Lennox 15GCSX Series Guide

505,040M
*P505040M*
05/09
*2P0509* Page 1
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
E2005 Lennox Industries Inc.
Dallas, Texas, USA
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause personal injury, loss of life,
or damage to property.
Installation and service must be performed by a
licensed professional installer (or equivalent),
service agency or the gas supplier.
USER’S
INFORMATION
MANUAL
15GCSX SERIES UNITS
GAS PACKAGED UNITS (2−5 TONS)
Armstrong # 38152A066
505,040M
05/09
Supersedes 08/05
Table of Contents
Parts Arrangement 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Notice to Homeowners 2. . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Information 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Operations 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermostat Operations 4. . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Reminders 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Planned Services 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Parts List 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
WHAT TO DO IF YOU SMELL GAS:
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other ap-
pliance.
Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
DDo not try to light any appliance.
DDo not touch any electrical switch; do not
use any phone in your building.
DImmediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
DIf you cannot reach your gas supplier, call
the fire department.
FIRE OR EXPLOSION HAZARD.
Failure to follow safety warnings exact-
ly could result in serious injury, death,
or property damage.
WARNING
DLeave the building immediately.
Litho U.S.A.

Page 2
15GCSX Parts Arrangement
R
Notice to Homeowners
This furnace is equipped with safety devices that protect
you and your property. If one or more of these devices is
activated, furnace operation will stop. If your home is left
unattended for an extended period of time, equipment
operation must be checked periodically. If this is not
possible, the water supply to the house should be shut off
and the pipes should be drained. This will prevent
problems associated with a NO HEAT condition (frozen
pipes, etc.)
Safety Information
1 − Keep unit area clear and free of combustible
materials, gasoline and other flammable vapors and
liquids.
2 − Inspect return air duct to ensure duct is sealed to
the unit and terminates outside the space
containing appliance.
3 − This unit requires air for combustion and ventilation
to ensure both proper and safe operation.
Combustion air is brought in through the condenser
section. Do not block or obstruct the condenser coil
or condenser fan opening.
4 − Examine the unit periodically to ensure that the
physical support of the unit is sound without sagging,
cracks, gaps, etc. There must be no obvious signs of
deterioration of the unit.
WARNING
Electric shock hazard. Can cause
injury or death. Before attempting to
perform any service or maintenance,
turn the electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
WARNING
Danger of explosion. Can cause injury
or product or property damage. Should
the gas supply fail to shut off or if
overheating occurs, shut off the gas
valve to the unit before shutting off the
electrical supply.
WARNING
Danger of electrical shock, explosion
and fire. Improper servicing could
result in dangerous operation, serious
inujry, death or property damage.

Page 3
WARNING
Danger of explosion and fire. Failure to
follow safety warnings exactly could
result in dangerous operation, serious
injury, death or property damage.
Your unit is a gas appliance. It is critical that the gas
supplied to the unit be completely burned to avoid the
production of carbon monoxide gas. Complete
combustion of the gas requires, but is not limited to,
correct gas pressure and gas flow rate, adequate
combustion, air, and proper venting.
WARNING
Carbon monoxide gas is invisible, odorless and
toxic. Exposure to carbon monoxide gas can
cause personal injury and even death to all
occupants, including pets. Any item that is
powered by or gives off heat from a combustion
process (including lawn mowers, automobiles,
and fireplaces) has the potential to produce
carbon monoxide gas. Because of this, we
recommend the use of a carbon monoxide
detector in your home, even if you do not own gas
appliances. Reliable detectors are available at
reasonable retail prices. Contact your dealer for
more details about this investment in your safety.
Your furnace is designed to meet standards set by
national agencies, and to operate safely when
properly installed and maintained. However, the
unit’s performance can be greatly impacted by the
individual installation and the operating
environment. It is your responsibility to ensure
that this appliance is maintained.
Proper maintenance is critical for your safety and
the satisfactory operation of the product. We
strongly recommend annual inspection and
maintenance of this appliance.
WARNING
Do not use this unit if any part has been under
water. A flood−damaged unit is extremely
dangerous. Attempts to use the unit can result in
fire or explosion. A qualified service agency
should be contacted to inspect the unit and to
replace all gas controls, control system parts,
electrical parts that have been wet or to replace the
unit if deemed necessary.
WARNING
Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you
to fiberglass wool. Breathing this may cause lung
cancer. (Fiberglass wool is known to the State of
California to cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact
your supervisor.
P.O. Box 799900
Dallas, TX 75379−9900
Unit Operation
WARNING
Danger of explosion and fire. Can
cause injury or product or property
damage. You must follow these
instructions exactly.
FOR YOUR SAFETY READ BEFORE LIGHTING
BEFORE LIGHTING smell all around the unit area for
gas. Be sure to smell next to the floor because some gas
is heavier than air and will settle on the floor.
Use only your hand to turn the gas control knob. Never
use tools. If the knob will not turn by hand, do not try to
repair it, call a qualified service technician. Force or
attempted repair may result in a fire or explosion.
This unit is equipped with an automatic spark ignition
system. There is no pilot. In case of a safety shutdown,
move thermostat switch to OFF and return the thermostat
switch to HEAT. An electro−mechanical thermostat is
shown in figure 1. On units with electronic temperature
controls, shut main disconnect off and back on to reset
ignition control.
To Place Unit into Operation:
1 − Turn off electrical power to unit.
2 − Set thermostat to lowest setting.
3 − Remove heat section access panel.
4 − Turn the gas valve knob to the ON position. Refer to
figure 2.
5 − Replace heat section access panel.
6 − Turn on electrical power to unit.

Page 4
7 − Set room thermostat to desired temperature. (If
thermostat setpoint temperature is above room
temperature after the pre−purge time expires, main
burners will light).
THERMOSTAT
HEAT COOL
FAN
50 60 70 80
10 15 2025 30
HEAT OFF COOLAUTO ON
Figure 1
Figure 2
Honeywell VR8205 Series Gas Valve
GAS VALVE SHOWN IN OFF POSITION
To Shut Down:
1 − Set the thermostat to the lowest setting.
2 − Turn off electric power to unit.
3 − Remove heat section access panel.
4 − Turn the gas valve knob to the OFF position.
5 − Replace heat section access panel.
WARNING
Danger of explosion. Can cause injury
or death. Do not attempt to light
manually. Unit has a direct spark
ignition system.
Thermostat Operation
There are many styles of thermostats. Though their
appearances may be different, there are many
similarities.
System Switch
The thermostat system switch allows you to choose
whether you wish the unit to operate in either the HEAT or
COOL mode. When the HEAT mode is selected, the unit
will operate to satisfy a heating demand. When the COOL
mode is selected, the unit will operate to satisfy a cooling
demand. Some thermostats feature an AUTO system
mode, which automatically switches between the HEAT
and COOL modes to ensure comfort.
Fan Operation
The thermostat fan switch allows you to choose whether
you wish the circulating air blower to operate in either the
AUTO or ON mode. When the AUTO mode is selected,
the circulating air blower will cycle on and off with the
cooling or heating demand. When the ON mode is
selected, the circulating air blower will operate
continuously.
Maintenance
To maintain efficiency and longevity, your equipment
must be serviced yearly by a qualified service technician.
Failure to provide proof of proper service can void the
warranty.
WARNING
Electric shock hazard. Can cause
injury or death. Before attempting to
perform any service or maintenance,
turn the electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
Filters
Filter(s) must be installed in the return air system. Filters
should be checked monthly and replaced when
necessary. Take note of air flow direction marking on filter
frame when reinstalling filters. Replace disposable or
clean permanent type as necessary. DO NOT replace
permanent type with disposable.
NOTE − Filters must be U.L.C. approved or equivalent for
use in Canada.
Motors
All motors are permanently lubricated and require no
further lubrication. Motors should be cleaned yearly to
prevent the accumulation of dust and dirt on the windings
or motor exterior.
Coil
Dirt and debris should not be allowed to accumulate on
the coil surfaces or other parts in the air conditioning
circuit. Cleaning should be performed as often as
necessary. Use a brush, vacuum cleaner attachment, or
other suitable means. If water is used to clean the coil, be
sure the power to unit is shut off prior to cleaning.
NOTE − Care should be used when cleaning the coil so
that the coil fins are not damaged.
Do not permit the hot condenser air discharge to be
obstructed by overhanging structures or shrubs.

Page 5
Burners
WARNING
Danger of explosion and fire. Can cause
injury or product or property damage.
Periodically inspect burner flame to en-
sure proper unit operation.
Inspect the burner flame periodically during heating
season to ensure proper burner operation.
Light the burners and allow unit to operate for a few
minutes to establish normal burning conditions. Observe
the burner flames. Flames should be predominantly blue
in color and strong in appearance. Verify that all burners
are lit and that the flame does not impinge on the sides of
the heat exchanger. See figure 3.
Distorted flame or yellow tipping of the natural gas
flame (or long yellow tips on LP/propane flame) may be
caused by one or more of the following: lint or dirt inside
the burner or burner ports; lint or dirt at the air inlet
between the burner and manifold pipe; or an
obstruction over the burner orifice.
Use a soft brush or vacuum to clean the affected areas.
Figure 3
Typical Flame Appearance
Burner
Flame
(Blue Only)
Burner
Gas Manifold
Heat Exchanger
Vent Outlet
Visually inspect vent outlet periodically to make sure that
the there is no buildup of soot and dirt . If necessary, clean
to maintain adequate opening to discharge flue products.
Service Reminder
Call a qualified service technician if the unit is
inoperative. Before calling, always check the following
to be sure service is required:
1 − Be sure electrical disconnect switches are ON.
2 − Check room thermostat for proper setting.
3 − Replace any blown fuses or reset circuit breakers.
4 − Gas valve should be ON.
5 − Air filters should not be plugged, limiting air flow.
6 − Make sure all access panels are in place.
Planned Services
You should expect a service technician to check the
following items during an annual inspection. Power to the
unit must be shut off for the service technician’s safety.
SFresh air grilles and louvers Must be open and
unobstructed to provide combustion air.
SBurners must be inspected for rust, dirt, or signs of
water.
SExhaust pipe must be inspected for signs of water,
damaged Rust or disconnected joints.
SUnit appearance must be inspected for rust, dirt,
signs of water, burnt or damaged wires, or
components. A good coat of auto wax can extend the
appearance.
SBlower access door must be properly in place.
SReturn air duct must be properly attached and
provide an air seal to the unit.
SOperating performance  Unit must be observed
during operation to monitor proper performance of
the unit and the vent system.
SCombustion gases  Flue products must be
analyzed and compared to the unit specifications.
Problems detected during the inspection may make it
necessary to temporarily shut down the furnace until the
items can be repaired or replaced.
Pay attention to your unit. Situations can arise between
annual furnace inspections that may result in unsafe
operation. For instance, items innocently stored next to
the unit may obstruct the combustion air supply. This
could cause incomplete combustion and the production
of carbon monoxide gas.
Repair Parts List
The following repair parts are available through Lennox
dealers. When ordering parts, include the complete unit
model number listed on the unit rating plate. All service
must be performed by a licensed professional installer (or
equivalent), service agency, or gas supplier.
CONTROL PANEL PARTS HEATING PARTS
Ignition control board Heat exchanger assembly
Contactor Combustion air inducer
Transformer Orifices
Capacitor Burners
BLOWER PARTS Gas valve
Blower wheel Manifold
Blower Motor Ignitor
Motor mounting arm Limit control
Blower housing Rollout switch
COOLING PARTS Pressure switch
Compressor
Condenser fan motor/blades
Coils
Drain pan