Carrier 48NHT024 - Page 18

Clean and lubricate the blower motor and wheel for direct
drive models as follows:
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 auxilliary 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, 5ce, 3/16 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 orien¬
tation and cutoff plate location.
b. Remove screws holding cutoff plate, and remove
plate from housing.
c. Lift wheel from housing. When handling and/or
cleaning blower wheel, be sure not to disturb bal¬
ance 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 cutoff plate into housing.
f. Reassemble motor into housing. Be sure setscrews
are tightened on motor shaft flats and not on round
part of shaft.
Jlean and lubricate the blower motor and wheel as follows
3 r belt drive models:
1. Remove blower assembly as follows:
a. Remove blower access door from unit.
b. Disconnect auxiliary limit switch leads at switch.
c. Remove blower assembly and motor from unit. Be
careful not to tear insulation in blower compart¬
ment. Support assembly to prevent damage to
motor leads.
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, 5cc, 3/16 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. R eplace dust caps or plugs in oil ports.
3. Remove and clean blower wheel as follows:
a. Remove blower belt, then remove blower pulley.
b. Remove blower shaft bearing retainers.
c. Loosen blower wheel setscrew, then pull blower
shaft from wheel.
d. Remove screws holding cutoff plate, then remove
cutoff plate.
e. Lift wheel from housing. When handling and/or
cleaning, be sure not to disturb balance weights on
blower wheel vanes.
f. 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.
g. Reassemble wheel and cutoff plate into housing.
h. Reinstall blower shaft, bearing retainers, blower
pulley, and belt.
4. Reinstall blower assembly into unit, route blower
motor leads into control compartment, and reconnect
all blower motor leads to proper termination point in
unit control box. Replace panels.
5. Restore electrical power, then gas supply to unit. Start
unit and check for proper blower rotation and motor
speeds during heating and cooling cycles.
D. Heating Section
Ensure dependable and efficient heating operation by
inspecting the heating section before each heating season,
and cleaning when necessary.
Proceed as follows to inspect and clean heating section:
1. Turn off gas and power to unit.
2. Remove burner access door.
3. Disconnect two wires from inducer motor.
4. Remove complete inducer assembly from unit.
5. Remove screws that secure collector box to heat
exchanger, exposing flue openings.
6. Remove flue choke.
7. Using field-provided small wire brush, steel spring
cable, reversible electric drill, and vacuum cleaner;
clean cells.
a. Assemble wire brush and steel spring cable.
(1.) Use 4-ft of 1/4-in. diameter high-grade steel
spring cable (commonly known as drain
cleanout or Roto-Rooter cable).
(2.) Use 1/4-in. diameter wire brush (commonly
known as 25-caliber rifle cleaning brush).
NOTE: The items called for in sections 1 and 2 can be pur¬
chased at a local hardware store.
(3.) Insert twisted wire end of brush into end of
spring cable, and crimp tight with crimping tool
or strike with ball-peen hammer. Tightness is
very important.
(4.) Remove metal sleeve from wire brush to allow
proper brush action.
b. Clean each heat exchanger cell.
(1.) Attach variable-speed reversible drill to end of
spring cable (end opposite brush).
(2.) Insert brush end of cable into upper opening of
cell and slowly rotate with drill. Do not force
cable. Gradually insert at least 3-ft of cable into
two upper passes of cell.
18