035-17443-000 Rev. A (800)
Unitary Products Group
19
four weeks. Inspect the filters every three weeks after that,
especially if the system is running constantly.
LUBRICATION
Blower and venter motors in these furnaces are permanently
lubricated and do not require periodic oiling.
BLOWER CARE
Even with good filters properly in place, blower wheels and
motors will become dust laden after long months of opera-
tion. The entire blower assembly should be inspected annu-
ally. If the motor and wheel are heavily coated with dust, they
can be brushed and cleaned with a vacuum cleaner.
The procedure for removing the blower assembly for cleaning
is as follows:
1.
Turn off electrical power supply to the furnace at discon-
nect switch(s). Remove access doors. Remove motor
harness using 3 wires on panel.
2.
Remove the screws holding the control box to the
blower. Swing the control box out of the way to allow
removal of the blower.
3.
Remove blower/motor assembly, shipping screws (2),
and deck screws; Stop and slide the blower assembly
out of the slots in the deck.
4.
When cleaning or servicing the blower assembly, DO
NOT remove or change the balance clips on the blower
wheel.
5.
To reassemble, reverse the procedure, restore power to
the furnace and verify operation.
6.
To re-assemble, reverse the procedure, restore power
and verify operation.
BURNER REMOVAL / CLEANING
The main burners should be checked periodically for dirt
accumulation.
If cleaning is required, follow this procedure:
1.
Turn off the electrical power to the unit and turn off gas
supply at the shutoff valve.
2.
Remove the blower and burner compartment access
doors.
3.
Unplug igniter from the wire harness and remove the
igniter / bracket assembly from the burner air shield.
Handle the igniter carefully as it is fragile and easily bro-
ken.
4.
Note the location and then disconnect the senser and
rollout switch wires located on the top of the air shield
and remove the shield.
5.
Remove the two screws securing each burner to the
burner assembly. Note the orientation of the burner
(flanged side down) before removing. Burners may be
cleaned by rinsing in hot water or by using a vacuum
cleaner.
6.
To re-assemble - reverse the procedure. Restore power
and verify operation.
CLEANING THE HEAT EXCHANGER
NOTE:If heat exchanger is sooted, it is recommended that
the heat exchanger be replaced due to difficulty in cleaning.
Lower Heat Exchanger Access
1.
Turn off the electrical power to the unit and turn off gas
supply at the shutoff valve.
2.
Remove the blower and burner compartment access
doors. Disconnect the gas supply piping at the union to
permit removal of the entire burner and gas control
assembly from the vestibule panel. Use the wrench boss
on the gas valve when removing or installing this piping.
3.
Unplug the igniter from the wire harness. Disconnect
senser and rollout switch wires located on top of the air
shield. Identify and note the location of all leads for ease
of reinstallation. Also disconnect the wires at the side
rollout switches (upflow only) and the gas valve wires.
4.
Remove the screws holding the burner assembly to the
vestibule panel and remove this assembly. Handle the
assembly carefully since it contains the igniter which is
fragile and easily broken. The lower portion of the heat
exchanger will now be exposed. To clean the burner
assembly, use a vacuum cleaner, or remove the burners
as outlined in burner cleaning, and clean in hot water.
When replacing filters, DO NOT use a type with
excessively high pressure drop. Some high effi-
ciency filters available will cause the furnace to
operate improperly and could result in a safety
hazard.
This blower motor assembly weighs 90 lbs. Have
adequate support to prevent injury.
