Lennox o23v User Manual
Corp. 0609−L1
Service Literature
O23V SERIES UNITS
The O23V is a member of the DAVE LENNOX SIGNATUREt COLLECTION t. The O23V is an upflow oil fur-
nace equipped with a variable speed motor and manufactured with a Beckett oil burner. The O23V is available in
heating capacities of 70,000 to 154,000 Btuh (20.5 to 45.1
kW) with AFUE up to 83% and cooling applications from 1
1/2 to 5 tons (5.3 through 17.6 kW). Refer to Engineering
Handbook for proper sizing.
The drum type heat exchanger comes with strategically
placed ports allowing easy cleaning, while the oil burner
can be removed for inspection and service. The maintenance section gives a detailed description on how this is
done.
Information contained in this manual is intended for use by
experienced HVAC service technicians only. All specifications are subject to change. Procedures outlined in this
manual are presented as a recommendation only and do
not supersede or replace local or state codes.
O23V
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect switch(es). Unit may have multiple
power supplies.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage,
personal injury or loss of life. Installation and service
must be performed by a qualified installer or service
agency.
IMPORTANT
If using programmable thermostat, be sure to use
a type of thermostat that retains its memory in
event of a power loss.
TABLE OF CONTENTS
General Page 1. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications Page 2. . . . . . . . . . . . . . . . . . . . . . .
Parts Arrangement Page 3. . . . . . . . . . . . . . . . . .
I Unit Components Page 3. . . . . . . . . . . . . . . . . .
II Placement and Installation Page 11. . . . . . . . . .
III Start Up Page 16. . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating Systems Service Checks Page 17. . .
V Disassembling Burner Page 19. . . . . . . . . . . . . .
VI Typical Operating Characteristics Page 21. . .
VII Maintenance Page 22. . . . . . . . . . . . . . . . . . . . .
VIII Wiring Diagrams Page 23. . . . . . . . . . . . . . . .
IX Troubleshooting Page 25. . . . . . . . . . . . . . . . . .
Page 1
© 2005 Lennox Industries Inc.
Litho U.S.A.
SPECIFICATIONS
Perf
g
g
Oil
Heating
ormance
Low Fire
High Fire
Flue Connection Round − in. (mm) 6 (152) 6 (152) 6 (152)
Temperature Rise Range °F (°C)
Oil Burner
Nozzle rating − gph (L/hr) − Low
Nozzle spray angle − Low 80° hollow 80° solid 80° solid
Oil Burner Pump Pressure − psig (Pa) 100 (690) 140 (965) 140 (965)
Oil Burner Air Inlet Connection (dia.) − in (mm) 4 (102) 4 (102) 4 (102)
Blower
Data
Wheel nom. diameter x width − in. (mm)
Nominal add−on cooling − Tons (kW) 1.5 − 3 (5.3 − 10.6) 2 − 3.5 (7.0 − 12.3) 3 − 5 (10.6 − 17.6)
2
Filter
Shipping weight lbs. (kg) 1 package 225 (102) 225 (102) 275 (125)
Electrical Characteristics 120V−60hz−1ph 120V−60hz−1ph 120V−60hz−1ph
Maximum overcurrent protection (amps) 15 15 15
Model Number O23V2/3−70/90 O23V3/4−105/120 O23V5−140/154
Input − Btuh (kW)
Output − Btuh (kW)
Input
Output
1
A.F.U.E.
70,000 (20.5)
58,000 (16.7)
90,000 (26.4) 119,000(34.8) 154,000(45.1)
74,000 (21.7)
83% 81% 81%
50 − 80 (28 − 44)
105,000 (30.8) 140,000 (41.0)
85,000 (24.9) 113,000 (33.1)
97,000 (24.9) 125,000 (36.6)
50 − 80 (28 − 44) 55 − 85 (31 − 47)
.50 (1.9) .65 (2.5) .85 (3.2)
4
High
4
High 80° solid 80° solid 80° solid
4
.65 (2.5)
4
.75 (2.8)
4
1.00 (3.8)
Oil Burner Pump 1 Stage 1 Stage 1 Stage
Motor hp (W) 1/2 (373) 1/2 (373) 3/4 (560)
10 x 8 (254 x 203)
Number of filters 1 1
Size of filters − in.
mm
16 x 25 x 1 16 x 25 x 1 16 x 25 x 1
406 x 635 x 25 406 x 635 x 25 406 x 635 x 25
10 x 10 (254 x 254) 12 x 11 (305 x 280)
3
2
Optional Accessories − Must Be Ordered Extra
Half−Height Coil Case
Fits uncased C33 coils B"−width B"−width C"−width
Dimensions − in. 5 x 19−1/2 x 21−3/4 5 x 19−1/2 x 21−3/4 5 x 22−1/2 x 22−7/8
mm 127 x 495 x 552 127 x 495 x 552 127 x 572 x 581
Oil Filters
10 micron without mounting bracket 81P89 81P89 81P89
10 micron with mounting bracket 53P92 53P92 53P92
Replacement cartridge − 10 micron, 45 gph 53P93 53P93 53P93
Filter restriction indicator gauge 53P90 53P90 53P90
SignatureStatt Home Comfort Control 81M27 81M27 81M27
Two Stage Oil Pump 65A44 65A44 65A44
1
Annual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations. Isolated combustion system rating for non−weatherized furnaces.
2
Cleanable frame type filters. Furnished with unit in Side Filter Adaptor Kit for field installation external to the cabinet.
3
Requires return air from both sides of cabinet.
4
Nozzle must be field provided for field conversion to higher heating input.
19M11 19M11 19M12
Page 2
O23 GENERAL PARTS ORIENTATION
HEAT EXCHANGER
CLEAN-OUT PORT
LIMIT SWITCH
CONTROL BOX
WITH FAN
CONTROL
BECKETT
AFII BURNER
INDOOR BLOWER
I−UNIT COMPONENTS
VENT OPENING
CLEAN-OUT PORT
OBSERVATION PORT
COMBUSTION AIR INTAKE
VARIABLE SPEED
BLOWER MOTOR
FIGURE 1
A−Blower Control Board (A54) Figure 2
General parts orientation for the O23V is shown in figure 1. The O23V control box, burner, limit switch and
clean-out ports may be accessed by removing the front
access panel. The blower can be accessed by removing
the blower access panel.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during unit installation and service to protect the unit’s electronic
controls. Precautions will help to avoid control
exposure to electrostatic discharge by putting
the unit, the control and the technician at the
same electrostatic potential. Neutralize electrostatic charge by touching hand and all tools on an
unpainted unit surface before performing any
service procedure.
WARNING
Electric shock hazard. Can cause
injury or death. Before attempting to
perform any service or maintenance,
turn the electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
O23V units are equipped with a variable speed motor
which is controlled by the A54 blower control board. Blower
control board settings and operation are described in this
section.
O23V units equipped with a variable speed motor are capable of maintaining a specified CFM throughout the external static range. A particular CFM can be obtained by positioning jumpers (COOL, HEAT, and ADJUST) on the
blower control board. The HEAT and COOL jumpers are
labeled A, B, C and D; each letter corresponds with an air
volume (CFM) setting. The ADJUST jumper is labeled
Test, −, +, and Norm. The + and − pin settings are used to
add or subtract a percentage of the CFM selected in the
COOL mode only. The Test jumper is used to operate the
motor in the test mode.
Page 3
Factory settings for the blower speed jumpers are given in
the wiring diagram. Use tables 1, 2 and 3 to determine the
correct air volume for operation in heat and cool mode.
The CFM LED located on the blower control board flashes
one time per 100 cfm to indicate selected blower speed.
For example, if the unit is operating at 1000 CFM, CFM
LED will flash 10 times.
At times, the light may appear to flicker or glow. This takes
place when the control is communicating with the motor
between cycles. This is normal operation. Read through
the jumper settings section before adjusting the jumper to
obtain the appropriate blower speed.
Blower Control Board (A54)
16−PIN PLUG
(BOARD TO MOTOR)
To change jumper positions, gently pull the jumper off the pins
and place it on the desired set of pins. Th e fo ll o w i n g sec t i o n
outlines the different jumper selections available and
conditions associated with each one (see figure 2).
After the CFM for each application has been determined, the jumper settings must be adjusted to reflect
those given in tables 1, 2 and 3. From the tables, determine which row most closely matches the desired CFM.
Once a specific row has been chosen (+, NORMAL, or
−), CFM volumes from other rows cannot be used.
Page 5 has descriptions of the jumper selections.
The variable speed motor slowly ramps up to and down
from the selected air flow during both cooling and heating demand. This minimizes noise and eliminates the
initial blast of air when the blower is initially energized.
DIAGNOSTIC LED
ADJUST
SELECTOR PINS
(Setting affect cooling
only)
HEATING SPEED
SELECTOR PINS (SEE
TABLE)
O23V−Q2/3−090
O23V−Q3/4−120
O23V−Q2/3−070
O23V−Q3/4−105
O23V−Q5−140
FIGURE 2
COOLING SPEED
SELECTOR PINS
NOTE − The JW1 resistor
must be cut to activate the
HUM terminal.
O23V−Q5−154
HEAT SPEED SELECTOR
PINS (JUMPERS)
Page 4
ADJUST
The ADJUST pins allow the motor to run at approximately
15% higher, or approximately 15% lower, than normal
speed. Tables 1, 2 and 3 give three rows (+, NORM, and −)
with their respective CFM volumes. Notice that the normal
(NORM) adjustment setting for cool speed position C in
table 1 is 800 CFM. The + adjustment setting for that position is 920 CFM (115% of 800 CFM) and for the − adjustment setting is 680 CFM (85% of 800 CFM). After the adjustment setting has been determined, choose the
remaining speed settings from those offered in the table in
that row.
The TEST pin is available to bypass the blower control and
run the motor at approximately 70% to make sure that the
motor is operational. This is used mainly in troubleshooting. The G terminal must be energized for the motor to run.
COOL
The COOL jumper is used to determine the CFM during
cooling operation. This jumper selection is activated for
cooling when Y1 is energized. Y1 and Y2 must be jumpered for single stage cooling.
The blower motor runs at 82% of the selected air flow for
the first 7−1/2 minutes of each cooling demand. This feature allows for greater humidity removal and saves energy.
Y
7.5 minutes
82%
Y − Cool Demand Present
y − Cool Demand Satisfied
100%
y
60
sec
82%
OFFCALL
When the demand for cool is met, the blower ramps down
to 82% for 60 seconds, then turns off.
HEAT
The HEAT jumper is used to determine CFM during heat
operation only. These jumper selections are activated only
when W1 is energized.
During the heat ON delay, the blower runs at 13% CFM for
the first minute, 50% for the second minute, and full CFM
after two minutes.
W
60
sec60sec
13%
50%
100%
W − Heat Demand Present
w − Heat Demand Satisfied
w
210 seconds
82%
OFFCALL
When the demand for heat is met, the blower ramps down
to 82% for 3−1/2 minutes, then turns off.
Continuous Fan
When the thermostat is set for Continuous Fan" operation
and there is no demand for heating or cooling, the blower
control will provide 50% of the COOL CFM selected.
G
50%
G − Fan switch ON
g − Fan switch OFF
g
OFFCALL
When a continuous fan is on (G demand present), the fan
runs at 50% until switched off; there is no ramp up or off delays.
NOTE − With the proper thermostat and subbase, continuous blower operation is possible by closing the R to G circuit.
Dehumidification
The A54 blower control board (see figure 2) includes a
HUM terminal which provides for connection of a humidistat. The JW1 resistor on the blower control board must be
cut to activate the HUM terminal. The humidistat must be
wired to open on humidity rise. When the dehumidification
circuit is used, the variable speed motor will reduce the selected air flow rate by 18% when humidity levels are high.
An LED (D1) lights when the blower is operating in the dehumidification mode.
Humidification
Terminals are provided on the A15 control board for 120
volt output to operate a humidifier. The HUM" terminal is
energized when there is a call for heat. See unit wiring diagram.
Electronic Air Cleaner
Terminals are provided on A15 control board for 120 volt
output to an electronic air cleaner. The EAC" terminal is
energized when there is a call for heat, cool, or continuous
blower. See unit wiring diagram.
Page 5
AD
ADJUST
Jumper
A
ADJUST
Jumper
A
ADJUST
Jumper
A
Jumper
Setting
+
NORM
−
AD
Jumper
Setting
+
NORM
−
TABLE 1
O23V−Q2/3−70/90 Blower Performance
0 through 0.80 in. w.g. (0 through 200 Pa) External Static Pressure Range
Jumper Speed Positions
COOL" Speed HEAT" Speed CONTINUOUS FAN" Speed
T"
A B C D A B C D A B C D
cfm L/sBcfm L/sCcfm L/sDcfm L/sAcfm L/sBcfm L/sCcfm L/sDcfm L/sAcfm L/sBcfm L/sCcfm L/sDcfm L/s
1380 565 1150 540 920 435 690 325 SAME AS NORM
1200 565 1000 470 800 380 600 285 1300 614 1100 520 1000 470 750 354 600 285 500 235 400 190 300 143
1020 480 850 400 680 320 510 240 SAME AS NORM
Do not use −90 −70
TABLE 2
O23V−Q3/4−105/120 Blower Performance
0 through 0.80 in. w.g. (0 through 200 Pa) External Static Pressure Range
Jumper Speed Positions
COOL" Speed HEAT" Speed CONTINUOUS FAN" Speed
T"
A B C D A B C D A B C D
cfm L/sBcfm L/sCcfm L/sDcfm L/sAcfm L/sBcfm L/sCcfm L/sDcfm L/sAcfm L/sBcfm L/sCcfm L/sDcfm L/s
1620 765 1380 650 1150 540 920 435 SAME AS NORM
1400 660 1200 565 1000 470 800 360 1500 713 1400 660 1300 613 1200 565 700 333 600 285 500 235 400 190
1190 560 1020 480 850 400 680 320 SAME AS NORM
Do not use −120 −105
Jumper
Setting
NORM
TABLE 3
O23V−Q5−140/154 Blower Performance
0 through 0.80 in. w.g. (0 through 200 Pa) External Static Pressure Range
Jumper Speed Positions
COOL" Speed HEAT" Speed CONTINUOUS FAN" Speed
Do not
"
A B C D A B C D A B C D
cfm L/sBcfm L/sCcfm L/sDcfm L/sAcfm L/sBcfm L/sCcfm L/sDcfm L/sAcfm L/sBcfm L/sCcfm L/sDcfm L/s
+
−
2300 1085 2070 975 1840 870 1380 650 SAME AS NORM
2000 944 1800 850 1600 755 1200 565 1850 873 1730 816 1550 732 1400 660 1000 470 900 425 800 380 600 285
1700 802 1530 720 1360 640 1020 480 SAME AS NORM
use
−154
Do not
use
−140
Page 6
B−Burner Control (A3)
All O23V units are equipped with a burner control R7184B
manufactured by Honeywell. The burner control, along with
the matching cad cell, proves flame and controls the burner.
An LED on the control shows unit status. See table 4 for status
codes. After the cad cell closes a circuit to the burner control,
the burner control de−energizes the safety switch heater to allow the unit to operate normally. When there is a call for heat
the control performs a 2 to 6 second delay safety check. Once
this is established a 15 second pre−purge will follow. The valve
then opens for a 15 second trial for ignition. If flame is not
sensed during the 15 second trial, the control shuts down and
must be manually re−set. After three consecutive lockouts the
control goes into restricted lockout. Once flame is established
after 10 seconds of run time, the ignitor is de−energized.
If flame is lost during the heat cycle the control will shut
down the burner and begin a 60 second recycle delay. After 60 seconds the control repeats the ignition process. If
flame is lost three consecutive times during a single thermostat demand the control goes into restricted lockout.
C−Control ST9103A (A15)
Control ST9103A manufactured by Honeywell, is a
printed circuit board which monitors limit operation and
oil burner operation. Line voltage and thermostat connections are made on this control. See table 5 for terminal designations.
TABLE 5
J58 Pin #
1 Limit S10
2 L1 120V
3 24V
4 L2 Common
5 Jumpered to Pin 4
6 24V
7 Burner Motor
8 Jumpered to Pin 7
9 Limit S21 (if used)
Function
Reset button
If the control locks out three consecutive times the control
will go into restricted lockout. To reset control hold down
the reset button for 30 seconds until the LED flashes twice.
At any time the burner motor is energized, press and hold
the reset button to disable the burner. The burner will remain disabled as long as the reset button is held down and
return to operation once the button is released.
TABLE 4
LED
On Flame sensed
Off Flame not sensed
Flashing
(1/2 sec on1/2 sec off)
Flashing
(2 sec on 2 sec off)
STATUS
Lockout /
Restricted Lockout
Recycle
D−Transformer (T1)
Transformer T1 provides power to the low voltage section of the unit. Transformers are rated 40VA with a
120V primary and 24V secondary.
E−Primary Limit Control (S10)
The primary limit on all O23V units, is located on the vestibule panel. When excess heat is sensed in the heat exchanger, the limit will open. If the limit is tripped, 24 volt
power to terminal R" on the indoor thermostat is lost and the
unit shuts down but the indoor blower continues to run. The
limit automatically resets when unit temperature returns to
normal. The switch is factory set and cannot be adjusted. The
setpoint is printed on the face plate of the limit.
IMPORTANT
If using programmable thermostat, be sure to use
a type of thermostat that retains its memory in
event of a power loss.
Page 7
O23V BURNER PARTS ARRANGEMENT
RETAINING
CLIP
HEAD
INSULATOR
AIR TUBE
ASSY FOR
FB HEADS
1/4" HEX
HEAD SCREW
FB−HEAD
NOZZLE
ADAPTER
ELECTRODE HEAD
FLANGE
GASKET
NOZZLE LINE
ASSY.
FLANGE
ELECTRODE
ASSY
AIR TUBE
SCREWS
ELECTRONIC IGNITION
TRANSFORMER
CONNECTOR
PEDESTAL
PREMOUNTED PRE−PURGE VALVE
MAIN
HOUSING
ASSY
ESCUTCHEON
PLATE
TUBE
REAR ACCESS
DOOR ASSY
SPLINED
NUT
FUEL PUMP
COUPLING
REAR ACCESS
DOOR GASKET
MOTOR
IGNITOR
PRIMARY
CONTROL
BLOWER
WHEEL
4X4
BOX
0
3
4
5
6
7
8
AIR
ADJ.
DIAL
INLET
AIR SCOOP
FIGURE 3
Page 8
Unit
Lennox Burner
Part Number
TABLE 6
FURNACE / BURNER SPECIFICATIONS
Burner
Model
*Initial
Air Dial
Setting
Output
Nozzle Size
(Delevan)
Pump
Pressure
Head
-70 39M85 AFII 85 3.0
-090 39M85 AFII 85 3.5
-105 39M86 AFII 85 4.0
-120 39M86 AFII 85 4.5
-140 39M87 AFII 150 6.0
-154 39M87 AFII 150 6.5
*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 initial 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 combustion 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 combustion 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 automatically 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.
57,000 BTU
(16.7 kW)
74,000 BTU
(21.7 kW)
84,000 BTU
(24.6 kW)
105,000 BTU
(30.8 kW)
112,000 BTU
(32.8 kW)
125,000 BTU
(36.6 kW)
0.50 X 80_A
0.50 X 80_A
0.65 X 80_B
0.75 X 80_B
0.85 X 80_B
1.00 X 80_B
H− Pump
The O23V units all utilize the Cleancut Fuel Unit manufactured by Beckett. This pump uses a solenoid valve to control 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 returns 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 pressure build up in the piston cavity. The piston opens and regulates 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.
100 psig
(689.5 kPa)
100 psig
(689.5 kPa)
140 psig
965.3 kPa)
140 psig
965.3 kPa)
140 psig
965.3 kPa)
140 psig
965.3 kPa)
FB0
FBO
FB3
FB3
FB6
FB6
Page 9
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