Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53480194-01
Printed in U.S.A.
Form 48P-2SO
Pg 8
6-19
Replaces: 48P-1SO
© Carrier Corporation 2019
2. Open gas section access door.
3. Using a flashlight, carefully inspect the burner areas for
dirt, soot, rust, or scale.
4. When you have completed your inspection, follow the
start-up procedures in this manual to restore your unit to
operation.
5. Observe unit heating operation, and watch the burner
flame core to see if it is bright blue. If you observe a sus-
pected malfunction, or if the burner flame cores are not
bright blue, call your dealer. See Fig. 5.
NOTE: Burner flame cores that have a mixture of orange, yellow,
or red flames together with the blue may not be burning gas effi-
ciently. Your dealer may have to adjust the air/gas mixture.
6. Replace gas section access panel.
Unit Panels and Doors
After performing any maintenance or service on the unit, be
sure all panels and doors are securely fastened in place to pre-
vent rain from entering unit cabinet and to prevent disruption
of the correct unit airflow pattern.
Fig. 5 — Proper Flame Appearance
REGULAR DEALER MAINTENANCE
In addition to the type of routine maintenance you might be will-
ing to perform, your unit should be inspected regularly by a prop-
erly trained service technician. An inspection (preferably each
year, but at least every other year) should include the following:
1. Inspection of all flue product passages — including the
burners, heat exchanger, flue collector box, and vent pipe.
2. Inspection of all combustion-air and ventilation-air pas-
sages and openings.
3. Close inspection of all gas pipes leading to and inside your
unit.
4. Adjustment of the air/gas mixture if the burner flames are
not bright blue. (See Fig. 4 and 5 for location of access
panel and proper flame appearance.)
5. Inspection, and if required, cleaning of the condenser and
evaporator coils.
6. Inspection, and if required, cleaning of the evaporator
drain pan.
7. Inspection, cleaning, and lubrication of blower wheel
housing and motor.
8. Inspection of all supply-air and return-air ducts for leaks,
obstructions, and insulation integrity. Any problems found
should be resolved at this time.
9. Inspection of the unit base to ensure that no cracks, gaps,
etc., exist which may cause a hazardous condition.
10. Inspection of the unit casing for signs of deterioration.
11. Inspection of all electrical wiring and components to
assure proper connection.
12. Inspection for leaks in the refrigerant circuit. Pressure-
check to determine appropriate refrigerant charge.
13. Operational check of the unit to determine working condi-
tions. Repair or adjustment should be made at this time.
14. 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 base unit Con-
trols, Start-Up, Operation, Service and Troubleshooting literature.
BEFORE YOU CALL FOR SERVICE, CHECK
FOR SEVERAL EASILY SOLVED PROBLEMS
If insufficient heat or cooling is suspected:
( ) Check for sufficient airflow. Check the air filters for dirt.
Check for blocked return-air or supply-air grilles. Be sure they
are open and unobstructed. Be sure heating and cooling set
points are correct. 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 heating temperature set point is set
above the indoor temperature during the heating season, or that
cooling temperature set point is below the indoor temperature
during the cooling season. Be sure the unit on/off switch is in
the ON position and not in the OFF position. Be sure unit has
been programmed with the appropriate time schedules and de-
sired operating set points.
( ) Is the electrical supply switch ON? Are any fuses blown,
or have any of the circuit breakers tripped?
( ) During the heating season, check the manual shutoff
valve. Is this lever parallel with the pipe, indicating that the
valve is open? Or is the lever at a right angle, indicating that
the valve is closed? If closed, has the gas been shut off for safe-
ty reasons? Otherwise, you may open the valve and follow the
start-up procedures listed in this manual.
NOTE: Before proceeding with the next check, turn OFF the elec-
trical power supply to the unit. Open the control access door.
( ) During the heating season, check the control switch on
the gas valve. It is in the ON position? If it is not, be sure it has
not been turned off for the purpose of safety. Follow the start-
up procedures in this manual.
( ) If your unit still fails to operate, call your servicing dealer for
troubleshooting and repairs. Specify the model and serial numbers
of your unit. (Record them in this manual in the space provided.)
If the dealer knows exactly which unit you have, he or she may be
able to offer suggestions over the phone, or save valuable time
through knowledgeable preparation for the service call.
IN CASE OF TROUBLE
If, after performing the above, unit performance is unsatisfac-
tory, shut off the unit and call your dealer.
Dealer’s Name _____________________________________
Telephone No. _____________________________________
Unit Model ________________________________________
Unit Serial Number _________________________________
Unit Address _______________________________________
Bus Number _______________________________________
CAUTION
If dirt, soot, rust, or scale accumulations are found, call
your dealer and do not operate your heating section.
