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356486-U
UM-J-1211
Manifold
Pi
Limit Switch
(Behind gas valve)
Junction Box
Rollout
Safety Switch
Flame Sensor
--
Gas Valve
Pipe
Draft Inducer
Assembly
Pressure
Switch
Condensate
Safety
Pan
Control
Board
Manifold
Ig
Gas
Junction Box
Silicone
Safety
PSC MOTOR
ECM MOTOR
FIGURE 5: Component Location - 97% Modulating PSC Models
FIGURE 6: Component Location - 97% Modulating
Rollout
Switch
Flame Sensor
Limit Switch
(Behind gas valve)
Vent Pipe
Draft Inducer
Assembly
Pressure
Switch
:ondensate
Pan
Board
Factor
Choke (Not
used on all
models)
ECM Models
1.
Examine the heat exchanger, vent pipe, combustion air passages,
vent connectors
and chimney to be sure they are clear and free of
obstructions.
2.
Examine
the vent pipe making sure it is firmly in place, that it
slopes slightly upward and is physically sound without holes and
all of the connections
are secure.
3.
Examine
the return-air
duct connections
to make sure they are
physically sound, sealed to the furnace casing, and the ducts ter-
minate outside the space containing the furnace.
4.
Examine the furnace casing making sure the physical support is
sound without sagging, cracks or gaps. Examine the furnace base
making sure it is physically sound without cracks, gaps or sagging
and has a good seal.
5.
Examine the furnace casing for obvious signs of deterioration.
6.
Examine the burner flames to make sure they are in good adjust-
ment. Refer to the pictorial sketch shown in Figure 7 as a compar-
ison to the actual flame.
Blue Cone Portion of Flame Should
Enter Heat Exchan_be
/
FIGURE 7: Burner Flame Drawing (Upflow Configuration
Shown)
7,
8.
Examine and replace external air filters as needed to make sure
they are not blocked, and proper airflow is provided to the furnace.
Examine any installed accessories
or system components such as
evaporator
coils to insure proper operation,
drainage of conden-
sate, and that there is no water leakage or damage to the furnace
or any components.
SECTION
II1: START-UP
AND
SHUTDOWN
INSTRUCTIONS
Read the Instructions
Below
Before
Trying
to Start the
Furnace!
AWARNING
If you do not follow these instructions
exactly, a fire or explo-
sion may result causing property
damage, personal
injury,
and/or loss of life.
HOW
YOUR
GAS
FURNACE
WORKS
Your furnace is a very easy appliance to take for granted. Season after
season, it sits there in your home, keeping you warm and comfortable.
For this reason, you may never have given much thought to the way
your furnace operates. In order to get the safest and most efficient oper-
ation from your furnace, you should understand
how your furnace does
its job.
When you set your thermostat to provide more heat in your home, you
are starting the heating cycle of the furnace.
First, the inducer motor
starts to purge the heat exchanger
of any remaining gases. Next, the
hot surface ignitor glows and after a warm-up
period the gas valve
opens and ignition occurs. A short time later, the blower starts and dis-
tributes the warm air throughout
the home. When the temperature
set-
ting on your thermostat
is reached,
the gas valve closes, the main
burners are turned off, and the blower continues to run until the remain-
ing warm air in the system is distributed.
When the blower stops, the
heating cycle has ended.
1.
This appliance does not have a pilot. It is equipped with an ignition
device which automatically
lights the burner. Do not try to light the
burner by hand.
2.
BEFORE
OPERATING;
smell all around the appliance
area for
gas. Be sure to smell next to the floor
because
some gas is
heavier than air and will settle on the floor.
3.
Use only your hand to push the gas control switch to the ON posi-
tion. Never use tools. If the switch will not operate by hand, don't
try to repair
it, call a qualified
service
technician.
Force
or
attempted repair may result in a fire or explosion.
4.
Do not use this appliance if any part has been under water. Imme-
diately call a qualified service technician
to inspect the appliance
and to replace any part of the control system and any gas control,
which has been under water.
Johnson Controls Unitary Products
3
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