Page 1
®
INSTALLATION
2004 Lennox Industries Inc.
Dallas, Texas, USA
WARNING
This product contain fiberglass wool.
Disturbing the insulation during installation, maintenance, or repair will expose you to fiberglass wool
dust. Breathing this may cause lung cancer. (Fiberglass wool is known to the State of California to
cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact
your supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
INSTRUCTIONS
OHR23 Series Units
OIL UNITS
504,628M
38152A061
06/04
Supersedes 4/02
Table of Contents
Elite Series Oil Furnace 1. . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping and Packing List 1. . . . . . . . . . . . . . . . . . . . . . . .
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OHR23 Unit Parts Arrangement 3. . . . . . . . . . . . . . . . . . .
Oil Burner Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . .
Requirements 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply & Return Air Plenums 5. . . . . . . . . . . . . . . . . . . . .
Optional Filter Kit 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Unit Adjustments 6. . . . . . . . . . . . . . . . . . . . . . . . . .
Venting 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Combustion and Ventilation Air 8. . . . . . . . . . . . . . . . . . . .
Flue Connections 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Supply Lines Sizing 12. . . . . . . . . . . . . . . . . . . . . . . . .
Oil Supply Line & Filter Connections 13. . . . . . . . . . . . . .
Leak Check 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Wiring 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Start−Up & Adjustments 15. . . . . . . . . . . . . . . . . . . . .
Service 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start−Up & Performance Checklist 17. . . . . . . . . . . . . . . .
Troubleshooting 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
Litho U.S.A.
Elite® Series Oil Furnace
These instructions are intended as a general guide and do
not supersede local codes in any way. Only qualified technicians can install and service the Lennox Elite® Series
OHR23 oil furnaces. In Canada, refer to CSA B139 for recommended installation procedures. Consult authorities
who have jurisdiction before installation.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause personal injury, loss
of life, or damage to property.
Installation and service must be performed by a
qualified installer or service agency.
06/04 504,628M
Page 1
Shipping & Packing List
1− Assembled oil furnace
1− Draft control
Check the components for shipping damage. If you find
any damage, immediately contact the last carrier.
CAUTION
Never burn garbage or paper in the heating system.
Never leave papers near or around the unit.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance.
When venting this appliance, keep vent terminal
free of snow, ice and debris.
*2P0604* *P504628M*
Page 2
OHR23 Unit Dimensions − Inches (mm)
OHR23Q3-
OHR23Q5-
Model No. A B C D E F G H
OHR23Q3-
105/120
OHR23Q5-
140/154
in. 20-1/2 20-1/2 18 18 18 18 3 10-1/4
mm 521 521 457 457 457 457 76 260
in. 23-1/2 23-1/2 21 21 21 21 4-3/4 11- 3/ 8
mm 597 597 533 533 533 533 121 289
53 (1346)
4 KNOCKOUTS
(For Suspending)
TOP VIEW
14-1/2
3-1/2
(89)
(368)
AIR
F A
FLOW
F
RETURN
E
AIR
OPENING
TOP VIEW
A
A
8
(203)
C
SUPPLY
D
AIR
OPENING
END VIEW FLUE OUTLET
(4) SPACER
LEGS
3/4
(19)
HEAT EXCHANGER
CLEAN OUT
PORTS (3)
1
(25)
BURNER
HORIZONTAL POSITION
OPTIONAL DOWNFLOW COMBUSTIBLE FLOOR BASE
B
3/4
(19)
FRONT OF
FURNACE
FLUE OUTLET
59 (1499)
G
32-1/2 (826)
H
SIDE
VIEW
RETURN
AIR
3/4
(19)
E B
RETURN
AIR
SUPPLY
AIR DUCT
(Not
Furnished)
AIR
FLOW
32-1/2
(826)
59
(1499)
HEAT
EXCHANGER
CLEAN OUT
PORTS (3)
BURNER
3/4
8
(203)
SUPPLY AIR OPENING
(19)
DC
SUPPLY AIR OPENING
SIDE VIEW FRONT VIEW
DOWNFLOW POSITION
105/120
16-1/4(413)
H
140/154
20-1/4(514)
FLUE
OUTLET
105/120
16-1/4(413)
140/154
20-1/4(514)
BURNER
Additive Base Raises Furnace
3/4 in. (19 mm) Inch above Floor Level
OPTIONAL
DOWNFLOW
ADDITIVE
BASE
COMBUSTIBLE
FLOOR
Page 2
Page 3
OHR23 Unit Parts Arrangement
BECKETT
AFII BURNER
CLEAN−OUT PORT
CLEAN−OUT PORT
WITH FAN CONTROL BOARD
FLUE OPENING
HEAT EXCHANGER
INDOOR
BLOWER
CONTROL BOX
OHR23 Oil Burner Parts Arrangement
RETAINING
CLIP
HEAD SCREW
HEAD
INSULATOR
FLANGE
GASKET
AIR TUBE
ASSY FOR
FB HEADS
1/4" HEX
FB−HEAD
NOZZLE
ADAPTER
NOZZLE LINE
ELECTRODE HEAD
ASSY.
FLANGE
ELECTRODE
ASSY
AIR TUBE
SCREWS
PEDESTAL
PRE−MOUNTED OIL−DELAY
Figure 1
ELECTRONIC IGNITION
TRANSFORMER
REAR ACCESS
DOOR ASSY
MAIN
HOUSING
ASSY
ESCUTCHEON
PLATE
CONNECTOR
TUBE
FUEL PUMP
COUPLING
VALV E
Figure 2
REAR ACCESS
DOOR GASKET
SPLINED
NUT
IGNITOR
MOTOR
PRIMARY
CONTROL
BLOWER
WHEEL
4X4
BOX
0
3
4
5
6
7
8
AIR
ADJ.
DIAL
INLET
AIR SCOOP
Page 3
Page 4
Requirements
Installation of Lennox oil−fired furnaces must conform with
the National Fire Protection Association Standard for the
Installation of Oil Burning Equipment, NFPA No. 31, the
National Electrical Code, ANSI/NFPA No.70 (in the
U.S.A.), CSA Standard CAN/CSA−B139 (in Canada),
Installation Code for Oil Burning Equipment, the Canadian
Electrical Code Part1, CSA 22.1 (Canada), the recommendations of the National Environmental Systems Contractors Association and any state or provincial laws or local ordinances. Authorities having jurisdiction should be
consulted before installation. Such applicable regulations
or requirements take precedence over general instructions
in this manual.
Chimneys and chimney connectors must be of the type
and construction outlined in section 160 of NFPA No. 31.
Air for combustion and ventilation must conform to standards outlined in section 140 of NFPA No. 31 or, in Canada, CSA Standard B139. When installing OHR23 units in
confined spaces such as utility rooms, two combustion air
openings are required. Dimensions of combustion air
openings are shown in table 1. One opening shall be below
burner level and the other opening shall be no more than 6
inches from the room’s ceiling.
Combustion air openings should provide a minimum free
area one-half square inch per 1,000 Btu per hour input.
This combustion air should be brought into the area containing the furnace below the level of the furnace burner.
IMPORTANT
An opening to the outside for combustion air is
strongly recommended, especially in new homes.
Refer to table 1 or the unit rating plate for specific
combustion air opening dimensions.
Table 1
Combustion Air Opening Dimensions
Model No. (2 openings required)
OHR23−105/120 10" X 20"
OHR23−140/154 11" X 22"
This unit is approved for clearances to combustible material as listed unit rating plate and in tables 2 or 3. Unit service
and accessibility clearances take precedence over fire
protection clearances.
Table 2
Horizontal Installation Clearances
Clearances Inches (mm)
Top of Cabinet 3 (76)
*Bottom and Rear of Cabinet 1 (25)
Front of Cabinet 24 (610)
Service Clearance (Front) 24 (610)
End of Supply Plenum 0 (0)
Supply Air Opening 0 (0)
Return Air Opening 0 (0)
Above Horizontal Warm Air Duct
within 3 ft. (914mm) of Furnace
Flue Pipe Horizontal 7 (178)
Flue Pipe Vertical 7 (178)
*NOTE−When furnace is installed on combustible floor, 1 "
(25 mm) spacer legs must be installed to elevate unit off of
mounting surface.
0 (0)
Table 3
Downflow Installation Clearances
Clearances Inches (mm)
Bottom of Plenum and Ductwork 1 (25)
Plenum Sides 1 (25)
Side of Cabinet 1 (25)
Rear of Cabinet 1 (25)
Front of Cabinet 16 (406)
Service Clearance (Front) 24 (610)
Flue Pipe Horizontal 1 (25)
Flue Pipe Vertical 7 (178)
Return Air Opening 0 (0)
*Floor *Combustible
*NOTE−Clearance for installation on combustible floor if optional additive base is installed between the furnace and
combustible floor. Not required in add−on coiling applications.
NOTE − Downflow Application Only For installation on
combustible floors, appliance shall not be installed directly
on carpeting, tile or other combustible material other than
wood flooring. When installed on wood flooring, the additive base must be used. See Unit Dimension illustration.
NOTE − Unit must be adjusted to obtain a temperature rise
within the range listed in table 7 (see Page 15).
When used in conjunction with a evaporator coil, the furnace shall be installed in parallel with, or on the upstream
side of the evaporator coil. In a parallel flow arrangement,
the dampers, or other measures used to control flow of air
flow, shall be adequate to prevent chilled air from entering
the furnace. If the furnace is manually operated, it must be
equipped with means to prevent operation of either unit unless dampers are in the full-heat or full-cool position.
Page 4
Page 5
When installed, furnace must be electrically grounded in
accordance with local codes or, in the absence of local
codes, with the current National Electric Code, ANSI/
NFPA No. 70, if an external electrical source is utilized.
Field wiring connection with unit must meet or exceed
specifications of type T wire and withstand a 63F (17C)
temperature rise.
Installation
When installed, OHR23 furnaces must be level. If the furnace is not level, place fireproof wedges or shims between
the low side of the furnace and floor. Make sure the weight
of the furnace is evenly distributed on all four corners.
Strain on sides of the cabinet causing cracking and popping noises may occur if weight of furnace is not evenly distributed.
Set the unit in desired location keeping in mind the clearances list in tables 2 and 3. Also keep in mind oil supply
connections, electrical supply, flue connections and sufficient clearance for installing and servicing unit.
OHR23 series units may be installed in a crawl space under a house, utility room or in a wide variety of suspended
applications.
Horizontal Application
The OHR23 furnace is shipped from the factory in the horizontal left hand air discharge application. Air flow may be
reversed to right side discharge or unit may be used as
downflow.
Reversing Airflow for Right Hand Discharge
1. Rotate the furnace 180 so that when facing the front,
the warm discharge is to the right.
2. Remove the nuts in the bracket that hold the burner to
the furnace front. Rotate the burner and burner mounting plate 180 and reinstall the nuts.
3. Remove the screws that hold the limit control in place.
Use the provided knockout hole to relocate the limit
control to the top side of the front panel.
Installation on Non−Combustible Material
Set the furnace on non-combustible material (such as concrete blocks, bricks or angle iron). Install spacer legs, provided with unit, by using the cabinet screws from each corner of the unit. Use a level to check level of furnace in at
least two directions. Use shims or non-combustible material. A minimum clearance of 1" must be maintained between bottom of furnace and combustible material.
Suspended Installation
To suspend furnace, remove knockouts in top of panel at
warm air discharge and at blower panel (Refer to unit dimensions). Use 3/8" rods cut to desired length. Use one
flat washer and two nuts for each rod. One nut and the
washer on the inside of unit and the other nut on the outside
of unit (the locking nut). Level the unit by adjusting the nuts
on the inside of unit. See figure 3 to suspend unit.
Hanger Rod Installation
rod
nut
blower compartment
top of
furnace
washer
nut
division panel
Figure 3
Downflow Application
When installing the OHR23 in a downflow position and on
combustible flooring, a combustible floor base must be
used. See Unit Dimension illustration.
1. Rotate the furnace so that return is on top and supply
is on bottom. Refer to table 3 for clearances to combustible flooring.
2. Remove the nuts in the bracket that hold the burner to
the furnace front. Rotate the burner and burner mounting plate 90 and reinstall the nuts.
3. It is also recommended that the upper rear screw holding the blower housing to the blower deck be removed
before installation in a closet. Removing this screw allows for easy service and removal of the blower assembly in a closet installation.
Supply & Return Air Plenums
NOTE − Following these suggestions when installing supply and return air plenums.
1. Use sealing strips of fiberglass.
2. In all cases, the plenum should be secured to furnace
or evaporator cabinet with sheet metal screws.
3. Both supply and return air plenums shall be square
and least 18" long. They should be the same dimension as the furnace opening.
4. If unit is installed in a confined space such as a utility
room where there is no complete return air duct system, a return air connection should be run (the same
size as the return air opening) to a location outside the
room containing the furnace.
5. Install supply and return air ducts as desired.
Optional Filter Kit
An Optional filter kit is available for OHR23 units. Kit 35K05
is used with OHR23−105/120 units, and kit 35K06 is used
with OHR23−140/154 units. All kits include the following:
2 filters
3 rods
7 screws
1 rack assembly
1 panel
Page 5
Page 6
OHR23−140/154 Filter Rack Installation
1. Slide filter rack over return duct flanges.
2. Using a scriber through the filter rack mounting holes,
mark seven mounting hole locations in the return end
of the cabinet. See figure 4.
3. Remove filter rack and drill 1/8" diameter holes at the
marked positions.
4. Place filter rack in position again and secure it to the
cabinet using the sheet metal screws provided. Clearance for the screw driver is provided in outside holes
of rack and in filter support angles.
5. Bend the ends of filter rods and hook ends through
holes provided in top and bottom filter support angles.
6. Slide filter between the support angles and the plenum
side for the filter rack. The filter rods hold the filter in
place.
OHR23 105/120 Optional Filter Kit
FILTER RACK
(FURNISHED)
22 (559)
14 (356)
RETURN
AIR DUCT
(NOT FURNISHED
BY LENNOX)
Oil vacuum gauge
Beckett T−500 gauge
Knowledge of proper test equipment operation
CAUTION
Improper nozzle and/or air adjustment of this unit
may result in sooting problems. Refer to the following set-up section for correct adjustment procedures.
Adjusting the Nozzle
Proper adjustment of the nozzle assembly is critical because alignment may have changed during shipping. Before the furnace and oil lines are installed, the nozzle assembly must be checked. This may easily be done by
removing the entire burner assembly (not just the nozzle)
from the furnace. The lower firing nozzle is factory
installed. This should be verified by the installer. Inspect
the spark transformer leads also to ensure they are still attached to the electrodes.
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 assembly
counterclockwise (figure 5), the entire burner assembly
will come out of the furnace. There is adequate wire to remove the burner without disconnecting wires. Once removed, just turn the burner around in the vest panel area.
FILTER
(FUR-
NISHED)
OPENING
IN UNIT
(EITHER SIDE)
Figure 4
Initial Unit Adjustments
Neither the nozzle setting nor the air adjustments are factory set. The furnace is fire−tested and the limit control is
checked to make sure it functions properly; no factory settings are made. During installation, the furnace must be set
up. The installing dealer/contractor must have and use
proper test equipment in order to correctly set up the oil furnace. Proper testing equipment is required to ensure correct operation of the unit. The use of test equipment is now
more critical than ever due to tighter tolerances needed to
keep the furnace operating efficiently.
Among the test equipment for an oil furnace, the proper
combustion test kit should contain the following:
Draft gauge
CO
or O2 analyzer
2
Smoke tester
Pressure gauge
High temperature thermometer
OHR23 Series Burner Removal
LOOSEN THREE NUTS WHICH ATTACH BURNER TO VEST PANEL.
ROTATE BURNER COUNTERCLOCKWISE
ON SLOTS THEN PULL TOWARD YOU.
Figure 5
To correctly adjust the nozzle, use a Beckett #T−500
gauge.
Insert the small end of the gauge into the end of the cone
and measure from the flat of the end cone to the tip of the
nozzle. When nozzle depth is correct, the tip of the nozzle
should just touch the end of the gauge. Refer to the illustration sheet provided with the gauge. Note that the scale side
of the gauge is not used for this purpose. Make corrections
by sliding the nozzle assembly forward or backward within
the blast tube (figure 6). At the same time, check the
nozzle alignment.
Page 6
Page 7
To check nozzle alignment, again insert the small end into
the end cone and measure the nozzle and electrode alignment against the center lines marked on the gauge (again
refer to enclosed illustration sheet). If the nozzle is not centered, but found to be too far left or right, a new nozzle assembly will need to be ordered. Do not attempt to adjust by
bending the 90 degree elbow in the oil line.
Beckett Oil Burner Nozzle Adjustment
BURNER MUST BE REMOVED FROM FURNACE FOR THIS PROCEDURE.
GAUGE
2
TO ADJUST NOZZLE:
1−LOOSEN SCREW.
2−SLIDE ENTIRE NOZZLE/ELECTRODE ASSEMBLY BACK AND FORTH UNTIL
NOZZLE JUST TOUCHES GAUGE.
1
Figure 6
Venting
WARNING
The barometric damper 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.
This furnace is certified for use with type L" vent.
B" vent must not be used with oil furnaces.
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
according to the requirements of the National Fire Protection Association. 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 installation requirements and should be consulted before
installation of unit.
2. The vent connector should be as short as possible to
do the job.
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 highest
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. Clearances 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 7.
Wall Thimble
THIMBLE
CAUTION
Do not store combustible materials near the furnace
or supply air ducts. The material (such as paint, motor oil, gasoline, paint thinner, etc.) may ignite by
spontaneous combustion creating a fire hazard.
NOTE − Oil burning equipment may be vented into an approved 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).
Page 7
COMBUSTIBLE
WALL
VENT PIPE
Figure 7
9. The vent pipe should slope upward toward the chimney 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 8.
Page 8
BAROMETRIC
CONTROL*
(IN EITHER
LOCATION)
HORIZONTAL
APPLICATION
SHOWN
Masonry Chimney
LINER
CLEAN
OUT
MASONRY
CHIMNEY
BAROMETRIC
CONTROL*
(IN EITHER
LOCATION)
HORIZONTAL
APPLICATION
SHOWN
Factory-Built Chimney
FACTORY
BUILT
CHIMNEY
DRAIN FOR
CONDENSATE
CLEAN OUT
*BAROMETRIC CONTROL MAY BE INSTALLED IN EITHER VERTICAL OR HORIZONTAL SECTION OF FLUE PIPE WITHIN 18" OF FLUE OUTLET OF FURNACE.
Figure 8
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 standard, or
masonry or concrete chimney lined with a lining material acceptable to the author ity having jurisdiction.
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. Chimney must be able to sufficiently vent
all appliances operating 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 9.
16. Where condensation of vent gas is apparent, the vent
should be repaired or replaced. Accumulation of condensation in the vent is unacceptable.
17. Vent connectors serving this appliance shall not be
connected into any portion of mechanical draft systems operating under positive pressure.
18. Keep the area around the vent terminal free of snow,
ice and debris.
*BAROMETRIC CONTROL MAY BE INSTALLED IN EITHER VERTICAL OR HORIZONTAL SECTION OF FLUE PIPE WITHIN 18" OF FLUE OUTLET OF FURNACE.
Figure 9
Combustion and Ventilation Air (Confined and
Unconfined Spaces)
Homes designed with energy conservation in mind use
air-tight construction practices. Therefore, it is necessary
to bring in outside air for combustion. Consideration must
also be given to the use of exhaust fans, appliance vents,
chimneys and fireplaces that force out air which might
have otherwise been used for combustion. Unless outside
air is brought into the home for combustion, negative pressure (pressure outside is greater than inside pressure) will
build to the point that a downdraft can occur in the furnace
vent pipe or chimney. Combustion gases entering the living space create a potentially dangerous situation.
NOTE − The importance of the previous paragraph cannot be overstated. Users may inadvertently block fresh
air intakes after installation.
In the absence of local codes concerning air for combustion and ventilation, the following section outlines guidelines and recommends procedures for operating oil furnaces in a manner that ensures efficient and safe
operation. Special consideration must be given to combustion air needs as well as requirements for exhaust vents and
oil piping.
Combustion Air Requirements
All oil-fired appliances require air to be used for the combustion process. If sufficient amounts of combustion air
are not available, the furnace or other appliance will operate in an inefficient and unsafe manner. Enough air must
be provided to meet the needs of all fuel-burning appliances, as well as appliances such as exhaust fans which
force air out of the home.
Page 8
Page 9
CAUTION
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rusting and premature heat exchanger failure. It can also
cause property damage.
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 incomplete
combustion which can result in sooting. Requirements for
providing air for combustion and ventilation depend largely
on whether the furnace is installed in an unconfined or confined space.
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
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 procedures outlined for
using air from the outside for combustion and ventilation.
Confined Space
A confined space is an area with volume less than 50 cubic
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 containing 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 confined space such as a closet or small
equipment room.
Small leaks 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 providing 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 centimeters). 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 10).
Equipment In Confined Space −
All Air From Inside
CHIMNEY OR
OIL VENT
WATER
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).
HEATER
OPENINGS
(TO ADJACENT
ROOM)
Figure 10
Air from Outside
If air from outside is brought in for combustion and ventilation, 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 11 and 12). 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 13).
Page 9
Page 10
Equipment In Confined Space − All Air From
Outside (Inlet Air from Crawl Space and
Outlet Air to Ventilated Attic)
CHIMNEY
OR OIL
VENT
Equipment In Confined Space − All Air From
CHIMNEY
OR OIL
VENT
Outside
VENTILATION LOUVERS
(EACH END OF ATTIC)
OIL
OIL
FURNACE
FURNACE
VENTILATION
LOUVERS
(FOR UNHEATED
CRAWL SPACE)
NOTE−THE INLET AND OUTLET AIR OPENINGS SHA LL 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 11
Equipment In Confined Space − All Air From
Outside (via Ventilated Attic)
CHIMNEY
OR OIL
VENT
OUTLET
AIR
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.
VENTILATION LOUVERS
(Each end of attic)
INLET AIR
(Ends 12" above
bottom)
WATER
HEATER
Figure 12
When ducts are used, they shall be of the same cross−sectional 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
considered. 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 percent 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 equipment so that
they are opened automatically during equipment operation.
OUTLET AIR
WATER
HEATER
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
EQUIPMENT 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 EQUIPMENT IN THE ENCLOSURE.
WATER
HEATER
Figure 13
CAUTION
The barometric control 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). The enclosed intake pipe ring may be used to facilitate direct air intake to the burner through the right side of
the cabinet. The AFG burner requires a special kit for direct
air intake. Refer to kit instructions.
To convert the AFII burner from confined space to outside
combustion air, simply remove the three screws attaching
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.
CAUTION
DO NOT USE a barometric draft relief in exhaust vent
pipe if outdoor combustion air is connected directly
to the burner.
Page 10
Page 11
Removal of Unit from Common Venting System
In the event that an existing furnace is removed from a
venting system commonly run with separate gas 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 other appliances not in operation remain
connected to the common venting system. If the 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 system.
2. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion or other deficiencies
which could cause an unsafe condition.
3. If possible, close all building doors and windows and
all doors between the space in which the appliances
remaining connected to the common venting system
are located and other spaces of the building. Turn on
clothes dryers and any appliances not connected to
the common venting system. Turn on any exhaust
fans, such as range hoods and bathroom exhausts, so
they will operate at maximum speed. Do not operate
a summer exhaust fan. Close fireplace dampers.
4. Following the lighting instruction, place the appliance
being inspected in operation. Adjust thermostat so appliance will operate continuously.
5. Test for spillage using a draft gauge.
6. After it has been determined that each appliance remaining connected to the common venting system
properly vents when tested as outlined above, return
doors, windows, exhaust fans, fireplace dampers and
any other gas burning appliance to their previous condition of use.
7. If improper venting is observed during any of the
above tests, the common venting system must be corrected.
Horizontal Venting
The OHR23 is approved for horizontal venting with the following mechanical vent systems:
Tjernlund (sideshot) #SS1C (Cat. #35E08) or Field Controls #SWG−5 (Cat. #35P08) with the CK−61 (Cat. #18N28)
control kit. Refer to the manufacturers’ installation instructions for proper installation procedures and service parts
information.
Do not use the same vent with any other appliance when
using a sidewall vent system.
Maximum permissible vent length is 70 equivalent feet.
Minimum length is 15 equivalent feet. 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.
Use the barometric draft control in the horizontal (sidewall)
venting system. Locate the barometric draft control within
18 inches of the furnace flue outlet. See figure 14 for barometric draft control location.
BAROMETRIC
CONTROL*
HORIZONTAL
VENTING CONTROL
Horizontal Venting / Downflow Application
BAROMETRIC
CONTROL*
CONTROL FOR
HORIZONTAL
VENTING
Horizontal Venting / Horizontal Application
*BAROMETRIC CONTROL MUST BE INSTALLED IN THE HORIZONTAL VENTING
SYSTEM AND LOCATED WITHIN 18" OF FLUE OUTLET OF FURNACE.
Figure 14
Flue Connections
IMPORTANT
When flue pipe is installed at less than minimum
clearance listed in tables 2 and 3, radiation shields
must be installed. See figure 15.
Use 24 gauge or heavier galvanized smoke pipe and fittings to connect furnace to vent. Maintain rise of at least
one inch per foot. Connect flue pipe to chimney using the
least number of elbows and angles possible. Flue pipe or
vent connector must be inserted into but not beyond the
outside wall of the chimney flue. No reduction in diameter of flue pipe is acceptable. It is best to have flue pipe as
short and direct as possible.
Where two or more appliances vent into a common flue,
the area of the common flue should be at least equal to
the area of the largest flue or vent connector, plus 50% of
the area of any additional flues or vent connectors.
Install barometric draft control (provided) and flue pipe
according to instructions packed with control.
1. Install draft control, provided, and flue pipe according
to instructions packed with control.
2. Connect flue outlet to chimney using at least 24 gauge
vent pipe and fittings, the same size as the flue outlet.
3. Use the least number of elbows and angles possible.
Slope flue pipe toward chimney approximately 1/4" for
Page 11
Page 12
every foot of horizontal run. Flue pipe or vent connector must be inserted into but not beyond the outside
wall of the chimney flue.
Where two or more appliances vent into a common flue,
the area of the common flue should be at least equal to the
area of the largest flue or vent connector, plus 50% of the
area of any additional flues or vent connectors.
Inspect flue pipe annually. Clean soot or ash from flue pipe,
if necessary. If pipe is rusted, replace.
NOTE − As an extra precaution, cycle heating on and off
ten times after bleeding air from the oil pump. This will
eliminate air in the gun assembly.
Oil Piping
air
vent
fill
pipe
One-Pipe System
fuel
pump
Aux
Filter
Radiation Shield Installation
COMBUSTIBLE
MATERIAL
OHR23 UNIT (TOP)
RADIATION
UNIT
CABINET
NON−
COMBUSTIBLE
SPACERS
NOTE 1−Radiation shields must be constructed of 24 gauge sheet metal minimum.
NOTE 2−Radiation shields required when A is less than 9" (229mm).
NOTE 3−Radiation shields should extend from the top of the unit to the top of the flue pipe.
SEE NOTE 2
SHIELDS
AA
RADIATION SHIELDS
FLUE
PIPE
OHR23 UNIT (FRONT)
(SEE NOTE 1)
1" (25mm)
min
12"
(305mm)
7" (178
mm)
B
SEE NOTE 3
Figure 15
Oil Supply Lines Sizing
Ensure that the restrictions of the piping system, plus any
lift involved, do not exceed the capability of the oil pump.
Use the following guidelines when determining whether to
use a single−or two−stage oil pump.
One−Pipe System
When using a one−pipe system with the oil tank even above
the burner and a vacuum of 6" (152 mm) Hg or less, a single−
stage fuel pump with a supply line and no return line should
be adequate. See figure 16. Manual bleeding of the fuel
pump is required on initial start up. Failure to bleed air from
the oil pump could result in an air lock/oil starvation condition.
Oil
Tank
Shut−off
Valve
8 FT (2.4 M)
MAXIMUM
ONE PIPE LIFT
Figure 16
Table 4
One−pipe Oil Sizing
Line Length Pipe Diameter (OD Tubing)
0−50’ (15 m) 3/8" (10 mm)
51−100’ (15 m) 1/2" (12 mm)
Two−Pipe System
When using a two−pipe system with the oil tank below the
level of the burner, a single−stage fuel pump should be
used in lift conditions of up to 10 feet (3 m) and/or a vacuum of 10" (254 mm) Hg or less. See figure 17. Use a two−
stage fuel pump when lift exceeds 10 feet (3 m) and/or a
va c uu m of 1 0" (254 mm) Hg to 15" (381 mm) Hg. Both conditions require that you use a two−pipe system, which consists of a return line that purges the fuel pump of air by returning it to the tank. To determine the run and lift for piping, refer
to table 5 .
To determine the length of the run for piping, refer to table 4 .
Oil Piping Two-Pipe System
Fill
Pipe
Tank
Return
pipe
Air Vent
Return
pipe
Oil
3"−4" (76 mm −102 mm)
R
outside tank fuel pump above bottom of tank.
fuel
pump
Aux
Filter
Inlet
H
Figure 17
Page 12
Page 13
Use continuous lengths of heavy wall copper tubing or
Lift H"
steel pipe for oil supply pipe. Install oil supply pipe under
floor or near walls to protect it from damage. Avoid running
pipes along joists or reverberating surfaces. Always use
flare fittings. All fittings must be accessible. Do not use
compression fittings.
IMPORTANT
Both oil supply and return pipes must be submerged in oil in the supply tank.
Table 5
Two−Pipe Maximum Pipe Length (H + R)
0’ (0.0m) 84’ (25.6m) 93’ (28.3 m) 100’ (30.5m) 100’ (30.5m)
2’ (0.6m) 73’ (22.3m) 85’ (25.9 m) 100’ (30.5m) 100’ (30.5m)
4’ (1.2m) 63’ (19.2m) 77’ (23.5 m) 100’ (30.5m) 100’ (30.5m)
6 ’ (1.8m) 52’ (15.8m) 69’ (21.0 m) 100’ (30.5m) 100’ (30.5m)
8’ (2.4m) 42’ (12.8m) 60’ (18.3 m) 100’ (30.5m) 100’ (30.5m)
10’ (3.0m) 31’ (9.4m) 52’ (15.9 m) 100’ (30.5m) 100’ (30.5m)
12’ (3.7m) 21’ (6.4m) 44’ (13.4 m) 83’ (25.3m) 100’ (30.5m)
14’ (4.3m) −−− 36’ (11.0 m) 41’ (12.5m) 100’ (30.5m)
16’ (4.9m) −−− 27’ (8.2 m) −−− 100’ (30.5m)
18’ (5.5m) −−− −−− −−− 76’ (23.2 m)
Oil Supply Line & Filter Connections
One−Pipe Systems
3450 RPM − 3 GPH (11.4 LPH)
"
3/8" (10mm) OD Tubing 1/2" (12mm) OD Tubing
1−Stage 2−Stage 1−Stage 2−Stage
5. Tighten the bleed valve securely.
Two−Pipe Systems
If the installation requires a two−pipe operation, install the
bypass plug included in the bag which is attached to the
pump. To convert the pump, install the bypass plug according to the provided pump instructions. Notice in the twopipe system the return pipe must terminate in the tank 3"
(76 mm) to 4" (102 mm) above the supply inlet. Ensure the
return pipe terminates at the correct measurement or air
may escape into the system. This 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.
1. Remove 1/4" plug from return port.
2. Insert bypass plug and tighten it. See figure 17.
3. Attach the return and inlet pipes. Start the burner. Air
bleeding is automatic.
NOTE − If a faster bleed is necessary, open the bleed
valve.
4. The return pipe must terminate 3" to 4" above the supply pipe inlet. See figure 17.
NOTE − If the return pipe does not terminate where it
should, air may enter the system, and prime may be lost.
An oil filter is required for all models. Install filter inside
the building between the tank shut-off valve and the burner. Locate filter close to burner for easy maintenance.
Table 6 lists the filters for the OHR23 furnace.
Table 6
Installation Clearances inches (mm)
CAUTION
Do not install the bypass plug into the pump on one−
pipe systems.
The burner is shipped with fuel pump set for one−pipe operation. For one−pipe systems, the oil supply pipe is connected to the inlet tap on the pump. A one−pipe system
should only be used where there is gravity oil flow to the
pump and the pipe is not run at any point above the oil level
in the tank.
1. Connect the inlet pipe to the pump inlet. Start the burner.
2. Arrange the primary burner control for continuous operation during purging. See figure 16.
3. Turn the bleed valve one turn counterclockwise to
open.
4. Bleed the unit until all air bubbles disappear.
NOTE − Hurried bleeding will prevent the unit from operating properly.
Cat.
Oil Filters
10 micron filter (no mounting bracket) 81P89
10 micron filter (mounting bracket) 53P92
10 micron replacement cartridge for filter,
45 gph
Filter restriction indicator gauge 53P90
Consult burner manufacturer’s instructions packaged with
unit for further details concerning oil supply pipe connections.
Number
53P93
Leak Check
After oil piping is completed, carefully check all piping connections (factory and field) for oil leaks.
Oil Line Heater (Optional)
An oil line heater is available for the burner nozzle. When
applied to units installed in cold areas, the heater warms
the oil line for start-up.
Page 13
Page 14
Electrical Wiring
All wiring must conform to the National Electric Code (NEC),
or Canadian Electric Code (CEC) and any local codes. Refer
to figure 18 for terminal designations on blower control.
1. Refer to appliance rating plate for proper fuse size.
2. Install room thermostat and make wire connections to
the blower control. Avoid installing thermostat on an
outside wall or where it can be affected by radiant heat.
Set the adjustable heat anticipator on thermostat according to the wiring diagram sticker provided on unit.
3. Install a separate fused disconnect switch near unit so
power can be shut off for servicing.
4. Complete line voltage wiring from disconnect switch
near unit to make-up box.
NOTE − An equipment ground screw is provided. Refer to unit wiring diagram (figure 19) and figure 18 for
OHR23 series units. Ground unit using a suitable
ground wire.
5. Any accessory rated up to 1 amp can be connected to
the accessory terminal. The accessory terminal is energized whenever the blower is in operation.
Typical OHR23 Wiring Diagram
Fan Control Board
THERMOSTAT
TERMINAL STRIP
Figure 18
Figure 19
Page 14
Page 15
Unit Start−Up & Adjustments
Before starting the unit, make sure the oil tank is adequately filled with clean No. 1 or No. 2 furnace oil.
NOTE − Water rust or other containments in oil supply system will cause malfunction and failure of the internal parts
of the fuel unit.
CAUTION
Never burn garbage or paper in the heating system.
Never leave papers near or around the unit.
Blower door must be in place before start-up.
Limit Control
Limit Control Do not adjust from factory setting.
Fan Control
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 20.Set the heat fan off delay switches to either
60, 90, 120, or 150 seconds. The factory setting is 90 seconds.
1. Set thermostat for heating demand and turn on electrical supply to unit.
2. Check initial air adjustment. All units are equipped with
an air adjustment dial on the right side of the burner.
See burner parts arrangement illustration.
3. Turn unit on. Place a can or container under the bleed
port located on the fuel pump. Loosen nut on bleed
port to release air and oil mixture from fuel line. Allow
mixture to escape until a steady stream of oil is emitted
from the port. Drain at least 1/2 pint of oil from the
pump. Retighten nut on bleed port. If lockout occurs,
press reset button and continue with bleed procedure.
NOTE − A two−line fuel system will normally bleed itself
by forcing air back to the tank through the return line.
This type of bleeding procedure is not necessary.
4. If burner fails to start, push reset button on primary
safety control and the burner motor reset button once.
See part arrangement illustration.
CAUTION
Do not push the reset button on the primary control
more than one time.
5. If burner fails to light again, refer to the troubleshooting
section in this manual (beginning on Page 18).
Fuel Pump Pressure
Measure fuel pump pressure with unit off. Attach pressure
gauge to pump outlet. Turn unit on and check pressure and
compare to table 7. Adjust if necessary.
Temperature Rise
To measure temperature rise, place plenum thermometers
in warm air and return air plenums. Locate thermometer in
warm air plenum where thermometer will not see" the heat
exchanger to prevent it from picking up radiant heat. Set
thermostat to its highest setting to start unit. After plenum
thermometers have reached their highest and steadiest
readings, subtract the readings. The difference in temperatures in the supply and return air plenums should approximate the temperature rise range listed in table 7 and the
appliance rating plate. If not, adjust the blower motor pulley
to adjust the blower speed.
Delay Off Switch Settings
60 sec 90 sec 120 sec 150 sec
Figure 20
Table 7
OHR23 Operating Parameters
Fuel Nozzle Size,
Spray Angle, &
Unit
Pattern
Type
.65 GPH -.80°, B
for −105 input
−105/
−120
*.75 GPH -.80°, B
for −120 input
.85 GPH - .80°, B
for −140 input
−140/
−154
*1.0 GPH -.80°, B
for −154 input
*Nozzle must be field provided for field conversion to higher heating input. Oil burner pump pressure is 140 psi for
each unit.
Input
Rating
Btu/Hr
105,000
119,000
140,000
154,000
Output
Rating
Btu/Hr
85,000
97,000
113,000
125,000
Temp. rise
+10° F hrz/
Head
down
Type
FB3 70/70
FB6 60/70
Burner Adjustment
The following steps are essential to the proper operation of
OHR23 series oil furnaces. To prevent sooting, follow
these instructions in the sequence given.
1. Perform Draft Test
Perform a draft test at the breach between the outlet of
the vent connector and the barometric draft control.
Drill a 1/4" access hole to allow the draft gauge to be
inserted into the vent connector.
A minimum draft of 0.03 inches w.c. must be established without the burner in operation. With the burner
in operation, the draft should be 0.04 to 0.05 inches
w.c. 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 shape and can accommodate the products of combustion. The temperature in the unconditioned space will also affect the
draft if long vent connectors are allowed to get too
cold.
Page 15
Page 16
2. Perform Overfire Draft
Perform this test with the burner in operation. Remove
the screw from the center of the inspection port. Insert
the draft gauge into the hole.
A reading of the overfire draft should be 0.02 inches
w.c. less than the reading found in the vent connector
during the Draft Test. If a positive reading is seen at
this point, the combustion fan is pumping too much air
into the heat exchanger. Make the necessary adjustments at the air adjustment dial.
3. Perform Smoke Test
Perform the smoke test at the same hole drilled in step 1.
Do not exceed #1 smoke.
4. Perform CO2 Test
Obtain the CO2 sample at the vent pipe. With the unit
firing at a trace of smoke, take a sample of the CO2.
From the results of this test, a window of operation"
(operational tolerance) will be determined. The built-in
tolerance provides room within the set-up for elements
affecting combustion. 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 going bad, draft that changes
during different climatic conditions, dirty oil, dirt obstructing the air inlet, etc.
To build a window of operation, set the burner up so it
does not exceed 13% co2.
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 less than
the draft pressure reading taken at the breach. You
may need to increase the stack draft by adjusting the
barometric draft control.
7. Perform Stack Temperature Test
Take a stack temperature reading in the vent pipe.
Subtract the room air temperature from the stack temperature. This will give you the net stack temperature.
Use the efficiency charts provided in most CO2 analyzers to determine furnace efficiency.
Service
Servicing Filter
NOTE − Under no circumstances should the access panels to
the blower compartment be left off or left partially open.
1. Throw-Away Type Filters Filters should be checked
monthly and replaced when necessary to assure prop-
er furnace operation. Replace filters with like kind and
size filters.
2. Reusable Type Filters Filters should be checked
monthly and cleaned when necessary to assure proper furnace operation. Use warm water and a mild detergent. Replace filter when dry. Permanent filters supplied with OHR23 furnaces do not require oiling after
cleaning. Examine filter label for any for special instructions that may apply.
Servicing Blower
Blower motor is pre−lubricated and sealed for extended operation. No further lubrication is required. Disconnect power to unit before cleaning blower wheel for debris.
Servicing Nozzle
Replace nozzle every year to to ensure proper operation.
Clogged nozzles will result in improper firing or non-firing of
unit.
Flue Pipe Inspection
The flue pipe should be inspected annually by a qualified
service technician. Remove and clean any soot or ash
found in the flue pipe. Inspect pipe for holes or rusted
areas. If replacement is necessary, replace with the same
size and type as required by code. Inspect the flue draft
control device and replace if found defective.
Cleaning Heat Exchanger
1. Remove the vent pipe from the furnace.
2. Remove the locking screws and the caps from the
clean−out tubes. Remove flue access elbow.
3. Using a long spiral wire brush, sweep down the outer
drum of the heat exchanger. Then using the hose attachment, vacuum out loose debris.
4. Remove the locking screw and cap from the observation tube and with the spiral wire brush, reach upward
toward the rear of the heat exchanger to clean out the
crossover tube.
CAUTION
Do not attempt to clean the combustion chamber. It
can be easily damaged.
5. Replace the clean−out caps and flue 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 burner, blower deck and vestibule area.
NOTE − A heat exchanger clean-out kit ABRSH380
(35K09) is available from Lennox.
Page 16
Page 17
OHR23 Start−Up & Performance Check List
Job Name Job no. Date
Job Location City State
Installer City State
Unit Model No. Serial No. Service Technician
HEATING SECTION
Electrical Connections Tight? Supply Voltage Blower Motor Amps
Blower Motor Burner Model No. Serial Number
Piping Connections Tight? All Valves Open? Blower Motor Lubrication OK?
Oil Pump Pressure (recommended minimum 140 psi)
PROPER DRAFT
Draft Reading (recommended .03 to .04 inches w.c.)
Percent CO2 (recommended 12%)
Flue Connections Tight? Fan Control Setting (maximum 130F 55C)
Percent CO2 (recommended 12%)
Fan Control Cutout Temperature Rise
Filter Clean & Secure? Vent Clear?
Calibrated?
THERMOSTAT
Heat Anticipator
Properly Set? Level?
Page 17
Page 18
Troubleshooting
Burner failure or improper operation can result from a number of different causes. Often the cause can be pinpointed
by observing the different types of failure or by the process
of elimination.
Troubleshooting: Fan board operating sequence
Action System Response
The following troubleshooting charts list some failures,
causes and a sequence of steps to isolate the point of failure. Check the simplest and most obvious items before
progressing to other items.
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
Established flame fails. Burner motor is de−energized and oil primary control goes into recycle
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.)
Limit switch string opens. Oil primary control shut off the burner.
Limit switch string closes. ST9103A begins heat fan off delay sequence.
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−energized.
ST9103A returns to standby mode (oil primary control and circulating fan
are off).
primary control).
Burner motor is de−energized.
If heat fan has started, it continues through the selected delay off period.
mode.
If selected heat fan off delay is longer than the recycle delay timing, the
heat fan continues 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.
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.
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.
table continued on next page
Page 18
Page 19
Troubleshooting: Fan board operating sequence
switch
starts, then fault is in the
the burner starts, fault is in the
p
Action System Response
Continuous circulating fan is connected.
(Optional connectors are available for
separate circulating fan speed tap.)
Electronic air cleaner is connected.
(Optional connectors are available for
120 Vac electronic air cleaner.)
Humidity control is connected.
(Optional connectors are available for
120 Vac humidifier.)
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.
Troubleshooting: Burner fails to start.
Source Procedure Causes Correction
Thermostat Check thermostat settings. Thermostat in OFF or COOL Switch to HEAT.
Thermostat is set too low Turn thermostat to higher
temperature.
Safety
Overloads safety control, & auxiliary limit
Power Check furnace disconnect
Thermostat Touch jumper wire across
CAD Cell Disconnect the flame detector
Primary
Control
Check burner motor, primary
switch.
.
switch & main disconnect.
thermostat terminals on
primary control. If burner
thermostat circuit.
wires at the primary control. If
the burner starts, fault is in the
detector circuit.
Place trouble light probes
between the black and white
leads. No light indicates that
no power is going to the
control.
Place trouble light probes
between the orange and white
leads. No light indicates faulty
control.
Burner motor overload tripped Push reset button pump motor.
Primary control tripped on safety Reset primary control.
Auxiliary limit switch tripped on
safety
Open switch Close switch.
Blown fuse or tripped circuit
breaker
Broken or loose thermostat wires Repair or replace wires.
Loose thermostat screw
connection
Dirty thermostat contacts Clean contacts.
Thermostat not level Level thermostat.
Faulty thermostat Replace thermostat.
Flame detector leads are shorted Separate leads.
Flame detector exposed to light Seal off false source of light.
short circuit in the flame detector Replace detector.
Primary or auxiliary control
switch is open
Open circuit between disconnect
switch and limit control
Low line voltage or power failure Call the power company.
Defective internal control circuit Replace the control.
Reset auxiliary limit.
Replace fuse or reset circuit
breaker.
Tighten connection.
Check adjustment. Set the
maximum setting.
Jumper terminals; if burner
starts, switch is faulty, replace
control.
Trace wiring and repair or replace
it.
table continued on next page
Page 19
Page 20
Troubleshooting: Burner fails to start.
the black and white leads to
blower wheel by hand. If seized,
Start the b
ilk
il
the oil spray (gun assembly must
size, spray angle, and spray
ifi
Source CorrectionCausesProcedure
Burner 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 black and white leads to
the blower motor. Light
indicates power to the motor
and burner fault.
Blown fuse Replace the fuse.
Binding burner blower wheel Turn off power and rotate the
blower wheel by hand. If seized,
Sized fuel pump
Defective burner motor Replace the motor.
free the wheel or replace the fuel
pump.
Troubleshooting: Burner starts, but no flame is established.
Source Procedure Causes Correction
Oil Supply Check tank gauge or use dip stick. No oil in tank Fill tank.
Coat dip stick with litmus paste and
insert into bottom of tank.
Listen for pump whine. Tank shut−off valve closed Open valve.
Oil Filters &
Oil Line
Oil Pump Install pressure gauge on pump and
Nozzle Disconnect ignition leads. Observe
Listen for pump whine. Oil line filter is plugged Replace filter cartridges.
Open bleed valve or gauge port.
urner. No oil or m
indicates loss or prime.
read pressure. Should not be less
than 140 psi.
y o
Water in oil tank If water depth exceeds 1 inch,
pump or drain water.
Kinks or restriction in oil line Repair or replace oil line.
Plugged fuel pump strainer Clean strainer or replace
pump.
Air leak in oil supply line Locate and correct leak.
Tighten all connections.
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.
Nozzle orifice plugged Replace nozzle with the same
Replace pump.
Re−engage or replace
coupling.
be removed from unit). Inspect the
nozzle for plugged or
build−up around orifice.
ce or carbon
Nozzle strainer plugged
Poor or off center spray
Page 20
type.
table continued on next page
Page 21
Troubleshooting: Burner starts, but no flame is established.
Source CorrectionCausesProcedure
Ignition
Electrodes electrodes and leads.
Ignition
Transformer
Burner Motor Motor does not come up to speed
Remove gun assembly and inspect
Connect ignition leads to the
transformer. Start burner and
observe spark. Check line voltage
to transformer primary.
and trips out on overload. Turn off
power and rotate blower wheel by
hand to check for binding or
excessive drag.
Fouled or shorted electrodes Clean electrode leads.
Dirty electrodes and leads
Eroded electrode tips Clean electrode tips and reset
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
insulators
Low line voltage Check voltage at power
Burned out transformer
windings.
No spark or weak spark Properly ground the
Low line voltage Check voltage at power
Pump or blower overloading
motor
Faulty motor Replace motor.
the gap to 5/32 inches and
correctly position tips.
Replace electrode leads.
source. Correct cause of
voltage drop or call the power
company.
Replace the transformer.
transformer case.
source. Correct cause of
voltage drop or the call power
company.
Correct cause of overloading.
Page 21
Page 22
Troubleshooting: Burner starts and fires, but lock out on safety.
be due to
p
After burner
,
Detector
jumper across
fault is in the
primary control
fault may be due to
fi
y
immediately
y
detector circuit
the primary
system
Source Procedure Check Causes Correction
Poor Fire If burner
continues to
run, this may
poor fire.
Inspect fire.
fires,
Flame
Primary
Control
immediately
jumper across
flame detector
terminals at the
If fire is good,
flame
detector.
.
Check
detector
circuit.
If burner locks
out on safety,
fault is in the
primary
control.
Unbalanced fire Replace nozzle
Too much air − −lean short
fire
Too little air − − long dirty
fire
Excessive draft Adjust barometric damper for correct
Too little draft or restriction Correct draft or remove restriction.
Dirty cad cell face Clean cad cell face.
Faulty cad cell − exceeds
15000 hms
Loose or defective cad cell
wires
Primary control circuit
defective
Reduce combustion air − check
combustion.
Increase combustion air − check
combustion.
draft.
Replace cad cell.
Secure connections or replace cad cell
holder and wire leads.
Replace primary control.
Troubleshooting: Burner Starts and Fires, but Loses Flame and Lock Out on Safety
Source Procedure Check Causes Correction
Poor Fire If burner continues
to run (does not
lock out of safety),
poor fire. Inspect
fire.
After burner
Flame
Detector
Oil Supply
res,
immediatel
jumper across
flame
detector
terminals at
the primar
control.
If fire is good, fault
is in the flame
detector. Check
If burner loses
flame (does not
lock out on safety),
fault is in the fuel
.
Unbalanced fire Replace nozzle
Too much air − − lean short fire Reduce combustion air −
check combustion.
Too little air − − long dirty fire Increase combustion air −
check combustion.
Excessive draft Adjust barometric damper for
correct draft.
Too little draft or restriction Correct draft or remove
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
Partially plugged nozzle or
nozzle strainer
Replace CAD cell.
Secure connections or replace
cad cell holder and wire leads.
Check supply line for loose
connections and tighten
fittings.
1 inch) pump or drain out
water.
Replace nozzle.
table continued on next page
Page 22
Page 23
Troubleshooting: Burner Starts and Fires, but Loses Flame and Lock Out on Safety
connections to
py
leads). If burner
y
it is cycling on limit
p
Source CorrectionCausesCheckProcedure
Oil Supply Listen for pump whine Restriction in oil line Clear restriction.
Plugged fuel pump strainer Clean strainer or replace
pump.
Cold oil − outdoor tank Change to number 1 oil.
Troubleshooting: Burner starts and fires, but short cycles (too little heat)
Source Procedure Causes Correction
Thermostat Check thermostat. Heat anticipator set too low Correct heat anticipator setting.
Vibration at thermostat Correct source of vibration.
Limit Control Connect voltmeter
between line
voltage
connections to
primary control
(black & white
cycles due to
power interruption,
Power If voltage
fluctuates, fault is
in the power
source. Recheck
voltage at the
power source.
Thermostat in the path of a warm air
draft
Dirty furnace air filters Clean or replace filter.
Burner running too slow Increase blower speed to maintain
Blower motor seized or burned out Replace motor.
Blower bearings seized Replace bearings and shaft.
Blower wheel dirty Clean blower wheel.
Blower wheel in backward Reverse blower wheel.
.
Wrong motor rotation Replace with properly rotating wheel.
Restrictions in return or supply air
system
Adjustable limit control set too low Reset limit to maximum stop setting.
Loose wiring connection Locate and secure connection.
Low or fluctuating line voltage Call power company.
Shield thermostat from draft or
relocate.
proper temp. rise.
Correct cause of restriction.
Page 23
Page 24
Troubleshooting: Burner runs continuously (too much heat).
sconnect
Disconnect
control
CO
if less
for smoke
g
than a trace
temperature
g
is more than
Source Procedure Check Causes Correction
Thermostat Check Burner; if burner
turns off, fault is in the
thermostat circuit.
Di
thermostat
wires at the
primary
.
Primary
control
Check Burner: if burner
does not turn off, fault is
in the primary control.
Shorted or welded
thermostat contacts
Repair or replace the
thermostat.
Stuck thermostat bimetal Clear obstruction or replace
thermostat.
Thermostat not level Level thermostat.
Shorted thermostat wires Repair short or replace wires.
Thermostat out of
Replace thermostat.
calibration
Thermostat in cold draft Correct draft or relocate the
thermostat.
Defective primary control Replace the defective primary
control.
Troubleshooting: Burner runs continuously (too little heat).
Source Procedure Causes Correction
Combustion Check burner
combustion
for CO
Low
2 −
2
than 10%.
Check burner
combustion
for smoke −
High smoke
reading more
Check burner
combustion
stack
High stack
temperature
550F Net.
Oil Pressure Inspect fire
and check oil
pressure.
Too much combustion air Reduce combustion air.
Air leaks into heat exchanger
Correct cause of air leak.
around inspection door, etc.
Excessive draft Adjust barometric draft control for correct draft.
Incorrect burner head adjustment Correct burner head setting.
Dirty or plugged heat exchanger Clean heat exchanger.
−
Readjust burner.
Insufficient draft Increase draft.
Incorrect burner head adjustment Correct burner setting.
.
Too little combustion air Increase combustion air.
Too little blower air Increase blower speed to maintain proper
temp. rise.
Blower belt too loose (if equipped) Tighten blower belt.
−
−
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
Readjust registers or dampers.
dampers
Partially plugged or defective
Replace nozzle.
nozzle
Oil pressure is too low: less than
Increase oil pressure top 100psi.
100 psi.
Page 24
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