Flue Gas Passageways; Combustion-Air Blower; Burners And Igniters - Carrier 48FC M20 Series Service And Maintenance Instructions

Flue Gas Passageways

To inspect the flue collector box and upper areas of the heat ex-
changer:
1. Remove the combustion blower wheel and motor assembly
according to directions in Combustion-Air Blower section.
See Fig. 49.
2. Remove the vestibule plate to inspect the heat exchanger.
3. Clean all surfaces as required using a wire brush.

Combustion-Air Blower

Clean periodically to assure proper airflow and heating efficiency.
Inspect blower wheel every fall and periodically during heating
season. For the first heating season, inspect blower wheel every
two months to determine proper cleaning frequency.
To access burner section, slide the burner partition panel out of
the unit.
To inspect blower wheel, shine a flashlight into draft hood open-
ing. If cleaning is required, remove motor and wheel as follows:
1. Remove the screw at the base of the burner partition panel
(see Fig. 51) and slide out the panel.
2. Remove the seven screws attaching the induced-draft motor
housing to the vestibule plate. (See Fig. 49.)
Pressure Switch
Hose Connection
Flue Cover
Assembly
Flue Hood
(Shown as
Shipped)
Gas
Valve
Inducer Fan-motor
Assembly
3.
4.
5.
6.

Burners and Igniters

EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in premature wear
and damage to equipment.
When working on gas train, do not hit or plug orifice spuds.
Seal Strips, Sponge Rubber
Burner
Assembly Vestibule Plate
Fig. 49 — Heat Exchanger Assembly
38
The blower wheel can be cleaned at this point. If additional
cleaning is required, continue with Steps 4 and 5.
Remove the blower from the motor shaft by removing two
setscrews.
Removing motor: remove the four screws holding the motor
to the mounting plate. Remove the motor cooling fan by
removing one setscrew. Remove nuts that hold the motor to
the mounting plate.
Reverse the procedure outlined above to reinstall the motor.
CAUTION
Heater Tube Assembly