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 fur-
nace’s combustion system (right or left side).
Secondary condensing heat exchanger (inside). Wrings
out more heat through condensation.
Constructed with polypropylene-laminated steel to en-
sure durability.
Pressure switch ensures adequate flow of flue gas
through furnace and out vent system.
Inducer motor. Pulls hot flue gases through the heat ex-
changers, 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. (Location in furnace may vary.)
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.
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MODEL PG9MAB FURNACE
(SHOWN IN UPFLOW POSITION) 1
3-amp fuse provides electrical and component
protection.
Status code light emitting diode (LED) on furnace control
board. Status code light is for diagnosing furnace opera-
tion 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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SAFETY CONSIDERATIONS
Installing and servicing of heating equipment can be hazardous due to gas and electrical components. Only trained and quali
fi
ed
personnel should install, repair, or service heating equipment.
Untrained personnel can perform basic maintenance functions such as cleaning and replacing air
fi
lters. All other operations must
be performed by trained service personnel. Observe safety precautions in this manual, on tags, and on labels attached to the furnace
and other safety precautions that may apply.
Recognize safety information. This is the safety-alert symbol
. When you see this symbol on the furnace and in instructions or
manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, CAUTION, and NOTE. DANGER, WARNING, and CAUTION are used
with the safety-alert symbol. DANGER identi
fi
es the most serious hazards which
will
result in severe personal injury or death.
WARNING signi
fi
es hazards which
could
result in personal injury or death. CAUTION is used to identify unsafe practices which
may
result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which
will
result in
enhanced installation, reliability, or operation.
To minimize the possibility of serious personal injury,
fi
re, damage to your furnace, or improper operation,
carefully follow these
safety rules
which apply to both direct-vent and non-direct vent applications:
Your new gas furnace may have been installed in 1 of 2 ways, as a direct-vent (2-pipe) application or as a non-direct vent (1-pipe)
application.
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