b.Remove screws holding cutoff plate and remove cutoff plate from housing.
c.Lift blower wheel from housing through opening.
14.Clean blower wheel and motor using a vacuum cleaner with soft brush attachment. Do not remove or disturb balance weights (clips) on blower wheel blades. The blower wheel should not be dropped or bent as balance will be affected.
15.Reinstall blower wheel by reversing steps 13 a. through c. Be sure wheel is positioned for proper rotation.
16.Reassemble motor and blower by reversing steps 5 through 11. If motor has ground wire, be sure it is connected as before.
CAUTION: Be sure the motor is properly positioned in the blower housing. The motor oil ports must be at a
minimum of 45° above the horizontal centerline of the motor after the blower assembly has been reinstalled in the furnace.
17.Reinstall blower assembly in furnace. Connect electrical leads to blower speed selector. Please note that connections are polarized for assembly. DO NOT FORCE.
18.Reinstall control box.
19.Reconnect wires to auxiliary limit switch on blower housing (downflow furnaces only).
20.Reinstall vent pipe and enclosure (downflow furnaces only).
21.Turn on electrical power and check for proper rotation and speed changes between heating and cooling.
22.Replace blower access door and secure with 2 screws (downflow furnace only).
C.Cleaning Heat Exchanger
The following steps should be performed by a qualified service technician:
NOTE: Deposits of soot and carbon indicate the existence of a problem which needs to be corrected. Take action to correct the problem.
If it becomes necessary to clean the heat exchanger because of carbon deposits, soot, etc., proceed as follows:
1.Turn off gas and electrical power to furnace.
2.Remove 2 screws from blower access door (downflow furnace only). Remove control and blower access doors.
3.Remove vent pipe enclosure (downflow furnace only) and disconnect vent pipe from relief box.
4.Remove 2 screws that secure relief box. (See Fig. 4 or 5.)
5.Disconnect wires to the following components:
a.Draft safeguard switch
b.Inducer motor
c.Pressure switch
d.Limit overtemperature switch
e.Gas valve
f.Edge connector leading to control box
6.Remove 8 screws that secure flue collector box to center panel. Be careful not to damage sealant.
7.Remove complete inducer assembly from furnace, exposing flue openings.
8.Clean cells using
Ð4Ð
a.Assemble wire brush and steel spring cable.
(1.) Use 48 in. of
(2.) Use
NOTE: The items needed in steps (1.) and (2.) can usually be purchased at local hardware stores.
(3.) Insert twisted wire end of brush into end of steel spring cable, and crimp tight with crimping tool or strike with
(4.) Remove metal screw fitting from wire brush to allow insertion into cable.
b.Clean each heat exchanger cell.
(1.) Attach
(2.) Insert brush end of cable into upper opening of cell and slowly rotate with drill. DO NOT force cable. Gradually insert at least 36 in. of cable into 2 upper passes of cell. (See Fig. 6.)
A91252
Fig. 6ÐCleaning Heat Exchanger Cell
(3.) Work cable in and out of cell 3 or 4 times to obtain sufficient cleaning. DO NOT pull cable with great force. Reverse drill and gradually work cable out.
(4.) Remove burner assembly and cell inlet plates.
(5.) Replace screws in center panel and cells before cleaning.
(6.) Insert brush end of cable in lower opening of cell, and proceed to clean 2 lower passes of cell in same manner as 2 upper passes.
(7.) Repeat foregoing procedures until each cell in furnace has been cleaned.
(8.) Remove residue from each cell using vacuum cleaner.
(9.) Clean burner assembly using vacuum cleaner with soft brush attachment.
(10.) Reinstall cell inlet plates and burner assembly. Care must be exercised to center the burners in the cell openings.
9.After cleaning flue openings, check sealant on flue collector to ensure that it has not been damaged. If new sealant is needed, contact your dealer or distributor.
10.Clean and replace flue collector assembly, making sure all 8 screws are secure.
11.Reinstall 2 screws in relief box.
