Scotsman DB-101 User manual

SCOTSMAN
WOOD FURNACE
Model DB-101
OWNER’S MANUAL
IMPORTANT
READ OWNER’S MANUAL THOROUGHLY BEFORE
INSTALLING FURNACE OR LIGHTING FIRE.
CONSULT LOCAL AUTHORITIES IF IN DOUBT
ABOUT YOUR 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 2
1.0 Operating Instructions 3
1.1 Introduction 3
1.2 Wood-Burning 3
1.3 Storage of Wood 4
1.4 Maximum Solid-Fuel Charge 5
1.5 Maintenance 5
1.5.1 Cleaning 5
1.5.2 Servicing 6
1.6 Safety 6
1.7 Controls 6
1.8 Electrical Power Failure 7
1.9 Homeowner Checklist 8
2.0 Installation Instructions 8
2.1 Introduction to Installers 8
2.2 Uncrating 9
2.3 Locating the Furnace 9
2.4.1 Combustion Air Supply 10
2.4.2 Flue Pipe & Chimney 10
2.5 Clearances 11
2.6.1 Free-Standing 13
2.6.2 Add-On 13
2.7 Duct Connection 14
2.8 Control System 16
2.9 Installers Checklist 17
Appendices
APPENDIX A – Warranty
DIAGRAMS
S101-1 Add-On to Oil – Clearances
S101-2 Add-On to Oil – “S” type duct
S101-3 Gravity Return Air Kit
S101-4 Base for use on Combustible Floor
S101-5 Controls Placement
S101-6 Add-On to Oil – Electrical Schematic Belt Drive
S101-7 Classic Oil, Add-On to Wood – Electrical Schematic with Relay
S101-8 Classic Oil, Add-On to Wood – Electrical Schematic without Relay
S101-9 Classic Air Oil, Add-On to Wood – Electrical Schematic with Relay
S101-10 Classic Air Oil, Add-On to Wood – Electrical Schematic without Relay
S101-11 Oil Furnace with EVO (9200i) Controls, Add-On to Wood
S101-12 Oil Furnace with MAX (9300i) Controls, Add-On to Wood
S101-13 Clearances Free Standing
S101-14 Cleaning
S101-15 Free Standing Wiring Diagram
S101-16 Approved Furnace Ductwork Configurations
S101-17 Prohibited Furnace Ductwork Configurations

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KERR SCOTSMAN Wood Furnace Model DB-101-ADD
Tested and Listed by: Energy Testing Laboratory of Maine
Certified by the Canadian Standards Association (CSA) Sept. 1981
COSP No. WCP 001 – Free-Standing
COSP No. WCP 005 – Add-On
Manufactured by: Parrsboro Metal Fabricators Ltd.
P.O. Box 637, Crossroads
12118 Highway 209
Parrsboro Nova Scotia Canada
B0M 1S0
www.KerrEnergySystems.com
SPECIFICATIONS
Length 39”
Width 29”
Height 44 1/2”
Shipping Weight 392 lb.
Fire Box 1/8”plate Length 36”
Diameter 23”
Secondary Heat Exchanger 14 gauge steel
Fire Box Door Cast Iron 13” x 13”
Warm Air Plenum 32” x 25 3/8”
Return Air Plenum N/A
Air Filter Size 16” x 20” x 1”
Blower Size G10 – 10
Blower Motor 1/3 hp
C.F.M. 1000 (Required)
Smoke Pipe 7” Inside Diameter
Floor to smoke pipe center 38 3/4”
Output (max) 140,000 Btu/h
Fuel ood 30” 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 Scotsman 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 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 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 furnace and will produce less creosote.
When refueling the furnace, 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 furnace
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. A percentage 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:
oClose the damper door by disconnecting chain.
oClose all draft regulators.
oThrow 1/2 lb. of coarse or table salt on the fire and close door immediately.
oCall 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 furnace will accept whole or split logs up to 34 in. (865 mm)
long, but a 30 in. (765 mm) log length is recommended for convenience and ease in handling.
Maximum damper gate opening is 11/16”. 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 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. S101-14)
The 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 furnace is
first installed the 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.
CLEANING PROCEDURE
oMake sure fire is completely out and the furnace has cooled.
oRemove the cleanout cover, located on the rear of the furnace heat exchanger, the
smoke pipe, and internal breech baffle.
oThe heat exchanger is now accessible for cleaning.
oUse the scraper provided to remove all soot and ash from the furnace heat exchanger
and exposed surfaces.
oScrape all residues in the top heat exchanger towards the rear of the furnace where it will
fall into the firebox.
oAlways check flue pipe for creosote or ash build-up in the pipe and clean if necessary.
oReinstall cleanout cover, internal breech baffle (See section 2.4.2) and smoke pipe
making sure that all joints are secured with at least 3 sheet metal screws.
oCheck chimney cleanout for ash build-up and remove any accumulation.
oResidue 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.

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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.
1.5.2 SERVICING
The furnace air filter must be checked monthly and replaced each year. 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 heat exchanger.
1.6 SAFETY
If the furnace overheats due to improper operation the following precautions should be taken:
DO NOT shut off power. The blower must be kept running to disperse excessive heat.
Manually close the damper door by unhooking the chain. 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 control mounted 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 140°F (60°C), the blower starts and runs until the
plenum cools to the “OFF” set point, usually 100°F (38°C), when the blower is switched off.
The limit function in this control is usually set at 280°F (138°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.

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1.8 ELECTRICAL POWER FAILURE (Fig. S101-3)
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.
For optimum heating during a power failure follow the procedure listed below:
For Power Failure operation 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.
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).
Place a coin under the damper flap in such a way that it will fall clear when power is restored.
Maintain a careful watch on the furnace temperature. If it should exceed 200°F (95°C) close
the damper door.
Do not leave the furnace unattended in this position.
Refuel frequently with small loads to maintain a small fire at 1/2 normal maximum volume.
Do not expect to maintain maximum comfort under no power conditions.
Do not allow anyone who is unfamiliar with the operation of the furnace to attend it during a
power failure.

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1.9 HOMEOWNER CHECKLIST
oKeep area around unit clean and clear of combustibles.
oUse only dry wood. DO NOT burn garbage, gasoline or naphtha.
oLoad carefully.
oRemove ashes as directed.
oWatch for soot build up in smoke pipe – clean regularly.
oClean furnace heat exchanger regularly.
oBe aware of danger due to over firing unit.
oDo not load above maximum loading level (middle of loading door) or overheating may
result.
oThis unit is NOT suitable for automatic stoking.
oLoad carefully. Do not slam fuel against rear or sides of firebox. This may damage the
firebox.
oAlways 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).
oDo not store solid fuel within the above clearances or within the space required for
charging and ash removal.
oEstablish 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 furnace, please read the following instruction manual carefully. This unit
is designed to be a freestanding or add-on 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 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.

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2.2 UNCRATING
When you receive your 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:
oFirebox/Heat exchanger
oPoker/coals rake
oMarking template (return air and power failure bypass inlet)
oInternal Breech Baffle (Scotsman only)
oFor free-standing model optional equipment required:
a) BC-10 Blower Kit (Scotsman only)
b) Control Kit “B” (Scotsman only)
CONTROL KIT A (Oil add-on), B(free-standing with BC–10 blower) or E(Electric add-on)
selected according to installation, which includes:
oL4064R Fan and Limit Control
oControl Mounting Plate
oDamper Motor
oThermostat (T822D or equivalent)
oWiring Harness and Parts
oSwitching Relay R8405C (8A05A – 4) – Kit “A” & “E” only
oTransformer – Kit “B” only
NOTE - Some parts may be packed inside furnace firebox. Check shipment carefully before
assuming shortage.
2.3 LOCATING THE FURNACE (Fig. S101-1, Fig. S101-4)
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 Fig. S101-1 or those of local
authorities are met. If the furnace must be installed on a combustible floor, a non-combustible
base must be built as shown in Fig. S101-4. 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 gauge 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.

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2.4.1 COMBUSTION AIR SUPPLY
Air inlets of at least 200 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
can 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.
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.
Operating a wood or oil fired appliance with inadequate combustion air could be hazardous.
2.4.2 FLUE PIPE & CHIMNEY
The internal breech baffle should be inserted through the breech towards the front of the
furnace until it hits the internal baffle stop. The open slot running the length of the baffle
should be located on the top. This baffle is removed during the cleaning procedure. The
purpose of the baffle is to prevent short-circuiting of the flue gases out through the rear breech.
The flue gases are forced to fully heat the secondary heat exchanger, which will maintain
higher furnace efficiency.
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 and
capable of venting the products of combustion. 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” wc 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 furnace be connected to its own chimney. However, two or more fuel
fired appliances, other than fireplaces 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:
1) The appliances are located on the same story;
2) A negative pressure is maintained at the flue collar of each appliance;
3) 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 key pipe
dampers, and check draft controls located on or in the flue pipe.
4) 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, the oil flue pipe shall be on top
(downstream); and the solid fuel flue pipe on the bottom (upstream); and
5) 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. S101-1)
The 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 in. (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
Side 6” 152 mm
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 (Free standing) 3” 76 mm
These clearances 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 furnace warm air plenum and first 6’ (1.8 m) of warm air supply duct in any direction must
be installed observing a minimum of 6 in (152 mm) clearance from the joists or combustible
materials. Beyond the first 6’ (1.8 m) of supply duct, a 2” (51 mm) minimum clearance must be
maintained between the warm air supply ducts and all joists or combustible material. See Fig.
S101-1.
Return air ducts, including main ducts and branch ducts, on solid fuel burning warm air
furnaces shall be installed to provide at least 3” (76 mm) clearance to combustible construction
for the first 6’ (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.
2.6.1 FREE-STANDING (Fig. S101-13)
The furnace in the free standing (stand-alone) system is the sole source of central heating
using an optional blower box kit to circulate the air. In this system connect the ductwork, as
you would for any conventional warm air heating system except you use increased clearances.
The return air ducts are connected to the blower box, which may be located on either side of
the furnace.
NOTE - With the optional blower, this furnace is not to be connected to ductwork that is still
connected to another furnace.

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2.6.2 ADD-ON (Fig. S101-7, Fig. S101-12)
The wood furnace may be installed very satisfactorily in conjunction with another furnace as
tested by ETLM under standard 78-1 and CSA under standard B365/1981.
In this installation the wood furnace is connected downstream in series with a new or the
existing oil furnace. The blower from the existing furnace provides the air circulation. The
wood furnace may only be added in series downstream from an oil furnace having an input
rating (on original nameplate) of between 0.85 and 1.50 gph (US) or SI equivalent.
For oil furnaces having multi-speed blowers with continuous circulation capability.
Add-on furnaces such as the Scotsman 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
installation is Fig. S101 – 7, Fig. S1019.
Disconnect Low Speed Circulation Fan Switch if Optional Relay is not used.
Fig. S101 – 8, Fig. S101-10.
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. S101 – 7, Fig. S101-9.
The Honeywell (R4222D 1013 or equiv.) relay is to prevent power from being fed to the blower
motor on two motor windings at the same time.
The red wire from the circulation fan switch (Low Speed) on the oil furnace.
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:
oSwitching Relay R4222D 1013 (120 V Coil, 12 amp @ 120 Vac), or equivalent.
oJunction box (4” x 4”) and cover.
oSquare extension box (4”x 4” gyproc extension).
oTwo plastic universal bushings or junction box connectors.
oWhite wire (12”), two insulated spade connectors.
oBlack wire (6”), two insulated spade connectors.
oBrown wire (12”), two insulated spade connectors.
oYellow wire (12”), two insulated spade connectors.
oTwo cabinet mounting screws.

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Low Speed Switching Relay Installation 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
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.
EVO/MAX Furnaces – For furnaces that use either the EVO (9200i) or MAX (9300i) controls,
two extra 120 volt relays are required to interconnect the oil furnace to the wood furnace. If
using the MAX (9300i) control, an AC/Auxiliary Temperature Sensor (Part # K00-KA-0090-F3)
MUST be used, which is installed in the wood furnace plenum. DO NOT use the AC/Auxiliary
temperature sensor with the EVO (9200i) and a wood furnace.
2.7 DUCT CONNECTION (Fig. S101-5, Fig. S101-1)
See figure S101-16 for Approved Furnace Ductwork Configurations.
See figure S101-17 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 180 sq. in.
with equal or larger size for return air.

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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.
DO NOT use duct elbows having an inside radius of less than 6 in (155mm). Use only 16 x 20
in. duct “S” type interconnection for this furnace.
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.
Make all duct connections for the “S” type interconnection, see Fig. S101-5.
CAUTION - The DB-101 Add-On is NOT certified for installations using a divider in the plenum
of the oil furnace. An Add-On unit must only be connected to a furnace, duct system and
chimney, which are in good operating condition. DO NOT relocate any of the safety controls in
the original furnace installation. Operate the oil-fired unit periodically to ensure that it will
operate satisfactorily when needed.
DO NOT connect to duct work so that a reverse flow is possible. Before attempting
installation, determine if there is suitable space available in the furnace area for the furnace
connection outlined herein.
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. S101-1.
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:
Drill hole in wood outlet plenum. Level inclined manometer and adjust to zero, insert
manometer tube (Pressure end). 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:
1) Change blower pulley size (usually decrease)
2) Change blower motor pulley (usually increase)
3) 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.

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As an alternative to the static pressure test method, the installer may make adjustments on the
basis of temperature measurement. For this test 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 40°F and 100°F during normal operation, and ideally around 80°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 technicians
experienced in such services. When required by the regulatory authority, such technicians
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.
2.8 Control System (Fig. S101-5)
The fan and limit control and the damper motor should be located as shown in Fig. S101 - 5.
The control system serves the following functions:
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.

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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.
2.9 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 disconnect 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” wc maximum?
6) Clearances of smoke pipe 18” or better from combustible material?
Metal protection is recommended.
DEALER TO INSTRUCT HOMEOWNER
1) Keep area around unit clean.
2) Use DRY wood only. Hardwood preferred.
3) Load carefully.
4) Load level no higher than center of door.
5) Remove ash regularly as directed.
6) Watch 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.

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ADDENDUM
FOR OIL FURNACES HAVING MULTI-SPEED BLOWERS
WITH CONTINUOUS CIRCULATION CAPABILITY.
Add-on furnaces such as the Kerr Scotsman and Scotty SS
can be installed with oil fired warm air furnaces such as the
Kerr Gemini that have continuous blower circulation capability.
A relay must be used if the furnace is to maintain the
continuous circulation feature. See wiring diagrams for the
proper electrical connections.