Carrier INDUCED COMBUSTION 58YAV User Manual

Page 4

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14. If furnace is operating properly, REMOVE TAPE TO RE-

LEASE BLOWER ACCESS DOOR SWITCH, replace
blower access door.

Step 3—Cleaning Heat Exchanger

The following steps should be performed by a qualified service
technician:

NOTE:

If the heat exchangers get a heavy accumulation of soot

and carbon, they should be replaced rather than trying to clean
them thoroughly due to their intricate design. A build-up of soot
and carbon indicates that a problem exists which needs to be
corrected, such as improper adjustment of manifold pressure,
insufficient or poor quality combustion air, incorrect size, or
damaged manifold orifice(s), improper gas, or a restricted heat
exchanger. Action must be taken to correct the problem.
If it becomes necessary to clean heat exchanger because of light
dust or corrosion proceed as follows:

1. Turn gas and electrical power to furnace to OFF.

2. Remove control access door.

3. Disconnect vent connector from furnace flue collar.

4. Remove 2 screws that secure relief box. (See Fig. 2.)

5. Disconnect wires to the following components. Mark wires to

aid in reconnection of:

a. Blocked vent safeguard switch.

b. Inducer motor.

c. Pressure switch.

d. Limit overtemperature switch(es).

e. Gas valve.

f. Hot surface ignitor.

g. Flame-sensing electrode

h. Flame rollout switch(es), if applicable.

6. Remove complete inducer assembly and relief box from

furnace.

7. Remove 8 screws that secure flue collector box to center

panel. Be careful not to damage collector box.

8. Remove burner assembly and cell inlet plates. IMPORTANT:

Replace screws in center panel before cleaning.

NOTE:

Be very careful when removing burner assembly to avoid

breaking ignitor. See Fig. 3 for correct ignitor location.

9. Using field-provided small wire brush, steel spring cable,

reversible electric drill, and vacuum cleaner, clean cells as
follows:

a. Assemble wire brush and steel spring cable.

(1.) Use 48 in. of 1/4-in. diameter high-grade steel spring

cable (commonly known as drain clean-out or Roto-
Rooter

cable).

(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 spring

cable, and crimp tight with crimping tool or strike with
ball-peen hammer. TIGHTNESS IS VERY IMPOR-
TANT.

(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 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. 4.)

(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.) 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.

(5.) Repeat foregoing procedures until each cell in furnace

has been cleaned.

(6.) Using vacuum cleaner, remove residue from each cell.

(7.) Using vacuum cleaner with soft brush attachment,

clean burner assembly.

(8.) Reinstall cell inlet plates and burner assembly. Care

must be exercised to center burners in cell openings.

Fig. 3—Position of Ignitor to Burner

A93347

BURNER

IGNITOR

11 32

7 8

IGNITOR
ASSEMBLY

CELL
PANEL

BURNER

13 32

HOT
SURFACE
IGNITOR
ASSEMBLY

Fig. 4–Cleaning Heat Exchanger Cell

A91252

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