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FURNACE COMPONENTS
Combustion-air intake connection to ensure
contaminant-free air (right or left side).
Burner sight glass for viewing burner flame.
Burner assembly (inside). Operates with energy-
saving inshot burners and hot surface igniter for safe,
dependable heating.
Redundant gas valve. Safe and efficient. Features 1 gas
control with 2 internal shutoff valves. Valve appearance
varies with furnace model.
Vent outlet. Uses PVC pipe to carry flue gas from
the furnace’s combustion system (right or left side).
Inducer motor. Pulls hot flue gases through the heat
exchangers, maintaining negative pressure for added
safety.
Blower access panel safety interlock switch.
Air filter and retainer.
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.
Secondary condensing heat exchanger (inside).
Wrings out more heat through condensation.
Constructed with polypropylene-laminated steel to
ensure durability.
Primary serpentine heat exchanger (inside).
Stretches fuel dollars with the S-shaped heat-flow
design. Solid construction of corrosion-resistant
aluminized steel means reliability.
Furnace control board.
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.
Pressure switch(es) ensure adequate flow of flue
gas through furnace and out vent system.
Rollout switch (manual reset) to prevent
overtemperature.
Junction box for 115-v electrical power supply. (May be
located on right or left side)
Transformer (24v) behind furnace control board pro-
vides low-voltage power to furnace control board and
thermostat.
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MODELS 340MAV, 350MAV,
AND 352MAV FURNACES
(UPFLOW POSITION)
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MODEL 355MAV
FURNACE (UPFLOW POSITION)
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