How Your Oil-Fired Furnace Works; Instructions For Examining The Furnace - York International DFAA User's Information, Maintenance And Service Manual

107273-UUM-C-0306
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7. NEVER Store cleaning materials near your furnace. Materials
such as bleaches, detergents, powdered cleansers, etc., can
cause corrosion of the heat exchangers.
...
8. NEVER Use the area around your furnace as a storage area for
items which could block the normal flow of air. This flow of air is
required for ventilation of the various furnace components.
FIRE OR EXPLOSION HAZARD - Failure to follow safety
warnings exactly could result in serious injury, death, or prop-
erty damage.
This furnace is designed and approved for use with #1 or #2 FUEL
OILS ONLY. DO NOT BURN ANY LIQUID FUEL OTHER THAN #1
OR #2 FUEL OILS OR ANY SOLID FUEL IN THIS FURNACE.
• Never attempt to use gasoline in your heating appliance.
• Never attempt to burn garbage or refuse in your appliance.
• Never attempt to light the burner / appliance by throwing burn-
ing material into the appliance.
• Never attempt to use crankcase or waste oil or material other
than the approved fuel oils in this burner.
Burning any unapproved fuel will result in damage to the furnace heat
exchanger, which could result in fire, personal Injury, and/or property
damage.

HOW YOUR OIL-FIRED FURNACE WORKS

This furnace must be installed in the downflow position only. Figure 1
shows a typical model in the downflow position. The furnace is
equipped with a forced-draft oil burner combustion air blower and
burner. Combustion air is drawn through a 2" PVC pipe; then pushed
through a 2" flexible hose into the burner box. Flue gas is pushed
through the heat exchanger by the oil burner combustion air blower and
discharged through the vent pipe to the outside atmosphere.
The furnace circulating air blower draws cool air from the house, passes
it over the hot furnace heat exchanger and circulates the warmed air
through the ductwork to the house.
The furnace is equipped with the controls necessary for proper opera-
tion. The various components referred to in this manual and on the fur-
nace rating plate are identified in Figure 1.
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 burner motor
starts to purge the heat exchanger of any remaining gases. Next, the
direct spark ignition starts and the solenoid valve on the oil pump opens
and ignition occurs. A short time later, the blower starts and distributes
the warm air throughout the home. When the temperature setting on
your thermostat is reached, the solenoid valve closes, the oil burner is
turned off, and the blower continues to run until the remaining warm air
in the system is distributed. when the blower stops, the heating cycle
has ended.
2
Roof Jack
Vent Connection
Blower Motor
Capacitor
Blower Motor
Auxiliary Limit
Control Box
Line Voltage
Connections
Ignition
Transformer
Oil Pump
FIGURE 1: Component Locations

INSTRUCTIONS FOR EXAMINING THE FURNACE

It is the owner's responsibility to ensure that an annual inspection of the
entire heating portion of the unit is made by a qualified service
agency. Examine the furnace as outlined below in steps "1 - 6" before
each heating season. Use Figures 2 and 3 for visual reference.
1. Examine the heat exchanger, through a field installed access
panel located on the supply air plenum. Visually examine the exte-
rior sections of the vent/combustion air piping and the connectors
to be sure that they are physically sound without holes or exces-
sive corrosion.
2. Examine the outside vent/combustion air pipe making sure it is
firmly in place, is physically sound without holes, and all of the con-
nections are secure.
3. Examine the return air filter rack connections on the blower door to
make sure they are physically sound, and secured to the furnace
casing.
4. Examine the furnace casing making sure the physical support is
sound without sagging, cracks or gaps.
5. Examine the furnace base and coil panels making sure it is physi-
cally sound without cracks, gaps or sagging and has a good seal.
6. Examine the burner flames to make sure the burner look is like it is
operating properly. The burner flames for fuel oil should appear
yellow without smoking at the tips. The flame should appear cylin-
drical in shape and should extend from the end of the burner into
the heat exchanger chamber. Refer to the pictorial sketch shown
in Figure 2 as a comparison to the actual flame.
#1 FUEL OIL
Light Yellow
Tips
Light Yellow
Tips Just
Starting to
Become
Pronounced
FIGURE 2: Oil Burner Flame Drawing
Combustion ir
PVC Connection
Blower Housing
& Wheel
4" Combustion
Air Pipe
Pressure Switch
Fan Switch
Limit Switch
Primary Control
2" Flexible
PVC Pipe
Burner Motor
DFAA Coil Cabinet
#2 FUEL OIL
Darker Yellow
to Yellow Flame
Light Yellow
Tips Just
Starting to
Become
Pronounced
Unitary Products Group