3
FURNACE COMPONENTS
Burner sight glass for viewing burner flame.
Burner assembly (inside). Operates with energy-
saving inshot burners and hot surface igniter for safe,
dependable heating.
Combustion-air intake connection (right or left side).
Redundant gas valve. Safe and efficient. Features 1 gas
control with 2 internal shutoff valves.
Junction box for 115-v electrical power supply.
Vent outlet. Uses PVC pipe to carry flue gas from
the furnace’s combustion system (right or left side).
Secondary condensing heat exchanger (inside).
Wrings out more heat through condensation.
Constructed with polypropylene-laminated steel to
ensure durability.
Pressure switch ensures adequate flow of flue
gas through furnace and out vent system.
Inducer motor. Pulls hot flue gases through the heat
exchangers, maintaining negative pressure for added
safety.
Condensate drain connection. Collects moisture
condensed from burned gases for disposal into home
drain system. (Location in furnace varies).
Heavy-duty blower. Circulates air across the heat
exchangers to transfer heat into the home.
Air filter and retainer.
Rollout switch (manual reset) to prevent
overtemperature.
Primary serpentine heat exchanger (inside).
Stretches fuel dollars with the S-shaped heat-flow
design. Solid construction of corrosion-resistant
aluminized steel means reliability.
3-amp fuse provides electrical and component
protection.
Light emitting diode (LED) on furnace control board.
Code light is for diagnosing furnace operation and
service requirements.
Furnace control board.
Blower access panel safety interlock switch.
Transformer (24v) behind furnace control board provides
low-voltage power to furnace control board and
thermostat.
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MODEL 345MAV FURNACE
(SHOWN IN UPFLOW POSITION)
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8
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5
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Summary of Contents for 345MAV
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