Carrier 48NLT - Manual (Page 23)

Air Filter
i
A CAUTION
Never operate the unit without a suitable air filter in
the return-air duct system. Always replace the filter with
the same dimensional size and type as originally
installed. See Table 1 for recommended filter sizes.
Inspect air filter(s) at least once each month and replace
(disposable-type) or clean (cleanable-type) at least twice dur­
ing each heating and cooling season or whenever the
filter(s) becomes clogged with dust and lint.
Replace filters with the same dimensional size and type
as originally provided, when necessary.
Unit Top Removal
A CAUTION
Condenser fan and motor are fastened to the unit top.
When removing the top, use extreme care to not pull
the fan motor leads loose.
NOTE; When performing maintenance or service proce­
dures that require removal of the unit top, be sure to per­
form
all of the routine maintenance procedures that require
top removal, including: inspection of the heat exchanger
area, coil inspection and cleaning, and condensate drain pan
inspection and cleaning.
Only qualified service personnel should perform mainte­
nance and service procedures that require unit top removal.
Refer to the following top removal procedures;
1. Turn off gas supply, then turn off electric power to unit.
2. Remove all screws that secure unit top, including screws
around 4 sides and those on top that screw into internal
divider panels. Save all screws.
3. Tape all side panels at each seam near unit top. Use tape
strips that are at least 5-in. long to prevent sides from
falling when top is removed.
4. Lift top from unit carefully. Set top on edge and make
sure that top is supported by unit side that is opposite
duct (or plenum) side.
Use extreme care to prevent dam­
age to the fan blades, motor and insulation.
5. Carefully replace and secure unit top to unit, using screws
removed in Step 2, when maintenance and/or service pro­
cedures are completed. (Be sure to use original screws
that have rubber washers to seal out water when secur­
ing top to internal divider panels.)
Evaporator Blower and Motor
NOTE: Motors without oilers are prelubricated. Do not at­
tempt to lubricate these motors.
For longer life, operating economy and continuing effi­
ciency, clean accumulated dirt and grease from the blower
wheel and motor annually.
Lubricate the motor every 5 years if the motor is used
intermittently (thermostat FAN switch in AUTO, position).
or every 2 years if the motor is used continuously (thermo­
stat FAN switch in ON position).
A WARNING
Turn off the gas supply, then disconnect and tag elec­
trical power to the unit before cleaning and lubricating
the blower motor and wheel. Failure to adhere to this
warning could cause personal injury or death.
To clean and lubricate the blower motor and wheel for
direct-drive models;
1. Remove and disassemble blower assembly as follows:
a. Remove blower access door.
b. Disconnect blower-motor leads from their termina­
tion points at motor. Disconnect yellow lead from
control box at capacitor. Disconnect auxiliary limit-
switch leads at switch.
c. Remove blower assembly from unit. Be careful not
to tear insulation in blower compartment.
d. Ensure proper reassembly by marking blower wheel
and motor in relation to blower housing before dis­
assembly.
e. Loosen setscrew(s) that secures wheel to motor shaft,
remove screws that secure motor mount brackets to
housing and slide motor and motor mount out of
housing.
2. Lubricate motor as follows;
a. Thoroughly clean all accumulations of dirt or grease
from motor housing.
b. Remove dust caps or plugs from oil ports located at
each end of motor.
c. Use a good grade of SAE 20 nondetergent motor oil
and put one teaspoon (5 cc, Vie oz., or 16 to 25 drops)
in each oil port.
d. Allow time for oil to be absorbed by each bearing,
then wipe excess oil from motor housing.
e. Replace dust caps or plugs in oil ports.
3. Remove and clean blower wheel as follows:
a. Ensure proper reassembly by marking wheel orienta­
tion and cutoff plate location.
b. Remove screws holding cut-off plate, and remove plate
from housing.
c. Lift wheel from housing. When handling and/or clean­
ing blower wheel, be sure not to disturb balance weights
(clips) on blower wheel vanes.
d. Remove caked-on dirt from wheel and housing with
a brush. Remove lint and/or dirt accumulations from
wheel and housing with vacuum cleaner, using soft
brush attachment. Remove grease and oil with mild
solvent.
e. Reassemble wheel and cut-off plate into housing.
f. Reassemble motor into housing. Be sure setscrews
are tightened on motor shaft flats and not on round
part of shaft.
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