Lennox International Inc. o23v - Manual (Page 9)

Page 9
TABLE 6
FURNACE / BURNER SPECIFICATIONS
Unit
Lennox Burner
Part Number
Burner
Model
*Initial
Air Dial
Setting
Output
Nozzle Size
(Delevan)
Pump
Pressure
Head
-70 39M85 AFII 85 3.0
57,000 BTU
(16.7 kW)
0.50 X 80
_A
100 psig
(689.5 kPa)
FB0
-090 39M85 AFII 85 3.5
74,000 BTU
(21.7 kW)
0.50 X 80 _A
100 psig
(689.5 kPa)
FBO
-105 39M86 AFII 85 4.0
84,000 BTU
(24.6 kW)
0.65 X 80
_B
140 psig
965.3 kPa)
FB3
-120 39M86 AFII 85 4.5
105,000 BTU
(30.8 kW)
0.75 X 80
_B
140 psig
965.3 kPa)
FB3
-140 39M87 AFII 150 6.0
112,000 BTU
(32.8 kW)
0.85 X 80 _B
140 psig
965.3 kPa)
FB6
-154 39M87 AFII 150 6.5
125,000 BTU
(36.6 kW)
1.00 X 80
_B
140 psig
965.3 kPa)
FB6
*NOTE: The initial air dial setting is provided to get unit started. The air dial setting MUST be adjusted after start-up to
achieve proper combustion.
F−Burner (Figure 3)
The O23V oil furnace uses the Beckett AFII burner. The oil
burner provides an atomized oil vapor mixed with the correct
proportion of air when it is ignited in the combustion chamber.
Oil burner minimum and maximum ratings are listed on the
unit nameplate. Proper air adjustment for these ratings is
achieved through the air adjustment dial. Set air dial to the ini-
tial air dial setting (see table 6). After start up adjust air dial to
achieve proper combustion. Remember to tighten set screw
on air dial.
The AFII burner is available in six sizes with either a single
or two stage pump. Table 6 identifies the burners used in
Lennox units.
G−Combustion Air Blower / Pump Motor (B6)
The burner is activated by the primary control. A com-
bustion air blower is mounted on the motor shaft. The
motor shaft also connects to the direct drive oil pump
through a coupler. The burner motor turns both the com-
bustion air blower and the oil pump. The motor operates
at 3500 RPM.
Burner motors are overload protected. In the event of
excess motor temperature or current, the overload
opens to de−energize the motor. The overload automat-
ically resets after temperature has returned to normal.
Keep motor clean to prevent starting switch from sticking.
All AFII motors are permanently lubricated. No further oiling is
required.
H− Pump
The O23V units all utilize the Cleancut Fuel Unit manufac-
tured by Beckett. This pump uses a solenoid valve to con-
trol the piston cut−on cut−off operation instead of a cone
valve and diaphram used by other conventional pumps.
The solenoid works with the R7184B Honeywell burner
control to provide cut−on cut−off operation while the burner
motor is at full speed.
At start up the pump shaft is brought to full speed before the
solenoid is energized. At this time low pressure oil
(approximately 20−25 psi) from the gear set circulates
around the pressure regulator piston which is closed and
through the open solenoid valve. The solenoid valve re-
turns the oil to either the cover cavity (one−pipe) or return
line (two−pipe). When the solenoid valve is energized, it
closes (and remains closed while energized) blocking the
return path to the cover cavity and return line creating pres-
sure build up in the piston cavity. The piston opens and reg-
ulates pressure and delivers pressurized oil to the nozzle.
At shutdown the solenoid valve will de−energize and open
before the pump shaft rotation stops. When the solenoid
valve opens the oil by−passes the cover cavity and return
line causing a pressure drop in the piston cavity. The piston
closes blocking oil to the nozzle while the burner motor is
running at full speed.