Carrier 48TC series Guide

User's Information Manual
NOTE: Read the entire instruction manual before starting
the installation.
NOTE TO INSTALLER:
This manual should be left with the equipment owner.
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS .................... i
TO LIGHT UNIT .............................. 2
TO SttUT UNIT OFF ........................... 4
ROUTINE MAINTENANCE AND CARE FOR THE
EQUIPMENT OWNER .......................... 5
BEFORE YOU CALL FOR SERVICE ............. 7
REGULAR DEALER MAINTENANCE ............ 7
SAFETY CONSIDERATIONS
hnproper installation, adjustment, alteration, service,
maintenance, or use can cause fire, electrical shock, or
other conditions which may cause personal injury or
property damage. Consult a qualified installer, service
agency or your distributor or branch for information or
assistance. The qualified installer or agency must use
factory-authorized kits or accessories when modifying
this product. Refer to the individual instructions packaged
with the kits or accessories when installing.
Follow all safety codes and wear safety glasses. Have fire
extinguisher available. Read these instructions thoroughly
and follow all warnings or cautions attached to the unit.
Consult local and state building codes and Sheet Metal
and Air Conditioning National Association (SMACNA)
for special installation requirements.
Recognize safety information. This is the safety-alert
symbol _. When you see this symbol on the unit or in
instructions and manuals, be alert to the potential for
personal injury. Understand the signal words DANGER,
WARNING, and CAUTION. These words are used with
the safety-alert symbol. DANGER identifies the most
serious hazards, which will result in severe personal injury
or death. WARNING signifies hazards, which could result
in personal injury or death. CAUTION is used to identify
unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
appliance.
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury or death.
What to do if you smell gas:
• Leave the building.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• hnmediately 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.
Installation and service must be performed by a
qualified installer, service agency or the gas supplier.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
Before performing maintenance, be sure main power
switch to unit is turned off and lockout tag is installed.
There may be more than one power switch.

ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury, death or personal injury.
Do not use this equipment if any part has been under
water. A flood-damaged equipment is extremely
dangerous. Attempts to use the equipment can result
in fire or explosion. A qualified service agency should
be contacted to inspect the equipment and to replace
all gas controls, control system parts, electrical parts
that have been wet or the equipment if deemed
necessary.
Your rooftop heating/cooling unit is equipped with an
automatic, direct spark ignitor and an induced-draft,
combustion blower.
IMPORTANT FACTS
• DO: READ AND UNDERSTAND THIS MANUAL.
• DO: Have your equipment and vent system inspected
annually by a qualified service technician.
• DO: Inspect your filter monthly and clean or replace
when needed.
• DO: Provide adequate airflow to the equipment for
efficient combustion and safe ventilation.
• DO NOT: Keep combustible materials, gasoline, and
other flammable liquids or vapors around your
equipment.
• DO NOT: Cover your equipment in any manner.
• DO NOT: Store anything (including trash or debris) near
your equipment.
• DO NOT: In any way block or restrict airflow around
your equipment.
• DO NOT: Contaminate the air used for combustion of
your equipment with any kind of chemical or fumes. This
could also cause heat exchangers, metal vent systems or
components to deteriorate.
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
1. Do not turn off the electrical power to unit without
first turning off the gas supply.
2. Before attempting to start the gas heating section,
familiarize yourself with all the procedures that
must be followed.
3. Never attempt to manually light the burners on the
unit with a match, lighter, or any other flame. If
the electric sparking device fails to light the burn-
ers, refer to the shutdown procedures, then call
your dealer as soon as possible.
CUT HAZARD
Failure to follow this caution may result in personal
injury.
When removing access panels or performing
maintenance functions inside your unit, be aware of
sharp sheet metal parts and screws. Although special
care has been taken to reduce sharp edges inside the
unit, be extremely careful when handling parts or
reaching into the unit.
TO LIGHT UNIT
Step 1 -- Set room thermostat/unit controller to the lowest
temperature setting and set the SYSTEM switch to HEAT or
AUTO position. See Fig. 1.
007381
Fig. 1 - Thermostat/Unit Controller
Step 2 -- Turn off the gas supply by closing the gas supply
shut-offvalve (external to RTU unit). See Fig. 2 for location.
Gas Supply Shut Off Valve
@
Fig. 2 - Gas Supply Shut-Off Valve
(Thru the base gas supply shown.)
Fig. 3 - Gas Supply Shut Off Valve
C07358
007380

Step 3 -- Turn off the electrical supply to the unit by
switching the RTU main disconnect to OFE Then, ensure
personal safety by installing a lockout tag on the disconnect.
....... MAI N.......................
C07331
Fig. 4-RTU Main Disconnect - Electrical Supply
Step 4 -- Remove the gas component access panel. For
location of the gas component access panel, see Fig. 5.
GAS COMPONENT
ACCESS PANEL
RTU GAS VALVE
C08397
Fig. 5-Gas Component Access Panel
and RTU Gas Valve Location
007383
Fig. 6 - Gas Component Access Panel Removal
Step 5 -- Move the RTU gas valve on/off switch to the OFF
position and wait 5 minutes. See Fig. 5 for location of RTU
gas valve.
Two Stage Single Stage
RTU gas valve RTU gas valve
On/Off
Switch
On/Off
Switch
007382
Fig. 7 - Single- and Two-Stage RTU Gas Valves
Step 6 -- Move the RTU gas valve on/off switch to the ON
position.
Step 7 -- Replace the compressor access panel.
Fig. 8 - Compressor Access Panel
007384
Step 8 -- Remove disconnect lockout tag and restore power
to the unit by switching the RTU main disconnect to ON.
C07386
Fig. 9 - RTU Main Disconnect - Electrical Supply
Step 9 -- Turn on the gas supply by opening the gas supply
shut-off valve.
Fig. 10 - Gas Supply Shut Off Valve
007337

Step 10 -- To start unit, set room thermostat/unit controller
heat setpoint to slightly above room temperature. The
induced-draft combustion air fan will start. The RTU gas
valve will open and main burners should ignite within 5
seconds. If the burners do not light, there is a 22-second
delay. Burners will attempt to ignite within 5-seconds. Each
time the burner fails to light, the 22-second time delay is
repeated. If the burner does not light within 15 minutes, the
unit will lockout the gas heat. To reset after a lockout, turn
off the main electrical supply to the unit by switching the
RTU main disconnect to OFF for a minimum of five seconds.
Repeat Steps 1-10. If burners still do not light, call for
service.
Step 11 -- Set the room thermostat/unit controller heating
setpoint to desired temperature setting.
Fig. 11 - Thermostat/Unit Controller
C07381
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death or property damage.
If the main burners fail to light, or the blower fails to
come on, shut down gas heating section and call your
dealer for service.
TO SHUT UNIT OFF
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
1. Turn off gas supply by closing the gas line supply
valve. Then, turn off the electrical power supply to
the unit by switching the disconnect to off. Install
lockout tag before servicing or performing main-
tenance.
2. Do not turn off the electrical power to unit without
first turning off the gas supply.
Step 1 -- Set room thermostat/unit controller heat setpoint
to the lowest temperature setting and set the SYSTEM
switch to OFF.
Fig. 12 - Thermostat/Unit Controller C07381
Step 2 -- Turn off gas supply by closing the gas supply
shut-offvalve (external to RTU unit). See Fig. i for location.
Fig. 13 - Gas Supply Shut Off Valve
C07330
Step 3 -- Turn off the electrical supply to the unit by
switching the RTU main disconnect to off. Then, ensure
personal safety by installing a lockout tag on the disconnect.
C07331
Fig. 14 -RTU Main Disconnect - Electrical Supply
Step 4 -- Remove the compressor access panel. For location
of compressor access panel, see Fig. 5.
Fig. 15 - Compressor Access Panel
C07383
Should overheating occur or the gas supply fail to shut
off, shut off the gas valve in the unit (by moving on/off
switch to off) before shutting off the electrical supply.

Step5-- MovetheRTUgasvalveon/offswitchtotheOFF
position.SeeFig.5forlocationofRTUgasvalve.
Two Stage Single Stage
RTU gas valve RTU gas valve
On/Off
Switch
On/Off
Switch
C07382
Fig. 16 - Single- and Two-Stage Gas Valves
Step 6 -- Replace compressor access panel.
Fig. 17 - Compressor Access Panel
C07384
Step 7 -- Remove disconnect lockout tag and restore power
to the unit by switching the RTU main disconnect to ON.
MAIN _F _
C07336
Fig. 18 -RTU Main Disconnect - Electrical Supply
Step 8 -- If unit is being shut down because of a malfunction,
call your dealer as soon as possible. If unit is being shut down
because the heating season has ended, restore electrical
power to the unit and set thermostat/unit controller to the
COOL position to ensure operation of the cooling system
during the cooling season.
ROUTINE MAINTENANCE AND
CARE FOR THE EQUIPMENT
OWNER
While some maintenance can be performed by laymen,
most should be performed by skilled, experienced
personnel. Follow the recommended service maintenance
schedule, and modify it as necessary for your
application/environment. For instance, dusty areas may
require more frequent filter changes.
After performing any maintenance or service on the unit,
be sure all panels are securely fastened in place to prevent
rain from entering unit cabinet and to prevent disruption
of the correct unit airflow pattern.
FIRE AND EQUIPMENT DAMAGE HAZARD
Failure to follow this warning could result in personal
injury and damage to equipment.
Do not use this unit if any part has been under water.
hmnediately call a qualified service technician to
inspect the unit and to replace any part of the control
system and gas control that has been under water.
To ensure proper functioning of the unit, flow of
combustion and ventilating air must not be obstructed
from reaching the unit. Follow service and performance
clearances as listed in the product data.
Consider the following information before maintaining or
servicing equipment:
Indoor Air Filter(s)
FIRE AND EQUIPMENT DAMAGE HAZARD
Failure to follow this warning could result in personal
injury and damage to equipment.
Never operate unit without filters in place. The
accumulation of dirt, dust or lint on the internal parts
of your unit can cause fire or a loss of efficiency.
Damage to the blower motor and/or compressors
could also result.
Indoor air filter(s) should be checked every 3 or 4 weeks
(application dependant) and changed or cleaned when
necessary. See Fig. 19 for air filter access panel location.
• Lift up and remove air filter access panel.
• While holding filters, tilt upper filter rack.
• Remove filters by pulling up and out toward you from the
track.
• Inspect filters. Clean or replace as necessary.
• Follow direction of airflow arrows as noted on filter
frame when returning filters to rack.
• Reinstall air filter access panel.
AIR FILTER ACCESS PANEL
Fig. 19 -Air Filter Access Panel
C07359

If you have difficulty in locating your air filter or if you
have questions concerning proper filter maintenance,
contact your dealer for instructions. When replacing your
unit filters, always use the same size and type of filter that
was originally supplied by the installer
Units with outdoor air capability have a cleanable filter
for the outdoor air. This filter should be checked
semi-annually and cleaned as necessary with steam or hot
water and a mild detergent. Do not use throwaway filters
in place of cleanable filters.
Compressor
All compressors are factory supplied with a normal charge
of the correct type refrigeration-grade oil in them and
should not require additional oil.
Condenser Fan
PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal
injury.
Do not poke sticks, screwdrivers, or other object into
revolving fan blades.
The fan must be kept free of all obstructions to ensure
proper cooling. Contact your dealer for any required
service.
Electrical Controls and Wiring
Ensure wires do not contact refrigerant tubing or sharp
edges. Electrical controls are difficult to check without
proper instrumentation. If inadequate cooling is suspected,
contact your qualified local dealer for service.
Combustion Area and Vent System
The combustion area and vent system should be visually
inspected before each heating season.
FIRE HAZARD
Failure to follow this warning could result in personal
injury equipment damage.
If your unit makes any unusual or especially loud
noises during heating, shut down the heating section
and call your qualified service technician.
Proceed as follows to inspect the combustion area and
power-venting system of your unit.
• Turn off gas supply to your unit.
• Turn off electrical power to your unit; install lockout tag.
• Remove compressor access panel.
• Using a flashlight, carefully inspect the burner areas for
dirt, soot, or scale.
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment.
If dirt, soot, rust or scale accumulations are found, call
your service technician and do not operate your
heating section.
• When you have completed your inspection, follow the
start-up procedures in this manual to restore your unit to
operation.
PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal
injury.
Components in heat section may be hot after unit has
been started up. When observing flame, be careful not
to get close to or touch heating components.
• Observe unit heating operation. Watch the burner flame
to see if it is bright blue. If you observe a suspected
malfunction or that the burner flame is not bright blue,
shut down the unit and call your dealer.
• Replace compressor access panel.
BEFORE YOU CALL FOR SERVICE,
CHECK FOR PROBLEMS THAT
CAN BE EASILY SOLVED
If insufficient heating or cooling is suspected:
( ) Check for sufficient airflow. Check the air filter for dirt
Check for blocked return- or supply-air grilles. Be sure
they are open and unobstructed. If these checks do not
reveal the cause, call your servicing dealer.
If your unit is not operating at all, check the following list
for easy solutions:
( ) Check to be sure that your thermostat/unit controller
temperature selector is set above the indoor temperature
during the heating season, or below the indoor
temperature during the cooling season. Be sure the
SYSTEM switch in the proper HEAT or COOL position
and not in the OFF position.
( ) Is the electrical supply switch ON? Are any fuses
blown, or has the circuit breaker tripped'?
( ) During the heating season, check the external manual
shutoff valve. Is this lever parallel with the pipe,
indicating that the valve is open'? Or is the lever at the
right angle, indicating that the valve is closed'? If closed,
has the gas been shut off for safety reasons'? Otherwise,
you may open the valve and follow the start-up
procedures listed in this manual.

NOTE:Beforeproceedingwiththenextcheck,turnOFF
theelectricalpowersupplyto theunit. Removethe
controlaccessdoor.
() Duringtheheatingseason,checkthecontrolswitchon
thegasvalve.Isit intheONposition?If it isnot,besure
it hasnotbeenturnedoffforthepurposeofsafety.If no
safetyhazardsarepresent,followthestart-upprocedures
inthismanual.
( ) If yourunitstill failstooperate,callyourservicing
dealerfortroubleshootingandrepairs.Specifythemodel
andserialnumbersof yourunit.(Recordthemin this
manualinthespaceprovided.)If thedealerkalowsexactly
whichunityouhave,hemaybeabletooffersuggestions
over the phone,or save valuabletime through
kalowledgeablepreparationfortheservicecall.
IN CASE OF TROUBLE
If, after performing the above checks, unit performance is
unsatisfactory, shut off the unit and call your dealer.
Dealer's Name
Telephone No.
Unit Model
[_it Serial Number
REGULARDEALER
MAINTENANCE
Heat Exchanger
NOTE: To ensure dependable and efficient heating
operation, the heat exchanger should be checked by a
qualified maintenance person before each heating season,
and cleaned when necessary.
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment.
This checkout should not be attempted by anyone not
having the required expertise and equipment to do the
job properly.
Checking and/or cleaning the heat exchanger involves
removing the gas controls assembly and the flue collector
box cover. When finished, the gas controls must be
reinstalled for proper operation. Also, the flue collector
box cover must be replaced correctly so that a proper seal
is maintained. Contact your dealer for the required
periodic maintenance. At the beginning of each
cooling/heating season and as conditions require.
Fans and Belts, and Fan Motor
Periodically check the condition of fan wheels and
housings, belt tension and fan motor shaft bearings. No
lubrication of condenser or evaporator fan bearings or
motors is required or recommended.
Evaporator and Condenser Coils
Cleaning of the coils should be done by qualified service
personnel. Contact you dealer for the required annual
maintenance.
Condensate Drain
The drain pan and condensate drain line should be
checked and cleaned at the same time the cooling coils are
checked by your dealer.
In addition to the type of routine maintenance you might
be willing to perform, your unit should be inspected
regularly by a properly trained and qualified service
technician. An inspection (preferably each heating/cooling
season, but at least every year) should include the
following:
• Inspection of all flue product passages, including the
burners, heat exchanger, and flue collector box.
• Inspection of all combustion- and ventilation-air
passages and openings.
• Close inspection of all gas pipes leading to and inside
your unit.
• Inspection and if required, cleaning of the condenser and
evaporator coils.
• Inspection, and if required, cleaning of the condensate
drain pan.
• Inspection and cleaning of blower wheel housing and
motor.
• Inspection of all supply- and return-air ducts for leaks,
obstructions, and insulation integrity. Any problems
found should be resolved at the time of inspection.
• Inspection of the unit base for cracks, gaps, etc., which
may cause a hazardous condition.
• Inspection of the unit casing for signs of deterioration.
• Inspection of all electrical wiring and components to
ensure proper connection.
• Inspection for leaks in the refrigerant circuit. Pressure
check to determine appropriate refrigerant charge.
• Inspection of fan wheels and housings, belt tension, and
fan motor shaft bearings.
• Operational check of the unit to determine working
conditions. Repair or adjustment should be made at the
time of inspection.
Your servicing dealer may offer an economical service
contract that covers seasonal inspections. Ask for further
details.
Complete service instructions can be found in the unit
Installation, Start-Up and Service Instructions.

Copyright 2008 CAC /BDP •7310 W. Morris St. • indianapolis, IN 46231 Printed in U.SA Edition Date: 05/08
Manufacturer reserves the right to change_ at any time_ specifications and designs without notice and without obligations.
8
Catalog No: OG-48TC580J-02
Replaces: OG-48TC580J-01