Electrical Controls and Wiring, Ð5Ð

(2.) Use 1/4-in. diameter wire brush (commonly known as 25-caliber rifle cleaning brush).

NOTE: The materials needed in items (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 ball-peen hammer. TIGHTNESS is very important.

(4.) Remove metal screw fitting from wire brush to allow insertion into cable.

b.Clean each heat exchanger cell.

(1.) Attach variable-speed, reversible drill to end of steel 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 36 in. of cable into 2 upper passes of cell. (See Fig. 8.)

A91252

Fig. 8ÐCleaning Heat Exchanger Cell

CAUTION: Be very careful when removing the burner assembly to avoid breaking the ignitor. See Fig. 9 for the correct ignitor location.

(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.) Clean flame sensor with fine sandpaper.
	(11.) 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 relief box.
12.	Reconnect wires to the following components.
→	a. Blocked vent safeguard
	b. Inducer motor
	c. Pressure switch

13 32"

BURNER

11 32"

CELL

PANEL

HOT

SURFACE

IGNITOR

ASSEMBLY

	d. Limit overtemperature switch(es)
	e. Gas valve
	f. Hot surface ignitor
	g. Flame-sensing electrode
13.	Reconnect vent pipe to relief box. Replace vent pipe
	enclosure (downflow/horizontal furnace only).
14.	Replace blower access door only.
15.	Turn on electrical power and gas.
16.	Set thermostat and check furnace for proper operation.

WARNING: Never use a match or other open flame to check for gas leaks. Use a soap-and-water solution. A failure to follow this warning could result in fire, personal injury, or death.

C IGNITOR

7 8"

C BURNER

IGNITOR

ASSEMBLY

A93347

Fig. 9ÐPosition of Ignitor to Burner

(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.

17.Check for gas leaks.

18.Replace control access door on upflow furnace.

19.On downflow/horizontal furnaces, remove blower access door, replace control access door first, then replace blower access door and secure with screw in front of door.

D.Electrical Controls and Wiring

CAUTION: There may be more than 1 electrical supply to the unit. Check accessories and cooling unit for additional electrical supplies.