Bard 2100-066 Rev. A - Manual (Page 3)

Cabinet
Generally speaking, all heating and cooling components (except
the thennostat) are housed in sheet steel cabinets. The cabinet
helps protect the components and adds to the attractiveness of
the units.
The heating unit or furnace cabinet is normally located indoors. It
has connection provisions for attaching the cooling coil, supply air
plenum and return air plenum. The cabinet also contains openings
or knockouts for electrical service and required plumbing.
Designed into the cabinet are removable access doors to allow for
servicing the unit. The front door to oil and gas furnaces is slotted
to allow combustion air to enter (this is not necessary on electric
furnaces, since no fuel is burned).
Since the cooling system’s outdoor unit is exposed to the weather
elements and in the public eye, it is especially important the
cabinet is durable, weather resistant and attractive in appearance.
Like the furnace cabinet, the outdoor cooling unit cabinet has
service access doors and provisions for electrical and mechanical
(i.e. refrigerant line) connections.
Temperature Treatment Section
The temperature treatment section of a heating or cooling unit is
that portion of the unit which produces the heating or cooling. (All
types of heating units and cooling systems are discussed in greater
detail in the sections that follow.)
Heat Sections
Most residential furnaces use either natural or liquefied propane
(LP) gas, oil or electricity as their source of heat.
The heat section of an electric furnace consists of one or more
electric heating elements. The element is much like that in an
electric toaster, only bigger. When the thermostat demands heat, an
electrical resistance to the flow of electricity in the element
produces heat. The heated air is moved by the furnace blower
through the ducts and distributed to points all over the home.
The heat section of a gas (either natural or propane) furnace
consists of a steel heat exchanger and gas burners. The
burners fit in a cavity at the bottom of the heat exchanger.
Gas is fed into the burners and ignited by a pilot flame on a call for
heat from the thermostat. The burning gas warms the heat
exchanger and the blower distributes the heat throughout the house.
The oil heat section is made up of a firebrick pot and steel heat
exchanger. When the thermostat calls for heat, oil is pumped
through a nozzle and ignited by a spark from a set of high voltage
electrodes. A ball of fire is produced in the firebrick pot, which
heats the steel heat exchanger. The blower then moves this heated
air to the various distribution points.
Bard Total Electric Features
Built-In Cooling Coil Compartment—Slide-
in type for easier conversion to summer cooling,
Accomodates 1-1/2, 2, 2-1/2, and 3 ion
cooling coils.
Controls—On demand from the wall
thermostat, the heating elements are energized
by electrical contactors. The 15 thru 30K.W
versions have the blower motor interlocked with
each stage for safety. Easily two staged.
Limit Switch—Thermal snap disc in each
heating element shuts oif power automatically
if system air temperature becomes excessive
Built-In Transformer—Provides power
supply for heating and optional cooling controls
Blower Relay—Provides automatic blower
speed change-over to meet heating and cooling
air delivery requirements.
Branch Circuit Fusing—Factory installed in
models rated over 48 amps.
Heating Elements—Nickel-chrome wire with
individual fusible links for long life. Entire
assembly slides out for easy maintenance.
Motor—Multi-speed for both heating and
cooling.
Blower—Heated air is quietly circulated by
large volume centrifugal blower that is matched
to the electrical heating system for efficiency.
Slides out for easy maintenance.
Fillers—Twin permanent type slide out from
front for easy cleaning on all models except
Models EFC5 andEFClO.