
The standard duct connector is designed for use on ducts
12” in width. However ducts narrower than 12” may not
allow sufficient clearances for this type of installation.
For an alternate installation method, see Narrow Duct
Attachment - Option 1 or Option 2 on page 17.
1. Center the duct connector in the floor opening with
bottom tabs resting on top of the supply air duct.
2. Mark the cut-out area on the supply air duct by tracing
around the connector tabs of the duct connector. See
Figure 12 (page 17).
3. Remove the duct connector and cut out the marked
area of the supply air duct 1/16” larger the actual cutout
drawn.
4. Install the duct connector back in the floor opening with
the bottom tabs extending into the supply air duct.
5. Install the mounting plate (Figure 12) under the back
side of the duct connector. Align the screw holes in
both components.
6. Secure the duct connector and the mounting plate to
the wood floor with appropriate size screws.
7. Bend the connector tabs on the bottom of the duct
connector upwards and as tight as possible against
the supply air duct. See Figure 12.
8. Seal all connections with industrial grade sealing tape
or liquid sealant. NOTE: Requirements for sealing
ductwork vary from region to region. Consult with local
codes for requirements specific to your area.
2 3/4
CL
FURNACE
OUTER
DOOR
CL
Figure 11. Ceiling Cut-Out Dimensions
16
Finger Tabs
Fold duct flap here
or
Remove
this Flap
Cut Here
Remove
this Flap
Mounting
Plate
Cu
ere
Cu
tH
ere
tH
Cutting
Option A
re
e
tH
Cut Here
ere
Tabs slide into slots
in back of furnace
Supply
Air Duct
Cu
Flo
tH
od
Wo
Cu
Hole for
Gas Line
Narrow
Duct
Fold duct flaps
into duct
connector
Fold duct flap here
Duct
Connector
Connector
Tabs
ply
Sup Duct
Air
Bend tabs tightly
against supply air duct
Figure 12. Finger Tabbed Duct Connector
Cutting
Option B
Cut Here
NOTE: The duct connector tabs may be attached to
the air duct with sheet metal screws or other suitable
fasteners as long as the duct connector and the air duct
are securely attached.
7. Seal all connections with industrial grade sealing tape
or liquid sealant.
NOTE: Requirements for sealing ductwork vary
from region to region. Consult with local codes for
requirements specific to your area.
Narrow Duct Attachment - Option 2
This alternate attachment method may be used to install
a furnace duct connector to narrow metal ductwork if
insufficient clearances prevent the bending of the duct
connector tabs at the side of the duct.
1. Cut and remove the top of the supply air duct as shown
in Figure 14.
2. Install the duct connector with the bottom tabs extending
into the supply air duct.
3. Bend the tabs on the bottom of the duct connector
upwards and as tight as possible against the supply
air duct (Figure 14).
4. Secure the duct connector tabs to the supply air duct
with staples (3 minimum) or sheet metal screws (2
minimum).
Supply
Air Duct
Narrow
Duct
Fold Flap Here
Figure 13. Narrow Air Ducts - Option 1
Narrow Duct Attachment - Option 1
This alternate attachment method may be used to install
a furnace duct connector to narrow metal ductwork if
insufficient clearances prevent the bending of the duct
connector tabs at the side of the duct.
1. Select Option A or Option B in Figure 13 and cut the
top of the supply air duct. Remove metal flaps from the
duct (shaded area) if Option A is selected.
2. Fold the duct flaps up to form an opening for the duct
connector (applies to Options A or B).
3. Install the duct connector with the bottom tabs extending
into the supply air duct.
4. Bend the tabs on the bottom of the duct connector
upwards and as tight as possible against the removed
ends of the supply air duct.
5. Form the duct flaps up against the side of the duct
connector as tight as possible. See Figure 13.
6. Secure the duct connector flaps to the supply air duct
with staples (3 minimum) or if a 2x block/joist is not
provided, use sheet metal screws (2 minimum).
Cut Here
Supply
Air Duct
Cut Here
Duct Connector
17
Secure Flaps with Staples
or sheet metal screws
Fold Flap Here
Secure finger tabs to
side of air duct with staples
or sheet metal screws
Finger Tabbed
Duct Connector
Supply Air Duct
Cut out & remove
Narrow
Duct
Bend tabs tightly
against supply air duct
Figure 14. Narrow Ducts - Option 2
Installing Screw-Down Duct Connectors
1. Apply a bead of caulking, mastic, or other approved
sealant around bottom side of 1/2” flange and restrictor
plate (when applicable). See Figure 15
2. Locate the screw down duct connector over the duct
and carefully lower it into place.
3. Secure the duct connector to the floor using flat head
screws or nails. NOTE: Make sure the duct connector
flanges stay in contact with the duct.
4. Secure the plenum to the duct using sheet metal screws
making sure a tight seal is made between the duct and
the duct connector. NOTE: Additional screws may be
added if required.
5. Cut away along edge of flange allowing the center to
drop into the duct. NOTE: Remove section of duct with
caution, as edges will be sharp.
Round Duct Connector Installation
1. Install and center the duct connector in the floor opening.
2. Install the mounting plate (Figure 16 (page 18)) under
the back side of the duct connector. NOTE: Make sure
the screw holes are aligned in both components.
3. Using appropriate size screws, secure the duct
connector and the mounting plate to the wood floor.
4. Connect the round supply duct to the underside of the
duct connector and secure them with field supplied
sheet metal screws or appropriate clamps.
5. Seal all connections with industrial grade sealing tape
or liquid sealant as required.
NOTE: Requirements for sealing ductwork vary
from region to region. Consult with local codes for
requirements specific to your area.
Installing the Furnace
Sides and back of the furnace may be enclosed by wall
framing such as in a closet or alcove. The dimensions
of the room or alcove must be able to accommodate the
overall size of the furnace and the installation clearances
outlined on page 5 and Figure 1, Figure 2, Figure 3,
& Figure 4. The furnace shall be appropriately connected
to the supply and return air distribution system as shown
in Figure 24 (page 30) & Figure 25 (page 31).
Hole for
Gas Line
od
Wo
or
Flo
Tabs slide into slots
in back of furnace
Mounting
Plate
Screw Down
Duct Connector
ply
Sup Duct
r
i
A
NOTE: Additional fasteners may be used at rear, sides
or through door frame, as desired, to secure furnace to
closet or alcove framing.
Condensate Drainage
WARNING:
The condensate produced by the furnace must
be drained. Do not connect a water supply to the
drainage hose of the furnace.
CAUTION:
Figure 15. Screw-Down Duct Connector
Tabs slide into slots
in back of furnace
1. Remove furnace outer door(s) and bottom fuel line
knockout.
2. Place furnace onto duct connector and center with floor
opening.
3. Slide onto mounting plate. (Bottom rear slots on furnace
should engage with mounting plate tabs.)
4. Secure front with one (1) fastener at each corner. See
Figure 17.
Mounting
Plate
Optional Hole
for Gas Line
Optional Hole
for Gas Line
14” Round
Duct Connector
Figure 16. Round Duct Connector
SLIDE FURNACE
ALL THE WAY BACK
ONTO MTG. PLATE
MTG. PLATE TABS
SECURE FURNACE WITH
2 FASTENERS IN FRONT
Knockout Over Holes
SUPPLY AIR DUCT
Do not install additional traps in the condensate
drain.
• If the furnace is installed in an area where
temperatures fall below freezing, special precautions
must be made for insulating condensate drain lines
that drain to the outdoors. If condensate freezes
in the lines, this will cause improper operation or
damage to the furnace. It is recommended that
all drain lines on the outside of the residence be
wrapped with an industry approved insulation or
material allowed by local code.
• Before routing the drain tube out of the furnace, loosen
the tube clamp and turn the tube so the preset 90° turn
faces the intended direction of exit from the cabinet.
Do not route the drain tube without rotating the tube
first. This will kink the tube and prevent condensate
from draining.
• Care should be taken to route the drain line away from
the burner box. Drain lines resting on the burner box
can become kinked or collapsed due to the heat from
the burner box.
• The condensate drain may exit through the left or
right slots in the bottom of the furnace. See Figure 18
(page 19). Make sure the flexible drain hose is not
kinked.
• The condensate should drain from the plastic collector
box as droplets or a small stream. If you notice the
furnace has operated for more than 5 minutes without
draining or the status lights on the control board
indicate an open pressure switch as listed in Table 6,
(page 28), follow the steps below.
Figure 17. Cabinet Furnace on Supply Air Duct
18
1. Remove the collector box soft tube (Figure 18) and
verify the exit from the collector box is clear of any
debris or obstructions.
2. Replace this tube and verify the fit to the header
spout is air tight. Air will be drawn into the header if this
connection is not tight.
3. Check other tube connections along the drain system.
Verify that all are air tight.
Collector
Box Drain
Collector
Box Drain
Inline Drain
Assembly
GAS SUPPLY & PIPING
WARNING:
FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could
result in serious injury or property damage.
• Installation and service must be performed
by a qualified installer, service agency or the
gas supplier.
• Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
AVERTISSEMENT :
Drain Pipe Routed
thru Slot in Cabinet
To External Drain
J-Trap
Figure 18. Condensate Drainage
RISQUE D’INCENDIE OU D’EXPLOSION
• Le non-respect des avertissements de sécurité
pourrait entraîner des blessures graves ou des
dommages matériels.
• L’installation et l’entretien doivent être effectués
par un installateur qualifié, un organisme de
service ou le fournisseur de gaz.
• Ne pas entreposer ni utiliser de l’essence ni
d’autres vapeurs ou liquides inflammables dans le
voisinage de cet appareil, ni de tout autre appareil.
QUE FAIRE S’IL Y A UNE ODEUR DE GAZ
• Ne tentez pas d’allumer quelque appareil que
ce soit.
• Ne touchez à aucun interrupteur électrique;
n’utilisez pas de téléphone dans votre immeuble.
• Évacuer l’immeuble immédiatement.
• Appelez immédiatement votre fournisseur de
gaz à l’aide du téléphone d’un voisin. Suivez les
directives données par le fournisseur de gaz.
• Si vous ne pouvez pas joindre le fournisseur de
gaz, appelez les pompiers.
19
• All gas piping must be installed in compliance with
local codes and utility regulations. In the absence
of local codes the gas line installation must comply
with the latest edition of the Federal Manufactured
Home Constructions & Safety Standard (H.U.D.
Title 24, Part 3280.707[a][2]), National Fuel Gas
Code (ANSI Z223.1) or (CAN/CGA B149.1 or .2)
Installation Codes.
• Some local regulations require the installation of a
manual main shut-off valve and ground joint union
external to the furnace as shown in Figure 19. The
shut-off valve should be readily accessible for
service and/or emergency use. Consult the local
utility or gas supplier for additional requirements
regarding placement of the manual main gas shutoff.
• Per ANSI 21.47, A 1/8-inch NPT plugged tapping,
accessible for test gauge connection, must be
installed immediately upstream of the gas supply
connection to the furnace external to the cabinet. If
local codes allow the use of a flexible gas appliance
connector, always use a new listed connector. Do
not use a connector that has previously serviced
another gas appliance.
• Gas piping must never run in or through air ducts,
chimneys, gas vents, or elevator shafts.
• Compounds used on threaded joints of gas piping
must be resistant to the actions of LP propane gas.
• The main gas valve and main power disconnect to
the furnace must be properly labeled by the installer
in case emergency shutdown is required.
• Flexible gas connectors are not recommended for
this type of furnace but may be used if allowed by
local jurisdiction. Only new flexible connectors
may be used. Do not use a connector which has
previously serviced another gas appliance.
• A drip leg should be installed in the vertical pipe
run to the unit if not entering the furnace through
the floor.
Table 12, (page 37) lists gas flow capacities for standard
pipe sizes as a function of length in typical applications
based on nominal pressure drop in the line.
The furnace is installed with a bottom gas entry. When
connecting the gas supply, provide clearance between the
gas supply line and the entry hole in the furnace casing
to avoid unwanted noise and/or damage to the furnace.
Typical gas hookups are shown in Figure 19.
Leak Check
WARNING:
FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Never test for gas leaks with an open flame.
Use a commercially available soap solution
made specifically for the detection of leaks
to check all connections. A fire or explosion
may result causing property damage, personal
injury or loss of life.
AVERTISSEMENT :
RISQUE D’INDENDIE OU D’EXPLOSION
Le non-respect des avertissements de sécurité
pourrait entraîner des blessures graves, la mort ou
des dommages matériels.
Ne jamais utiliser une flamme nue pour vérifier la
présence de fuites de gaz. Pour la vérification de tous
les joints, utiliser plutôt une solution savonneuse
commerciale fabriquée spécifiquement pour la
détection des fuites de gaz. Un incendie ou une
explosion peut entraîner des dommages matériels,
des blessures ou la mort.
STATUS LIGHTS
L2-OUT
RED
L2-IN
GREEN
RED
OUTPUT TERMINALS
W_OUT
Y/Y2_OUT
L1-IN
Y1_OUT
L1-OUT
FAN SPEED
DHUM_IN
1 2 3 4 5678
HEAT
Y1_IN
COOL
SENSOR
C
EXPANSION PORT
CONNECTION TO
FURNACE CONTROL
BOARD
GROUND
INPUT TERMINALS
OFF ON
H_OUT
R
MOTOR WIRING
HARNESS
Elbows
Gas Valve
Alternate Fuel
Line Entrance
Shut-Off
Valve
MG2S Front Return Model Shown
Figure 19. Typical Gas Connections
After the gas piping to the furnace is complete, all
connections must be tested for gas leaks. This includes
pipe connections at the main gas valve, emergency
shutoff valve and flexible gas connectors (if applicable).
The soap and water solution can be applied on each
joint or union using a small paintbrush. If any bubbling is
observed, the connection is not sealed adequately and
must be retightened. Repeat the tightening and soap
check process until bubbling ceases.
IMPORTANT NOTE
When pressure testing gas supply lines at pressures
greater than 1/2 psig (14 inch W.C.), the gas supply
piping system must be disconnected from the furnace
to prevent damage to the gas control valve. If the test
pressure is less than or equal to 1/2 psig (14 inch
W.C.), close the manual shut-off valve.
20
High Altitude Application
High altitude conversion with this furnace depends on
the installation altitude and the heating value of the gas.
Installation of this furnace at altitudes above 2,000 feet
shall be in accordance with local codes, or in the absence
of local codes, the National Fuel Gas Code, ANSI Z223.1/
NFPA 54 or National Standard of Canada, Natural Gas &
Propane Installation Code CGA B149.1. Please consult
your local code authority.
The installer must indicate the furnace has been
converted to high altitude. This may be accomplished
by marking the rating plate with a permanent marker.
WARNING:
The reduction of input rating necessary for high
altitude installation may only be accomplished
with factory supplied orifices. Do not attempt to
drill out orifices in the field. Improperly drilled
orifices may cause fire, explosion, carbon
monoxide poisoning, personal injury or death.
The furnaces are shipped from the factory with orifices
and gas regulator settings for natural gas operation at sea
level altitudes. At 2000 feet, the NFGC requires that this
appliance be derated 4% for each 1000 feet of altitude.
For example, the input needs to be reduced 8% at 2,000
feet, 12% at 3,000 feet, etc. This deration is in reference
to the input rate and gas heating value at sea level.
To derate the furnace requires knowing the heating value of
the gas at the installation site. Heating values at particular
job sites vary for two reasons:
1. The chemical mixture of the gas varies across regions
and is expressed as the sea level heating value.
2. The heating value varies by altitude. For this reason,
especially in high altitude areas, the local gas utility
specifies the heating value at the residence’s gas meter
as the local value.
For added flexibility, two tables have been provided for
natural gas installations with high or low heating values
at sea level. Table 14 & Table 15, (page 37) contain
the manifold pressure and orifice sizes to use at various
altitudes. Table 14 (HIGH) is for natural gas installations
with a heating value of more than 1,000 Btu per cubic foot
and Table 15 (LOW) is for less than 1,000 Btu per cubic
foot. To determine which table to use:
1. Consult the local utility for the local heating value at
your installation site.
2. From Table 13, (page 37), find your local heating
value as supplied by the utility company. Follow down
the column and stop at your altitude level.
3. If your sea level heating value is HIGH, use Table 14
or if it’s LOW, use Table 15. See example above.
21
After changing the orifices, it is required that you measure
the gas input rate. This may be accomplished in the usual
way, by clocking the gas meter and using the local gas
heating value. See Verifying & Adjusting the Input Rate
section on page 24.
EXAMPLE
Elevation:................................................... 5,000 feet
Type of Gas:............................................ Natural Gas
Local Heating Value of Gas:............................... 750
From Table 12, find 750 and follow down the column,
stop at the 5,000 feet row. The heating value listed is
LOW. Table 15 will be used to determine orifice size
and manifold pressure.
IMPORTANT NOTE:
Observe the action of the burners to make sure there
is no yellowing, lifting or flashback of the flame.
Converting to LP/Propane Gas at Altitudes
between 0 & 10,000 FT.
Converting two-stage furnaces to LP/Propane requires
the replacement of the burner orifices and converting the
regulator to LP. All furnace models need to be derated
when converted to LP. See Table 12, (page 37).
WARNING:
The furnace was shipped from the factory
equipped to operate on natural gas. Conversion
to LP / Propane gas must be performed by
qualified service personnel using a factory
supplied conversion kit. Failure to use the proper
conversion kit can cause fire, explosion, property
damage, carbon monoxide poisoning, personal
injury, or death.
WARNING:
Shut off the gas supply at the manual gas shutoff
valve, before disconnecting the electrical power.
A fire or explosion may result causing property
damage, personal injury or loss of life. Failure to
follow the safety warnings exactly could result in
serious injury, death or property damage.
WARNING:
To avoid electric shock, personal injury, or death,
turn off the electric power at the disconnect or the
main service panel before making any electrical
connections.
WARNING:
The reduction of input rating necessary for high
altitude installation may only be accomplished
with factory supplied orifices. Do not attempt to
drill out orifices in the field. Improperly drilled
orifices may cause fire, explosion, carbon
monoxide poisoning, personal injury or death.
Generally, conversion requires the replacement of the
burner orifices and the spring & stem assembly in the
pressure regulator. In the U.S., if the installation is above
2,000 ft., refer to Table 12, (page 37) to determine the
correct orifice size and regulator pressure. See example
below.
Conversion to LP / Propane is detailed in the installation
instructions provided with the conversion kit. The
conversion instructions for US installations are only to
be used to convert natural gas furnaces to LP/Propane
gas in the United States. For installations in Canada, the
Canadian conversion instructions must be used. Please
follow the instructions provided with the kit.
When conversion is complete, verify the manifold pressure
and input rate are correct as listed in the Tables.
EXAMPLE
Elevation:................................................... 5,000 feet
Type of Gas:..........................................Propane Gas
Input BTU of Furnace:.................................... 60,000
From Table 12, find 60,000 Btuh and follow across the
row to the 5,000 FT column. The manifold pressure
listed is 4.2 for Low and 10.0 for High. The listed orifice
size is 56.
ELECTRICAL WIRING
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
AVERTISSEMENT :
RISQUE DE DÉCHARGE ÉLECTRIQUE,
D’INCENDIE OU D’EXPLOSION
Le non-respect des avertissements de sécurité
pourrait entraîner des blessures graves ou des
dommages matériels.
Un entretien inapproprié peut provoquer un
fonctionnement dangereux, des blessures graves,
la mort ou des dommages matériels.
• Avant toute intervention, couper l’alimentation
électrique du générateur d’air chaud.
• Pour l’entretien des commandes, étiqueter tous
les fils avant de les débrancher. Rebrancher les
fils correctement.
• Vérifier le bon fonctionnement après l’intervention.
Line Voltage Wiring
• Electrical connections must be in compliance with all
applicable local codes with the current revision of the
National Electric Code (NFPA 70).
• For Canadian installations the electrical connections
and grounding shall comply with the current Canadian
Electrical Code (CSA C22.1 and/or local codes).
• It is recommended that the line voltage (115 VAC) to
the furnace be supplied from a dedicated branch circuit
containing the correct fuse or circuit breaker for the
furnace as listed in Table 9, (page 34).
IMPORTANT NOTES:
If replacing any of the original wires supplied with the
furnace, the replacement wire must be copper wiring
and have a temperature rating of at least 105°F (40°C).
For electrical specifications, refer to the furnace
nameplate or Table 9.
Proper line voltage polarity must be maintained in
order for the control system to operate correctly.
Verify the incoming neutral line is connected to the
22
white wire and the incoming HOT line is connected
to the black wire. The furnace will not operate unless
the polarity and ground are properly connected as
shown in Figure 26 (page 34).
Grounding
WARNING:
To minimize personal injury, the furnace cabinet
must have an uninterrupted or unbroken electrical
ground. The controls used in this furnace require
an earth ground to operate properly. Acceptable
methods include electrical wire or conduit
approved for ground service. Do not use gas
piping as an electrical ground!
Thermostat / Low Voltage Connections
• The furnace is designed to be controlled by a 24 VAC
thermostat. The thermostat’s wiring must comply with
the current provisions of the NEC (NFPA 70) and with
applicable local codes having jurisdiction.
• The thermostat must be installed according to the
instructions supplied by the thermostat manufacturer.
Low voltage connections (24 VAC) from the thermostat
are wired to the terminal strip on the integrated control
in the furnace. For heating applications, Figure 20 &
Figure 21 (page 24) show how to properly connect
single stage and two-stage thermostats. Recommended
minimum wire gauge for thermostat wiring is shown in
Table 9, (page 34).
• The thermostat should be mounted about 5 feet
above the floor on an inside wall. DO NOT install the
thermostat on an outside wall or any other location
where its operation may be adversely affected by radiant
heat from fireplaces, sunlight, or lighting fixtures, and
convective heat from warm air registers or electrical
appliances. Refer to the thermostat manufacturer’s
instruction sheet for detailed mounting information.
Single Stage AC & Single Stage Thermostat
This option does not use the full two-stage control
capability of the furnace, but the possibility of timed
autostaging is available. See also Autostaging for Single
Stage Thermostats.
• Connect the thermostat’s W output to the furnace
control boards W1 terminal. This allows the furnace
to always run in low output mode. See (Figure 19)
• Always connect the thermostat C & R to the furnace
control board C & R.
• For cooling, connect the thermostats Y signal to the
furnace control board Y / Y2 terminal.
• Field supplied wires should also connect Y / Y2 & C
to the outdoor unit’s Y & C terminals.
Single Stage AC & Two Stage Thermostat
This option uses the full two stage heating capability of the
furnace with a single stage outdoor unit. See Figure 20.
• Connect the thermostat’s W1 & W2 outputs to the
furnace control board’s W1 & W2 terminals.
• Always connect the thermostat C & R to the furnace
control board C & R
• For cooling, connect the thermostats Y signal to the
furnace control board Y / Y2 terminal.
• Field supplied wires should also connect Y / Y2 & C
to the outdoor unit’s Y & C terminals.
Autostaging for Single Stage Thermostats
The Autostaging feature makes it possible to use a single
stage thermostat and still receive some of the benefits of
2-stage furnace operation. If Autostage is enabled, the
furnace will drop to LOW fire after initially starting in HIGH
fire. After a period of 10 minutes, the furnace will then stage
up to HIGH fire, until the heating load is met. See Figure
20 (page 24) and the Low Voltage Connection section.
The autostaging option is selected using the autostage
jumper located near the thermostat terminal block. See
Figure 27 (page 34). When the autostage jumper is
moved from OFF to ON, the following occurs during a
call for heat:
Setting the Autostage jumper in the ON position signals
the control to utilize a 10 minute delay between LOW fire
and HIGH fire when a call for heat is supplied via 24V
signal to W1.
NOTE: If the autostage jumper is in the ON position and
a W1 demand is present when power is applied to the
furnace, the first heat cycle will run in second stage heat
with no autostaging. After the first cycle, the furnace will
resume normal autostaging operation.
Autostaging for Two-Stage Thermostats
23
START-UP & ADJUSTMENTS
Pre-Start Check List
ROOM THERMOSTAT
(SINGLE STAGE)
G
W
1 C R DHUM
DHUM
Y
Y
C
HIGH EFFICIENCY
BLOWER MOTOR
CONTROL BOARD
A/C CONDENSING UNIT
(SINGLE STAGE)
Y/Y2 G
W1 R
Y1 W2 C
TWO STAGE FURNACE BOARD
Figure 20. Wiring Configuration 1
ROOM THERMOSTAT
(TWO - STAGE)
WW
G 2 1 C R DHUM
DHUM
Y
Y
C
HIGH EFFICIENCY
BLOWER MOTOR
CONTROL BOARD
A/C CONDENSING UNIT
(SINGLE STAGE)
√ Verify the polarity of the connections are correct, the
line voltage power leads are securely connected and
the furnace is properly grounded.
√ Verify that all needed thermostat wires are securely
connected to the correct leads on the terminal strip of
the circuit board. See Figure 20 & Figure 21.
√ Verify the gas line service pressure does not exceed
10.0 inches of water column, and is not less than 4.5
inches W.C. for natural gas. For LP gas the line service
pressure must not exceed 14 in. W.C., and must not
be less than 11.0 in. W.C.
√ Verify the roll-out and manual reset switch is closed.
If necessary, press the button to reset the switch. DO
NOT install a jumper wire across a switch to defeat
its function. If a switch reopens on start-up, DO NOT
reset the switch without identifying and correcting
the fault condition.
√ Verify the blower door is in place, closing the door
switch in the line voltage circuit.
√ Verify the gas line has been purged and all connections
are leak free.
Start-up Procedures
Y/Y2 G
W1 R
Y1 W2 C
TWO STAGE FURNACE BOARD
Figure 21. Wiring Configuration 2
The Autostage setting on the furnace control board
(Figure 27 (page 34)) is disabled when shipped from
the factory. This feature will be not used when paired with
a two-stage thermostat. The autostage jumper setting
(P7) must be kept on OFF to allow the thermostat to
adjust stages.
CAUTION:
The terminal marked “Y1_IN” on the variable
speed motor control board is not an output to
drive the outdoor unit. DO NOT connect Y1_IN
on the motor control board to the outdoor unit.
Fixed Speed Blower Applications
The fixed speed motor control board (Figure 27
(page 34)) contains a set of dip switches for setting the
blower speed. Use pins 1 to 4 to set the blower speed
for heating and pins 5 to 8 to set the speed for cooling.
To determine the appropriate switch settings for your
installation, see Table 7 (page 31) and Table 8 (page 32).
For thermostats with a dehumidifier output, use a field
supplied wire to connect the thermostat’s dehumidifier
output to the terminal marked DEHUM. The thermostat
should be set so that the DEHUM output should be high
(positive) when dehumidification is needed.
Do not perform these steps until all of the checks in the
previous steps have been completed:
1. Set the thermostat to the lowest setting.
2. Turn off all electrical power to the furnace.
3. Follow the Operating Instructions on the label attached
to the furnace.
4. Set the thermostat above room temperature and verify
the Operating Sequence. See page 26.
5. After 5 minutes of operation, set the thermostat below
room temperature and verify steps 9 - 10 of the Operating
Sequence.
Verifying & Adjusting Input Rate
The input rate must be verified for each installation to
prevent over-firing of the furnace. NOTE: The input rate
must not exceed the rate shown on the furnace rating plate.
At altitudes above 2,000 feet, it must not exceed that on
the rating plate less 4% for each 1,000 feet. To determine
the exact input rate, perform the following procedures:
1. Shut off all other gas fired appliances.
2. Start the furnace and run it for at least 3 minutes.
3. Measure the time (in seconds) required for the gas
meter to complete one revolution.
4. Convert the time per revolution to cubic feet of gas per
hour using Table 10, (page 36).
5. Multiply the gas flow rate in cubic ft per hr by the heating
value of the gas in Btu per cubic ft to obtain the input
rate in Btuh. See example.
Example:
• Time for 1 revolution of a gas meter with a 1 cubic
ft dial = 40 seconds.
• From Table 10 read 90 cubic ft gas per hr.
• Local heating value of the gas (obtained from gas
supplier) = 1,040 Btu per cubic ft.
• Input rate = 1,040 x 90 = 93,600 Btuh.
24
6. The manifold pressure must be set to the appropriate
value for each installation by a qualified installer, service
agency or the gas supplier.
WARNING:
Do not attempt to drill the gas orifices. Use only
factory supplied orifices. Improperly drilled
orifices may cause fire, explosion, carbon
monoxide poisoning, personal injury or death.
a.) Obtain the manifold pressure setting required for
this installation by referring to Table 12 for Propane
or Table 14 or Table 15, (page 37) for Natural
Gas.
b.) Remove the regulator capscrew from the INLET
side of the regulator. See Figure 21.
c.) Slowly turn the adjustment screw inside the regulator
to obtain the appropriate manifold pressure.
NOTE: Turning the screw clockwise increases the
pressure and turning the screw counter-clockwise
decreases the pressure. To prevent backing the
screw all the way out from the valve, turn the screw
slowly.
d.) Replace and tighten the regulator capscrew over
the adjustment screw.
3. Adjust all registers and duct dampers to the desired
position and run the furnace for 10 to 15 minutes before
taking any temperature readings. The temperature rise
is the difference between the supply and return air
temperatures.
NOTE: The settings in Table 7 refer to the small white
switches on the red HEAT / COOL switch socket on the
motor control board. The switches are set by the factory
for good performance in a typical installation. If needed,
the switches can be changed to ON or OFF by sliding
them with a small screwdriver. See Figure 27 (page 34).
Verifying Burner Operation
CAUTION:
The door over the burners may only be open
for inspection purposes only. The door must be
installed during unattended operation.
1. Set the thermostat above room temperature and observe
the ignition sequence. NOTE: The burner flame should
carry over immediately between all burners without
lifting off, curling, or floating. The flames should be
blue, without yellow tips.
HI Input
Adjusting Screw
Verifying & Adjusting Temperature Rise
After installation of the furnace, confirm the temperature
rise of the furnace is within the limits specified on the rating
plate. Any temperature rise outside the specified limits
could result in premature failure of the heat exchanger.
For typical duct systems, the temperature rise will fall
within the limits specified on the rating plate with the
blower speed at the factory recommended setting. If the
measured temperature rise is outside the specified limits,
it may be necessary to change the speed of the blower.
NOTE: Lowering the blower speed will increase the
temperature rise and a higher blower speed will decrease
the temperature rise.
Manual
ON / OFF
Switch
Lo Input
Adjusting Screw
The furnace is equipped with a multi-speed motor.
Heating and cooling speed selection is made by moving
the switches on the blower control in the box in front of
the blower.
1. Place thermometers in the return and supply air stream
as close to the furnace as possible.
IMPORTANT: The thermometer on the supply air
side must be shielded from direct radiation from
the heat exchanger to avoid false readings.
2. Consult Table 8, (page 33) and the rating plate for the
proper circulating air flow and temperature rise.
NOTE: This furnace is designed to operate with a maximum
external pressure rise of 0.3 inches of water column. It
is important that the duct system be designed to provide
the correct flow rates and external pressure rise. An
improperly designed duct system can result in nuisance
shutdowns, and comfort or noise issues.
25
Inlet Pressure Tap
Model VR9205Q1127
Figure 22. Gas Valve
2. After validating the flame, change thermostat setting to
below room temperature.
3. Verify the burner flame is completely extinguished.
4. Replace the burner compartment door.
Verifying Operation of the Supply Air Limit
Switch
NOTE: A properly functioning limit switch should turn off
the gas valve when the return is blocked (time depends
on how well the return air is blocked). The circulating air
and combustion blowers should continue to run when the
limit switch opens.
1. Verify the blower door is securely mounted in place and
that there is power to the furnace.
2. Block the return airflow to the furnace by installing a
close-off plate in place of or upstream of the filter(s).
3. Set the thermostat above room temperature and observe
the Operating Sequence.
4. Remove the close-off immediately after the limit switch
opens. If the furnace continues to operate with no return
air, set the thermostat below room temperature, shut
off power to the furnace, and replace the limit switch.
OPERATING SEQUENCE
The operating sequences for the heating, cooling, and
fan modes are described below. Refer to the field and
furnace wiring diagrams: Figure 26 (page 34) and Figure
29 (page 35)).
Heating Cycle
1. The thermostat calls for heat by energizing the W1
terminal with 24VAC.
2. The control checks to see the pressure switch is open.
If the switch is closed, the furnace will shut down for 5
minutes before retrying
3. If the pressure switch is open, the control energizes the
inducer motor and waits for the pressure switch to close.
The pressure switch must close within 12 seconds.
4. The control runs the inducer for a 30 second pre-purge
time.
5. The control energizes the igniter output for the
appropriate adaptive warm-up time limit.
6. The furnace always ignites the burners in high fire. If
the call for heat is for low rate, the furnace will move
down to low fire after the flames stabilize.
7. If the flame is proved and ignites the gas, the control
de-energizes the igniter. The gas valve and inducer
remains energized. The control goes to blower on delay.
8. The control energizes the blower on the selected HEAT
speed 22 seconds after the gas valve opened. The gas
valve and inducer remain energized.
9. If there is a call for high fire, the gas valve moves to the
high fire position and the blower speeds are increased.
The furnace will remain in high fire until the demand
for heat is satisfied.
10. If autostaging is enabled (single stage thermostat) the
demand for heat has lasted more than the selected
time, the furnace automatically moves up to high fire.
Autostage time is ON (10 minutes) or OFF, depending
on the Jumper (P7) setting on the furnace control
board.
11. When the thermostat demand for heat is satisfied,
the control de-energizes the gas valve. The inducer
output remains on for a 30 second post-purge period.
12. The circulating air blower will continue to run for the
selected Blower Off Delay(P5). This may be 60, 90,
or 120 seconds depending on the jumper setting on
the furnace control board.
Cooling Cycle
1. The thermostat calls for cooling by energizing the Y /
Y2 or Y1 terminal with 24VAC.
2. The control energizes the blower in the cooling speed
and sends 24VAC to the contactor in the condensing
unit.
3. When the thermostat removes the call for cooling, the
contactor in the outdoor condensing unit is de-energized
and the control continues to run the fan for a period of
60 seconds.
26
Fan Mode
• When the thermostat energizes the G terminal for
continuous fan (without calling for heat or cooling), the
blower will operate at 50% of the selected high cooling
speed for continuous fan operation.
• If a call for cooling occurs during continuous fan, the
blower will switch over to the selected COOL speed.
• If the W terminal receives a call for heat during
continuous fan, the blower will de energize.
• A call for fan is ignored while in lockout.
MAINTENANCE
WARNING:
Air Filter(s) - An air filter is supplied with the front return
furnace as shipped from the factory. Filters should be
changed or cleaned monthly during the heating season.
Newly built or renovated homes may require more frequent
changing until the construction dust has minimized.
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Never operate the furnace without a filter in place.
Dust and lint can build up on internal components,
resulting in loss of efficiency, equipment damage,
and possible fire.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
Filters designed to remove smaller particles such as
pollen, may require additional maintenance.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
AVERTISSEMENT :
RISQUE DE DÉCHARGE ÉLECTRIQUE,
D’INCENDIE OU D’EXPLOSION
Le non-respect des avertissements de sécurité
pourrait entraîner des blessures graves ou des
dommages matériels.
Un entretien inapproprié peut provoquer un
fonctionnement dangereux, des blessures graves,
la mort ou des dommages matériels.
• Avant toute intervention, couper l’alimentation
électrique du générateur d’air chaud.
• Pour l’entretien des commandes, étiqueter tous
les fils avant de les débrancher. Rebrancher les
fils correctement.
• Vérifier le bon fonctionnement après l’intervention.
Proper maintenance is most important to achieve the best
performance from a furnace. Follow these instructions for
years of safe, trouble free operation.
• These maintenance instructions are primarily intended
to assist qualified technicians experienced in the proper
maintenance and operation of this appliance.
• Always close the door on the furnace after servicing
or cleaning/changing the filters. Do not operate the
furnace without the door closed.
27
• Verify the thermostat is properly installed and will
not be affected by drafts or heat from lamps or other
appliances.
• To achieve the best performance and minimize
equipment failure it is recommended that a yearly
maintenance checkup be performed. At a minimum,
this check should include the following items:
Blower Compartment - Dirt and lint can create excessive
loads on the motor resulting in higher than normal operating
temperatures and shortened service life. It is recommended
that the blower compartment be cleaned of dirt or lint
that may have accumulated in the compartment or on
the blower and motor as part of the annual inspection.
Cleaning of Burners - If the burners must be cleaned,
follow steps 1-12. For component locations see
Figure 23 (page 29).
1. Shut off gas supply to the furnace at the meter or at a
manual valve in the supply piping.
2. Turn off all power to the furnace and set the thermostat
to it’s lowest setting.
3. Move the manual ON/OFF switch to the OFF position.
See Figure 22 (page 25).
4. Disconnect the wires from the gas valve, igniter, flame
sensor, and flame rollout switch.
CAUTION:
To prevent damage to the unit or internal
components, it is recommended that two
wrenches be used when loosening or tightening
nuts. Do not over tighten!
5. Using two wrenches, separate the ground-joint union
in the gas supply piping at the furnace.
6. Remove the piping between the gas valve and the
ground-joint union. (If applicable).
7. Remove all screws securing the burner box door.
8. Remove all screws securing the manifold assembly to
the burner box.
9. Remove all screws from the corners of the box and
carefully remove the burner assembly from the furnace.
IMPORTANT: DO NOT damage the igniter while
removing the burner assembly.
10. Inspect the burners for accumulated dust or debris.
If necessary carefully clean them with a soft wire
brush and a vacuum cleaner. IMPORTANT: DO
NOT damage the igniter while cleaning the burner
assembly.
11. Replace all the parts in reverse order that they were
removed.
12. Follow the lighting instructions found on the furnace
door to return the furnace to operation. Verify proper
operation after servicing.
Vent System
WARNING:
Holes in the vent pipe or heat exchanger can
cause combustion products to enter the home.
Replace the vent pipe or heat exchanger if leaks
are found. Failure to prevent the circulation of
combustion products into the living space can
create potentially hazardous conditions including
carbon monoxide poisoning that could result in
personal injury or death.
TROUBLESHOOTING
• Is evaporator coil clean and free of debris (If applicable).
• Are all the LED’s on the furnace control board constantly
ON? If not, refer to Table 6 below or the wiring diagram
(Figure 28, page 33) to determine fault condition.
IMPORTANT NOTE: The furnace will lock out after 5
failed attempts for ignition and will try again every
hour if the call for heat remains.
• If the inducer blower is operating, and items above have
been verified, check the blower limit switch and reset
if necessary. For component locations see Figure 23
(page 29).
• If the furnace operates when the Blower Limit Switch is
reset, contact a qualified service technician to identify
and repair the problem.
• If the furnace still doesn’t operate, check the flame
roll-out switch and reset if necessary.
• If the furnace operates when the flame rollout switch is
reset, contact a qualified service technician to identify
and repair the problem.
Furnace Control Board
Diagnostic Description
Green
LED
Red
LED
Off
Flash
Check the inlet pipe (if applicable) and outlet pipe to ensure
they are not blocked by debris. Any damaged section
of vent pipe must be replaced, and any obstruction or
blockage must be removed prior to operating the furnace.
Control Fault (No Power)
L1/Neutral Polarity Fault
Off
Flash
1 Hour Lockout
Alternating Flash
Normal Operation
On
On
Heat Exchanger & Burner Maintenance - The furnace
should operate for many years without soot buildup in the
flue passageways, however, the flue, vent system, and
burners should be inspected and cleaned (if required) by
a qualified service technician annually to ensure continued
safe operation. Pay attention to any deterioration from
corrosion or other sources.
Pressure Switch Closed Fault
On
Flash
Pressure Switch Open Fault
Flash
On
Open Limit Switch Fault
Flash
Off
Motor Fault
On
Off
Lubrication - The bearings in the blower motor and
inducer blower used in these furnaces are pre-lubricated
and sealed by the manufacturer. No further oiling of the
bearings is required for the life of the motor.
If the furnace fails to operate check the following:
• Is the thermostat operating properly?
• Are the blower compartment door(s) in place?
• Is the furnace disconnect closed?
• Has the circuit breaker tripped or the control board
fuse burned open?
• Is the gas turned on?
• Are any manual reset switches open?
• Is the filter dirty or plugged?
• Is the flame sensor coated? (Remove and clean with
steel wool. (Do not use emery cloth or sandpaper!)
• Is there blockage in the condensate drain switch? Also
verify that there is no double trapping of condensate.
• Is the secondary heat exchanger free of debris and
clogs?
Diagnostic Description
Low Flame Sensor Signal
Flame Present
Yellow LED
Continuous Flash
On
Motor Control Board (Variable Speed)
Green
LED
Red
LED
Control Fault (No Power)
Off
Off
Normal Operation
On
On
Motor Fault
Communications Fault
On
Flash
Flash
Flash
DIAGNOSTIC
DESCRIPTION
Table 6. Control Board Fault Conditions
28
FURNACE COMPONENTS
The descriptions below are various functional components that affect the operation and shutting down of this furnace.
Some of these components and their locations are shown in Figure 23. If any component of the furnace must be
replaced, use only factory authorized replacement parts specified in the Replacement Parts List provided online.
Blower Limit Switch: Prevents operation when blower is not operational.
Flame Sensor: Verifies when a flame has carried over from the igniter to the opposite end burner. If no flame is
detected, the furnace will shut down within 4 seconds.
Flame Roll-Out Switch: Verifies that the burner flames are drawn into the heat exchanger tubes. If the burner
flames are not properly drawn into the heat exchanger, the flame roll-out switch will close the gas valve and initiate
the shutdown cycle.
Gas Valve: Controls the flow of gas to the burners. When the gas valve is energized it automatically opens and
regulates the gas pressure in the manifold.
Inducer Assembly: Vents products of combustion to the outside.
Pressure Switch: Verifies that the inducer is drawing the combustion gases through the heat exchanger. The
pressure switch prevents furnace operation with excessive flue/condensate blockage or improper inducer operation.
Main Air Limit Switch: Prevents the air temperature leaving the furnace from exceeding the maximum allowable
outlet air temperature.
Blower Assembly
STATUS LIGHTS
Control Board
Inline Drain
Assembly
Limit Switch
Gas Valve
Igniter
L1-IN
RED
Y1_OUT
L1-OUT
R
FAN SPEED
DHUM_IN
1 2 3 4 5 6 78
Y1_IN
HEAT
COOL
SENSOR
C
CONNECTION TO
FURNACE CONTROL
BOARD
GROUND
INPUT TERMINALS
OFF ON
H_OUT
EXPANSION PORT
ON/OFF Switch
L2-IN
GREEN
Y/Y2_OUT
RED
OUTPUT TERMINALS
Exhaust Vent Pipe
L2-OUT
W_OUT
Motor Control Board
MOTOR WIRING
HARNESS
Inducer Assembly
Combustion Air Pipe
24V Transformer
Main Air Limit Switch
Flame Sensor
Roll-Out Switch
Gas Manifold &
Burner Assembly
Figure 23. Furnace Components
29
FIGURES & TABLES
1
17 3/4
Knockouts (x4)
15 1/2
5
2 1/2 x 5
(Ventilaire)
3
2
2 3/4
2 5/8
2
18 1/2
Knockouts (x4)
3 1/2
(X2)
1 1/2
1/2
1 1/2
18 1/2
2
Knockouts (x4)
18 1/2
18 1/2
20 1/4
17 1/8
7/8
(Electric)
55
2 3/4
76
3 1/2
1 7/8
43 1/2
1 1/2 X 3 1/2
(Gas or Condensate)
21 1/4
20
21.250
1 1/2 X 3 1/2
(Gas or Condensate)
19 7/8
24 5/8
1 1/2 X 3 1/2
(Gas, Condensate, or Linesets - Typical)
15
21 5/8
TYP.
15
2 3/8
1 1/8
Figure 24. Front Return Model Dimensions
30
17
2 1/2 x 5
(Ventilaire)
3 1/2
(X2)
5
1 1/2
2
15 1/2
3
2
2 3/4
2 5/8
1 1/2
18 1/2
Knockouts (x4)
Knockouts (x4)
18 1/2
18 1/2
7/8
(Electric)
18 1/2
2 3/4
55
76
1 1/2 X 3 1/2
(Gas)
1 1/2 X 3 1/2
(Gas)
3 1/2
1 7/8
43 1/2
21 1/4
19 7/8
19 7/8
24 5/8
1 1/2 X 3 1/2
(Gas or Condensate - Typical)
1/2 TYP.
15
21 5/8
TYP.
15
2 3/8
1 1/8
Figure 25. Top Return Model Dimensions
31
21.250
2
Airflow Data
MOTOR SWITCH
SETTINGS
(0 =OFF,1 =ON)
MODEL NUMBER
MG2S-B045F*
MG2S-B060F*
MG2S-B072F
COOLING
HEATING
EXTERNAL STATIC PRESSURE (IN.W.C.)
EXTERNAL STATIC PRESSURE (IN.W.C.)
0.2
0.3
0.4
0.5
0.2
0.3
0.4
0.5
1/5
2/6
3/7
4/8
CFM
CFM
CFM
CFM
CFM
RISE
CFM
RISE
CFM
RISE
CFM
RISE
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
913
965
1037
1112
1185
1256
1289
1354
1396
1442
1485
1510
1550
1588
1635
1646
913
965
1037
1112
1185
1256
1289
1354
1396
1442
1485
1510
1550
1588
1635
1646
923
964
1052
1117
1196
1258
1283
1335
1389
1442
1480
1506
1542
1583
1630
1633
868
944
1000
1079
1155
1216
1258
1319
1366
1411
1451
1473
1517
1561
1606
1612
868
944
1000
1079
1155
1216
1258
1319
1366
1411
1451
1473
1517
1561
1606
1612
884
922
1017
1088
1163
1219
1248
1299
1356
1406
1446
1475
1507
1554
1601
1599
841
886
973
1047
1118
1180
1222
1283
1331
1379
1421
1446
1494
1530
1582
1582
841
886
973
1047
1118
1180
1222
1283
1331
1379
1421
1446
1494
1530
1582
1582
843
886
977
1049
1131
1190
1213
1268
1322
1374
1415
1442
1474
1518
1563
1564
795
848
933
1012
1082
1151
1186
1247
1299
1351
1388
1416
1460
1503
1554
1550
795
848
933
1012
1082
1151
1186
1247
1299
1351
1388
1416
1460
1503
1554
1550
798
843
938
1017
1092
1151
1177
1234
1292
1340
1382
1410
1443
1488
1530
1529
913
965
1037
1112
1185
1256
1289
1354
44
41
39
36
34
32
31
30
868
944
1000
1079
1155
1216
1258
1319
46
42
40
37
35
33
32
30
841
886
973
1047
1118
1180
1222
1283
48
45
41
38
36
34
33
31
795
848
933
1012
1082
1151
1186
1247
50
47
43
40
37
35
34
32
913
965
1037
1112
1185
1256
1289
1354
58
55
51
48
45
42
41
39
868
944
1000
1079
1155
1216
1258
1319
61
56
53
49
46
44
42
40
841
886
973
1047
1118
1180
1222
1283
63
60
55
51
48
45
44
42
795
848
933
1012
1082
1151
1186
1247
67
63
57
53
49
46
45
43
923
964
1052
1117
1196
1258
1283
1335
1389
1442
1480
1506
1542
1583
1630
69
66
61
57
54
51
50
48
46
44
43
42
42
40
39
884
922
1017
1088
1163
1219
1248
1299
1356
1406
1446
1475
1507
1554
1601
72
69
63
59
55
53
51
49
47
46
44
43
42
41
40
843
886
977
1049
1131
1190
1213
1268
1322
1374
1415
1442
1474
1518
1563
76
72
66
61
57
54
53
50
48
47
45
44
43
42
41
798
843
938
1017
1092
1151
1177
1234
1292
1340
1382
1410
1443
1488
1530
80
76
68
63
59
56
54
52
50
48
46
45
44
43
42
NOTE: Blower speeds highlighted in gray do not meet government mandated efficiency requirements and are not available for use in heating mode.
Table 7. Blower Performance - Front Return
32
MOTOR SWITCH
SETTINGS
(0 =OFF,1 =ON)
MODEL NUMBER
MG2S-B045T*
MG2S-B060T*
MG2S-B072T
COOLING
HEATING
EXTERNAL STATIC PRESSURE (IN.W.C.)
EXTERNAL STATIC PRESSURE (IN.W.C.)
0.2
0.3
0.4
0.5
0.2
0.3
0.4
0.5
1/5
2/6
3/7
4/8
CFM
CFM
CFM
CFM
CFM
RISE
CFM
RISE
CFM
RISE
CFM
RISE
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
872
924
1005
1076
1155
1220
1269
1321
1399
1448
1495
1531
1564
1611
1645
1683
872
924
1005
1076
1155
1220
1269
1321
1399
1448
1495
1531
1564
1611
1645
1683
885
944
1020
1087
1161
1225
1265
1330
1388
1447
1489
1513
1556
1599
1639
1670
831
888
969
1043
1122
1187
1230
1290
1360
1423
1463
1490
1534
1576
1609
1653
831
888
969
1043
1122
1187
1230
1290
1360
1423
1463
1490
1534
1576
1609
1653
848
901
976
1055
1132
1195
1239
1299
1353
1413
1454
1484
1523
1566
1609
1651
797
855
939
1014
1078
1158
1199
1251
1325
1382
1427
1457
1501
1543
1583
1624
797
855
939
1014
1078
1158
1199
1251
1325
1382
1427
1457
1501
1543
1583
1624
804
862
940
1019
1089
1164
1204
1265
1320
1382
1423
1452
1492
1534
1578
1613
745
809
899
972
1046
1126
1164
1218
1293
1347
1390
1424
1464
1510
1547
1594
745
809
899
972
1046
1126
1164
1218
1293
1347
1390
1424
1464
1510
1547
1594
764
816
906
985
1060
1137
1175
1228
1289
1346
1388
1420
1459
1502
1547
1583
872
924
1005
1076
1155
1220
46
43
40
37
35
33
831
888
969
1043
1122
1187
48
45
41
38
36
34
797
855
939
1014
1078
1158
50
47
43
39
37
35
745
809
899
972
1046
1126
54
49
44
41
38
36
872
924
1005
1076
1155
1220
61
58
53
50
46
44
831
888
969
1043
1122
1187
64
60
55
51
48
45
797
855
939
1014
1078
1158
67
62
57
53
49
46
745
809
899
972
1046
1126
72
66
59
55
51
47
885
944
1020
1087
1161
1225
1265
1330
72
68
63
59
55
52
51
48
848
901
976
1055
1132
1195
1239
1299
75
71
66
61
57
54
52
49
804
862
940
1019
1089
1164
1204
1265
80
74
68
63
59
55
53
51
764
816
906
985
1060
1137
1175
1228
84
78
71
65
60
56
54
52
NOTE: Blower speeds highlighted in gray do not meet government mandated efficiency requirements and are not available for use in heating mode.
Table 8. Blower Performance - Top Return
33
Electircal Diagrams & Data
Furnace
Model
Number
MG2S-
Furnace
Input
(Btuh)
Cabinet
Width
(in.)
Nominal
Electrical
Supply
Maximum
Operating
Voltage
Minimum
Operating
Voltage
Maximum
Furnace
Amperes
Minimum
Wire
Gauge
Maximum
Fuse or Circuit
Breaker Amps*
045A
45,000
19 7/8
115-60-1
127
103
8.8
14
15
060A
60,000
19 7/8
115-60-1
127
103
8.8
14
15
072A
72,000
19 7/8
115-60-1
127
103
8.8
14
15
NOTE: Minimum wire gauge and maximum fuse/circuit breaker amperage are based on MCA1 and MOP2 calculations. This furnace is
approved for installation with a 15 or 20 amp fuse/circuit breaker however wiring sizing must adhere to current version of the NEC and/or
applicable local codes depending upon the overcurrent protection.
Recommended Thermostat Wire Length
Thermostat Wire Gauge
2 - wire - Heating
4 or 5 wire - Cooling
55 ft.
25 ft.
22
90 ft.
45 ft.
20
140 ft.
70 ft.
18
225 ft.
110 ft.
24
* Time-delay fuses or circuit breakers are required.
Table 9. Wire Length & Voltage Specifications
Field Supplied
Fused Service
Panel
Junction box may be interior or exterior to the furnace,
but must be installed such that it is inaccessible without
tools. These connections can be made in the field supplied
disconnect at the furnace. NOTE: Connections made within
the furnace burner compartment do not require a junction box.
Black (Hot)
Black
White (Neutral)
White
Green or Bare
(Ground)
Black
White
Ground
Ground
Field Supplied
Panel Connector
Field Line Voltage Wiring
Factory Line Voltage Wiring
Figure 26. Line Voltage Field Wiring
DHUM Y1
C
R
OFF
ON
10
7
FOR WIRING TO THE
MOTOR CONTROL
BOARD
3
4
5
Y1
G
W2
W1
C
R
EXPANSION
PORT
STATUS
GREEN RED
60
90
120
180
W1
LINE- N
YELLOW
(FLAME)
LINE- N
BLOWER
OFF
DELAY
NEUTRALS
XMFR-N
THERMOSTAT CONNECTIONS
12
9
6
2
EXPANSION
PORT
MOTOR WIRE
HARNESS
Figure 27. MG2S Motor Control Board
Y/Y2
11
8
5
3
1
NOT USED
NOT USED
CONNECTION TO
FURNACE CONTROL
BOARD
STATUS
GREEN
2
HUM
RED
4
LINE
LINE
1
THERMOSTAT
CONNECTION
TERMINAL TO
TWIN FURNACES
FUSE
XMFR
INPUTS
FAN SPEED
COOL
1 2 3 4 5 6 78
HEAT
EAC
AUTO
STAGE
TWIN
OFF ON
Figure 28. Two-Stage Furnace Control Board
34
Figure 29. MG2S Wiring Diagram
FLAME
ROLL-OUT
BLACK
WHITE
BLUE
DOOR
SWITCH
VENT LIMIT
RED
6
3
2
4
1
LINE
EAC
L
H
RESISTOR
(ON SELECT
MODELS)
LINE
C
9
8
5
7
1 2 3 4 5
W2 W1 C R
10 11 12
XMFR
INDUCER
BLUE
BLK W/ WHITE STRIPES
WHITE W/ BLK STRIPES
Y/Y2 Y1 G
1 2 3 4
1 2 3 4
BLACK
24 V
BLK W/ WHITE STRIPES
HUM
FIELD WIRING
LOW VOLTAGE
HIGH VOLTAGE
BLUE
FLAME SENSOR
BROWN W/ WHITE STRIPE
BROWN
YELLOW
GREEN
BLUE
3
2
1
GREEN
VIOLET
LOW
PRESSURE
SWITCH
VIOLET
ORANGE
WHITE W/ BLK STRIPES
1 2 3
1 2 3
BLACK
120 V
WHITE
1 1
2 2
IGNITOR
BLACK
BROWN
RED
ORANGE
YELLOW
GREEN
BLUE
WHITE
6
5
4
2
3
1
BLOWER
LIMIT
Use copper conductors only.
BLWR OFF
DELAY
XMFR-N
LEGEND:
WHITE
(NEUTRAL)
BLACK 120V
GROUND
SUPPLY
AIR LIMIT
C 3
HI 2
LO 1
GAS
VALVE
HIGH
PRESSURE
SWITCH
ORANGE
R
C
W
R TX
C RX
GND GND
RX C
TX R
W
W1
If any of the origInal wire as supplied with the
furnace must be replaced, it must be replaced
with wiring material having a temperature
rating of at least 105° C.
BLUE
This wiring diagram shows connections and
termination required for the blower kit only.
Use in addition to the wiring diagram for the
furnace.
BLACK
WHITE
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
Y1 DEHUM
TWIN
SPEED
HP
COMMON
NONE
PWM
MODE
NONE
BLACK
WHITE
RED
ORANGE
YELLOW
GREEN
BLUE
BROWN
6
5
4
2
3
1
PART OF
MOTOR
TORQUE
MOTOR
BROWN
GRAY
FAULT CONDITIONS
Diagnostic Description
Green LED
Red LED
Control Fault (No Power)
Off
Off
L1 / Neutral Polarity Fault
Flash
Flash
1 Hour Lockout
Alternating Flash
Normal Operation
On
On
Pressure Switch Closed Fault
On
Flash
Pressure Switch Open Fault
Flash
On
Open Limit Switch Fault
Flash
Off
Motor Fault
On
Off
Diagnostic Description
Yellow LED
Low Flame Sensor Signal
Continuous Flash
Flame Present
On
08/18
1021492B
(Replaces 1021492A)
YELLOW
RED
Refer to the Installation Instructions
provided with the kit for the proper
heating and cooling speeds for your
application.
RED
W
RX
TX
COM
C
R
BLACK
BLACK
FAN SPEED
WHITE
BLACK
1 2
11
22
33
44
55
66
77
88
BLACK
WHITE
ORANGE
BLUE
For 96% 2-Stage Fixed Speed Downflow Furnaces
BLACK
WIRING DIAGRAM
WHITE
35
COOL HEAT
LINE- N
LINE- N
Gas Information
GAS FLOW RATES
(Cubic Feet Per Hour)
GAS FLOW RATES
(Cubic Feet Per Hour)
CUBIC FEET PER
REVOLUTION OF GAS METER
TIME FOR
ONE REVOLUTION
(SECONDS)
CUBIC FEET PER
REVOLUTION OF GAS METER
1
5
10
TIME FOR
ONE REVOLUTION
(SECONDS)
10
12
360
300
1,800
1,500
3,600
3,000
66
68
14
257
1,286
2,571
70
51
257
514
16
225
1,125
2,250
72
50
250
500
18
200
1,000
2,000
74
49
243
486
20
180
900
1,800
76
47
237
474
22
164
818
1,636
78
46
231
462
24
150
750
1,500
80
45
225
450
26
138
692
1,385
82
44
220
439
28
129
643
1,286
84
43
214
429
30
120
600
1,200
86
42
209
419
32
113
563
1,125
88
41
205
409
34
106
529
1,059
90
40
200
400
36
100
500
1,000
92
39
196
391
38
95
474
947
94
38
191
383
40
90
450
900
96
38
188
375
42
86
429
857
98
37
184
367
44
82
409
818
100
36
180
360
46
78
391
783
102
35
176
353
48
75
375
750
104
35
173
346
50
72
360
720
106
34
170
340
52
69
346
692
108
33
167
333
54
67
333
667
110
33
164
327
56
64
321
643
112
32
161
321
58
62
310
621
114
32
158
316
60
60
300
600
116
31
155
310
62
64
58
56
290
281
581
563
118
120
31
30
153
150
305
300
1
5
10
55
53
273
265
545
529
Table 10. Gas Flow Rates
CAPACITY OF BLACK IRON GAS PIPE (CU. FT. PER HOUR)
FOR NATURAL GAS (SPECIFIC GRAVITY - 0.60)
Length of Pipe Run (Feet)
Nominal Pipe
Diameter (IN.)
10
1/2
130
90
75
65
3/4
280
190
150
130
1
520
350
285
245
1 1/4
1,050
730
590
1 1/2
1,600
1,100
890
20
30
Cubic Feet Per Hour Required =
40
50
60
70
80
55
50
45
40
115
105
95
90
215
195
180
170
500
440
400
370
350
760
670
610
Input To Furnace (Btu/hr)
Heating Value of Gas (Btu/Cu. Ft.)
NOTE: The cubic feet per hour listed above must be greater than the cubic feet per hour of gas flow required by the furnace.
To determine the cubic feet per hour of gas flow required by the furnace, divide the input rate of the furnace by the heating
value (from gas supplier) of the gas.
Table 11. Gas Pipe Capacities
36
ALTITUDE ABOVE SEA LEVEL
0 to 1,999 FT
INPUT
(BTU)
Orifice
Size
2,000 to 2,999 FT
Manifold
Pressure
3,000 to 4,999 FT
Manifold
Pressure
Orifice
Size
Low High
5,000 to 5,999 FT
Manifold
Pressure
Orifice
Size
Low High
Orifice
Size
Low High
Manifold
Pressure
6,000 to 7,999 FT
Manifold
Pressure
Orifice
Size
Low High
8,000 to 10,000 FT
Orifice
Size
Low High
Manifold
Pressure
Low High
39,000 1.1mm
4.2
10.0
1.1mm
3.8
9.0
1.1mm
3.6
8.5
#59
4.2
10.0
#59
3.8
9.0
#59
3.6
8.5
57,000 1.25mm
4.2
10.0 1.25mm
3.8
9.0
1.25mm
3.6
8.5
1.1mm
4.2
10.0
1.1mm
3.8
9.0
1.1mm
3.6
8.5
63,000 1.2mm
4.2
10.0
3.8
9.0
1.2mm
3.6
8.5
1.1mm
4.2
10.0
1.1mm
3.8
9.0
1.1mm
3.6
8.5
1.2mm
Table 12. Liquid Propane Conversion Chart
LOCAL HEATING VALUES FOR NATURAL GAS
ALTITUDE ABOVE
SEA LEVEL
BTU PER CUBIC FOOT
650
700
750
800
850
900
950
1,000
1,050
2,000 FT
LOW
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
3,000 FT
LOW
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
4,000 FT
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
5,000 FT
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
6,000 FT
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
7,000 FT
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
8,000 FT
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
9,000 FT
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
10,000 FT
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
Table 13. Natural Gas Heating Values
NATURAL GAS with LOW HEATING VALUE
NATURAL GAS with HIGH HEATING VALUE
ALTITUDE
ABOVE SEA
LEVEL.
O.S
&
M.P
0 FT
to
1,999 FT
O.S.
2,000 FT
to
2,999 FT
3,000 FT
to
3,999 FT
4,000 FT
to
4,999 FT
5,000 FT
to
5,999 FT
6,000 FT
to
6,999 FT
7,000 FT
to
7,999 FT
8,000 FT
to
8,999 FT
9,000 FT
to
9,999 FT
M.P.
INPUT (BTU)
45000
49
1.7
1.7
M.P.
2.7
5,000 FT
to
5,999 FT
3.5
6,000 FT
to
6,999 FT
3.3
7,000 FT
to
7,999 FT
3
8,000 FT
to
8,999 FT
2.8
9,000 FT
to
9,999 FT
47
2.8
1.7
1.7
49
3.5
1.7
48
3
1.7
51
49
3.3
1.7
48
2.8
1.7
51
1.7
1.7
49
3
1.7
48
2.6
1.7
49
2.8
1.7
NOTE: O.S.=Orifice Size, M.P. = Manifold Pressure
Table 14. Orifices for Natural Gas
High Heating Value
37
2.8
4,000 FT
to
4,999 FT
47
2.9
1.7
51
O.S.
1.7
48
3.3
1.7
3.1
1.7
51
O.S.
M.P.
3
3,000 FT
to
3,999 FT
47
45
2.5
1.7
1.7
45
2.6
1.7
1.7
47
3.3
1.7
49
O.S.
M.P.
1.7
49
1.7
3.5
45
2.8
1.7
O.S.
M.P.
3.2
2,000 FT
to
2,999 FT
47
45
2.9
49
O.S.
M.P.
1.7
49
O.S.
M.P.
O.S.
3.5
0 FT
to
1,999 FT
72000
45
3.5
1.7
O.S.
M.P.
O.S
&
M.P
LOW HIGH LOW HIGH LOW HIGH
O.S.
M.P.
60000
ALTITUDE
ABOVE SEA
LEVEL
M.P.
INPUT (BTU)
45000
49
1.7
1.7
M.P.
M.P.
3.5
1.7
1.7
1.7
3.5
1.7
1.7
3.3
1.7
3.4
49
1.7
48
2.9
2.8
49
48
3.1
2.9
47
2.9
1.7
51
O.S.
1.7
48
51
3.1
47
3.1
1.7
3.3
1.7
45
2.6
1.7
1.7
47
3.2
1.7
51
O.S.
3.4
1.7
3.5
47
45
2.7
1.7
1.7
45
2.9
3.5
47
3.5
1.7
49
O.S.
M.P.
3.1
1.7
1.7
45
49
O.S.
M.P.
1.7
49
1.7
47
3.5
45
3.5
1.7
O.S.
M.P.
1.7
49
O.S.
M.P.
45
3.5
49
O.S.
M.P.
72000
LOW HIGH LOW HIGH LOW HIGH
O.S.
M.P.
60000
3.2
49
3.1
1.7
NOTE: O.S.=Orifice Size, M.P. = Manifold Pressure
Table 15. High Altitude Deration Chart for
Natural Gas - Low heating Value
2.9
Venting Information
VENT TERMINAL
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
CANADIAN INSTALLATIONS a
A
B
C
US INSTALLATIONS b
Clearance Location
Direct Vent (2-pipe) &
Conventional Vent (1-pipe) Furnaces
Direct Vent
(2-pipe) Furnaces
Conventional Vent
(1-pipe) Furnaces
Clearance above grade, veranda, porch, deck,
balcony, or maximum expected snow level.
12 inches (30cm)
12 inches (30cm)
12 inches (30cm)
6 inches (15cm) for appliances
< 10,000 Btuh (3kW)
6 inches (15cm) for appliances
< 10,000 Btuh (3kW)
12 inches (30cm) for appliances
10,000 Btuh - 100,000 Btuh (30kW)
9 inches (23cm) for appliances
10,000 Btuh - 50,000 Btuh (30kW)
36 inches (91cm) for appliances
> 100,000 Btuh (30Kw)
12 inches (30cm) for appliances
> 50,000 Btuh (30Kw)
Clearance to window or door that may be
opened.
Clearance to permanently closed window
4 ft. (1.2m) below or to side of
opening; 1 ft. (300mm) above
opening
12 inches (30cm) suggested or as needed to avoid
condensation on glass.
12 inches (30cm) suggested or as needed to avoid condensation on glass.
Clearance must be greater than the depth of
the soffit unless it complies with Figure 30
(page 38)
Clearance must be greater than the depth of the soffit unless
it complies with Figure 30 (page 38)
Clearance must be greater than the depth of the
soffit unless it complies with Figure 30 (page 38)
Clearance must be greater than the depth of the soffit unless
it complies with Figure 30 (page 38)
D
Vertical clearance to ventilated soffit located
above the terminal within a horizontal distance of
2 feet (61cm) from the center line of the terminal.
E
Clearance to unventilated soffit.
F
Clearance to outside corner.
All Clearances in this Figure apply
on both walls
All Clearances in this Figure apply on both walls
G
Clearance to inside corner.
All Clearances in this Figure apply
on both walls
All Clearances in this Figure apply on both walls
H
Clearance to each side of center line extended
above meter/regulator assembly.
3 feet (91cm) within a height 15 feet
above the meter/regulator assembly
3 feet (91cm) within a height of 15 feet
I
Clearance to service regulator vent outlet.
J
Clearance to non-mechanical air supply inlet to
building or the combustion air inlet to any other
appliance.
3 feet (91cm)
3 feet (91cm) in any direction
6 inches (15cm) for appliances
< 10,000 Btuh (3kW)
6 inches (15cm) for appliances
< 10,000 Btuh (3kW)
12 inches (30cm) for appliances
10,000 Btuh - 100,000 Btuh (30kW)
9 inches (23cm) for appliances
10,000 Btuh - 50,000 Btuh (30kW)
36 inches (91cm) for appliances
> 100,000 Btuh (30Kw)
12 inches (30cm) for appliances
> 50,000 Btuh (30Kw)
4 ft. (1.2m) below or to side of
opening; 1 ft. (300mm) above
opening
K
Clearance to mechanical air supply inlet.
6 feet (1.83m)
3 feet (91cm) above if within
10 feet (3m) horizontally
3 ft. (91cm) above if within
10 feet (3m) horizontally
L
Clearance above paved sidewalk or driveway
located on public property.
7 feet (2.13m) c
7 feet (2.13m) c
7 ft. (2.13m)
M
Clearance under open veranda, porch, deck,
or balcony.
12 inches (30cm) d
12 inches (30cm) d
12 inches (30cm) d
NOTES:
a = In accordance with the current CSA B149.1 Natural Gas and Propane Installation Guide Code
b = In accordance with the current ANSI Z223.1 / NFPA 54 Natural Fuel Gas Code
c = A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
d = Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
Table 16. Vent Termination Clearances
38
Seal/Caulk Around
Pipes at Building
Straps or Other Suitable
Supports at minimum of 5 ft. Intervals
Support System on
Vertical Rise
90° Elbow
Couplings with 2
Hose Clamps (Optional)
See Table 2 for
PVC Pipe Lengths
(Field Supplied)
COMBUSTION AIR
90°
Elbow
FLUE PIPE
See Table 2 for
PVC Pipe Lengths
(Field Supplied)
COMBUSTION AIR
FLUE PIPE
90°
Elbow
Upward Pitch - 1/4” per foot
(Flue Pipe)
Wall
First support placed
as close to furnace
connection as possible
12” Min.
7”
Normal
Snow Level
MG2S Front Return Model Shown
STATUS LIGHTS
STATUS LIGHTS
RED
L2-IN
GREEN
Y/Y2_OUT
RED
RED
GREEN
RED
OUTPUT TERMINALS
L2-IN
L1-IN
Y1_OUT
L2-OUT
W_OUT
OUTPUT TERMINALS
L2-OUT
W_OUT
Y/Y2_OUT
L1-IN
Y1_OUT
L1-OUT
H_OUT
L1-OUT
Y1_IN
COOL
SENSOR
C
EXPANSION PORT
CONNECTION TO
FURNACE CONTROL
BOARD
GROUND
MOTOR WIRING
HARNESS
R
FAN SPEED
DHUM_IN
1 2 3 4 5 6 78
HEAT
Y1_IN
COOL
SENSOR
C
EXPANSION PORT
CONNECTION TO
FURNACE CONTROL
BOARD
GROUND
INPUT TERMINALS
DHUM_IN
HEAT
OFF ON
FAN SPEED
1 2 3 4 5 6 78
INPUT TERMINALS
OFF ON
H_OUT
R
MOTOR WIRING
HARNESS
Outlet
Outlet
Must be
outside
of line.
Clearance =
depth of soffit
Depth
NOTE: Only outlet vents are shown.
For placement with combustion air
inlet see Figure 1.
CLEARANCES FROM SOFFIT
VERTICAL VENTING
HORIZONTAL VENTING
Figure 30. Horizontal / Vertical Venting & Clearances from Soffit
39
INSTALLATION CHECKLIST
ATTENTION INSTALLERS:
It is your responsibility to know this product better than your customer.
This includes being able to install the product according to strict
safety guidelines and instructing the customer on how to operate
and maintain the equipment for the life of the product. Safety should
always be the deciding factor when installing this product and using
common sense plays an important role as well. Pay attention to all
safety warnings and any other special notes highlighted in the manual.
Improper installation of the furnace or failure to follow safety warnings
could result in serious injury, death, or property damage.
These instructions are primarily intended to assist qualified individuals
experienced in the proper installation of this appliance. Some local
codes require licensed installation/service personnel for this type of
equipment. Please read all instructions carefully before starting the
installation. Return these instructions to the customer’s package for
future reference.
ELECTRICAL SYSTEM
Electrical connections tight?
YES
NO
Line voltage polarity correct?
YES
NO
Supply Voltage
VOLTS:
Has the thermostat been calibrated?
YES
NO
Is the thermostat level?
YES
NO
Is the heat anticipator setting correct?
YES
NO
Gas Type: (circle one)
Natural
Gas
Propane
Gas pipe connections leak tested?
YES
NO
GAS SYSTEM
INSTALLER NAME:
CITY:
STATE:
Gas Line Pressure
(in - W.C.)
Installation Altitude
(FT.)
UNIT MODEL #
Deration Percentage
(%)
UNIT SERIAL #
Furnace Input
(Btuh)
Supply Air Temperature
(° F)
Return Air Temperature
(° F)
Temperature Rise
(° F)
INSTALLATION ADDRESS:
CITY:
Minimum clearances per
Table 1, (page 5)?
STATE:
YES
NO
Has the owner’s information
been reviewed with the homeowner?
YES
NO
Has the literature package been
left near the furnace?
YES
NO
COMBUSTION AIR & VENTING SYSTEM
Is there adequate fresh air supply for
combustion and ventilation?
YES
NO
Vent free from restrictions?
YES
NO
Filter(s) secured in place?
YES
NO
Filter(s) clean?
YES
NO
Flue connections tight?
YES
NO
Is there proper draft?
YES
NO
40
LEFT INTENTIONALLY BLANK
41
Specifications & illustrations subject to change without notice or incurring obligations (06/24).
O’Fallon, MO, © Nortek Global HVAC LLC 2024. All Rights Reserved.
10485510
(Replaces 1034909C)
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