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Figure 22. *SD Component Locations
Furnace
Control
Board
Combustion Air
Orifice Plate
Air / Fuel
Mixing Tube
Blower
Assembly
Blower Door
Switch
Gas Burner Head
Gas Valve
Pressure
Switches
Inducer
Assembly
Transformer
Sight Glass
Igniter / Flame
Sensor Assembly
Access
Blower Limit
Switch
Pressure
Switch
Primary Air
Limit Switch
Motor
Choke
Inducer Motor
In-Line Drain
Asssembly
Flexible Gas Line
Pressure
Transducer
Pressure Switch
FURNACE COMPONENTS
The descriptions below are various functional components
that affect the operation and shutting down of this furnace.
Some of these components and their locations are shown in
. If any component of the furnace must be replaced,
use only factory authorized replacement parts specified in
the Replacement Parts List provided online.
Condensate Drain Switch:
The Condensate Drain Switch
will shut down the furnace if the condensate drain from the
Collector Pan becomes clogged.
Blower Limit Switch:
Prevents operation of the blower motor
when the blower door is not in place. Line power will still be
at the control board when the blower door is not in place.
Flame Sensor:
Verifies the presence of a flame. If no flame
is detected, the furnace will shut down within 2.5 seconds.
Gas Valve:
Controls the flow of gas to the burners. When the
gas valve is energized it automatically opens and regulates
the gas pressure in the manifold.
Inducer Assembly:
Vents products of combustion to the
outside.
Pressure Switches:
Verifies that the inducer is drawing
the combustion gases through the heat exchanger. The
pressure switch prevents furnace operation with excessive
flue/condensate blockage or improper inducer operation.
Supply Air Limit Switch:
Prevents the air temperature
leaving the furnace from exceeding the maximum allowable
outlet air temperature.
