Furnace Maintenance; Furnace Cleaning - York International DFAA User's Information, Maintenance And Service Manual

107273-UUM-C-0306
• Check the burner performance. Refer to the section "Set combus-
tion with instruments."
It is good practice to make a record of the service performed and the
combustion test results.

FURNACE MAINTENANCE

The furnace should be cleaned and adjusted by a certified dealer or
qualified service contractor once a year or before the start of every
heating season. The following items must be cleaned and serviced or
replaced if there are signs of deterioration.
1. The furnace vent and combustion air intake passageways. Should
it be necessary to service the vent/air intake system, the manufac-
turer recommends this service be conducted by a qualified service
agency. The operation of this appliance requires the reassembly
and resealing of the vent/air intake system.
2. The furnace burners, igniter and flame sensor.
3. Ignition transformer, electrodes, and electrode insulators.
4. Cad cell flame detector.
5. Oil burner nozzle.
6. Oil line filter (if applicable).
Direct Spark Ignition System
DIRECT SPARK IGNITION SYSEM
Do not attempt to light this furnace by hand (with a match or
any other means). There may be a potential shock hazard from
the components of the ignition system. The furnace can only be
lit automatically by its direct spark ignition system.
Z
(With Heat Shield)
F Head
Heat Shield
Nozzle Adapter
Air Tube
Static Plate
Nozzle Line
Splined Nut
FIGURE 8: Oil Burner Assembly
TABLE 2: Oil Burner Assembly Dimensions
DIMENSION
A (Usable Tube Length)
L (Total Tube Length)
R (Electrode Length ± 1/4)
S (Adapter to Static Plate ± 1/4)
Q (Nozzle Line Length)
Z (F Head - With Heat Shield)
6
L
A
R
S
Q
INCHES
3-5/8
4-1/8
6
1-5/8
4-11/16
1-3/8

FURNACE CLEANING

NOTE: The cleaning operations listed below must be performed only by
a qualified service agency.
Servicing Nozzle Line Assembly
Make certain the nozzle is selected for the fuel unit pressure
used. For applications with fuel unit pressure above 100 psig,
the nozzle rated capacity will be less than the appliance firing
rate. Use only the specified spray pattern unless combustion
test results indicate the need for a change. Failure to use the
correct nozzle size and type can result in unacceptable com-
bustion, possibly causing severe personal injury, death, or sub-
stantial property damage.
Remove the nozzle line assembly to verify that the nozzle size and
spray pattern are correct for the application. See Table 3. Verify that the
electrode tip settings comply with Figure 10.
TABLE 3: Burner Specifications
DFAA084BBTA
Furnace Model
DFAH084BBSA
Burner Spec
ATC AF35YHHS
Head
Static Plate
0.65 x 70° A
Nozzle
Pump Pressure
Air Boot Setting
Burner Removal/Cleaning
The oil burner should be checked annually for dirt accumulation and the
nozzle must be changed. If cleaning is required, follow this procedure:
1. Turn off the electrical power to the unit.
2. Turn off the oil supply at the external manual shut-off valve on the
oil pump on the oil burner and/or at the oil tank.
3. Remove the lower access panel.
4. Loosen the screws and move the retaining clips at the front of the
transformer. Pull up and back on the transformer and let it rest on
the burner assembly. The nozzle assembly will now be visible.
5. Remove the flare nut from the nozzle line on the connector tube
assembly.
6. Push the nozzle assembly in at the flare fitting end until the
assembly is inside the burner housing. Be sure to keep the flare
end at a slight angle upwards to avoid dripping oil on the combus-
tion air fan below.
7. Slide the nozzle assembly up and out of the burner assembly.
Take extra precautions with the electrodes when removing the
nozzle assembly so the insulators do not get broken or cracked.
8. Clean the assembly with a degreaser and wipe dry with a cloth.
9. Change the nozzle. Be sure to place a wrench on the nozzle
adapter before attempting to loosen the nozzle. After the nozzle
has been removed, dump the remaining fuel oil into a bucket. This
will remove any dirt or sludge that fell off the nozzle screen when
you were removing it.
DFAA066BBTA
DFAH066BBSA
EVC - 201 EVC - 201
AF35YHHS
F3 F3
3 - 3/8 U 3 - 3/8 U
0.50 x 70° A
Delavan Delavan
100 psi 100 psi
4.0 3.0
Unitary Products Group