SCOTTY SS DB-202A User manual

SCOTTY SS
WOOD FURNACE
Model DB-202A
OWNER’S MANUAL
IMPORTANT
READ OWNER’S MANUAL THOROUGHLY BEFORE
INSTALLING FURNACE OR LIGHTING FIRE.
CONSULT LOCAL AUTHORITIES IF IN DOUBT
ABOUT YOU
R LOCAL FIRE SAFETY REGULATIONS.
ALL INSTALLATIONS MUST BE MADE IN
ACCORDANCE WITH LOCAL AND STATE OR
PROVINCIAL CODES WHICH MAY DIFFER FROM
THIS MANUAL.
IMPROPER INSTALLATION WILL RESULT IN
VOIDING OF WARRANTY.

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TABLE OF CONTENTS
Specifications 3
1.0 Operating instructions 4
1.1 Introduction 4
1.2 Wood-Burning 4
1.3 Storage of Wood 5
1.4 Maximum Solid-Fuel Charge 6
1.5 Maintenance 6
1.5.1 Cleaning 6
1.5.2 Servicing 7
1.6 Safety 7
1.7 Controls 7
1.8 Electrical Power Failure 8
1.9 Homeowner Checklist 9
2.0 Installation Instructions 9
2.1 Introduction to Installers 9
2.2 Uncrating 10
2.3 Locating the Furnace 10
2.4 Flue Pipe & Chimney 11
2.5 Clearances 12
2.6 ADD-ON to Another Furnace 13
2.7 Duct Connection 15
2.8 Control Systems 17
2.8.1 Static Pressure Drop Test 17
2.8.2 Temperature Rise Test 18
2.9 Additional Notes 19
2.10 Installers Checklist 19
3.0 Add-On to Oil Furnace 20
3.1 Combustion Air for Wood & Oil Furnaces 20
3.2 Duct Connections 21
3.2.1 S-Type Duct Connection 21
3.2.2 Divided Plenum 21
3.3 Control Systems 22
3.3.1 Add-On to Oil Control Kit “A” 22
4.0 Add On to Electric Furnace 23
4.1.1 Nortron 21 FRK 10H –25 Series 23
4.1.2 Other Approved Electric Furnaces 24
4.2 Duct Connection to an Electric Furnace 24
4.2.1 Duct Connection 25
4.2.2 Minimum Duct Sizes 25
4.2.3 L-Type Duct Connection & Frame 25
4.3 Installation Summary 25
4.4 Control System 25
4.5 Add-On to Electric Control Kit “E” 26

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DIAGRAMS
S202-1 Add-On to Oil –Clearances
S202-2Add-On to Oil –“S” type duct
S202-3A Gravity Return Air Kit
S202-3B Base for use on combustible floor
S202-4Add-On to Oil –Divided Plenum
S202-5A Add-On to Oil –Electrical Schematic Belt Drive
S202-5B Add-On to Oil –Electrical Schematic Direct Drive
S202-5C Add-On to Oil –Electrical Schematic Direct Drive
S202-6Add-On to Electric –Clearances
S202-7Add-On to Electric –Installation
S202-8Add-On to Electric –Nortron Wiring Schematic
S202-9Add-On to Electric –General Schematic
S202-10 Cleaning
S202-11 Approved Furnace Ductwork Configurations
S202-12 Prohibited Furnace Ductwork Configurations
Appendices
APPENDIX A –Warranty Rear Cover
Copyright 2004 Kerr Heating Products, 2004 Parrsboro Metal Fabricators Ltd.
KERR SCOTTY SS Wood Furnace Model DB-202A
Certified by the Canadian Standards Association (CSA) Sept. 1982 and Sept. 1988
Manufactured by: Parrsboro Metal Fabricators Ltd.
12118 Highway 209
P.O. Box 637, Crossroads
Parrsboro Nova Scotia, Canada
B0M 1S0

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SPECIFICATIONS
Length 34”
Width 22 1/2”
Height 43”
Shipping Weight 238 lb
Fire Box 1/8”plate Length 27 1/2”
Diameter 18”
Secondary Heat Exchanger 14 gauge steel
Fire Box Door Cast Iron 12” x 12”
Warm Air Plenum 21” x 30 1/2”
Return Air Plenum Not Applicable
Air Filter Size Not Applicable
Blower Size Not Applicable
Blower Motor Not Applicable
CFM 1000 (Required)
Smoke Pipe 7” Inside Diameter
Floor to smoke pipe center 36”
Output (max): 70,000 Btu/h
Fuel: Wood up to 24” logs
Electrical Rating: Volts 120, Cycles 60, Amps 15
NOTE –Keep this manual in a safe place for future reference. Follow manual carefully for the
correct way to install and operate this unit.
CAUTION –Do not fire this unit until operating instructions have been read and fully
understood.
INSTALL WOOD FURNACE ONLY ON A FURNACE DUCT SYSTEM AND CHIMNEY THAT
ARE IN GOOD CONDITION.
SAVE THESE INSTRUCTIONS

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1.0 OPERATING INSTRUCTIONS
1.1 INTRODUCTION
Congratulations on your purchase of the KERR SCOTTY SS Wood Furnace. Developed in
Atlantic Canada, this KERR Furnace has been designed to allow you to heat your home with
wood, one of North America’s most abundant fuels. Designed with you in mind, the KERR
SCOTTY SS Wood Furnace will provide you with many years of safe, efficient central heating.
To ensure you have a clear understanding of the operating procedures of this furnace, please
take the time to read the remainder of this section on operating procedures. If you have any
questions, your KERR dealer will be happy to answer them for you.
1.2 WOOD-BURNING
The SCOTTY SS Wood Furnace will burn most wood fuels, however it is recommended that
only dry, seasoned hardwood be used as much as possible since it affords cleaner, safer and
more efficient operation. Burning seasoned hardwood will leave less ash, soot and creosote
residue and will require fueling less often. Use smaller loads of wood on warmer days.
WARNING: DO NOT use chemicals or fluids to start the fire or during operation.
DO NOT burn driftwood or manufactured logs (compressed wood).
Before adding fuel to an existing fire turn up the thermostat for about five minutes or lift damper
chain to hold damper fully open for about one minute before opening the loading door. This
action will allow residual smoke to clear from the combustion chamber and reduce smoke
entering the basement during refueling.
Twice daily refueling may be sufficient in modern well-insulated homes. However, KERR
recommends that small fuel loads be added morning, noon and early evening and late
evening, rather than large quantities infrequently. A small intense fire will burn more efficiently
than a large smoldering fire in the SCOTTY SS Wood Furnace and will produce less creosote.
When refueling the SCOTTY SS, the remaining coals should be raked to the front of the
combustion chamber before adding any new fuel. Place the fresh supply of wood to the rear of
the combustion chamber. This gives more of an even cigar type fuel burn, rather than a large
hot fire to a slow amber fire. This will help create a more even and efficient burn. The
SCOTTY SS owner should attempt to gauge fuel quantities with outdoor temperatures; a little
practice will provide greater satisfaction and efficiency.
WARNING: This furnace is not to be used with an automatic stoker.
Keep firing door tightly closed and maintain door seal in good condition.

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CREOSOTE
Wood combustion is never 100% complete. Wood smoke always contains some unburned
gases and a mixture of unburned tar-like liquids. Apercentage of these materials will
condense out on any cool surface, leaving a dark brown or black substance with an unpleasant
acrid odor. This substance is commonly called creosote.
If these wood gases condense out on cool surfaces such as a cold chimney or a long smoke
pipe, they retain large amounts of water and will be very fluid. At higher temperatures the
condensed creosote will resemble tar (thick and tacky).
Creosote generation is highest during low heat outputs common with long smoldering burns.
Creosote generation is lowest during high heat outputs common with intense fires. It is
recommended that a small intense fire be used for best results against creosote build up even
though the wood furnace will require refueling more often.
Creosote generation is also higher when burning green wood. The moisture in the green wood
absorbs the heat from the fire, cooling the fire below the point at which the creosote can be
consumed. The low temperature smoke is then further cooled in the upper furnace chambers’
smoke pipe and chimney allowing large amounts of creosote to form.
To reduce creosote build-up during periods of low heat requirements (i.e. Spring and Fall) it is
recommended to fuel the wood furnace with smaller quantities of smaller diameter logs.
Matching fuel loads and heat requirements will result in cleaner combustion and higher
efficiency.
IN CASE A SERIOUS CREOSOTE FIRE BEGINS:
a) Close the damper door by disconnecting chain
b) Close all draft regulators
c) Throw 1/2 lb of coarse or table salt on the fire and close door immediately.
d) Call the FIRE DEPARTMENT at once!
Have a firmly established Emergency Procedure in place for the handling of a flue fire.
1.3 STORAGE OF WOOD
Once cut, green wood dries (or seasons), quickly at first and then at a slower and slower rate.
When the wood has been cut to the proper length and split, it should be piled outside during
the summer months. Place two poles on the ground to serve as rails to keep the firewood off
the moist ground. Stack the wood so that both ends of the logs are exposed to the air if space
is available, since more drying occurs through the cut ends than through the sides. This is true
even with wood that has been split. The woodpile should be under cover so that it will not
absorb moisture from the rain and snow before it is used, but still open on the sides and ends
to the drying effect of the wind and sun. Store wood in neat, well-supported piles.

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1.4 MAXIMUM SOLID-FUEL CHARGE
The maximum level for a solid-fuel charge is the middle of the loading door, or the level of the
handle. DO NOT OVERFILL. The KERR SCOTTY SS Wood Furnace will accept whole or
split logs up to 27 inch (686 mm) long, but a 24-inch (610 mm) log length is recommended for
convenience and ease in handling. Maximum damper gate opening is 9/16”. Do not tamper or
adjust to greater opening in an attempt to increase fire or over-firing and hazard may result.
1.5 MAINTENANCE
Some regular maintenance is necessary on the KERR SCOTTY SS furnace. A good practice
is to establish a routine for the storage of fuel, care of the appliance, and firing techniques.
1.5.1 CLEANING (Fig S202-10)
The KERR SCOTTY SS Wood Furnace must be cleaned regularly to maintain top efficiency.
The furnace needs cleaning more often when burning green wood, or during long periods of
low fire. When the KERR SCOTTY SS Wood Furnace is first installed the furnace heat
exchanger should be checked visually from the firebox and smoke pipe hole every week to
determine the rate at which creosote or ash is accumulating within the furnace. Cleaning
should be done whenever there is more than 1/4 inch of build-up on the heat exchanger or 3
inches of ash in the base. If the wood furnace is to be left unused for an extended period of
time (more than one month) then the appliance should be cleaned of all ash and residual left
from the burning of wood. See FIG. S202-10
CLEANING PROCEDURE:
1) Make sure fire is completely out and the furnace has cooled.
2) Remove the smoke pipe, located on the rear of the furnace heat exchanger.
3) The heat exchanger is now accessible for cleaning.
4) Use the scraper provided to remove all soot and ash from the furnace heat exchanger
and exposed surfaces.
5) Scrape all residue ash in the top heat exchanger towards the front of the furnace where it
will fall into the firebox.
6) Always check flue pipe for creosote or ash build-up in the pipe and clean if necessary.
7) Reinstall the smoke pipe making sure that all joints are secured with at least 3 sheet
metal screws.
8) Check chimney cleanout for ash build-up and remove any accumulation.
9) Residue may be removed from the firebox or left to be burnt during the next fire. It is
good practice to leave a layer of ash approximately one inch deep in the base of the
firebox.
DISPOSAL OF ASHES
Ashes should be placed in a metal container with a tight fitting lid. The closed container of
ashes should be placed on a non-combustible floor or on the ground, well away from all
combustible materials, pending final disposal. If the ashes are disposed of by burial in soil or
otherwise locally dispersed, they should be retained in the closed container until all cinders
have thoroughly cooled. IMPORTANT –No other waste shall be placed in this container.
WARNING –Ashes usually contain live dormant coals, which may burn for many hours after a
recognizable flame has disappeared. Use extreme caution when handling and disposing
ashes.

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1.5.2 SERVICING
The furnace air filter must be checked monthly and replaced when necessary. Annually
lubricate the blower motor, if it is not permanently lubricated, with 4-6 drops of SAE-30 oil in
each bearing.
CAUTION: Failure to keep air filter clean will result in poor furnace performance and
possible damage to wood furnace heat exchanger.
1.6 SAFETY
If the furnace overheats due to improper operation the following precautions should be taken:
1) DO NOT shut off power. Blower must be kept running to disperse excessive heat.
2) Manually close the damper door by unhooking the chain.
3) Check controls for proper operation before starting a new fire.
WARNING–The maximum opening of the combustion air damper is preset at the factory.
DO NOT adjust the stop or attempt to increase the combustion air by any means.
1.7 CONTROLS
Thermostat
The primary control is the room thermostat located near the center of the house on the main
floor or near an existing thermostat. The thermostat operates the damper motor to open and
close the damper door thus allowing more or less air into the combustion area to control the
fire.
Fan and Limit
The fan and limit controlmounted in the plenum controls the operation of the circulating blower
and prevents the furnace from over-heating. When the air temperature in the plenum reaches
the “ON” set point of the fan switch (usually 140º F (60º C)) the blower starts and runs until the
plenum cools to the “OFF” set point (usually 100º F (38º C)) when the blower is switched off.
The limit function in this control is usually set at (280º F (138º C)) and will override the room
thermostat to close the damper door if the furnace overheats, and will also prevent the oil
furnace from starting.
1.8 ELECTRICAL POWER FAILURE (Fig S202-3A)
If no one is home during a power failure, the damper will automatically close and some gravity
heating will take place. Combustion air will continue to enter through the secondary air holes
and a fire should be maintained.
IMPORTANT –This furnace is CSA certified for operation under Power Failure only if optional
gravity air inlet kit is installed.

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For optimum heating during a power failure follow the procedure listed below:
1) Remove the power failure gravity air inlet cover before starting or refueling during power
failure. The cover is an option available from your KERR dealer. The kit must be installed
on the cabinet side directly opposite to the entry of the blower or oil furnace “S”
connection ductwork. (See Fig. S202-3A).
2) Manually open the blower compartment access door of wood or connected oil furnace to
allow gravity flowing air to all areas. (Check with your installer)
3) Place a coin under the damper flap in such a way that it will fall clear when power is
restored.
4) Maintain a careful watch on the furnace temperature. If it should exceed 200º F (95º C)
close the damper door.
5) Do not leave the furnace unattended in this position.
6) Refuel frequently with small load to maintain a small fire at 1/2 normal maximum volume.
7) Do not expect to maintain maximum comfort under no power conditions.
8) Do not allow anyone who is unfamiliar with the operation of the furnace to attend it during
a power failure.
1.9 HOMEOWNER CHECKLIST
a) Keep area around unit clean and clear of combustibles.
b) Use only dry wood. DO NOT burn garbage, gasoline or naphtha.
c) Load carefully.
d) Remove ashes as directed.
e) Watch for soot build up in smoke pipe –clean regularly.
f) Clean furnace heat exchanger regularly.
g) Be aware of danger due to over firing of the unit.
h) Do not load above maximum loading level (middle of loading door) or overheating may
result.
i) This unit is NOT suitable for automatic stoking.
j) Load carefully. Do not slam fuel against rear or sides of firebox this may damage the
firebox.
k) Always observe the following minimum clearances to combustible materials –Front 48”
(1220 mm); one side 6” (152 mm); opposite side and rear 24” (610 mm); and flue pipe 18”
(465 mm).

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l) Do not store solid fuel within the above clearances or within the space required for
charging and ash removal.
m) Establish a routine for storage of fuel, care of the appliance, and firing techniques.
2.0 INSTALLATION INSTRUCTIONS
2.1 INTRODUCTION TO INSTALLERS
Before installing this KERR SCOTTY SS Wood Furnace, please read the following instruction
manual carefully. This unit is designed to be an add-on to a central heating furnace to provide
complete central heating in medium sized well-insulated homes. Before installing be sure unit
is properly sized for the intended application. Warranty does not cover misapplication of unit.
Applicable Standards
The KERR SCOTTY SS Wood Furnace must be installed in accordance with the requirements
of the National Fire Protection Association codes, the Canadian Heating, Ventilation and Air
Conditioning Code, The National Board of Fire Underwriters, and the CSA Standards for solid
fuel burning equipment as outlined in B365-01. In all cases consult your local authorities and
fire insurance company for specific regulations.
2.2 UNCRATING
When you receive your KERR SCOTTY SS Wood Furnace, check it carefully to ensure that all
components are present and in good condition. If there has been any damage or loss in
transportation, please notify the carrier and retailer at once. Inspect for the following:
1) Firebox/Heat exchanger
2) Poker/Coals rake
3) Marking template (return air and power failure bypass inlet)
CONTROL KIT A (Oil add-on), or E(Electric add-on) selected according to installation, which
includes:
1) L4064R Fan and Limit Control
2) Control Mounting Plate
3) Damper Motor
4) Thermostat (T822D or equivalent)
5) Wiring Harness and Parts
6) Switching Relay R8405C (8A05A –4) –Kit “A” & “E” only
NOTE: Some parts may be packed inside furnace firebox. Check shipment carefully before
assuming shortage.

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2.3 LOCATING THE FURNACE (Fig S202-1, Fig S202-3B)
The location of the furnace must be as close as possible to the tile-lined brick chimney, or
factory-built solid-fuel approved chimney (ULC S629). Keep in mind also the day-to-day
operation, and place for ease of fueling and cleaning. KERR recommends installation, if
possible, in a central location in relation to the outlet registers and the use of large warm air
ducts to improve heat distribution during a power failure.
It is important to provide adequate combustion air to the furnace. It may be necessary to add a
ventilator to an exterior wall of a closed furnace room or an airtight basement.
The furnace must be installed so that the clearances as shown in Figure S202-1, or those of
local authorities are met. Also if the furnace must be installed on a combustible floor, a non-
combustible base must be built as shown in Figure S202-3B. Two layers of hollow masonry
block (4” thick) are placed at right angles to each other so that the ventilation holes of one
layer are opposite to those of the other layer. Also there must be a minimum of one layer of
fireproof board and one layer of 26 galvanized metal beneath the masonry blocks. This base
must extend beyond the furnace to a minimum distance of 18 in (457 mm) in front and 8 in.
(204 mm) on all sides.
2.4 FLUE PIPE & CHIMNEY
The furnace must be located to meet a minimum venting distance needed between the furnace
and the flue. It should also be ducted so that there are a minimum number of elbows used.
The flue pipe must be installed with a gradual rise of 1/2” or more per foot from the furnace to
the flue.
NEVER ALLOW THE SMOKE PIPE TO RUN DOWNHILL TO THE FLUE!
The smoke pipe and chimney should be at least 7 inches in diameter. The flue pipe or a
chimney may be of different cross-sectional area than that of the appliance smoke pipe,
provided that sufficient draft is available at the appliance. Space must be provided around the
smoke pipe and the back of the furnace to allow easy access for the purpose of cleaning.
Smoke pipes must not be lighter than 24 gauge black steel. All pipes must be securely
fastened with at least 3 sheet metal screws at every joint, and properly supported.
Always meet or exceed flue pipe clearance specifications -18” clearance from flue pipe to
combustibles in all directions.
Connect the furnace only to an approved chimney suitable for solid fuel appliances, which has
a flue size equal or greater than furnace smoke pipe outlet area. The chimney must be
installed with proper clearances above roof and from adjacent structures and trees. If a
masonry chimney is used it must be in good condition and be equipped with a tile liner. Flue
thimble or flue pipe must not extend into the chimney flue, as it will reduce the draft.
Connect only to a flue or chimney capable of maintaining a negative draft of .05” w.c. at all
times and conditions.

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WARNING: If this setting is exceeded it could cause a solid fuel fire to burn out of control.
We recommend that the KERR SCOTTY SS Wood Furnace be connected to its own chimney.
However, two or more fuel-fired appliances, other than fireplaces, wood stoves or incinerators,
may be connected to the same chimney.
The National Standard of Canada, Installation Code for Solid-Fuel-Burning Appliances and
Equipment, CSA-B365-01 clause 5.2.9 states that:
Two or more appliances shall not be connected to the same chimney flue unless:
a. The appliances are located on the same story;
b. A negative pressure is maintained at the flue collar of each appliance;
c. Each appliance is provided with a means to control the rate of flow of air or flue gases
through the appliance combustion and heat exchanger chambers. Where limitations on
flue pressure (draft) are contained in the manufacturer’s instructions, such means shall be
capable of maintaining at the flue collar, the pressure specified by the appliance
manufacture; NOTE: For the purpose of this Clause, draft controls include ash pit air
control dampers, dampers or draft slides wherever located, over-fire and flue pipe key
dampers, and check draft controls located on or in the flue pipe.
d. The flue pipes of the appliances are connected to a manifold as close to the chimney as
practicable or directly to the chimney in the following order:
(i) If only solid fuel is used, the flue pipe from the smallest appliance shall be on top
(downstream);
(ii) If different fuels are used as permitted in Clause 5.2.7 CSA-B365-01, the oil flue pipe
shall be on top (downstream); and the solid fuel flue pipe on the bottom (upstream);
and
e. The chimney flue is capable of venting the flue gas by natural draft when all appliances
not interlocked to prevent simultaneous firing are firing at their maximum rate at the same
time.
When installing a wood-burning appliance to an existing chimney carefully inspect entire
chimney for the presence of old inlet holes, which may be improperly covered by metal caps or
other unacceptable means. Fill any openings with brick and mortar to ensure no hazardous
openings exist.
2.5 CLEARANCES (Fig S202-1)
The KERR SCOTTY SS Wood Furnace is to be installed in accordance with National Building
Code or local regulations. Allowances front and rear must be made for cleaning and servicing.
NOTE: Regardless of minimum clearances to combustibles for safety reasons, a minimum
clearance of 30 inches (765 mm) should be allowed at the furnace rear for cleaning
(due to length of cleaning rake) and access to smoke pipe.

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Minimum safety clearances to combustibles are:
Front 48” 1220 mm
One Side 6” 152 mm
Other Side (for rear access) 24” 610 mm
Rear (see Note above) 24” 610 mm
Flue Pipe to combustible, other furnace & electrical wiring 18” 457 mm
Wood Furnace Above Plenum and 6’(1.8 m) of duct 6” 152 mm
Supply Duct beyond 6’ 2” 50 mm
Return Duct Plenum and 6’(1.8 m) of duct on solid fuel burning warm air furnaces
3” 76 mm
This clearance will also allow adequate combustion air to reach the furnace.
WARM AIR DUCT & PLENUM CLEARANCES
The following clearances must be observed and must meet all local building, electrical and fire
codes. Follow the National Standard of Canada, Installation Code for Solid Fuel Burning
Appliances and Equipment, CSA-B365-01; the National Board of Fire Underwriters and in the
US the NFPA codes.
The KERR SCOTTY SS Wood Furnace warm air plenum and first 6ft (1.8 m) of warm air
supply duct in any direction must be installed observing a minimum of 6 inches (152 mm)
clearance from the joists or combustible materials. Beyond the first 6ft (1.8 m) of supply duct,
a 2 inches (51 mm) minimum clearance must be maintained between the warm air supply
ducts and all joists or combustible material (See Fig. S202-1).
Return air ducts, including main ducts and branch ducts, on solid fuel burning warm air
furnaces shall be installed to provide at least 3 inches (76 mm) clearance to combustible
construction for the first 6ft (1.8 m) away from the furnace plenum. This requirement is not
intended to apply to return air ducts serving an oil-fired, gas fired or electric furnace to
which an add-on furnace is connected.
It is recommended that a non-combustible rigid board be fastened on the underside of the floor
joists in the area of the ceiling above the furnace, warm air ducts and smoke pipe.
2.6 ADD-ON TO ANOTHER FURNACE (Fig S202-5B, Fig S202-5C)
The KERR Wood Furnace may be installed very satisfactorily in conjunction with another
furnace as tested by CSA under standard B365. In this installation the wood furnace is
connected downstream in series with a new or the existing electric or oil furnace. The blower
from the existing furnace provides the air circulation. The SCOTTY SS may only be added in
series downstream from an oil furnace having an input rating (on original nameplate) of
between 0.75 and 0.90 gph (US) or SI equivalent.
For oil furnaces having multi-speed blowers with continuous circulation capability.
Add-on furnaces such as the Kerr Scotty SS can be installed with oil fired warm air furnaces
such as the Kerr KD Gemini that have continuous blower circulation capability. A relay must
be used if the furnace is to maintain the continuous circulation feature. The wiring diagram for
this installationis Fig. S202 –5B.
Disconnect Low Speed Circulation Fan Switch if Optional Relay is not used.
Fig. S202 –5C.

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Disconnecting the circulation fan low speed switch.
If the red wire from the circulation fan switch, in the furnace wiring box, were disconnected
from the yellow wire leading to the blower compartment and both, red and yellow wires
marretted off then there would be no need for the switching relay (Honeywell R4222D 1013 or
equiv.).
In that case the two blue wires would marrette together at location “A” of “Add-On Wiring”
diagram, and provide power to the blower on high speed (black wire). The two blue wires being
1.) Wood fan “ON” control and, 2.) Oil fan “ON” control.
Also 120 Volts can be fed back through any unused wire from the blower. All unused wires
should be marretted off.
Low Speed Switching Relay (This is an optional part) Fig. S202–5B
The Honeywell (R4222D 1013 or equivalent.) relay is to prevent power from being fed to the
blower motor on two motor windings at the same time.
1) The red wire from the circulation fan switch (Low Speed) on the oil furnace.
2) The blue heating wire from the wood fan limit control on high speed.
This relay will disconnect the circulation fan low speed switch and connect the high speed to
the blower motor when there is a call for heat.
Items required:
1) Switching Relay R4222D 1013 (120 V Coil, 12 amp @ 120 Vac), or equivalent.
2) Junction box (4” x 4”) and cover.
3) Square extension box (4”x 4”gyproc extension).
4) Two plastic universal bushings or junction box connectors.
5) White wire (12”), two insulated spade connectors.
6) Black wire (6”), two insulated spade connectors.
7) Brown wire (12”), two insulated spade connectors.
8) Yellow wire (12”), two insulated spade connectors.
9) Two cabinet mounting screws.
INSTRUCTIONS
1) Turn off power to the oil furnace and wood furnace.
2) Mount the switching relay in a junction box, in the blower compartment near the blower
motor and motor wires. (If possible mount relay on rubber or foam pad to reduce noise in
ductwork).
3) Remove the white neutral wire from the blower motor, and connect it to a selected neutral
side of the relay coil.
4) Connect the white wire (item 2) to the second spade of the selected neutral side of the
relay coil, and the other end into the blower neutral wire location (where initial white wire
was removed).
5) Remove the black high-speed wire from the blower motor (this should be the selected
blower heating speed), and connect it to the power side of the relay coil (no relay spade
#).
6) Connect the black wire (item 3) to the second spade of the selected power side of the
relay coil, and the other end of the wire on to one side of the normally open contacts
(relay spade #1).
7) Connect the brown wire (item 4) to the high-speed connection on the blower motor, and
the other end of the wire on to the other side of the normally open contacts (relay spade
#3).
8) Remove the yellow low-speed wire from the blower motor (this should be the selected

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low-speed in the furnace wiring box), and connect it to one side of the normally closed
contacts (relay spade #4).
9) Connect the yellow wire (item 5) to the low-speed connection on the blower motor, and
the other end of the wire on to the other side of the normally closed contacts (relay spade
#5).
10)Turn on power to the oil furnace and wood furnace. Check relay operation.
2.7 DUCT CONNECTION(Fig S202-1, Fig S202-2)
See figure S202-11 for Approved Furnace Ductwork Configurations.
See figure S202-12 for Prohibited Furnace Ductwork Configurations.
The use of A/C coils is not recommended unless special arrangements are made.
Minimum cross-sectional area of ductwork from furnace should be approximately 160 square
inches with equal or larger size for return air.
The furnace must not be installed as a gravity system as the controls are not designed for this
type of operation.
The dimensions and locations of permissible openings in casings for ducts, blower, or
emergency air are clearly identified on the furnace or on specific templates enclosed in the
firebox.
Make or enlarge the openings in the wood furnace casing exactly as identified for add-on
connection and on the appropriate side, trim the furnace insulation flush with cut opening.
Fasten edges of insulation securely with metal straps or bend tabs of duct starting collar over
insulation edge to hold it in place.
DO NOT use duct elbows having an inside radius of less than 6 in (152 mm). Use only 16 x 20
in. duct “S” type interconnection for this furnace. Make all duct connections for the “S” type
interconnection (See Fig. S202-2).
CAUTION:
a) The DB-202A is certified for installations using a divider in the plenum of the oil furnace.
b) An ADD-ON unit must only be connected to a furnace, duct system and chimney, which
are in good operating condition.
c) DO NOT relocate any of the safety controls in the original furnace installation.
d) Operate the oil-fired unit periodically to ensure that it will operate satisfactorily when
needed.
e) DO NOT connect to duct work so that a reverse flow is possible.
f) Before attempting installation, determine if there is suitable space available in the furnace
area for the furnace connection outlined herein.
g) The external static pressure in the warm air duct to the house of the original system must
be measured prior to any changes to the system. These are to be reset to the same
values after the add-on procedure to maintain airflow through the oil furnace.
An important requirement of this type of installation is that when installed in an existing system
the main ducts may have to be lowered to assure proper and safe clearances from
combustible material. (See Fig. S202-1 and S202-2).

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After all connections are made a static pressure test and/or temperature measurement must
be made in the outlet plenum of the wood furnace. This is a simple procedure and is outlined
as follows using a Dwyer Model 25 or equal inclined manometer.
a) Drill hole in wood outlet plenum
b) Level inclined manometer and adjust to zero, insert manometer tube (Pressure end)
c) With all duct work and doors in place static pressure should measure 0.2 in (50 Pa) with
blower running.
Pressure may be corrected by the following measures:
a) Change blower pulley size (usually decrease)
b) Change blower motor pulley (usually increase)
c) Increase return air duct area (if restricted)
CAUTION –Current draw by blower motor should be checked after making any pulley change.
If motor now draws greater current than that shown on the nameplate a larger more powerful
motor must be installed.
IMPORTANT –DO NOT change the blower.
As an alternative to the static pressure test method, the installer may make adjustments on the
basis of temperature measurement. For this test the wood furnace must be at full operating
temperature.
Take one temperature measurement in the front of the oil furnace plenum 12” to 16” up or
approximately center. Take a second measurement in the wood furnace plenum (same
position). Subtract one measurement from the other to arrive at a temperature difference (TD).
The TD must be between 40º F and 100º F during normal operation, and ideally around 80º F.
The same adjustment procedure for pulleys applies for correction when using this method.
CAUTION –Most thermometers have a large time lag in reaching accurate measuring levels.
It is important that this interval be measured for your thermometer by immersing it in boiling
water and observing the time required for it to reach correct reading.
IMPORTANT –This equipment shall be installed in accordance with the instructions of the
manufacturer and in a manner acceptable to the regulatory authority by mechanics
experienced in such services. When required by the regulatory authority, such mechanics
shall be licensed to perform this service.
The installation shall comply with the applicable requirements of CSA standard B365,
Installation Code for Solid Fuel Burning Appliances and Equipment, and if changes are made
to the oil furnace this shall comply with CSA standard B139, Installation Code for Oil Burning
Equipment.

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2.8 CONTROL SYSTEM
The fan and limit control and the damper motor should be located as shown in Figure S202-2.
T822 –Room Thermostat –Wood Furnace
The primary control is the room thermostat located near the center of the house in the main
floor or near an existing thermostat. The thermostat operates the damper motor to open and
close the damper door thus allowing more or less air into the combustion area to control the
fire.
M847 –Damper Motor
The damper door lever should be attached to the damper motor wheel with the chain included.
Be sure the damper door is fully closed and the damper motor is not powered. Connect the
chain to the damper door level and to the bottom hole in the damper motor wheel. As a final
adjustment bend the top chain link slightly to vary the damper position.
L4064R –Wood Furnace/Limit Control
The fan and limit control mounted in the plenum controls the operation of the circulating blower
and limits the air temperature to prevent the furnace from overheating.
Set Points
1) “ON” is usually set to 140?F (60°C). It turns on the circulating blower when the air
temperature in the plenum reaches this temperature.
2) “OFF” is usually set to 100°F (38°C). It turns off the circulating blower when the
circulating air temperature in the plenum drops to this temperature.
3) “Hi limit” is preset to 280°F (138°C). This will over ride the room thermostat to close fire
damper door if the wood furnace overheats.
ALL ELECTRICAL WIRING MUST CONFIRM TO NATIONAL AND LOCAL CODES.
2.8.1 STATIC PRESSURE DROP TEST (Fig S202-4)
After all connections are made and the ADD-ON installation is complete check the static
pressure in the outlet plenum of the wood furnace. This is done with an inclined manometer,
similar to the Dwyer Model 25, capable of reading 0.2” w.c. to 0.50” of water column.
Procedure:
1) Drill hole in wood outlet plenum as indicated, in fig. S202 -4
2) Level the inclined manometer, and adjust the zero.
3) Insert the pressure tube in the hole in the wood outlet plenum.
4) With all duct work and blower doors in place the static pressure at point “P” in the wood
outlet plenum should measure 0.2” watercolumn (50Pa) with the blower running.

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If the pressure is less than 0.2” w.c. (50 Pa) or that recommended by the electric furnace
manufacturer, it may be corrected by the following means:
1) Change blower pulley size (usually decrease).
2) Change blower motor pulley (usually increase).
3) Increase return air duct (if restricted). If pressure is less than 0.2” w.c. (50Pa) It may be
corrected by increasing the flow area in the return air duct.
4) If it is a direct drive blower in an oil furnace, you may increase the blower speed.
PRESSURE CORRECTION –ELECTRIC FURNACE WITH DIRECT DRIVE BLOWER:
If pressure is less than 0.2” w.c. (50Pa) It may be corrected by increasing the flow area in the
return air duct.
Nortron 21B15H –Series B and similar.
CAUTION –Do not change the wiring of the direct drive blower motor.
IMPORTANT –DO NOT CHANGE BLOWER.
CAUTION –Check the blower motor current draw after making any pulley change. If the
blower motor now draws a larger current than that shown on the nameplate a larger more
powerful motor must be installed.
2.8.2 TEMPERATURE RISE TEST
As an alternative to the static pressure test the installer may make adjustments on the basis of
temperature measurements. For this test the wood furnace must be at full operating
temperature.
Procedure:
1) Take one air temperature T1 through a small hole in the front of the electric outlet duct.
Make sure you leave the thermometer in the air stream long enough for the reading to
stabilize.
2) Take a second air temperature T2 through a small hole in the front of the WOOD furnace
outlet plenum.
3) The temperature difference T2 –T1 is the air temperature rise and must be within the
range 40-100°F during normal operation. Ideally it should be 80°F.
4) Use the same adjustments as in 2.8.1 above to correct a temperature rise above 100°F or
below 40°F.
CAUTION –Most thermometers take several minutes to reach their true reading. With the
thermometer in the same position in the hot air stream take two successive readings 10
minutes apart –if they are the same the temperature reading may be taken as stabilized.
To check your thermometer accuracy immerse it in boiling water –it should read 212°F.

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2.9 ADDITIONAL NOTES
-DO NOT relocate any of the safety controls in the original oil furnace installation
-DO NOT relocate any of the safety controls in the electric furnace installation.
-Operate the oil-fired unit or electric furnace periodically to ensure that it will operate
satisfactory when needed.
-DO NOT connect ductwork so that reverse flow is possible.
-Before attempting installation, determine if there is space available in the furnace area for
the proposed ADD-ON.
-The external static pressure in the warm air duct to the house in the original system must
be measured prior to any changes in the system. The static pressure is to be reset to the
same value after the ADD-ON is installed to maintain the airflow through the oil/electric
furnace.
-An ADD-ON unit must only be connected to an oil furnace, duct system and chimney,
which are in goodoperating condition.
-DO NOT interconnect an add-on with duct elbow less than 6” (152 mm) inside radius.
-CAUTION: MAINTAIN COMBUSTION AIR TO FURNACES –AIR STARVATION IS
DANGEROUS.
2.10 INSTALLERS FINAL CHECKLIST
DUCTWORK INSPECTION
1) Furnace ducted properly?
2) Proper duct clearances maintained?
FURNACE INSPECTION
1) DO NOT use firebrick in the furnace
2) Check settings on fan limit controls.
WIRING INSPECTION
1) Is main disconnecting switch within view?
2) Wiring cables protected from heat and not touching hot surfaces?
FLUE AND SMOKE PIPE INSPECTION
1) Flue inner size equivalent to 7” round or larger?
2) Separate entry and lower to flue for both solid-fuel and oil or gas smoke pipes?
3) Smoke pipe 24 gauge or better?
4) Smoke pipe secured by screws?
5) Draft regulator (if used) set at .05” w.c. maximum?
6) Clearances of smoke pipe 18” or better from combustible material?
Metal protection is recommended.

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DEALER TO INSTRUCT HOMEOWNER
1) Keep area around unit clean.
2) Use DRY wood only. Hardwood is preferred.
3) Load carefully.
4) Load levelno higher than center of door.
5) Remove ash regularly as directed.
6) Look for soot build up in smoke pipe.
7) Danger of flue fire if poor fuel or poor maintenance produces creosote buildup.
8) Operation of unit during power failure. (i.e. manual operation.)
9) When shutting down for extended periods, clean unit thoroughly.
3.0 ADD ON TO OIL FURNACE (Fig S202-1)
Scotty SS DB-202A may be connected downstream of a new or existing oil furnace. The
blower from the existing oil furnace provides the air circulation. The Scotty SS DB-202A may
only be connected downstream from an oil furnace having an input rating (on original name
plate) of between 0.75 and 0.90 USGPH, or at least 1000 cfm.
For details and required duct clearances see Fig. S202-1. The minimum cross-sectional area
of supply ductwork from the wood furnace should be 100 Square inches. The return air duct
area should be equal or larger.
As the controls are not suitable, the Scotty SS DB-202A must NOT be installed for normal
operation as a GRAVITY system.
IMPORTANT –This equipment should be installed in accordance with the manufacturer’s
instructions in a manner acceptable to the regulatory authorities and by technicians
experienced in such work. When required by the regulatory authority, such technicians should
be licensed to perform this service.
The installation shall comply with CSA standard B365, Installation Code for Solid Fuel Burning
Appliances and Equipment. Changes made to the oil furnace installation shall comply with
CSA standard B139, Installation Code for Oil Burning Equipment.
3.1 COMBUSTION AIR FOR WOOD & OIL BURNING APPLIANCES
It is important to provide adequate combustion air to the furnace. It may be necessary to add a
ventilator to an exterior wall of a closed furnace room or an airtight basement.
Air inlets of at least 100 square inches free area (1.5 in2/1000Btu) must be provided to the
room occupied by the wood fired or oil fired furnace. These fresh air inlets must provide or
allow free access of fresh outside air to the furnace. At no time or under any circumstances
should a wood or oil-burning appliance be starved of combustion air.
The appliance must at all times be able to maintain the approved stack draft. The barometric
draft regulator must be installed on the furnace smoke pipe in the same room or at least in
such a way that there is unrestricted free passage of air between the combustion air inlet to the
furnace or burner and the barometric draft regulator.
Operating a wood or oil fired appliance with inadequate combustion air could be hazardous.