L.B. White AW250 - Manual (Page 15)

Heater Component Function
Air Proving Switch
Safety device used to insure that the proper air flow is being
achieved before the gas valve is opened.
Burner
Cast iron component used to channel gas and provide an
area at which the fuel may ignite.
Burner Orifice
Brass metering device used to feed gas to burner at a
specific rate.
Fan Housing
Chamber used for compressing air for efficient air
movement.
Fan Wheel
Component used in conjunction with the motor and fan
housing to pull the hot air from heater and blow it into room
for heating (also known as a squirrel cage).
Flame Sensor
Also known as a flame rod or flame probe, this device works
in conjunction with the ignition module in proving that
burner flame has been established.
Gas Control Valve
A device which consists of a low pressure regulator and
electrical solenoids which are used for the control of gas
flow to the burner assembly. A feature of the control is a
built in gas shut off which is used to isolate the heater from
its gas supply when servicing.
Gas Hose
Flexible connector used to convey gas from supply line in
building to heater.
Heat Chamber
Metal fire box within the appliance that provides an area
where burner flame mixes with combustion air thereby
providing heat.
High Limit Switch
Safety device wired into the control system which is used to
break an electrical circuit to the gas control valve in event of
overheat situation.
Hot Surface Igniter
Electrical ignition device used on automatic ignition control
systems. Ignites gas by surface temperature rather than by
spark or flame.
Ignition Control Module
Controls the ignition sequence and operation of the heater
as well as monitoring the safety sevices. A major service
feature is the board’s ability to diagnose component and
flame failure by means of a diagnostic light located within
the module. This light will provide a specific flash pattern
repetitively, depending on the type of componenet failure
that has occurred.
Motor
Electric device used to force preheated air through the
heater and to circulate heat within a certain area. Converts
electrical energy into mechanical energy.
Regulator
The heart of any gas supply installation. Used to deliver a
working pressure to the heater under varying conditions in
tank pressure.
Thermostat
Electrical device used as an automatic on/off switch which
will respond to changes in temperature in a certain area.
Can be wired so contacts in the thermostat open or close on
temperature increase or decrease.
Throttle Valve
Manually adjustable component used to increase or
decrease the flow of gas to the burner. The throttle valve is
located between the gas control valve and burner assembly.
Transformer
This device is responsible for reducing a higher incoming
voltage (normally 120 V.A.C.) to a lower outgoing voltage.
The lower voltage (24 V.A.C.) is essential to operate the
ignition control module.
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