Lennox O23Q3-105, O23Q3-120, O23Q5-140, O23Q5-154, OHR23Q3-105 Unit Information

Corp. 9535−L8

Service Literature

Revised 09/2003

O23 / OHR23 / OF23 SERIES UNITS

O23 (Elite 80) series units are mid−efficiency upflow oil fur
naces manufactured with Beckett oil burners. O23 units are
available in heating capacities of 70,000 to 154,000 Btuh
(20.5 to 45.1 kW) and cooling applications from 2 through 5
tons (7.0 through 17.6 kW). Refer to Engineering Hand
book for proper sizing.

OHR23 (Elite 80) series units are mid−efficiency horizontal /
downflow oil furnaces. The OF23 (Elite 80) series units are
mid−efficiency loboy upflow oil furnaces, which come in front
(OF23) or rear (OF23R) flue openings, both with Beckett oil
burners. The OHR23 and OF23(R) units are available in heat
ing capacities of 105,000 to 154,000 Btuh (30.8 to 45.1 kW)
and cooling applications from 2 through 5 tons (7.0 through

17.6 kW). Refer to Engineering Handbook for proper siz
ing.

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 mainte
nance section gives a detailed description on how this is
done.

O23/OHR23

OF23

Information contained in this manual is intended for use by
experienced HVAC service technicians only. All specifica
tions 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.

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 discon
nect switch(es). Unit may have multiple
power supplies.

WARNING

Improper installation, adjustment, alteration, ser
vice 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.

O23 SHOWN

TABLE OF CONTENTS

General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Specifications 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Indoor Blower Data 4. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Parts Arrangement 5. . . . . . . . . . . . . . . . . . . . . . . . . . . .

I Unit Components 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

II Placement and Installation 16. . . . . . . . . . . . . . . . . . . .

III Start Up 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

IV Heating Systems Service Checks 22. . . . . . . . . . . . .

V Disassembling Burner 24. . . . . . . . . . . . . . . . . . . . . . . .

VI Typical Operating Characteristics 26. . . . . . . . . . . . . .

VII Maintenance 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VIII Wiring Diagrams 28. . . . . . . . . . . . . . . . . . . . . . . . . .

IX Troubleshooting 31. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page 1

 1995 Lennox Industries Inc.

Litho U.S.A.

SPECIFICATIONS − O23

Blower wheel nominal

Fil

Model Number O23Q270 O23Q3105/120 O23Q5140/154

InputBtuh (kW) low/high 70,000 (20.5) 105,000 / 120,000(30.8 / 35.2) 140,000 / 154,000(41.0 / 45.1)

Output Btuh (kW) low/high 57,000 (16.7) 85,000 / 97,000 (24.9 / 28.4) 113,000 / 125,000 (33.1 / 36.6)

*A.F.U.E. 83.8% 82.8% (105) / 82.5% (120) 82.5% (140) / 81.4% (154)

Nozzle Rating  gph (L/hr) and spray angle .50 (1.9)  80°hollow

Flue Size Diameterin. (mm) 6 (152) 6 (152) 6 (152)

Oil Burner Pump 1 Stage 1 Stage 1 Stage

Oil Burner Pump Pressure  psig (Pa) 100 (690) 140 (965) 140 (965)

Blower wheel nominal

diameter x width

Blower Motor Output  hp (W) 1/3 (249) 1/3 (249) 3/4 (560)

Nominal cooling that can be added

**Number and size of filtersin. (mm) (1) 16 x 25 x 1 (1) 16 x 25 x 1 (2) 16 x 25 x 1

Shipping weight  lbs. (kg) 1 package 225 (102) 225 (102) 275 (125)

Electrical characteristics 115 volts  60 hertz  1 phase

Two Stage Oil Pump 65A44

Oil Filter 81P89

*Annual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations. Isolated combustion system rating for nonweatherized furnaces.
**Cleanable frame type filters. Furnished with unit in Side Filter Adaptor Kit for field installation external to the cabinet.

Requires return air from both sides of cabinet.
Nozzle must be field provided for field conversion to higher heating input.

in. 10 x 6 10 x 8 12 x 9

mm 254 x 152 254 x 203 305 x 229

Tons 2 thru 2.5 2 thru 3.5 3 thru 5

kW 7.0 thru 8.8 7.0 thru 12.3 10.6 thru 17.6

 Optional Accessories (Must Be Ordered Extra) 

.65 (2.5)  80° (105 input) solid

.75 (2.8)  80°(120 input) solid

.85 (3.2)  80° (140 input) solid

1.00 (3.8)  80° (154 input) solid

SPECIFICATIONS − OHR23

Model Number OHR23Q3105/120 OHR23Q5140/154

InputBtuh (kW) low/high 105,000 / 120,000(30.8 / 35.2) 140,000 / 154,000(41.0 / 45.1)

OutputBtuh (kW) low/high 85,000 / 97,000 (24.9 / 28.4) 113,000 / 125,000 (33.1 / 36.6)

*A.F.U.E. (low/high) 81.8% / 81.3% 81.5% / 81.7%

Nozzle RatingU.S. gph (L/hr)
and spray angle

Flue Size Diameterin. (mm) 6 (152) 6 (152)

Oil Burner Pump 1 Stage 1 Stage

Oil Burner Pump Pressure  psig (Pa) 140 (965) 140 (965)

Blower wheel nominal diameter x width  in. (mm) 10 x 10 (254 x 254) 12 x 9 (305 x 229)

Blower motor outputhp (W) 1/2 (373) 3/4 (560)

Nominal cooling that can be added

Shipping weightlbs. (kg) 1 package 225 (102) 265 (120)

Electrical characteristics 115 volts  60 hertz  1 phase

Two Stage Oil Pump 65A44

ter Kit

Downflo Additive Base 35K07 35K08

Horizontal Venting Kit 62J01

Burner Cover 84H26

Vestibule Cover Kit (full front cover) 37K28 37K29

Oil Filter 81P89

*Annual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations. Isolated combustion system rating for nonweatherized furnaces.
Nozzle must be field provided for field conversion to higher heating input.

Catalog no. 35K01 35K06

No. & size of filtersin. (mm) (2) 101/4 x 201/2 x 1 (260 x 521 x 25) (2) 113/4 x 231/2 x 1 (298 x 597 x 25)

Tons 2 to 3 3 to 5

kW 7.0 to 10.6 10.6 to 17.6

 Optional Accessories (Must Be Ordered Extra) 

.65 (2.5)  8 0 (105 input) solid

.75 (2.8 )  80 (120 input) solid

.85(3.2) 8 0(140 input) solid

1.00 (3.8)  80 (154 input) solid

Page 2

SPECIFICATIONS − OF23

Blower wheel nominal

External Static

External Static

External Static

Model Number

InputBtuh (kW) low/high 105,000 / 120,000(30.8 / 35.2) 140,000 / 154,000(41.0 / 45.1)

OutputBtuh (kW) low/high 85,000 / 97,000 (24.9 / 28.4) 113,000 / 125,000 (33.1 / 36.6)

*A.F.U.E. (low/high)

Nozzle Ratinggph (L/hr) and spray angle

Flue Size Diameterin. (mm) 6 (152) 6 (152)

Oil Burner Pump 1 Stage 1 Stage

Oil Burner Pump Pressure  psig (Pa) 140 (965) 140 (965)

Optional 2 Stage Fuel Pump 65A44

Blower wheel nominal

diameter x width

Blower Motor Outputhp (W) 1/3 (249) 3/4 (560)

Nominal cooling that can be addedTons (kW) 2 thru 3 (7.0 thru 10.6) 3 thru 5 (10.6 thru 17.6)

Number and size of filters

Shipping weightlbs. (kg) 1 package 255 (116) 290 (132)

Electrical Characteristics 115  60 hertz  1 phase

 Optional Accessories (Must Be Ordered Extra) 

Two Stage Oil Pump 65A44

Oil Filter 91P89

*Annual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations. Isolated combustion system rating for nonweatherized furnaces.
Nozzle must be field provided for field conversion to higher heating input.

in. 10 x 8 12 x 9

mm 254 x 203 305 x 229

in. (1) 18 x 19 x 1 (1) 19 x 21 x 1

mm (1) 457 x 483 x 25 (1) 483 x 533 x 25

OF23Q3105/120

OF23Q3105/120R

82.4% / 81.5%

82.5% / 82.4% R Models

.65 (2.5)  80° (105 input)

.75 (2.8)  80° (120 input)

OF23Q5140/154

OF23Q5140/154R

81.8% / 81.5%

82.0% / 81.8% R Models

.85 (3.2)  80° (140 input)

1.00 (3.8)  80° (154 input)

BLOWER PERFORMANCE DATA − O23

O23Q270 BLOWER PERFORMANCE

External Static

Pressure

in.w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 1260 595 870 410 520 245

.30 75 1205 570 825 390 500 235

.40 100 1135 535 780 370 480 225

.50 125 1050 495 720 340 450 210

.60 150 960 455 660 310 410 195

NOTE  All air data is measured external to the unit with the air filter in place.

Air Volume at Various Blower Speeds

High Medium Low

O23Q5140/154 BLOWER PERFORMANCE

External Static

Pressure

in. w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 1950 920 1620 765 1250 590

.30 75 1900 895 1590 750 1230 580

.40 100 1880 885 1560 735 1210 570

.50 125 1850 875 1540 725 1190 560

.60 150 1800 850 1490 705 1155 545

NOTE  All air data is measured external to the unit with the air filter in place.

O23Q3105/120 BLOWER PERFORMANCE

External Static

Pressure

in. w.g. Pa cfm L/s cfm L/s cfm L/s

.20. 50 1350 635 1215 575 1080 510

.30 75 1280 605 1180 555 1060 500

.40 100 1210 570 1140 540 1040 490

.50 125 1180 444 1085 510 1000 470

.60 150 1100 520 1025 485 950 450

NOTE  All air data is measured external to the unit with the air filter in place.

Air Volume at Various Blower Speeds

High Medium Low

Air Volume at Various Blower Speeds

High Medium Low

Page 3

BLOWER PERFORMANCE DATA − OHR23

External Static

External Static

External Static

External Static

External Static

External Static

OHR23Q3105/120 BLOWER PERFORMANCE

External Static

Pressure

in w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 1470 695 1360 640 1070 505

.30 75 1400 660 1300 615 1040 490

.40 100 1330 630 1230 580 1020 480

.50 125 1260 595 1160 545 980 460

.60 150 1180 555 1085 510 920 435

NOTE  All air data is measured external to the unit with air filter in place.

Air Volume at Various Speeds

High Medium Low

BLOWER PERFORMANCE DATA − OF23

FRONT FLUE MODELS

OF23Q3105/120 BLOWER PERFORMANCE

External Static

Pressure

in. w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 1490 705 1370 645 1190 560

.30 75 1430 675 1345 635 1180 555

.40 100 1375 650 1280 605 1160 545

.50 125 1300 615 1230 580 1120 530

.60 150 1230 580 1160 545 1080 510

NOTE  All air data is measured external to the unit with the air filter in place.

Air Volume at Various Blower Speeds

High Medium Low

OHR23Q5140/154 BLOWER PERFORMANCE

External Static

Pressure

in w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 1950 920 1700 800 1340 630

.30 75 1920 905 1650 780 1300 615

.40 100 1900 895 1600 755 1270 600

.50 125 1870 880 1580 745 1220 575

.60 150 1780 840 1500 710 1170 550

NOTE  All air data is measured external to the unit with air filter in place.

Air Volume at Various Speeds

High Medium Low

OF23Q5140/154 BLOWER PERFORMANCE

External Static

Pressure

in. w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 2110 995 1850 875 1500 710

.30 75 2035 960 1810 855 1480 700

.40 100 1970 930 1750 825 1450 685

.50 125 1950 920 1690 800 1420 670

.60 150 1880 885 1620 765 1375 650

NOTE  All air data is measured external to the unit with the air filter in place.

Air Volume at Various Blower Speeds

High Medium Low

OF23Q3105/120R BLOWER PERFORMANCE

External Static

Pressure

in. w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 1470 695 1330 630 1150 545

.30 75 1410 665 1295 610 1140 540

.40 100 1340 630 1250 590 1125 530

.50 125 1280 605 1190 560 1080 510

.60 150 1205 670 1130 535 1030 485

NOTE  All air data is measured external to the unit with the air filter in place.

Air Volume at Various Blower Speeds

High Medium Low

REAR FLUE MODELS

OF23Q5140/154R BLOWER PERFORMANCE

External Static

Pressure

in. w.g. Pa cfm L/s cfm L/s cfm L/s

.20 50 2010 950 1765 835 1380 650

.30 75 1960 925 1720 810 1350 635

.40 100 1900 895 1660 785 1330 630

.50 125 1880 885 1600 755 1295 610

.60 150 1800 850 1560 735 1230 580

NOTE  All air data is measured external to the unit with the air filter in place.

Page 4

Air Volume at Various Blower Speeds

High Medium Low

O23 GENERAL PARTS ORIENTATION

HEAT EXCHANGER

CLEANOUT PORT

LIMIT SWITCH

CONTROL BOX

WITH FAN
CONTROL

BECKETT

AFII BURNER

INDOOR BLOWER

VENT OPENING

CLEANOUT PORT

OBSERVATION PORT

COMBUSTION AIR INTAKE

BLOWER MOTOR

CAPACITOR

FIGURE 1

LIMIT SWITCH

BECKETT

AFII BURNER

COMBUSTION

AIR INTAKE

OBSERVATION

PORT

CLEANOUT

OHR23 GENERAL PARTS ORIENTATION

CLEANOUT PORT

HEAT EXCHANGER

PORT

VENT OPENING

CONTROL BOX

WITH FAN

CONTROL

BLOWER MOTOR

INDOOR BLOWER

FIGURE 2

Page 5

OF23 GENERAL PARTS ORIENTATION

CLEANOUT

PORT

LIMIT SWITCH

CONTROL BOX

WITH FAN
CONTROL

BECKETT

AFII BURNER

FRONT VENT

OPENING (OF23)

COMBUSTION

AIR INTAKE

FILTER

INDOOR BLOWER

REAR VENT

OPENING (OF23R)

HEAT EXCHANGER

CLEANOUT PORT

OBSERVATION PORT

FIGURE 3

NEUTRAL

TERMINALS

24VAC OUTPUT

TO BURNER

(HEAT DEMAND)

24VAC IN FROM

PRIMARY LIMIT

24VAC THERMOSTAT

DEMAND OUTPUT

BCC2 / BCC3 BLOWER CONTROL BOARD

120VAC LINE

VOLTAGE IN

THERMOSTAT TERMINAL STRIP TB1

(DETACHABLE ON EARLY −1 AND −2

MODELS ONLY)

COOLING

SPEED TAP

TERMINAL

TRANSFORMER

120VAC

COMMON

FROM TRANSFORMER

CONTINUOUS FAN

TERMINAL

BLOWER TIME

ADJUSTMENT

JUMPER

24VAC INPUT

HEATING SPEED

TAP TERMINAL

ACCESSORY

TERMINAL

To Remove Terminal Strip,

Grasp Ends of Block Between

Thumb and Forefinger. Push

Block Down and Out.

(Jack / Plug 94)

24VAC COMMON

FROM TRANSFORMER

FIGURE 4

Page 6

I−UNIT COMPONENTS

General parts orientation for the O23, OHR23 and OF23 are
shown in figures 1, 2 and 3 respectively. The O23 and OF23
control box, burner, limit switch and cleanout ports may be ac
cessed by removing the front access panel, while the OHR23
components are exposed. The blower can be accessed in the
O23 and OF23 by removing the blower access panel, while in
the OHR23 units two 1/4" screws must be removed before the
blower access panel can be removed.

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can affect electronic
components. Take precautions during unit instal
lation 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 electro
static charge by touching hand and all tools on an
unpainted unit surface before performing any
service procedure.

A−Blower Control Board

BCC2 Blower Control Board (Figure 4)

−1 and −2 units

All O23, OHR23 and OF23−1 and −2 oil units utilize the BCC2
(A15) blower control manufactured by Heatcraft. The BCC2 is
a printed circuit board which controls the supply air blower and
monitors the limit controls and oil burner operation. The control
has a nonadjustable, factory preset fanon" timing. Fan off"
timing is adjustable. The board is divided into two sec
tions, 120 and 24VAC. Line voltage comes into the board
on the 120VAC side. See figure 4. See table 1 for BCC2
terminal designations.

DANGER

Shock hazard. Avoid personal injury. Make sure to
disconnect power before changing fan off" timing.

Blower Operation and Timing

Blower off" timing (time that the blower operates after the heat
demand has been satisfied) is determined by the arrange
ment of a jumper across pins on the BCC2 blower control
board. See figure 4. To adjust fan off " timing, gently discon
nect jumper and reposition across pins corresponding with
new timing. Fan on" time is factory set at 45 seconds and is
not adjustable.

NOTEIf fan off" time is set too low, residual heat in
heat exchanger may cause primary limit S10 or auxilary
limit S21 to trip resulting in frequent cycling of blower. If
this occurs, adjust blower to longer time setting.

Figure 5 shows the various fan off" timings and how
jumper should be positioned. Unit is shipped with a fac
tory fan off" setting of 150 seconds. Fan off" time will
affect comfort and efficiency and is adjustable to satisfy
individual applications. The fan off" timing is initiated
after a heating demand but not after a blower or cooling
demand (that is, when indoor thermostat switch is
changed from ON to AUTO and heating/cooling demand
is not present, the blower stops immediately).

FANOFF TIME ADJUSTMENT

TIMING

JUMPER

270

150 90

To adjust fan−off timings:

Remove jumper from BCC2

and select one of the other pin com

binations to achieve the

desired time.

Leave jumper off to achieve

210

330 second fan−off timing.

TIMING PINS (seconds)

Fanoff timing is factory

set at 150 seconds

FIGURE 5

Thermostat Connection

Thermostat wires are connected to terminal strip TB1 found
on the BCC2 control board. The terminal strip is c l early
marked with the corresponding thermostat designation.
The terminal strip (jack / plug 94) is simply removed by
grasping the ends of the block and rotating down while pull
ing away (see figure 4).

TABLE 1

BLOWER CONTROL A15 TERMINAL DESIGNATIONS

Term inal Type Function

W

R

Y

C

G

NEUTRAL 1/4" Spade 120VAC Neutral

L1 1/4" Spade 120VAC Line Voltage In

A 1/4" Spade

XFMRN 1/4" Spade 120VAC Transformer Common

CF 1/4" Spade

H 1/4" Spade

ACC 1/4" Spade

VALVE SENSE 3/16" Spade 24VAC Output To Burner

LIMIT 1/4" Spade

WI 1/4" Spade

24V 1/4" Spade

COM 1/4" Spade

Detachable
Screw Strip

Detachable
Screw Strip

Detachable
Screw Strip

Detachable
Screw Strip

Detachable
Screw Strip

Heating Demand

24VAC to Thermostat

Cooling Demand

24VAC Common

To Indoor Thermostat

Blower Demand

Switched 120VAC

to Blower Cooling Tap

Switched 120VAC to

Continuous Blower Tap

Switched 120VAC to

Blower Heating Tap

Switched 120VAC to Accessory

(Electronic Air Cleaner,

Humidifier, Etc. 1 amp rating.)

24VAC In From Primary Limit.

Limit Open: Stops Burner and Turns

On Blower

Limit Closed: Allows Burner

Operation

24VAC Thermostat

Demand Output

24VAC Input

From Transformer

24VAC Common

From Transformer

Page 7

BCC3 Blower Control Board (Figure 4)

−3 and −4 units

All O23, OHR23 and OF23−3 and −4 oil units utilize the BCC3
(A15) blower control manufactured by Heatcraft. The BCC3 is
a printed circuit board which controls the supply air blower and
monitors the limit controls and oil burner operation. The control
has a nonadjustable, factory preset fanon" timing. Fan off"
timing is adjustable. The board is divided into two sec
tions, 120 and 24VAC. Line voltage comes into the board
on the 120VAC side. See figure 4. See table 2 for BCC3
terminal designations.

DANGER

Shock hazard. Avoid personal injury. Make sure to
disconnect power before changing fan off" timing.

Blower Operation and Timing

Blower off" timing (time that the blower operates after the heat
demand has been satisfied) is determined by the arrange
ment of a jumper across pins on the BCC3 blower control
board. See figure 4. To adjust fan off " timing, gently discon
nect jumper and reposition across pins corresponding with
new timing. Fan on" time is factory set at 45 seconds and is
not adjustable.

NOTEIf fan off" time is set too low, residual heat in
heat exchanger may cause primary limit S10 or auxilary
limit S21 to trip resulting in frequent cycling of blower. If
this occurs, adjust blower to longer time setting.

Figure 5 shows the various fan off" timings and how
jumper should be positioned. Unit is shipped with a fac
tory fan off" setting of 150 seconds. Fan off" time will
affect comfort and efficiency and is adjustable to satisfy
individual applications. The fan off" timing is initiated
after a heating demand but not after a blower or cooling
demand (that is, when indoor thermostat switch is
changed from ON to AUTO and heating/cooling demand
is not present, the blower stops immediately).

FANOFF TIME ADJUSTMENT

TIMING

JUMPER

To adjust fan−off timings:

Remove jumper from BCC2

and select one of the other pin com

binations to achieve the

desired time.

Thermostat Connection

Thermostat wires are connected to terminal strip TB1 found
on the BCC3 control board. The terminal strip is clea r ly
marked with the corresponding thermostat designation.
The terminal strip (jack / plug 94) is simply removed by
grasping the ends of the block and rotating down while pull
ing away (see figure 4).

TABLE 2

BLOWER CONTROL A15 TERMINAL DESIGNATIONS

Term inal Type Function

W

R

Y

C

G

NEUTRAL 1/4" Spade 120VAC Neutral

L1 1/4" Spade 120VAC Line Voltage In

A 1/4" Spade

XFMRN 1/4" Spade 120VAC Transformer Common

CF 1/4" Spade

H 1/4" Spade

ACC 1/4" Spade

VALVE SENSE 3/16" Spade 24VAC Output To Burner

LIMIT 1/4" Spade

WI 1/4" Spade

24V 1/4" Spade

COM 1/4" Spade

Detachable
Screw Strip

Detachable
Screw Strip

Detachable
Screw Strip

Detachable
Screw Strip

Detachable
Screw Strip

Heating Demand

24VAC to Thermostat

Cooling Demand

24VAC Common

To Indoor Thermostat

Blower Demand

Switched 120VAC

to Blower Cooling Tap

Switched 120VAC to

Continuous Blower Tap

Switched 120VAC to

Blower Heating Tap

Switched 120VAC to Accessory

(Electronic Air Cleaner,

Humidifier, Etc. 4 amp rating.)

24VAC In From Primary Limit.

Limit Open: Stops Burner and Turns

On Blower

Limit Closed: Allows Burner

Operation

24VAC Thermostat

Demand Output

24VAC Input

From Transformer

24VAC Common

From Transformer

270

150 90

Leave jumper off to achieve

210

330 second fan−off timing.

TIMING PINS (seconds)

Fanoff timing is factory

set at 150 seconds

FIGURE 6

Page 8

ST9103A Blower Control Board (Figure 8)

−5 units

All O23, OHR23 and OF23 −5 oil units utilize the ST9103A
(A15) blower control manufactured by Honeywell. The
ST9103A is a printed circuit board which controls the supply
air blower and monitors the limit controls and oil burner opera
tion. The control has a nonadjustable, factory preset fanon"
timing. Fan off" timing is adjustable. See figure 8 and
table 3 for ST9103A terminal designations

ST9103A Blower Control Board

120V

DANGER

Shock hazard. Avoid personal injury. Make sure to
disconnect power before changing fan off" timing.

Blower Operation and Timing

The fan on time of 30 seconds is not adjustable. Fan off
time (time that the blower operates after the heat demand
has been satisfied) can be adjusted by moving the delay
switches on the fan control board. Fan off time will affect
comfort and is adjustable to satisfy individual applications.
See figure 7. Set the heat fan off delay switches to either
60, 90, 120, or 150 seconds. The factory setting is 90 sec
onds.

NOTEIf fan off" time is set too low, residual heat in
heat exchanger may cause primary limit S10 or auilary
limit S21 to trip resulting in frequent cycling of blower. If
this occurs, adjust blower to longer time setting.

Thermostat Connection

Thermostat wires are connected directly to the terminlas on
the ST9103A board. See figure 8.

Continuous Blower

If the ST9103A blower control board is wired for continuous
blower, the blower will energized on low speed and remain
energized when heat or cool demand is satisfied. Continuous
blower will also energized when indoor thermostat is left in the
OFF mode.

Fan Off Delay Switch Settings

ONON ON ON

120 sec90 sec60 sec

Figure 7

150 sec

fan off

delay switches

thermostat

terminal strip

Figure 8

TABLE 3

BLOWER CONTROL A15 TERMINAL DESIGNATIONS

J58 Pin # Function

1 Limit S10

2 L1 120V

3 T1 24V

4 L2 Common

5 Jumpered to Pin 4

6 T2 24V

7 Combustion Air Inducer

120V
8 Jumpered to Pin 7

9 Limit S21 (if used)

Thermostat Connections

G Blower Demand

W Heating Demand

R 24V

Y Cooling Demand

C Common

24 VAC CONNECTIONS

X 24V Transformer

C Common Transformer

120 VAC

S2 Line

S3 120V To Transformer

N, 2, 3, 4, 6, 7 Neutral

CONT Continuous Blower

COOL Cool Tap

HEAT Heat Tap

Page 9

RETAINING

CLIP

HEAD

INSULATOR

−1THROUGH −4 UNIT OIL BURNER PARTS ARRANGEMENT

AIR TUBE
SCREWS

HOLE PLUG

ELECTRONIC IGNITION

TRANSFORMER

MAIN

HOUSING

ASSY

ESCUTCHEON

PLATE

CONNECTOR

TUBE

AIR TUBE

ASSY FOR

FB HEADS

FB–HEAD

NOZZLE

ADAPTER

NOZZLE LINE

ELECTRODE HEAD

FLANGE

GASKET

ASSY.

FLANGE

ELECTRODE

ASSY

REAR ACCESS

DOOR GASKET

VIEW PORT

REAR ACCESS

DOOR ASSY

OIL PUMP

SPLINED

NUT

ELECTRONIC IGNITION

TRANSFORMER

BURNER

CONTROL

RESET

BUTTON

AIR

ADJUSTMENT

0

3
4
5

6
7
8

DIAL

COUPLING

COMBUSTION AIR

MOTOR

BLOWER

FIGURE 9

Page 10

WHEEL

INLET

AIR SCOOP

−5 UNIT 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.

ELECTRODE

FLANGE

ASSY

AIR TUBE
SCREWS

ELECTRONIC IGNITION

TRANSFORMER

ESCUTCHEON

CONNECTOR

PEDESTAL

PREMOUNTED PRE−PURGE VALVE

MAIN

HOUSING

ASSY

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 10

Page 11

TABLE 4

FURNACE / BURNER SPECIFICATIONS

Unit

70 35K74 AFII 85 3.0

105 35K75 AFII 85 4.0

120 35K75 AFII 85 4.5

140 35K76 AFII 150 6.0

154 35K76 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.

Lennox Burner

Part Number

Burner

Model

*Initial
Air Dial
Setting

Output

57,000 BTU

(16.7 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)

Nozzle Size

(Delevan)

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

Pump

Pressure

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)

Head

FB0

FB3

FB3

FB6

FB6

B−Burner (Figures 9 & 10)

The O23, OHR23, and OF23 oil furnaces use 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 com
bustion 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 4). After start up
adjust air dial to achieve proper combustion. Remember to
tighten set screw on air dial.

The AFII burner is available in five sizes with either a single
or two stage pump. Table 4 identifies the burners used in
Lennox units. Figures 9 and 10 show the typical layout of the
burner assembly.

1−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.

2−Combustion Air Blower / Pump Fuse (F22)

(−140 and −154 CSA units only)

In the −140 and −154 Canadian units an in line fuse (F22) is
used between the line voltage from the BCC2 blower con
trol and the blower / pump motor. The fuse is rated at 300
volts and 15 amps.

3− Pump (−1 through −4 units)

The O23, OHR23, and OF23 oil furnaces use a single
stage, 3450 RPM pump. A two stage pump is available
as an option (catalog # 65A44). The oil burner is shipped
from factory for use in a single line system. To convert the
pump to a two line system, install the bypass plug pro
vided in the attached bag according to the accompany
ing instructions.

4− Pump (−5 units only)

The O23, OHR23 and OF23−5 units all utilize the Cleancut
Fuel Unit manufactured by Becket. This pump uses a sole
noid valve to control the piston cut−on cut−off operation
instead of a cone valve and diaphram used by other con
ventional pumps. The solenoid works with the R7184B
Honeywell burner control to provide cut−on cut−off opera
tion while the burner motor is at full speed.

At startup the pump shaft is brought to full speed before the
solenoid is energized. At this time low pressure oil
(approximatley 20−25 psi) from the gearset 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 vavle 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.

Page 12

5−Burner Control (A3) & Transformer (T1)

−1 through −4 units

The burner control, along with the matching cad cell, proves
flame and controls the burner. After the cad cell closes a circuit
to the burner control, the burner control de−energizes the safe
ty switch heater to allow the unit to operate normally. The
burner control allows 45 seconds for the cad cell to close. If the
cad cell remains open after the 45 second time frame, the
burner control locks out. The burner control must be manually
reset by depressing the red reset button on top of the burner
control.

Transformer (T1) is part of the burner control. T1 provides
24VAC to the low voltage components in the unit and to the
thermostat.

6−Burner Control (A3) −5 units

All O 23, OHR23 and OF23 −5 units are equipped with a burn
er 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 5 for status codes. After the cad cell closes a circuit
to the burner control, the burner control de−energizes the safe
ty 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−
puge 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 manual re−set. After three
consecutive lockouts the control goes into restricted lockout.
Once flame is established after 10 seconds of run time, the ig
niiton shuts off.

If flame is lost during the heat cycle the control will shut
down the burner and begin a 60 second recycle delay. Af
ter 60 seconds the control repeats the ignition process. If
flame is lost three consecutive times during a single ther
mostat demand the control goas into restricted lockout.

Reset button

If the control lockouts 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 buner. The burner will re
main disabled as long as the reset button is held and return
to operational once the button is released.

TABLE 5

LED STATUS

On Flame sensed

Off Flame not sensed

Flashing

(1/2 sec on1/2 sec off)

Flashing

(2 sec on 2 sec off)

Lockout /

Restricted Lockout

Recycle

7−Heat Shutoff Relay (K125)

−1 and −2 units only

Heat shutoff relay K125 is a SPST N.O. relay, with a 24V
coil. K125 is located on the vestibule and wired in series
with the burner. When secondary limit S21 or primary limit
S10 open, the circuit breaks opening K125 contacts which
in turn de−energizes the burner.

8−Cad Cell (R26)

Together the cad cell and the burner control prove flame.
The cad cell senses the presence of burner light (less re
sistance) to close a circuit to the burner control.

IMPORTANT−Burner should not be installed so it is ex
posed to direct sunlight or electric bulb light. If the cell
is exposed to light on start up, the burner will not oper
ate.

O23, OHR23 & OF23 −5 Units Only

Resistance for the cad cell can be checked while the burn
er is firing and after ignition is off. Press (1/2 second or
less) and release the reset button. The LED will flash 1 to 4
times depending on the cad cell resistance. The cad cell
resistance should read less than 1600 Ohms. See table 6.

O23, OHR23 & OF23 −5 UNITS

LED FLASHES RESISTANCE

1 0 − 400Ohms

2 400 − 800 Ohms

3 800 − 1600 Ohms

4

TABLE 6

 1600 Ohms

Page 13

9−Electronic Ignitor (A73)

The electronic ignitor provides the needed hot spark at the
electrodes to ignite the fuel mixture. The ignitor is a solid
state transformer . O23, OHR23 and OF23−1 through −4
units have 115V primary and 14,000V secondary wind
ings. O23, OHR23 and OF23−5 units have 120V primary
and 20,000V secondary windings. The center of the sec
ondary winding is grounded. Each secondary terminal is
7000V to ground and the total voltage between the elec
trodes is 14,000V.

NOTE−The leads for the solid state transformer are re
placeable and are available in a kit form.

NOTE−When testing the solid state transformer, do not
use a transformer tester designed for iron magnet trans
formers. Damage to the tester may result.

Testing the Ignitor

WARNING

SHOCK HAZARD
Do not touch ignitor or any metal touching ignitor
when ignitor is energized. Can result in serious per
sonal injury.

10−Gun Assembly

The gun assembly receives oil from the oil pump and feeds
it to the nozzle. The nozzle converts liquid oil into a fog−like
mist that is discharged through the flame retention head
into the combustion chamber.

11−Flame Retention Heads

The stainless steel flame retention head (see figure 11)
is used to swirl (cone) the foglike oil and air mixture as it
enters the combustion chamber. Three different heads
are used in the O23/OHR23/OF23. The firing rate dic
tates which head is used. See table 4. The greater the
FB number the larger the slots on the head. When com
bustion takes place, the flame will be cylindrical com
pact shaped as a result.

FLAME RETENTION HEAD

FB3 SHOWN

If the ignitor fails it will not produce a spark. Looking and
listening for the arc is a simple way to check. The most sure
way is to perform the screwdriver check. By placing the
blade of an insulated screwdrivere across the ignitor termi
nal leads will test for an arc. First, remove power from the
burner and disconnect the oil supply from nozzle. The cad
cell will not let the control energize the ignitor if the cad cell
senses light. Therefore remove one lead of the cad cell
from the burner control, or remove the cad cell all together
(do not forget to put back when test is complete). Place the
screwdriver blade across the terminals and slowly raise
one end of the blade off the terminal while the other re
mains in contact with the other terminal. There should be
an arc from terminal to the blade up to 3/4" away. If not re
place the ignitor. If an arc is present then place one end of
the screwdriver on one terminal and the other end with the
grounded baseplate. Raise the blade from the baseplate
and draw an arc. Repeat with the other terminal. If the arc
from the baseplate to one terminal is weaker than the arc
from the baseplate to the other terminal, replace the ignitor.

FIGURE 11

C−Primary Limit Control (S10)

The primary limit on all O23, OHR23, and OF23 units, is
located on the vestibule panel (see figures 1 through 3 for
location and figure 12 for type). When excess heat is
sensed in the heat exchanger, the limit will open. If the limit
is tripped, the blower control deenergizes the thermostat,
in turn shutting down the unit. The limit automatically re
sets when unit temperature returns to normal. The switch is
factory set and cannot be adjusted. The switch has a different
setpoint for each unit model number (see table 7). The set
point is printed on the face plate of the limit.

Page 14

TABLE 7

PRIMARY LIMIT CONTROL (S10)

UNIT

ACTUATES

ON TEMP. RISE

O23Q2−70 210F (99C) 180F (82C)

O23Q3−105/120 220F (104C) 190F (88C)

O23Q5−140/154 210F (99C) 180F (82C)

OHR23Q3−105/120 240F (116C) 210F (99C)

OHR23Q5−140/154 190F (88C) 160F (71C)

OF23Q3−105/120

OF23Q3−105/120R

OF23Q5−140/154

OF23Q5−140/154R

SPADE CONNECTORS

240F (116C) 210F (99C)

210F (99C) 180F (82C)

LIMIT CONTROL (S10)

INSULATING COVER

ACTUATES

ON TEMP. FALL

LIMIT

1.Blower Motor (B3) and Capacitor (C4)

All O23, OHR23, and OF23 series units use single phase
direct drive blower motors. All motors used are 115V perma
nent split capacitor motors to ensure maximum efficiency.
See SPECIFICATIONS tables for horsepower and motor
nameplate for capacitor rating.The blower motor is con
nected to the blower control board via the blower motor
plug P43.

2.Secondary Limit Control (S21)

The secondary limit (S21) is used on the OHR23 series unit
only. The N.C. limit is mounted on the side and toward the
back of the blower housing. See figure 13 for location and fig
ure 14 for type. When excess heat is sensed in the blower
compartment, the limit will open. If the limit is tripped, the blow
er control deenergizes the thermostat, inturn shutting down
the unit. The limit automatically resets when unit tempera
ture returns to normal. The switch opens at 150F + 5F
(65.5C + 2.8C) on a temperature rise and resets at
140F + 5F (60.0C + 2.8C) on a temperature fall. The
switch is factory set and cannot be adjusted. The set
point is printed on the face plate of the limit.

FIGURE 12

D−Blower Compartment (Figure 13)

Blower motor (B3), capacitor (C4), and secondary limit con
trol (S21) are located in the blower compartment. The blow
er compartment can be accessed by removing the blower
access panel.

BLOWER COMPARTMENT

(OHR23 SIDE VIEW SHOWN)

SECONDARY LIMIT

CONTROL (S21)

(OHR23 ONLY)

(BACK SIDE)

BLOWER

MOTOR

CAPACITOR

(C4)

SECONDARY LIMIT CONTROL (S21)

FIGURE 14

E−Optional Accessories

Optional accessories are available from Lennox for the O23,
OHR23, and OF23 series units. Some accessories are in kit
form which come with instructions.

1.Low Speed On − Off Switch (S68)

The low speed on  off switch is a kit (catalog # 67H91) which
permits continuous low speed blower operation. The switch is
a DPDT toggle switch.

FIGURE 13

BLOWER MOTOR

(B3)

2.Economizer Relay (K43)

The economizer relay (catalog # 65G40) is used to energize
the economizer if used. The relay is a 120V coil, single pole
contact which is energized by the accessory terminal of the
blower control board.

Page 15

II−PLACEMENT AND INSTALLATION

g

Make sure unit is installed in accordance with installation in
structions and applicable codes.

A−Piping

The piping system and it’s components (oil filter, safety valves,
shutoff valves, etc.) must be designed to provide clean, air
free fuel to the burner.

An oil filter is required for all models. Use an oil filter of gener
ous capacity for all installations. Install filter inside the building
between the tank shut−off valve and the burner. Locate filter
close to burner for easy servicing. The GAR−Ber 11BV−R or
equivalent filter (with the below specifications) is recom
mended.

Fill

Pipe

Air Vent

OIL PIPING

ONEPIPE SYSTEM

Fuel
Unit

Oil

Tank

Shut−off

Valve

Aux

Filter

8 ft (2.4 m)

Maximum

One Pipe Lift

Maximum Firing Rate: 10GPH (38LPH)

Micron Removal: 10

Filtering Area: 500 in.2 (3225.8 cm2)

Working Pressure: 15 PSI (103.4 kPa)

Inlet/Outlet Dimension: 3/8" (9.5 mm) NPT

Flow Rate: 45GPH (171LPH)

Care must be taken to ensure the restriction of the piping sys
tem, plus any lift involved, does not exceed the capabili
ty of the oil pump. Each installation will be different. Use
the following guide lines when determining to use a single or
two stage pump.

When using a single pipe system with the fuel supply level
with or above the burner (see figure 15) and a vacuum of 6"
(152 mm) Hg or below, a single stage fuel unit with a supply
line and no return line should be adequate. Manual bleeding of
the fuel unit is required on initial start up. Failure to bleed air
from the pump could result in an air lock/oil starvation condi
tion.

NOTE−As an extra precaution, cycle heating on and off
ten times after bleeding air from the pump. This will elim
inate air in the gun assembly.

When using a two pipe system with the fuel supply level
below the level of the burner (see figure 16) a single
stage fuel unit should be used in lift conditions of up to
10 feet (3 m) and/or a vacuum of 10" (254 mm) Hg or be
low. A two stage fuel unit should be used when lift ex
ceeds 10 feet (3 m) and/or a vacuum of 10" (254 mm) Hg
to 15" (381 mm) Hg. Both conditions require the use of a re
turn line that purges the fuel unit of air by returning it to the fuel
tank. Use table 8 when determining the run and lift for piping.

Before converting a onepipe system to a twopipe sys
tem the pump must be converted to a twopipe system.
To convert the pump, install the bypass plug according
to the instructions. Notice in the twopipe system the re
turn line must terminate 3" (76 mm) to 4" (102 mm)
above the supply inlet. Failure to do this may introduce
air into the system and could result in loss of prime.

NOTE−If using an outside tank in cold climates a number one
fuel or an oil treatment is strongly recommended.

Page 16

FIGURE 15

OIL PIPING

TWOPIPE SYSTEM

Air Vent

Fill

Pipe

Return

Line

Oil

Tank

3"−4"

Return

Line

OUTSIDE TANK FUEL UNIT ABOVE BOTTOM OF TANK.

(76mm −102mm)

R

FIGURE 16

TABLE 8

Fuel
Unit

Aux

Filter

Inlet

H

TWO−PIPE MAXIMUM LINE LENGTH (H + R)

3450 RPM − 3 GPH (11.4 LPH)

Lift H"

Figure 15

0’

(0.0 m)

2’

(0.6 m)

4’

(1.2m)

6’

(1.8m)

8’

(2.4m)

10’

(3.0m)

12’

(3.7m)

14’

(4.3m)

16’

(4.9m)

18’

(5.5m)

3/8" (10 mm) OD

Tubing

Single

Stage

84’

(25.6 m)

73’

(22.3 m)

63’

(19.2 m)

52’

(15.8 m)

42’

(12.8 m)

31’

(9.4 m)

21’

(6.4 m)

−−−

−−−

Two

Stage

93’

(28.3 m)

85’

(25.9 m)

77’

(23.5 m)

69’

(21.0 m)

60’

(18.3 m)

52’

(15.9 m)

44’

(13.4 m)

36’

(11.0 m)

27’

(8.2 m)

−−− −−− −−−

1/2" (12 mm) OD

Tubing

Single

Stage

Stage

100’

(30.5 m)

(30.5 m)

100’

(30.5 m)

(30.5 m)

100’

(30.5 m)

(30.5 m)

100’

(30.5 m)

(30.5 m)

100’

(30.5 m)

(30.5 m)

100’

(30.5 m)

(30.5 m)

83’

(25.3 m)

(30.5 m)

41’

(12.5 m)

−−−

(30.5 m)

(30.5 m)

(23.2 m)

Two

100’

100’

100’

100’

100’

100’

100’

100’

100’

76’

B−Venting Considerations

2− The vent connector should be as short as possible to

do the job.

WARNING

Combustion air openings in front of the furnace
must be kept free of obstructions. Any obstruction
will cause improper burner operation and may re
sult in a fire hazard or injury.

WARNING

The barometric shall be in the same atmospheric
pressure zone as the combustion air inlet to the
furnace. Deviation from this practice will cause im
proper burner operation and may result in a fire
hazard or injury.

CAUTION

Do not store combustible materials near the fur
nace or supply air ducts. The material (such as
paint, motor oil, gasoline, paint thinner, etc.) may
ignite by spontaneous combustion creating a fire
hazard.

3− The vent connector should not be smaller than the

outlet diameter of the vent outlet of the furnace.

4− Pipe should be at least 24 gauge galvanized.

5− Single wall vent pipe should not run outside or through

any unconditioned space.

6− Chimney should extend 3 feet (0.9 m) above the high

est point where the vent passes through the roof, and 2
feet (0.6 m) higher than any portion of a building within
a horizontal distance of 10 feet (3 m).

7− The vent must not pass through a floor or ceiling. Clear

ances to single wall vent pipe should be no less than 6"
(152 mm); more if local codes require it.

8− The vent may pass through a wall where provisions have

been made for a thimble as specified in the Standards of
the National Board of Fire Underwriters. See figure 17.

9− The vent pipe should slope upward toward the chim

ney on horizontal run at least 1/4 inch (6 mm) to the
foot (0.3 m) and should be supported by something
other than the furnace, such as isolation hangers. See
figure 18.

WARNING

This furnace is certified for use with type L" vent.
B" vent must not be used with oil furnaces.

NOTE−Oil burning equipment may be vented into an ap
proved masonry chimney or type L vent. (Type L vent is
similar in construction to type B gas vent except it carries a
higher temperature rating and is constructed with an inner
liner of stainless steel rather than aluminum).

Prior to installation of unit, make a thorough inspection of the
chimney to determine whether repairs are necessary. Make
sure the chimney is properly constructed and sized accord
ing to the requirements of the National Fire Protection Asso
ciation. The smallest dimensions of the chimney should be
at least equal to the diameter of the furnace vent connector.
Make sure the chimney will produce a steady draft sufficient
to remove all the products of combustion from the furnace.
A draft of at least .04" w.c. (9.9 Pa) is required during burner
operation.

1− Local building codes may have more stringent instal

lation requirements and should be consulted before
installation of unit.

10− Extend the vent pipe into the chimney so that it is flush

with the inside of the vent liner. Seal the joint between
the pipe and the liner.

11− The furnace shall be connected to a factory built

chimney or vent complying with a recognized stan
dard, or masonry or concrete chimney lined with a
lining material acceptable to the authority having
jurisdiction.

WALL THIMBLE

THIMBLE

COMBUSTIBLE

WALL

VENT PIPE

FIGURE 17

Page 17

BAROMETRIC

CONTROL*
(IN EITHER
LOCATION)

CLEANOUT

*Barometric control may be installed in either vertical or horizontal
section of vent pipe within 18" (457 mm) of vent outlet of furnace.

LINER

CLEANOUT

MASONRY

CHIMNEY

FIGURE 18

12− When two or more appliances vent into a common vent,

the area of the common vent should not be less than the
area of the largest vent or vent connection plus 50% of
the areas of the additional vent or vent connection. Chim
ney must be able to sufficiently vent all appliances oper
ating at the same time.

13− The vent pipe shall not be connected to a chimney vent

serving a solid fuel appliance or any mechanical draft
system.

14− All unused chimney openings should be closed.

15− All vent pipe run through unconditioned areas or outside

shall be constructed of factory built chimney sections.
See figure 19.

16− Where condensation of vent gas is apparent, the vent

should be repaired or replaced. Accumulation of con
densation in the vent is unacceptable.

FACTORY−BUILT CHIMNEY

MASONRY CHIMNEY

17− Vent connectors serving this appliance shall not be

connected into any portion of mechanical draft sys
tems operating under positive pressure.

18− Keep the area around the vent terminal free of snow,

ice and debris.

NOTE−If vent pipe needs to exit from side of cabinet, use the
cross hairs (located on either side of the unit) to cut a 6" (152
mm) round hole. Attach finishing plate (provided) with four
sheet metal screws to cover rough edges.

Combustion and Ventilation Air
(Confined and Unconfined Spaces)

Until recently, there was no problem in bringing in suffi
cient amounts of outdoor air for combustion −− infiltration
provided all the air that was needed and then some. In
today’s homes built with energy conservation in mind,
tight construction practices make it necessary to bring in
air from outside for combustion. Consideration must also be
given to the use of exhaust fans, appliance vents, chimneys
and fireplaces because they force additional air that could
be used for combustion out of the house. Unless outside
air is brought into the home for combustion, negative
pressure (pressure outside is greater than inside pres
sure) will build to the point that a down draft can occur in
the furnace vent pipe or chimney. Combustion gases e n ter
the living space creating a potentially dangerous situa
tion.

The importance of the previous paragraph cannot be
overstated. Users may inadvertently block fresh air in
takes after installation.

In the absence of local codes concerning air for combus
tion and ventilation, the following section outlines guide
lines and recommends procedures for operating oil fur
naces in a manner that ensures efficient and safe
operation. Special consideration must be given to com
bustion air needs as well as requirements for exhaust vents
and oil piping.

Combustion Air Requirements

BAROMETRIC

CONTROL*
(IN EITHER
LOCATION)

*Barometric control may be installed in either vertical or horizontal
section of vent pipe within 18" (457 mm) of vent outlet of furnace.

FIGURE 19

FACTORY

BUILT

CHIMNEY

CAUTION

Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also
cause excess water in the heat exchanger result
ing in rusting and premature heat exchanger fail
ure. It can also cause property damage.

All oil−fired appliances require air to be used for the com
bustion process. If sufficient amounts of combustion air are not
available, the furnace or other appliance will operate in an inef
ficient and unsafe manner. Enough air must be provided to
meet the needs of all fuel−burning appliances, as well as ap
pliances such as exhaust fans which force air out of the home.
When fireplaces, exhaust fans, or clothes dryers are used at
the same time as the furnace, much more air is required
to ensure proper combustion and to prevent a down−
draft situation. Insufficient amounts of air also cause in

Page 18

comp l ete combustion which can result in sooting. Require
ments for providing air for combustion and ventilation depend
largely on whether the furnace is installed in an uncon
fined or confined space.

Unconfined Space

CHIMNEY OR

OIL VENT

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM INSIDE

An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cu
bic feet (1.4 cubic meters) per 1,000 Btu (293 W) per
hour of the combined input rating of all appliances
installed in that space. This space also includes adjacent
rooms which are not separated by a door. Though an area
may appear to be unconfined, it might be necessary to bring in
outdoor air for combustion if the structure does not provide
enough air by infiltration. If the furnace is located in a
building of tight construction with weather stripping and
caulking around the windows and doors, follow the proce
dures outlined for using air from the outside for combus
tion and ventilation.

Confined Space

A confined space is an area with volume less than 50 cu
bic feet (1.4 cubic meters) per 1,000 Btu (293 W) per
hour of the combined input rating of all appliances
installed in that space. This definition includes furnace closets
or small equipment rooms.

When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space con
taining the furnace, the return air must be handled by ducts
which are sealed to the furnace casing and which terminate
outside the space containing the furnace. This is especially
important when the furnace is mounted on a platform in a con
fined space such as a closet or small equipment room. Even a
small leak around the base of the unit at the platform or at the
return air duct connection can cause a potentially dangerous
negative pressure condition. Air for combustion and ventilation
can be brought into the confined space either from inside the
building or from outside.

Air from an Adjacent Space

If the confined space housing the furnace adjoins space
categorized as unconfined, air can be brought in by pro
viding two permanent openings between the two
spaces. Each opening must have a minimum free area
of 1 square inch (6.4 square centimeters) per 1,000 Btu
(293 W) per hour of the total input rating of all fuel−fired
equipment in the confined space. Each opening must
be at least 100 square inches (614.5 square centime
ters). One opening shall be within 12" (305 mm) of the
top of the enclosure and one opening within 12" (305
mm) of the bottom (See figure 20).

OIL

FURNACE

NOTE−Each opening shall have a free area of at least 1 square inch
(6.4 square centimeters) per 1,000 Btu (293 W) per hour of the total
input rating of all equipment in the enclosure, but not less than 100
square inches (614.5 square centimeters).

WATER

HEATER

OPENINGS

(To Adjacent Room)

FIGURE 20

Air from Outside

If air from outside is brought in for combustion and ven
tilation, the confined space shall be provided with two
permanent openings. One opening shall be within 12"
(305 mm) of the top of the enclosure and one within 12"
(305 mm) of the bottom. These openings must communicate
directly or by ducts with the outdoors or spaces (crawl or attic)
that freely communicate with the outdoors or indirectly
through vertical ducts. Each opening shall have a minimum
free area of 1 square inch (6.4 square centimeters) per 4,000
Btu (1172 W) per hour of total input rating of all equipment in
the enclosure (See figures 21 and 22). When communicating
with the outdoors through horizontal ducts, each opening
shall have a minimum free area of 1 square inch (6.4
square centimeters) per 2,000 Btu (586 W) per total input
rating of all equipment in the enclosure (See figure 23).

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

(Inlet Air from Crawl Space and

Outlet Air to Ventilated Attic)

CHIMNEY

OR OIL

VENT

VENTILATION LOUVERS

(Each end of attic)

OIL

FURNACE

VENTILATION

LOUVERS

(For unheated

crawl space)

NOTE−The inlet and outlet air openings shall each have a free area of
at least one square inch (6.4 square centimeters) per 4,000 Btu (1172
W) per hour of the total input rating of all equipment in the enclosure.

OUTLET

AIR

WATER

HEATER

INLET

AIR

FIGURE 21

Page 19

CHIMNEY

OR OIL

VENT

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

(All Air Through Ventilated Attic)

VENTILATION LOUVERS

(Each end of attic)

OUTLET

AIR

CAUTION

Combustion air openings in the front of the furnace
must be kept free of obstructions. Any obstruction
will cause improper burner operation and may result
in a fire hazard or injury.

OIL

FURNACE

NOTE−The inlet and outlet air openings shall each have a free area of at
least one square inch (6.4 square centimeters) per 4,000 Btu (1172 W)
per hour of the total input rating of all equipment in the enclosure.

INLET AIR

(Ends 12" above

bottom)

WATER

HEATER

FIGURE 22

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

CHIMNEY

OR OIL

OIL

FURNACE

VENT

WATER

HEATER

OUTLET AIR

CAUTION

The barometric shall be in the same atmospheric
pressure zone as the combustion air inlet to the
furnace. Deviation from this practice will cause
improper burner operation and may result in a fire
hazard or injury.

Direct Connection of Outdoor Air for Combustion

The Beckett AFII burner was designed to allow for direct air
intake piping (4" [102 mm]). The maximum equivalent
length of pipe is 70 feet (21.3 m). A 90 elbow equals
6feet (1.8 m).

To convert the AFII burner from confined space to out
side combustion air, simply remove the three screws at
taching the inlet air scoop to the burner and insert 4"
(102 mm) direct air intake piping.

The use of a barometric relief placed in the intake pipe is
recommended when outdoor combustion air is directly
connected to the burner. This will allow confined space
air to be used as combustion air in the event that the
opening to the outdoor air becomes blocked. Using a
barometric relief in the intake will reduce the chance of
sooting.

INLET AIR

NOTE−Each air duct opening shall have a free area of at least one
square inch (6.4 square centimeters) per 2,000 Btu (586 W) per hour
of the total input rating of all equipment in the enclosure. If the equip
ment room is located against an outside wall and the air openings
communicate directly with the outdoors, each opening shall have a
free area of at least one square inch (6.4 square centimeters) per
4,000 Btu (1172 W) per hour of the total input rating of all other equip
ment in the enclosure.

FIGURE 23

When ducts are used, they shall be of the same cross−sec
tional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3" (76 mm). In calculating free area, the
blocking effect of louvers, grilles, or screens must be con
sidered. If the design and free area of protective covering is
not known for calculating the size opening required, it may
be assumed that wood louvers will have 20 to 25 per
cent free area and metal louvers and grilles will have 60
to 75 percent free area. Louvers and grilles must be
fixed in the open position or interlocked with the equip
ment so that they are opened automatically during equip
ment operation.

CAUTION

DO NOT USE a barometric draft relief in exhaust
vent pipe if outdoor combustion air is connected
directly to the burner. The only exception are baro
metric draft reliefs as required by FIELD or TJERN
LUND power vents.

Removal of Unit from Common Venting System

In the event that an existing furnace is removed from a venting
system commonly run with separate appliances, the venting
system is likely to be too large to properly vent the remaining
attached appliances. The following test should be conducted
while each appliance is in operation and the o t her a p
pliances not in operation remain connected to the com
mon venting system. If venting system has been installed
improperly, the system must be corrected as outlined in the
previous section.

1− Seal any unused openings in the common venting sys

tem.

2− Visually inspect venting system for proper size and hori

zontal pitch and determine there is no blockage or restric
tion, leakage, corrosion or other deficiencies which could
cause an unsafe condition.

Page 20

3− Insofar as is practical, close all building doors and

windows and all doors between the space in which
the appliances remaining connected to the com
mon venting system are located and other spaces of
the building. Turn on clothes dryers and any ap
pliances not connected to the common venting sys
tem. Turn on any exhaust fans, such as range hoods
and bathroom exhausts, so they will operate at maxi
mum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.

4− Following the lighting instruction on the unit, place the

appliance being inspected in operation. Adjust thermo
stat so appliance will operate continuously.

5− Test for spillage using a draft gauge.

6− After it has been determined that each appliance re

maining connected to the common venting system
properly vents when tested as outlined above, return
doors, windows, exhaust fans, fireplace dampers and
any other fuel burning appliance to their previous condi
tion of use.

7− If improper venting is observed during any of the

above tests, the common venting system must be
corrected.

Horizontal Venting

(152 mm) is permissible. Calculate the equivalent vent pipe
footage from the furnace to the mechanical vent system
(Tjernlund or Field Controls) by adding the straight vent pipe
length and the equivalent elbow lengths together.

The barometric draft control must be used in horizontal (side
wall) venting system. It must be located within 18" (457 mm) of
the furnace vent outlet. See figure 24 for barometric draft con
trol location.

III−STARTUP

A−Preliminary and Seasonal Checks

1− Inspect electrical wiring, both field and factory installed

for loose connections. Tighten as required.

2− Check line voltage. Voltage must be within range

listed on the nameplate. If not, consult the power
company and have voltage condition corrected be
fore starting unit.

B−Heating StartUp

FOR YOUR SAFETY READ BEFORE LIGHTING

WARNING

Do not attempt to start the burner when excess
oil has accumulated in the chamber, when the
furnace is full of vapor or when the combus
tion chamber is very hot.

HORIZONTAL VENTING

BAROMETRIC

CONTROL*

*When using indoor air,

barometric control must be

installed in the horizontal

venting system and located

within 18" (457 mm) of vent

When using direct connection,

barometric control must be

installed in the intake air pipe.

CONTROL FOR

HORIZONTAL

VENTING

outlet of furnace.

FIGURE 24

The O23 is approved for horizontal venting with the fol
lowing mechanical vent systems:
Tjernlund (sideshot) #SS1C and Field Controls #SWG−5 with
the CK−61 control kit. Refer to manufacturers’ installation
instructions for proper installation procedures and service
parts information.

Do not common vent with any other appliance when using
sidewall vent system.

Maximum permissible vent length is 70 equivalent feet (21.3
m). Minimum length is 15 equivalent feet (4.6 m). Each 90
elbow is equal to 6 feet (1.8 m) of straight pipe, each 45 el
bow is equal to 3 feet (0.9 m) of straight pipe. Minimum vent
pipe diameter is 4" (102 mm). Vent pipe of 5" (127 mm) and 6"

1− Set thermostat for heating demand.

2− Turn on electrical supply to unit and open all shutoff

valves in the oil supply line to the burner..

3− Check air adjustment dial on the right side of the burn

er (see figure 9). Set according to table 4.

4− On single line applications the oil pump must be

primed by bleeding the oil line. Open air bleed port and
start burner. A hose may be attached to direct oil into a
container. After last bubble is seen, bleed pump for 15
seconds. Hurried bleeding will impair efficient unit op
eration. Close port to stop bleeding. Single line instal
lations must be absolutely air tight to prevent leaks or
loss of prime.

5− If burner stops after flame is established, repeat the

bleeding procedure.

NOTE−Air bleeding is automatic on two line applica
tions; however, opening air bleed port will allow a faster
bleed. Run return line back to tank and terminate three to
four inches above the inlet line. Failure to bleed the sys
tem may cause air to be introduced into the system result
ing in a loss of prime.

6− If the burner does not start immediately, check the

safety switch on the burner primary control.

7− If burner fails to light again, refer to the trouble

shooting section in the back of this manual.

8− Proceed to section IV to complete start up.

C−Safety or Emergency Shutdown

Turn off unit power. Close all shutoff valves in the oil sup
ply line.

Page 21

D−Extended Period Shutdown

Turn off thermostat or set to UNOCCUPIED" mode.
Close all shutoff valves in the oil supply line to guarantee no
oil leaks into burner. Turn off all power to unit. All access
panels, covers and vent caps must be in place and se
cured.

To check that the nozzle is approximately centered with
the head inside diameter, align the center mark of the
gauge with the center of the nozzle orifice, as shown in
figure 27, and move the gauge from side to side at sev
eral points. Be careful not to scratch the nozzle sur

face.

IV−HEATING SYSTEM SERVICE CHECKS

A−Oil Piping

All oil supply piping (factory and field) must be carefully
checked for oil leaks.

B−Electrode Adjustment

When adjusting the electrode, use the AFII multipurpose
gauge (Beckett part # T−500) packaged with each oil fur
nace, also available from Beckett.

To set the electrode tip gap spacing, position the gauge as
shown in figure 25. Align the center mark with the nozzle
and adjust the electrodes to the two outer marks (1/8"
[3mm] to 1/16" [2mm] minimum).

AFII ELECTRODE TIP

GAP

The Z" or zero dimension is important because it locates the
nozzle for the precise relationship with the combustion head.
To set the Z" dimension, position the gauge as shown in fig
ure 27 and loosen the nozzle line electrode assembly so that
it can be moved forward or backward in the air tube until the
nozzle becomes flush against the gauge. Tighten the nozzle
line escutcheon plate screw (shown in figure 9) to lock this
Z" dimension securely.

AFII NOZZLE CENTERING

FIGURE 25

To position the electrode tips beyond the face of the nozzle
and above the center line, position the gauge as shown in
figure 26. Align the center mark with the nozzle and adjust
the electrodes to the AC cross marks.

AFII ELECTRODE POSITIONING

FIGURE 26

FIGURE 27

C−Pressure Check

On −1 through −4 units use either the gauge port or
nozzle port to check operating pressure. On −5 units use
the nozzle port (−5 unit pumps are not equipped with
gauge port). The pump is factory set at 100 psig (689.5
kPa) for the O23Q2−70 and 140 psig (965.3 kPa) for all
other O23, OHR23, and OF23 units but is adjustable (see fig
ure 28). Never operate the pump in excess of 10 ps ig (6 9
kPa) above set point. Average nozzle cutoff pressure is
80 psig (551.6 kPa). To check the cutoff pressure install
a pressure gauge in nozzle port. For −5 units use the
same gauge used for operating pressure. Run the burn

Page 22

er for a short period and then turn off. The gauge shows
cutoff pressure.

OIL PUMP PRESSURE CHECK

*PRESSURE GAUGE

**REGULATE PRESSURE

NOT SHOWN

(beside the inlet port)

PRESSURE

GAUGE

PORT (1/8" [3mm])

NOZZLE PORT

(1/8" [3mm])

INLET PORT

(1/4" [6mm])

*PRESSURE CHECKS: NORMAL OPERATING PRESSURE IS
100 PSIG (689.5 kPa) FOR THE 023Q270 AND 140 PSIG (965.3 kPa)
FOR ALL OTHER O23, OHR23, AND OF23 UNITS. NOZZLE CUTOFF
PRESSURE IS APPROXIMATELY 80 PSIG (551.6 kPa).

**TO ADJUST PRESSURE: INSERT STANDARD SCREWDRIVER.
TURN COUNTERCLOCKWISE BELOW DESIRED PRESSURE,
THEN TURN CLOCKWISE TO SET DESIRED PRESSURE.

RETURN PORT

(1/4" [6mm])

INLET PORT

SHOWN (1/4" [6mm])

BLEED PORT

1/16" (2mm) BYPASS PLUG

INSERT FOR TWOPIPE SYSTEM

(use 5/32" [4mm] allen wrench)

FIGURE 28

D−Burner Adjustment

The following instructions are essential to the proper opera
tion of O23 series oil furnaces. To prevent sooting, these in
structions must be followed in sequence:

NOTE−All w.c. measurements are below atmospheric
pressure (negative readings).

1−Draft

This test should be taken at the vent connector between
the breaching and the barometric damper. Generally a 1/4"
(6 mm) hole will need to be drilled for the draft gauge to be
inserted into the vent connector.

A minimum of 0.03" w.c. (7.5 Pa) draft must be estab
lished without the burner in operation. With the burner in
operation, the draft should be 0.04" w.c. (9.9 Pa) to 0.05"
w.c. (12.4 Pa). This is VERY critical to the flame retention
head burners.

Oil furnace installations also require careful inspection to
make sure the chimney is in good condition and can ac
commodate the products of combustion. The temperature
in unconditioned space will also affect the draft if long vent
connectors are allowed to get too cold.

2−Overfire Draft

This test should be taken with the burner in operation.
Remove the screw from the center of the center inspec
tion port. Insert your draft gauge into the hole.

A reading of the overfire draft should be 0.02" w.c. (5.0 Pa)
less than the reading found in the vent connector. If a posi
tive reading is seen at this point, the secondary heat ex
changer may be sooted or to much air may be entering
into the heat exchanger from the combustion fan. Adjust
ments to the combustion fan can be made using the air
adjustment dial.

3−Smoke Test

The smoke test should be taken at hole drilled in step 1.

Using a smoke test gun adjust the air inlet shutter so that
you will have just a trace of smoke. Somewhere be
tween a 0 and #1 smoke. This is the starting point. Do
not stop here. After the smoke test take a CO sample.
C.S.A. requires no more than 400ppm. However, a
properly installed unit under normal operating condi
tions should not read more than 50ppm.

4−CO2 Test

Again to be taken at the vent connector pipe. With the
unit firing at a trace of smoke, test for percentage of CO
in the vent gas.

From the results of this test, a window of operation" will be
determined. This window of operation establishes some tol
erance. The tolerance the installer builds in provides room
within the setup for those things which might affect com
bustion. Those things which might affect combustion can
then do so without causing the unit to start sooting/smoking.
Things which might affect combustion include a nozzle go
ing bad, draft that changes during different climatic condi
tions, dirty oil, dirt obstructing the air inlet, etc.

To build in a window of operation," set up the burner to be
2% less in CO2. For example, if you find a reading of 12%
CO2, adjust the air inlet shutter to increase the air and drop
the CO2 to 10%.

5−Retest the Smoke

With a drop in the CO2 and increase in the air you should
see that the smoke has returned to 0.

6−Retest the Overfire Draft

This test serves to confirm that you have not increased the air
too much. Again you do not want a positive pressure at the
test port. It should still be 0.02" w.c. (5.0 kPa) less than the
draft from the vent connector. You may need to increase the
stack draft by adjusting the barometric damper.

2

Page 23

7−Stack Temperature

Take a stack temperature reading in the vent connector pipe.
Subtract the room air temperature from the stack temperature.
This will give you the net stack temperature. Using efficiency
charts provided in most CO2 analyzers you can tell at what ef
ficiency the furnace is operating.

V−DISASSEMBLY PROCEDURES

Use the following procedures to access and disassemble the
burner or blower if service to either is needed.

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 discon
nect switch(es). Unit may have multiple
power supplies.

A−Disassembling Burner

The burner assembly is attached to the vestibule panel by
three nuts. Slots are provided in the mounting flange for
removing the burner assembly from the vestibule. By
loosening the nuts and by turning the whole burner as
sembly counterclockwise (figure 29), the entire burner as
sembly will come out of the furnace. There is adequate wire
to remove the burner without disconnecting wires. Once re
moved, just turn the burner around in the vest panel area.

NOTE−Before disassembling any part of the burner, turn
off power and oil supply to the burner.

BURNER REMOVAL

First, loosen three nuts which

attach burner to vest panel.

nuts

Next, rotate burner counterclockwise

on slots then pull toward you.

IGNITION TRANSFORMER

IGNITION

TRANSFORMER

SCREWS

SCREW TO OPEN

ACCESS DOOR

FIGURE 30

SCREWS

ACCESS

DOOR

2−Removing Cad Cell

1− Loosen the screw to the back access door until door

opens. See figures 30 and 31.

2− The cad cell will be located on the right side of the

chassis wall hung on a bracket. See figure 31.

3− Remove by loosening the screw on the bracket.

4− Disconnect the leads from the primary control termi

nal strip.

FIGURE 29

1−Removing Ignition Transformer

1− Remove all four screws located on the side of the

ignition transformer. See figure 30.

2− Lift the ignition transformer straight up. Do

not hinge back. Porcelain isolators may break if
hinged back.

NOTE−When testing the solid state transformer, do not
use a transformer tester designed for iron magnet trans
formers. Damage to the tester may result

CAD CELL

CAD CELL

SCREW

ACCESS

DOOR

FIGURE 31

Page 24

3−Removing Gun Assembly

1− Loosen the screw to the back access door until door

opens. See figures 30 and 31.

2− Remove flare fitting nut on oil line at pipe adjusting

plate located on outside of blower housing.

3− Remove nut connecting oil line to gun assembly oil

line. See figure 32.

4− Remove gun assembly from air tube.

5− Remove transformer leads.

NOTE−When reinstalling gun assembly, check and
set position and Z" dimension as shown in figure

27.

NOTE−When reconnecting gun assembly oil line, make
sure flat side of nut goes first.

5−Removing Motor / Combustion Air Blower

1− Disconnect supply line at pump and oil line at gun

assembly as shown in figure 33.

2− If motor and blower wheel are to be removed away

from the burner, disconnect motor wiring harness
from the primary control. If the motor and blower
wheel only need to be removed to check and clean,
there is adequate wire in the motor wiring harness
without disconnecting.

3− Loosen two bolts securing motor to blower hous

ing. Key hole slots are provided for easy removal.
See figure 34.

4− Loosen allen set screw holding the blower wheel

onto the motor shaft and remove blower wheel.

COMBUSTION AIR MOTOR & WHEEL

GUN ASSEMBLY

Remove

both nuts

Gun

Assembly

FIGURE 32

4−Removing Oil Pump

1− Disconnect supply line at pump and oil line at gun

assembly.

2− Loosen two bolts on sides of pump securing pump

to blower housing. See figure 33.

3− Detach pump and motor shaft coupler from pump.

OIL PUMP

OIL LINE GUN

ASSEMBLY ENTRANCE

SUPPLY LINE

INLET

BLOWER

MOTOR

BOLT

BOLT

PUMP

FIGURE 34

NOTE−When reinstalling blower wheel use the AFII mul
tipurpose gauge (Beckett part # T−500) to space the dis
tance from the back of the blower wheel to the face of the
motor (1/16" [2 mm]).

B−Removing Indoor Blower

1− Turn off electric power to furnace.

2− Remove blower access door.

3− Remove two screws located in the front blower rails. See

figure 35.

4− Pull blower forward enough to disconnect the motor leads

and the secondary limit on OHR units.

5− Pull blower assembly out and place to the side.

INDOOR BLOWER (OHR23 SHOWN)

BOLT BOLT

OIL PUMP MOTOR

FIGURE 33

Page 25

MOTOR LEADS

SCREW

SECONDARY

LIMIT

(OHR only)

SCREW

FIGURE 35

VI−TYPICAL OPERATING CHARACTERISTICS

Unit

Speeds

A−Blower Operation and Adjustment

NOTE− The following is a generalized procedure and
does not apply to all thermostat controls.

1− Blower operation is dependent on thermostat con

trol system.

2− Generally, blower operation is set at thermostat sub

base fan switch. With fan switch in ON position, blower
operates continuously. With fan switch in AUTO position,
blower cycles with demand.

3− In all cases, blower and entire unit will be off when line

voltage is disconnected.

B−Temperature Rise

Temperature rise for O23, OHR23, and OF23 units depends
on unit input, blower speed, blower horsepower and static
pressure. The blower speed must be set for unit operation
within the range of AIR TEMP. RISE °F" listed on the unit rat
ing plate.

To Measure Temperature Rise:

1. Place plenum thermometers in the supply and return air
plenums. Locate supply air thermometer in the first hori
zontal run of the plenum where it will not pick up radiant
heat from the heat exchanger.

2. Set thermostat to highest setting.

3. After plenum thermometers have reached their
highest and steadiest readings, subtract the two
readings. The difference should be in the range
listed on the unit rating plate. If the temperature is too low,
decrease blower speed. If temperature is too high in
crease blower speed to reduce temperature. To change
blower speed see Blower Speed section.

C−Blower Speed

Blower speed selection is accomplished by changing the
wires at the blower motor spade connector.

To Change Blower Speed

1− Turn off electric power to furnace.

2− Remove blower access door.

3− Remove two screws located in the front blower rails.

4− Pull blower assembly forward enough to disconnect the

motor leads.

5− Disconnect heating (red) and / or Cooling (black)

wire(s) from the motor. The common (white) wire al
ways remains on C = common.

6− Select the desired speed for heating and cooling

(H = high, M = medium, L = Low). Table 9 lists the
factory connections.

7− If cooling and heating speeds are to be the same

speed, disconnect and discard the cooling wire.
Jumper the A and H spade terminals on the BCC2 and
BCC3 board and jumper COOL to HEAT on the
ST9103A board. Run the heating terminal wire from
the BCC2, BCC3 and ST9103A board to the correct
spade connection on the blower motor.

8− To achieve low speed on continuous blower on the

ST9103A board, run a FIELD supplied wire (16 AWG
or larger) from blower motor low speed terminal to the
ST9103A CONT terminal.

TABLE 9

BLOWER SPEED SELECTION

Factory Connected

Speed Taps

Cool

(Black)

Q270 M L 3
Q3105/120 H M 3
Q5140/154 H M 3

Heat

(Red)

Speeds

Available

D−External Static Pressure

1. Measure tap locations as shown in figure 36.

2. Punch a 1/4" (6 mm) diam
eter hole in supply and re
turn air plenums. Insert
manometer hose flush with
inside edge of hole or in
sulation. Seal around the
hose with permagum. Con
nect the zero end of the ma
nometer to the discharge (supply) side of the sys
tem. On ducted systems, connect the other end of
manometer to the return duct as above. For systems
with non−ducted returns, leave the other end of the
manometer open to the atmosphere.

3. With only the blower motor running and the evapo
rator coil dry, observe the manometer reading. Ad
just blower motor speed to deliver the air desired
according to the job requirements.

4. Pressure drop must not exceed 0.5" W.C. (124.3 Pa).

5. Seal around the hole when the check is complete.

STATIC PRESSURE

TEST

MANOMETER

OIL UNIT

FIGURE 36

Page 26

VII−MAINTENANCE

CAUTION

Never operate unit with access panels to the
blower compartment off or partially open.

A−Filters

If throwaway type filters are used, check monthly and
replace when necessary to assure proper furnace op
eration. Replace filters with like kind and size.

If reusable type filters are used, check monthly and clean with
water and mild detergent when necessary. When dry, they
should be sprayed with filter handicoater prior to reinstallation.
Filter handicoater is RP Products coating no. 418 and is avail
able as Lennox part no. P85069.

B−Cleaning Heat Exchanger

NOTE−Use papers or protective covering in front of fur
nace while cleaning furnace.

Cleaning the heat exchanger is made easier with a heat
exchanger cleanout kit ABRSH380 (catalog # 35K09)
available from Lennox.

1− Remove vent pipe from furnace.
2− Remove locking screws and caps from cleanout

tubes. Remove vent access elbow.

3− Using a long spiral wire brush, sweep down the outer

drum of the heat exchanger. Then using the hose at
tachment, vacuum out loose debris.

4− Remove locking screw and cap from the observation

tube and with the spiral wire brush, reach upward to
ward the rear of the heat exchanger to clean out the
crossover tube.

NOTE− Do not attempt to clean the combustion chamber.
It can be easily damaged.

5− Replace the cleanout caps and vent access elbow.

Make sure locking screws are secure.

6− Brush out and vacuum the vent outlet area of the outer

drum and replace vent pipe.

7− Clean around the burner, blower deck and vestibule

area.

C−Annual Burner Maintenance

1− Replace the oil supply line filter.

2− Remove and clean the pump strainer if applicable.

3− Replace the nozzle with an equivalent nozzle.

4− Check the pump pressure when changing nozzle.

5− Clean and inspect the electrodes for damage, re

placing any that are cracked or chipped.

6− Clean the combustion head of all lint and soot.

7− Inspect the transformer cables and connectors.

8− Remove and clean the cad cell.

9− Clean the blower wheel and the air control of any lint.

10− Check all wiring for secure connections or insulation

breaks.

11− Readjust the burner as described in section IV of this

manual.

D−Supply Air Blower

1 Disconnect power to unit.

2 Check and clean blower wheel.

3 Motors are prelubricated for extended life; no further lu

brication is required.

E−Vent Pipe

The vent pipe should be inspected annually. Remove and
clean any soot or ash found in the vent pipe. Vent pipe dete
riorates from the inside out and must be disconnected in or
der to check thoroughly. Inspect pipe for holes or rusted
areas. Inspect the vent control device and replace if found
defective. Check for tightness and to make sure there is no
blockage or leaks.

F−Electrical

1 Check all wiring for loose connections.
2 Check for correct voltage at unit (unit operating).
3 Check ampdraw on blower motor.

Motor Nameplate_________Actual_________

4 Check to see that heat is operating.

Page 27

VIII−WIRING DIAGRAMS AND SEQUENCE OF OPERATIONS

2

7

4

1

6

10

4

81212

3

7

9

5

8

12

4

9

O23 / OHR23 / OF23−1 through −4 UNIT OPERATION SEQUENCE:

1. When disconnect is closed, 120V is routed to the blower
control board BCC2 (A15). The BCC2 feeds line voltage
to transformer (T1).

2. T1 supplies 24VAC to the burner control (A3). In turn, A3
supplies 24VAC to A15, which supplies the indoor ther
mostat (not shown) with 24VAC.

3. When there is a call for heat, W1 of the thermostat ener
gizes W of the A15 board with 24VAC.

4. A15 energizes combustion air blower relay (K13). When
K132 closes, assuming primary limit (S10) and [secon
dary limit (S21) in OHR units only] are closed, 24VAC is
routed to 1K, which closes 1K1 and 1K2. When 1K2
closes combustion air blower / pump (B6) is energized.
Simultaneously 24VAC is routed through the blower relay
(K36). When K361 closes blower motor (B6) is ener
gized on heating speed.

5. When 1K2 closes the electronic ignitor is energized
causing a 14,000VAC spark, igniting the burner. When
1K1 closes the solid state switch and cad cell are ener
gized. When the cad cell senses light the solid state
switch deenergizes the safety heater, keeping the burner
operating.

6. A15 energizes accessory relay (K109). When K1091
closes the accessory terminal on the A15 board is ener
gized with 120VAC.

7. When heat demand is satisfied, W1 of the thermostat
deenergizes W of the ignition control. W deenergizes
K13 in turn deenergizing 1K. When 1K is deener
gized B6 and A73 stop immediately. The indoor blower
runs for a designated fan off" period (90−330 seconds)
as set by jumper on BCC2 control.

8. When there is a call for cooling, Y1 of the thermostat ener
gizes Y and G of the A15 board with 24VAC.

9. A15 energizes blower relay K3. When K31 closes B3
starts on the speed set for cooling.

10. A15 energizes accessory relay K109. When K1091
closes the accessory terminal on the A15 board is ener
gized with 120VAC.

11.Provided that condensing unit is connected to Y ter
minal, cooling will start.

12. When cooling demand is satisfied, Y1 of the thermostat
deenergizes Y and G. The indoor blower and condensing
unit stops immediately.

Page 28

1

6

6

10

9

7

10

9

1

2

4

5

3

8

4

O23 / OHR23 / OF23−5 UNIT OPERATION SEQUENCE:

1. When disconnect is closed, 120V is routed to the blower
control board (A15). The blower control board feeds line
voltage to transformer (T1).

2. When there is a call for heat, W1 of the thermostat ener
gizes W of the A15 board with 24VAC.

3. A15 energizes combustion air inducer B6 assuming pri
mary limit (S10) and [secondary limit (S21) in OHR units
only] are closed.

4. Burner control A3 energizes the electronic ignitor caus
ing a 20,000VAC spark . Burner motor (B6) and pump
valve (L35) are delayed for a 15 second pre−purge. The
pre−purge is followed by a 15 second trial for ignition.

5. After the pre−purge and trial for ignition (30 seconds)
voltage passes through contactor K1 the energizing the
indoor blower B3 on heating speed.

6. When heat demand is satisfied, W1 of the thermostat
deenergizes W of the ignition control. Combustion air
inducer B6 is de−energized. The indoor blower runs for
a designated fan off" period (60−150 seconds) as set
delay switch on blower control.

7. When there is a call for cooling, Y1 of the thermostat ener
gizes Y and G of the A15 board with 24VAC.

8. A15 energizes relay K2. When K2 contacts close, the in
door blower B3 energizes on cooling speed.

9. When cooling demand is satisfied, Y1 of the thermostat
deenergizes Y and G. The indoor blower and condensing
unit stops immediately.

10. When there is a call for continuous fan the indoor blower
(B3) is energized on cool speed. If blower control board
is wired for continuous fan, the indoor blower will energize
on low speed and remain energized after thermostat de
mand is satisfied.

Page 29

1

3

2

TJERNLUND HORIZONTAL VENTING SYSTEM (SIDESHOT) OPERATION SEQUENCE:

1. When 1K2 closes, 120VAC is routed through the relay/timer, electronic ignitor (A73), and the limit switch.

2. The relay/timer energizes the venter motor.

3. After the venter motor establishes a draft, the N.O. fan proving switch closes completing the circuit to the burner motor.

1

2

3

FIELD CONTROL HORIZONTAL VENTING SYSTEM OPERATION SEQUENCE:

1. When 1K2 closes, 120VAC is routed through the relay.

2. The relay energizes the venter motor.

3. After the venter motor establishes a draft, the N.O. fan proving switch closes, completing the circuit to the burner motor and electronic ignitor (A73).

Page 30

IX−TROUBLESHOOTING

Burner failure or improper unit operation can be caused by various conditions. Often the problem can be solved by a logical pro
cess of checks and eliminations. The following pages lists a few common problems along with the solutions . Careful l y che c k
the most obvious items first before proceeding to more involved procedures.

COMMON CHIMNEY VENTING PROBLEMS

Problem: Top of chimney lower
than surrounding objects.
Solution:Extend chimney above
all objects within 10 feet
(3 meters).

Problem: Chimney cap or ventilator.
Solution: Remove.

Problem:Obstruction in chimney. Obstruction can be found by

light and mirror reflecting conditions in chimney.

Solution: Use weight to break and dislodge.

Problem: Joist projecting into chimney.

Can be found by lowering a light on an ex
tension cord.
Solution: Must be handled by a
competent brick contractor.

Problem: Break in chimney lining. Can be
found by Smoke testbuild smudge fire block
ing off other opening and watching for smoke
to escape.
Solution: Must be handled by a
competent brick contractor.

Problem: Collection of soot at narrow space in the
flue opening. Can be found by lowering light on
extension cord.

Problem: Clean out with weighted brush or bag of
loose gravel on end of line.

Problem: Loose−seated pipe in flue
opening. Detected by smoke test.
Solution: Leaks should be eliminated
by cementing all pipe openings.

Problem:Coping restricts opening.
Solution:Make opening as large as

inside of chimney.

Problem: Offset. Can be found
by lowering light on extension.
Solution: Change to straight or
long offset.

Problem: Two or more openings
into same chimney. Can be found
by inspection.
Solution: The least important
opening must be closed

FIRE

PLACE

DAMPER

FIREPLACE

Problem: Smoke pipe extends into chimney.
Detected by measurement of pipe from within or ob
servation of pipe by means of a lowered light.
Solution: Length of pipe must be reduced to allow end
of pipe to be flush with inside of tile.

Problem: Failure to extend the length of
the flue partition down to the floor. De
tected by inspection or smoke test.
Solution: Extend partition to floor level.

ASH DUMP

Problem:Loose fitting clean−out door.
Detected by smoke test.
Solution: Close all leaks with cement.

Page 31

START

BCC2 / BCC3

TROUBLESHOOTING

FLOWCHART

REPLACE

BCC2

NO

(REMOVE R & G JUMPER)

IS

120VAC ACROSS

N & ACC?

YES

JUMPER ACROSS

R &W

YES

YES

DOES UNIT

OPERATE?

NO

IS

24VAC ACROSS

R & C?

YES

JUMPER ACROSS

SCREWS R & G

IS

BLOWER

RUNNING ON HIGH

SPEED?

IS

UNIT LIT?

YES

NO

NO

NO

CHECK:
1−UNIT POWER
2−TRANSFORMER
3−LIMIT SWITCH

IS

120VAC ACROSS

N & A?

YES

CHECK BLOWER

WIRING AND

BLOWER

CHECK:
1−PRIMARY CONTROL
2−IGNITION TRANSFORMER
3−FUEL PUMP
4−ELECTRODES
5−LIMIT SWITCH(ES)

NO

REPLACE

BCC2

IS

120VAC ACROSS

N & ACC?

YES

REMOVE

R & W

JUMPER

AFTER

THE SELECTED

TIME, DOES THE

BLOWER TURN

OFF?

END OF TEST

NO

REPLACE

BCC2

YES

YES

IS BLOWER

RUNNING ON LOW

SPEED, 45 SEC.

AFTER FURNACE LIGHTS?

NO

REPLACE

BCC2

Page 32

NO

IS

120VAC ACROSS

N & H?

NO

IS

24VAC ACROSS

C & V?

NO

CHECK
WIRING

YES

CHECK BLOWER

WIRING AND

BLOWER

REPLACE

YES

BCC2

Troubelshooting: Blower Control ST9103A

Action System Response

Thermostat calls for heat.
(W terminal is energized.)

Thermostat ends call for heat.
(W terminal is de−energized.)

Burner fails to light. Oil primary control locks out within lockout timing (timing depends on oil primary control).

Established flame fails. Burner motor is de−energized and oil primary control goes into recycle mode.

Thermostat begins call for cool.
(G and Y terminals are energized.)

Thermostat ends call for cool.
(G and Y terminals are de−energized.)

Thermostat begins call for fan.
(G terminal is energized.)

Thermostat ends call for fan.
(G terminal is de−energized.)

ST9103A closes oil primary control T−T connections.

Ignition system and oil primary control start the furnace. Oil flows as long as oil primary
control senses flame.

Burner motor is energized and heat fan on delay timing begins. When timing is complete,
the circulating fan is energized at heat speed and warm air is delivered to the controlled
space.

Oil primary control is de−energized, terminating the burner cycle.

Heat fan off delay timing begins. When timing is complete, the circulating fan is de−ener
gized.

ST9103A returns to standby mode (oil primary control and circulating fan are off).

Burner motor is de−energized.

If heat fan has started, it continues through the selected delay off period.

If selected heat fan off delay is longer than the recycle delay timing, the heat fan contin
ues to run through the next trial for ignition.

Circulating fan is energized at the cool speed.

Cooling compressor turns on immediately.

Circulating fan and cooling compressor turn off immediately.

Circulating fan is energized immediately at cool speed.

ST9103A may be factory−configured to operate heat speed in this mode.

Circulating fan is de−energized.

Limit switch string opens. Oil primary control shut off the burner.

Circulating fan is energized immediately at heat speed.

ST9103A opens oil primary control T−T connections.

Circulating fan runs as long as limit string stays open.

If there is a call for cooling or fan, the circulating fan switches from heat speed to cool
speed.

Limit switch string closes. ST9103A begins heat fan off delay sequence.

Circulating fan turns off after the selected heat fan off delay timing.

ST9103A closes oil primary control T−T connections.

Oil primary control is energized, initiating burner light off.

Continuous circulating fan is connected.
(Optional connectors are available for separate circu
lating fan speed tap.)

Electronic air cleaner is connected.
(Optional connectors are available for 120 Vac elec
tronic air cleaner.)

Humidity control is connected.
(Optional connectors are available for 120 Vac humidi
fier.)

Circulating fan is energized at low speed when there is no call for heat, cool or fan.

If fan operation is required by a call for heat, cool, or fan, the ST9103A switches off the
continuous fan speed tap before energizing the other fan speed.

Electronic air cleaner (EAC) connections are energized when the heat or cool speed of
the circulating fan is energized. EAC connections are not energized when the optional
continuous fan terminal is energized.

Humidifier connections are energized when the burner motor is energized.

Page 33

Troubleshooting O23 / OHR23 / OF23 −1 through −4 Units

y

yy

Check f

t

Thermostat

mostat terminals on primary
fault is in the thermostat circuit

the burner starts, fault is in the

Pri

ili

l

indi

black

hite leads to th

p

blower wheel by hand. If seized,
power to the motor and burner

Burner fails to start.

Source Procedure Causes Correction

Thermostat in OFF or COOL Switch to HEAT.

Thermostat Check thermostat settings.

Check burner motor, primary

Safety Overloads

Power

CAD Cell

Primary Control

Burner

safety control, & auxiliary limit
switch.

urnace disconnec

switch & main disconnect.

Touch jumper wire across ther
mostat terminals on primary
control. If burner starts, then

Disconnect the flame detector
wires at the primary control. If

detector circuit.

Place trouble light between the
black and white leads. No light

cates that no power is going

to the control.

Place trouble light between the
orange and white leads. No light
indicates faulty control.

Place the trouble light between
the black and white leads to the
burner motor. No light indicates
that no power is getting to the
motor.

Place trouble light between the

and w

blower motor. Light indicates

ower to the motor and burner

fault.

e

Thermostat is set too low

Burner motor overload tripped Push reset button pump motor.

Primary control tripped on safe
ty

Auxiliary limit switch tripped on
safety

Open switch Close switch.

Blown fuse or tripped circuit
breaker

Broken or loose thermostat
wires

Loose thermostat screw con
nection

Dirty thermostat contacts Clean contacts.

.

Thermostat not level Level thermostat.

Faulty thermostat Replace thermostat.

Flame detector leads are
shorted

Flame detector exposed to light Seal off false source of light.

short circuit in the flame detec
tor

mary or aux

switch is open

Open circuit between discon
nect switch and limit control

Low line voltage or power fail
ure

Defective internal control circuit Replace the control.

Blown fuse Replace the fuse.

Binding burner blower wheel

Sized fuel pump

Defective burner motor Replace the motor.

ary contro

Turn thermostat to higher tem
perature.

Reset primary control.

Reset auxiliary limit.

Replace fuse or reset circuit
breaker.

Repair or replace wires.

Tighten connection.

Separate leads.

Replace detector.

Check adjustment. Set the
maximum setting.

Jumper terminals; if burner
starts, switch is faulty, replace
control.

Trace wiring and repair or re
place it.

Call the power company.

Turn off power and rotate the
blower wheel by hand. If seized,
free the wheel or replace the
fuel pump.

Page 34

Burner starts, but no flame is established.

pp

Oil Filters & Oil Line

S

ilk

Air leak i

pggpp

pray (g

serve the oil spray (gun assem

Inspect the nozzle for plugged
t
Cl

gap

the gap to 5/32 inches and cor

g

to transformer primary

pp

ing or excessive drag

Source Procedure Causes Correction

Check tank gauge or use dip
stick.

Oil Supply

Oil Filters & Oil Line

Oil Pump

Coat dip stick with litmus paste
and insert into bottom of tank.

Listen for pump whine. Tank shut−off valve closed Open valve.

Listen for pump whine.

Open bleed valve or gauge port.

tart the burner. No oil or m

oil indicates loss or prime.

Install pressure gauge on pump
and read pressure. Should not
be less than 140 psi.

y

No oil in tank Fill tank.

Water in oil tank

Oil line filter is plugged Replace filter cartridges.

Kinks or restriction in oil line Repair or replace oil line.

Plugged fuel pump strainer Clean strainer or replace pump.

n oil supply line

Pump is partially or completely
frozen. No pressure and the
motor locks out on overload.

Coupling disengaged or broken

− no pressure

Fuel pressure too low Adjust to 100 psi.

If water depth exceeds 1 inch,
pump or drain water.

Locate and correct leak.

Tighten all connections.

Replace pump.

Re−engage or replace coupling.

Nozzle

Ignition Electrodes

Ignition

Transformer

Burner Motor

Disconnect ignition leads. Ob
serve the oil s
bly must be removed from unit).
Inspect the nozzle for plugged
orifice or carbon build−up around
orifice.

Remove gun assembly and in
spect electrodes and leads.

Connect ignition leads to the
transformer. Start burner and ob
serve spark. Check line voltage

Motor does not come up to
speed and trips out on overload.
Turn off power and rotate blower
wheel by hand to check for bind

un assem

.

.

Nozzle orifice plugged

Nozzle strainer plugged

Poor or off center spray

Fouled or shorted electrodes

Dirty electrodes and leads

Eroded electrode tips

Improper electrode gap spacing

Improper position of electrode
tips

Bad buss bar connection Retension and realign.

Cracked or chipped insulators Replace electrode.

Cracked or burned lead insula
tors

Low line voltage

Burned out transformer wind
ings.

No spark or weak spark

Low line voltage

Pump or blower overloading
motor

Faulty motor Replace motor.

Replace nozzle with the same
size, spray angle, and spray

ype.

ean electrode leads.

Clean electrode tips and reset
the
rectly position tips.

Replace electrode leads.

Check voltage at power source.
Correct cause of voltage drop
or call the power company.

Replace the transformer.

Properly ground the transformer
case.

Check voltage at power source.
Correct cause of voltage drop
or the call power company.

Correct cause of overloading.

to 5/32 inches and cor

Page 35

Burner starts and fires, but locks out on safety.

due to poor

,

across flame

If fire is good

fault may be

p

After burner

,

If fire is good

Fl

detector termi

in the fuel sys

pp

Source Procedure Causes Correction

Unbalanced fire Replace nozzle

Too much air − −lean short fire

Too little air − − long dirty fire

Excessive draft

Too little draft or restriction

Dirty cad cell face Clean cad cell face.

,

Faulty cad cell − exceeds 1500
hms

Loose or defective cad cell
wires

Primary control circuit defective Replace primary control.

Poor Fire

Flame Detector

Primary Control

After burner
fires, immedi
ately jumper
across flame
detector termi
nals at the pri
mary control.

If burner con
tinues to run,
this may be

fire. Inspect
fire.

If fire is good
fault is in the
flame detector.
Check detec
tor circuit.

If burner locks
out on safety,
fault is in the
primary con
trol.

Reduce combustion air − check
combustion.

Increase combustion air − check
combustion.

Adjust barometric damper for
correct draft.

Correct draft or remove restric
tion.

Replace cad cell.

Secure connections or replace
cad cell holder and wire leads.

Burner starts and fires, but loses flame and locks out on safety.

Source Procedure Causes Correction

Unbalanced fire Replace nozzle

Poor Fire

ame Detector

Oil Supply

After burner
fires, immedi
ately jumper
across flame
detector termi
nals at the pri
mary control.

Listen for pump whine

If burner con
tinues to run
(does not lock
out of safety),

due to poor
fire. Inspect
fire.

If fire is good
fault is in the
flame detector.
Check detec
tor circuit.

If burner loses
flame (does
not lock out on
safety), fault is
in the fuel sys
tem.

Too much air − − lean short fire

Too little air − − long dirty fire

Excessive draft

Too little draft or restriction

Dirty CAD cell face Clean CAD cell face.

,

Faulty CAD cell − − exceeds
15000 hms

Loose or defective cad cell
wires

Pump loses prime − air slug Prime pump at bleed port

Pump loses prime − air leak in
supply line

Water slug in line Check oil tank for water (over 1

Partially plugged nozzle or
nozzle strainer

Restriction in oil line Clear restriction.

Plugged fuel pump strainer Clean strainer or replace pump.

Cold oil − outdoor tank Change to number 1 oil.

Reduce combustion air − check
combustion.

Increase combustion air − check
combustion.

Adjust barometric damper for
correct draft.

Correct draft or remove restric
tion.

Replace CAD cell.

Secure connections or replace
cad cell holder and wire leads.

Check supply line for loose con
nections and tighten fittings.

inch) pump or drain out water.

Replace nozzle.

Page 36

Burner starts and fires, but short cycles (too little heat).

Thermostat

Check thermostat

(

Limit Control

control (black & white leads). If

P

If burner turns

Thermostat

Disconnect

circuit.

wires at the pri

Source Procedure Causes Correction

Heat anticipator set too low Correct heat anticipator setting.

Thermostat Check thermostat.

Connect voltmeter between line
voltage connections to primary

Limit Control

ower

control
burner cycles due to power inter
ruption, it is cycling on limit.

If voltage fluctuates, fault is in the
power source. Recheck voltage
at the power source.

black & white leads). If

.

Vibration at thermostat Correct source of vibration.

Thermostat in the path of a
warm air draft

Dirty furnace air filters Clean or replace filter.

Burner running too slow

Blower motor seized or burned
out

Blower bearings seized Replace bearings and shaft.

Blower wheel dirty Clean blower wheel.

Blower wheel in backward Reverse blower wheel.

Wrong motor rotation

Restrictions in return or supply
air system

Adjustable limit control set too
low

Loose wiring connection Locate and secure connection.

Low or fluctuating line voltage Call power company.

Shield thermostat from draft or
relocate.

Increase blower speed to main
tain proper temp. rise.

Replace motor.

Replace with properly rotating
wheel.

Correct cause of restriction.

Reset limit to maximum stop
setting.

Burner runs continuously (too much heat).

Source Procedure Causes Correction

If burner turns

Thermostat

Disconnect
thermostat

mary control.

Primary control

off, fault is in
the thermostat
circuit.





If burner does
not turn off,
fault is in the
primary control.

Shorted or welded thermostat
contacts

Stuck thermostat bimetal

Thermostat not level Level thermostat.

Shorted thermostat wires Repair short or replace wires.

Thermostat out of calibration Replace thermostat.

Thermostat in cold draft

Defective primary control

Repair or replace the thermo
stat.

Clear obstruction or replace
thermostat.

Correct draft or relocate the
thermostat.

Replace the defective primary
control.

Page 37

Burner runs continuously cont.

L

CO

l

Dirt

g

Check b

reading more
CO2, stack tem

High stack tem

550 F Net.

Oil P

Inspect fire and check

)

Source Procedure Causes Correction

urner

Combustion

ressure

combustion for
CO2, stack tem
perature, and
smoke

Inspect fire and check

oil pressure.

Too much combustion air Reduce combustion air.

Air leaks into heat exchanger

ow

2

than 10%.

ess

around inspection door, etc.

Excessive draft

Incorrect burner head adjust
ment

y or plugged heat exchanger

High smoke
readin

more

Insufficient draft Increase draft.

than a trace. Incorrect burner head adjust

ment

Too little combustion air Increase combustion air.

Too little blower air

Blower belt too loose (if

High stack tem
perature is
more than

F Net.

550

equipped)

Dirty or plugged heat exchanger Clean heat exchanger.

Dirty blower wheel Clean blower wheel.

Dirty furnace air filters Clean or replace filter.

Restricted or closed registers or
dampers

Partially plugged or defective
nozzle

Oil pressure is too low: less
than 100 psi.

Correct cause of air leak.

Adjust barometric draft con
trol for correct draft.

Correct burner head setting.

Clean heat exchanger.

Readjust burner.

Correct burner setting.

Increase blower speed to
maintain proper temp. rise.

Tighten blower belt.

Readjust registers or damp
ers.

Replace nozzle.

Increase oil pressure top
100psi.

Troubelshooting O23 / OHR23 / OF23 −5 Units

Procedure Status Correction

CONDITION 1: BURNER DOES NOT ENERGIZE WITH A CALL FOR HEAT.

1.1 Check limit switch contacts are
closed and clean.

1.2 Check for line votage at oil pri
mary control. Voltage should be
120V

1.3 Check LED light with burner off,
no call for heat (no flame

1.4 Sheild cad cell from external
light

1.5 On warm air systems, Remove
one thermostat lead and jumper
thermostat (T to T) terminals on
burner control.

LED is on

LED is off See step 1.5.

LED is off Eliminate exteranl light or shield light from cad cell

LED stays on

Burner energizes

Burner does not energize

Clean contacts. Replace limit switch if necessary.

Check primary voltage source. Take appropiate measures to cor
rect if necessary.

Cad cell or control is bad. Control sees external light or connections
are shorted. See step 1.4.

Replace cad cell and recheck.
 If LED stays on remove cad cell lead wires from burner control
and recheck.

 If LED turns off, replace cad cell bracket assembly.
 If LED stays on replace buner control

Trouble in thermostat or limit circuit. Check thermostat or limit wir
ing connections.

Disconnect line voltage power and open line switch

 Check all wiring and tighten any loose connections. Recheck
 If burner does not energize replace burner control

Page 38

Troubelshooting O23 / OHR23 / OF23 −5 Units Cont.

)

Ignit

Ignition is off

l

cell back in socket
B

S

K

p

 Replace cad cell with new cad cell

Reconnect line voltage and close

LED i

S

line switch

control and leave wires open.
LED i

Repl

CONDITION 2: BURNER STARTS, THEN LOCKS OUT ON SAFETY WITH LED FLASHING 1/2 SECOND ON

2.1 Check limit switch contacts are
closed and clean.

2.2 Check for line votage at oil pri
mary control. Voltage should be
120V

2.3 Check LED light with burner off,
no call for heat (no flame

2.4 Sheild cad cell from external
light

2.5 On warm air systems, Remove
one thermostat lead and jumper
thermostat (T to T) terminals on
burner control.

2.6 Hit reset button on burner con
trol

2.7 Listen for spark after burner en
ergizes (after 2 second delay)

2.8 Check LED after flame is estab
lished, but before buner control
lockcs out.

2.9 Check cad cell sighting for view
of flame
 Disconnect line voltage and open
line switch
 Unplug cad cell and clean cad cell
face with soft cloth. Check sighting
for clear view of flame. Place cad
cell back in socket.
 Reconnect line voltage and close
line switch.
Start burner

2.10 Check cad cell.
 Disconnect line voltage and open
line switch

lace cad cell with new cad cell

 Re
 Disconnect all wires from thermo

stat to prevent a call for herat.
 Reconnect line voltage and close
line switch.
 Expose new cad cell to bright light,
such as a flash light

2.11 Check cad cell bracket assem
bly.
 Disconnect line voltage and open
line switch
 Remove cad cell wires from quick
connect connectors on the burner
control and leave wires open.

 Apply power to buner control.
 Place jumper across cad cell termi

nals after buner motor is energized.

.

LED is on

LED is off See step 2.5.

LED is off Eliminate exteranl light or shield light from cad cell

LED stays on

Burner energizes

Burner does not energize

LED stops flashing See step 2.7.

LED continuse to flash

Ignition is off

Ignition is on

Ignition is on but no oil is
sprayed to combustion cham
ber

LED is on until the burner
control locks out and starts
flashing during lock out.

Burner locks out See step 2.10

LED is on. Go back to step 2.6

LED is on. Replace cad cell assembly.

1/2 SECOND OFF

urner continuse to run

s off.

s off.

Clean contacts. Replace limit switch if necessary.

Check primary voltage source. Take appropiate measures to cor
rect if necessary.

Cad cell or control is bad. Control sees external light or connections
are shorted. See step 2.4.

Replace cad cell and recheck.
 If LED stays on remove cad cell lead wires from burner control
and recheck.

 If LED turns off, replace cad cell bracket assembly.
 If LED stays on replace buner control

Trouble in thermostat or limit circuit. Check thermostat or limit wir
ing connections.

Disconnect line voltage power and open line switch

 Check all wiring and tighten any loose connections. Recheck
 If burner does not energize replace burner control

Verify burner control is not in restricted mode.
(1/2 second flash)

or could be bad. Check line voltage at ignitor terminals. If line

voltage is present, replace burner contro

Wait for 15 second pre−purge to complete. Check oil valve, oil valve
wiring, pump and oil supply.

Replace burner control

ystem is O.

ee step 2.11

ace burner control.

Page 39