Nature's Comfort NCB-175 User manual

INSTALLATION AND
OPERATING INSTRUCTIONS
FOR
NATURE’S COMFORT
WOOD HOT WATER
OPEN BOILERS
(FURNACE)
NCB-175
NCB-250
NCB-325
Manufactured by
Nature’s Comfort LLC.
Lancaster Wisconsin
http://www.naturescomfortllc.com
BUILT LIKE A TANK
WITH LASER PRECISION

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INTRODUCTION
Thank-you and congratulations on the purchase of your new Nature’s Comfort!
With the purchase of this Nature’s Comfort, you can now appreciate the high degree of
craftsmanship and reliability that are a result of every furnace being carefully hand-built.
Your choice shows the recognition you have for high quality products.
We deem it important to provide you with this users and maintenance manual, to allow you
to use your equipment under the best possible conditions and in the most optimal manner,
and furthermore to increase its operating life. We strongly advise you to read it carefully
and keep it handy.
THIS MANUAL INCLUDES IMPORTANT SAFETY INFORMATION.
Your new furnace should have the following:
1. Owner’s manual complete with Safety, Hook-Up and Operating Installation.
2. Warranty & Return Warranty Card.
3. Wilo Star 16 Water Pump.
Again, thank-you for purchasing the Nature’s Comfort.
We appreciate your business!
Nature’s Comfort LLC
4689 Airport Rd.
Lancaster Wisconsin 53813
608-723-7900
We are always here to help!

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Table of Contents
Page Page
I. GENERAL INFORMATION
A. Terminology.......................................................4 E. SafetyPrecautions....................................5
B. Specifications....................................................4 F. 20YearLimited Warranty.......................6
C. Clearance to Combustibles........................4 G. WarrantyCard.............................................7
D. Furnace Dimension........................................4
II. Outdoor Boiler Best Burn Practices
A. FuelUsed...........................................................................8 G. HeatingtheHome..................................................9
B. Loading Fuel....................................................................8 H. HeatingHotWater...............................................10
C. Starters................................................................................8 I. ThermostatControl............................................10
D. Location..............................................................................8 J. PexPipeConnections......................................11
E. WoodRecommendations........................................9 K InsulatedPexPipe...............................................11
F. BurningCoal.....................................................................9
III. Installing the NCB Boiler
A. LocationofFurnace...................................................12 J. InstallingHeat Exch’erinsmallPlenum ..18
B. ConcreteBlock Footing ..........................................13 L. BleedingtheHeatExchanger.......................19
C. PlumbingandElectricalHook .............................13 M. AirFlow throughPlenum................................19
D. WaterLinesandTheirFunctions........................14 N. Power---WaterPumpStartsw/Fan.............20
E. ElectricLines..................................................................14 O. Power---WaterPumpRuns Continuous.21
F. InstallationofPexPipe...............................................15 P. RunningWiretotheHouse............................21
G. FillingBoilerwithWater.............................................15 Q. ThermostatWireLayout..................................22
H. PlumbingPartsNeeded............................................15 R. WaterLineLayoutinHouse...........................23
I. AddingShutOffValues.............................................16 S. SummerHotWaterBy-Pass ........................23
K. InstallingHeatExchangerinPlenum.................17
IV. Other Hook Ups--Heating Water, Pools, and Spa’s
A. PlateHeatExchangerforHotWater.........................................................................................................................................24
B. HeatingaPoolor Spa.......................................................................................................................................................................25
C. HookingUptheOutdoorFurnacetoExistingBoiler.......................................................................................................25
V. Maintenance
A. CleanOutAsh........................................................................................................................................................................................26
B. Creosote....................................................................................................................................................................................................26
C. DoorSeals................................................................................................................................................................................................26
D. EndofSeason........................................................................................................................................................................................26
VI. Trouble Shooting
A. PoorWaterFloworLittletoNo Heat..........................................................................................................................................27
B. DifficulttoStartFire.............................................................................................................................................................................28
VII. Disclaimer........................................................................................................................................28
MailinWarrantyCard....................................................................................................................29

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I. GENERAL INFORMATION
A. Terminology.
a. Boiler: refers to an outdoor unit which heats water. The unit you
purchased.
b. Furnace: refers to an indoor gas or oil fire unit which heats air. It is your
existing furnace.
B.Specifications.
Type of fuel: Wood and coal only.
Location: Outdoor use only.
Electrical Rating: 115 VAC/ 60 HZ
Circuit Breaker: 15 Amps.
Draft Blower: 146 CFM, 110 volts.
Water Pump: Star 16 3 speed, 110 volts.
C. Clearance to Combustibles.
Top, Rear, Sides: 18 inches
Front: 10 feet
Flooring: Non-Combustible
Chimney Connector: 18 inches
Always used a double-wall pipe when going through any kind of roof with at least
6” to 2 feet of clearance from any combustibles. Check with the manufacturer for
their recommendations. Use metal asbestos stove pipe for the flue, which is
insulated to prevent fires.
D. Boiler Dimensions---.
NCB-175 - 184,000 BTU and a 175-gallon water tank. 4000 sq ft.*
46 1/2" x 60" x 90" tall 1717 pounds
NCB-250 - 263,000 BTU and a 250-gallon water tank. 5,500 sq ft.*
46 1/2" x 78 " x 90" tall 2260 pounds
NCB-325 - 342,000 BTU and a 325-gallon water tank. 8,000 sq ft.*
46 1/2" x 96 " x 90" tall 2626 pounds
FIREBOX SIZE
Model Description Width Depth Ash Pan
NCB-175 29” cylinder 28” 36” 30” X 11.75”X 6”
NCB-250 29” cylinder 28” 54” 44” X 11.75”X 6”
NCB-325 29” cylinder 28” 72” 58” X 11.75”X 6”
E. Safety Precautions.
Do not operate this equipment for other than its intended purpose nor other than in
accordance with the instructions contained in this manual and all other instructions
accompanying the furnace.
It is important to observe safety precautions to protect yourself from possible injury.
Among the many considerations, you are advised to: observe all safety stickers
on the boiler.

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This boiler must be wired by a qualified electrician in accordance with the National
Electrical Code.
1. Never use any type of petroleum product, petroleum based product, charcoal starter,
lighter fluid, lantern fuel, kerosene or any other flammable accelerant to start the fire
in the firebox of your boiler.
2. Keep all such liquids well away from firebox.
3. Keep antifreeze, which is flammable, well away from the boiler. Only use non-toxic
antifreeze. Test antifreeze annually.
4. The use of treated wood (painted, treated, etc.) and any other salvaged material that
can emit noxious gases for the environment and is corrosive towards the components
of the appliance is not allowed and eliminates the rights of guarantee.
5. The furnace is designed to burn seasoned cordwood and coal. Do not burn
garbage, household or yard waste. In most areas this is illegal. Burning these
materials can reduce the life of the furnace and will void your warranty.
6. When opening the fire box door, pausing momentarily between the first latch and the
safety latch to allow any combustion gases to burn off. Always close the fire-box door
securely.
7. Check to be sure, the ash pan is fully inserted. Leaving a small crack or opening can
cause over-firing in the fire-box.
8. Always use proper care when installing, operating and maintaining the boiler.
9. Always wear protective gloves and glasses and be aware that hanging and loose
clothing can catch fire!
10.Do not modify the boiler.
11.Do not substitute repairs that can be provided by your dealer or manufacturer.
12.Failure to heed these warning or any additional warnings on the boiler may result in
an accident causing personal injury and damage.
CALL DIGGER HOTLINE BEFORE YOU DIG THAT TRENCH!
Disposal of Ashes:
Open the ash pan door to removed ashes. The ashes should be placed in a metal
container with a tight fitting lid. The closed container should be placed on the ground or a
non-combustible floor. The ashes should be buried in the soil or otherwise retained in the
closed container until they have thoroughly cooled.
All installation and operation must follow Federal, Provincial, State and Local
Codes
F. 20 YEAR WARRANTY.
5 Year On-Site Warranty! We have a 5-YEAR warranty on the furnace - NOT prorated.
Plus we have a 20-YEAR warranty on the whole furnace - Parts AND Labor.
Electrical components such as the fan, thermostat and pump have a one-year
manufacturer's warranty.
Years 6-20 are prorated as follows: Year 6 - 90% Year 7- 80% Year 8-70% Year 9 - 60% Year
10 - 50% Year 11- 40% Year 12-14 - 30% Year 15-20 - 20%

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Nature’s Comfort does not warrant against freezing, over heating, any
boiler that has been altered, pressurizing, or the use of inappropriate fuels
and negligence. Transportation, installation or loss of fluids is not
covered. It is the responsibility of the owner to follow proper maintenance
procedures as outlined in this operator’s manual. All boilers must have
authorized water treatment added to their boiler water, and a
water sample must be sent in for testing annually.
EXCLUSIONS:
1. Disasters, breakdown or faulty operation linked to:
a. Inadequate relation between the nominal power of the equipment and the
heat requirements of the premises;
b. A faulty installation or faulty connections;
c. Damage to the thermostat through overheating due to intensive use:
i. The ash pan is left out or open;
ii. When the ventilation convection fan is left off with high fires.
2. Failure to clean out ashes.
a. Moisture combined with ashes will eat through a boiler in short order and is
NOT covered under warranty.
3. Incorrect use.
4. An insufficient or excessive draft.
5. Non-compatible fuels, destructive and/or damp fuels (treated wood, etc...)
6. Lack of maintenance.
7. The use of electrical or electronic components that are not approved by Nature’s
Comfort, LLC.
8. Any modification or transformation inside the appliance.
9. Transportation and packing costs.
10.All costs not previously accepted by Nature’s Comfort.
11.The cost of any incidentals or consequential damage, including the loss of anti-
freeze and water treatment.
12.The guarantee starts on the date of delivery. The invoice showing the delivery date
is the only document valid for the guarantee.

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Warranty Card
Please fill in the following information…recorded for future reference.
Your Name: ____________________________________
(First) (Last)
Your Address: ___________________________________
(Street)
___________________________________
(City) (State) (Zip)
Your Phone: _________ ________________________
(Area Code) (Number)
NCB Serial Number: ___________________________
Date of Purchase: ___________________________
Date of Installation: ___________________________
Mail to:
Nature’s Comfort, LLC
4689 Airport Rd.
Lancaster WI 53813
A duplicate for mailing is at the end of this manual. Retain this copy for your
records.
Please keep this manual with all other important papers. The information in this manual is
necessary for the installation, operation and proper use of this boiler. If you should ever
have a problem or question please refer to this manual or have it available when you call
Nature’s Comfort, 608-723-7900.

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II.OUTDOOR BOILER BEST BURN PRACTICES.
Read and follow all operating instructions.
A. Fuel Used: You may burn any hardwood or softwood, as well as pallets that have been split up
and coal but NEVER burn driftwood, painted, stained or pressure treated wood. Do not burn:
trash, plastics, gasoline, rubber, naphtha, household garbage, material treated with petroleum
products (particle board, railroad ties and pressure treated wood), leaves, paper products, and
cardboard. If you burn softwood, you will have to clean the chimney more often.
B. Loading Fuel: For a more efficient burn, always add wood before the wood has burned out.
Most often it can be loaded in the morning and at night. Load coal before wood.
C. Starters: Do not use lighter fluids, naphtha, gasoline, or chemicals.
D. Location: It is recommended that the boiler be located with due consideration to the
prevailing wind direction. Chimney height can be easily extended with 6” Stovepipe.
1We recommend a distance of at least 100 feet if prevailing winds blow towards any other
residence not served by the boiler, it is recommended that the stack be at least 2 feet
higher than the eave line of that residence.
2If located more than 100 feet but no more than 150 feet to any residence, it is
recommended that the stack be at least 50% of the eave line of that residence, plus an
additional 2 feet.
3If located more than 150 feet but no more than 200 feet to any residence, it is
recommended that the stack be at least 25% of the height of the eave line of that residence,
plus an additional 2 feet.
Chimney height relative to nearest downwind neighbor
The chimney can easily be extended with standard 6” stove pipe, to any height necessary,
with zero adverse affect on performance. In fact, it may even draft better. Always use a
double wall pipe when going through any kind of roof! The chimney should extend at least 2
feet higher than any portion of a building within a horizontal distance of 10 feet.
Always remember to comply with all applicable state and local codes and laws.

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E. Wood Recommendations:
You should only burn cordwood that has been seasoned for 12-18 months. Burning unseasoned
wood is wasteful and inefficient. Non-dry, “green” wood uses much of the combustion energy to
boil off the excess moisture. Ideally the wood should be split to aid in seasoning and should be
around 25% moisture content by weight. However, whole rounds burn well and are cheaper. This
type of wood will have to be dried longer.
The following are general guidelines for wood selection:
a. Hardwoods burn better than softwoods.
b. Larger pieces burn better than small pieces.
c. 25% moisture content is optimum:
Wood with higher moisture content wastes energy boiling off water. Wood with a lot of moisture
can cause more smoke than the chimney can dispose of.
Lower moisture content (very dry, old wood) burns rapidly and inefficiently.
F. Burning Coal:
For best results coal should be mix with wood to help the air pass through.
G. Heating The House.
The NCB is designed to save energy and provide the most comfortable heating available. It
heats your home by heating a firebox surrounded by a steel tank filled with water. The boiler is
a non-pressurized boiler with an atmospheric vent. This hot water is then circulated through
underground hot water Pex pipes to a water coil (heat exchanger) installed inside your existing
central duct system.
A typical water-to-air heat exchanger -- much like a small
radiator or heater core in a car-- is installed in your ductwork.
When air blows through it, heat is extracted and hot air blows
out of your vents.
The Nature’s Comfort outdoor boiler can also be connected to any existing radiant heating
system that operates at 180 degrees or less.

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H. Heating Hot Water.
The hot water from the outdoor boiler is circulated through a “water to water” heat exchanger
which is connected to your existing hot water heater. The hot water from the boiler usually
goes to your hot water heater and then on your furnace. You may use either a “plate” or “side
arm” water to water exchanger with your hot water heater.
I. Thermostat Controls.
The only visible addition to the heating system inside your home is a second thermostat, which
should be located near the existing thermostat. This second thermostat is installed so that if
the outside wood boiler is not in operation, your existing furnace will automatically take over to
maintain your household temperature. The wall thermostat that regulates the heat from the
outside boiler performs two functions when it senses need for heat, according to your
temperature setting. First, it starts the circulating water pump on the outdoor boiler to circulate
hot water through the heat exchanger. Second, it starts the blower inside your existing furnace
to force air across the hot water coils of the heat exchanger and this “warmed” air through your
central duct system.
The outside boiler has a hot water thermostat (aqua stat sensor) that senses the water
temperature of the unit. When the temperature of water in the boiler falls below the “low”
temperature setting on the “Aqua stat sensor”, the combustion air blower turns on to build a
hotter fire and remains on until the water temperature in the boiler reaches the “high”
temperature setting of the aqua stat sensor.

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J. Pex Pipe Connections.
The boiler shown is a single zone. All
boilers come with another hookup for
another building at no cost (not shown).
2nd Pump not
included.
Single zone setup with
one pump
1. Blue Pex pipe return from house
heat exchanger.
2. Red Pex pipe goes to house heat
exchanger.
3. Power to pump, Aqua-stat and
blower.
4. Water drain to empty boiler.
5. Blower to feed oxygen to fire.
6. Wilo Star 16 pump to circulate
water. (one is included.)
7. Aqua-stat sensor for blower and
pump.
Note:
Water flow in at top and out at bottom.
(See arrows #1 and #2.)
K. Insulated Pex Pipe.
If you have a situation where burying below the frost line gets into rock or water, you can
use insulated Pex Pipe and bury it closer to the surface. You may also want to weigh the
energy savings. Even though the ground is warm, there is heat loss with non-insulated
pipe. This results in more wood being burnt. If your wood is free, you may not care to
throw in a couple extra sticks of wood. If you’re buying wood, you may want to consider
insulated Pex Pipe to reduce wood consumption. We leave that up to each individual to
decide for themselves. Is it worth paying for insulated pipe, in order to save 10% on
wood? Maybe over several years it would be worth it if your runs are short, like 50 feet or
less. You decide.

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III. Installing your NCB.
A. Location of Boiler.
The outdoor boiler should be located at least 10 feet from your home, with the door facing
away from the house, so that all fire danger is removed from your home. The boiler may be
installed as much as 100 feet away and still heat your house and hot water. The chimney
should extend at least 2 feet higher than any portion of a building within a horizontal distance
of 10 feet.
If the boiler is located more than 100 feet away, you may experience some heat loss in the
water going to your heat exchanger (and water heater). A larger pump than the one supplied
may be needed for distances over 150 feet or any rise in elevation over 15 feet. For extreme
distances (200 ft plus) we recommend that your pump stays on all the time so there is no delay
in getting heat. That way there is always hot water available at the heat exchanger when the
furnace fan comes on.
Locate the outdoor wood boiler where it will be convenient for refueling and wood storage.
The I-Pex pipe and power lines are installed underground between the house and the outside
wood boiler and ALWAYS buried below the frost line.
1 It is recommended that the boiler be located with due consideration to any
neighboring residences and to the prevailing wind direction.
2. Do not locate an outdoor wood burning boiler within 100 ft of a residence not served
by the boiler. Be considerate of neighboring residences, properties, parks, etc.
3 Review the recommended smoke stack heights on page 8.
4 Do not locate the boiler near any combustible materials, gasoline or other
flammable liquids or gases.
5. The boiler should be located away from dry grassy areas and any buildings
to minimize danger of fires..
6. Check with your insurance company and local codes or ordinances.
7. Do not install the boiler in an area where nearby structures or trees might cause
down drafts.
8. Typically, outdoor wood burning boilers are located 40 to 100 ft down wind from the
structure served.
9. The “hot water” lines in excess of 150 ft may require a larger size pump than the
one provided with the boiler.
10.Locate the boiler to allow easy access to wood supply.
11.To aid in smoke dispersal, extra chimney lengths may be required depending on the
distance to surrounding structures. See page 8 for additional guidance.
12.The boiler requires 115 V, 15 Amp electrical services to operate.
Failure to keep the NCB Boiler area clear and free of combustible materials, gasoline
and other flammable liquids and vapors can result in severe personal injury, death
or substantial property damage.

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B. Concrete Block Footing.
All you need is four concrete footing blocks 8” X 16” X 4”
C. Plumbing and Electrical Hook Up.
1. Simply open the large rear door to gain access to the rear of the boiler, to make
plumbing and electrical connections.
2. The plumbing and electrical lines for your boiler must be installed underground in a
watertight 4” pipe.
3. The water lines must be buried below the frost line to prevent freezing. The depth
of the trench varies in different regions of the country. Be completely sure about the
correct depth before the Insulated Pex Pipe are installed underground. Call your
local building inspector’s office for that information.
4. A trench must be dug wide enough to accommodate a 4’ Insulated Pex pipe. All
plumbing and electrical lines should be run inside the watertight pipe.
5. The twine in the pipe in for adding your Electrical wire.
6. If more than one location is to be heated, then an additional pipe must be installed
underground to that location.
7. This pipe will run from the rear of the boiler to the location to be heated. Inside the
watertight pipe are the water lines and electrical supply wire (12/3 w/ground UF) or
12/2 if your pump is going to run continues.
8. If you have rocky ground, make sure you place straw around the pipe to give it extra
protection.

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D. Water Lines and Their Functions.
1. Run a 1” pex water supply line from nipple on bottom of the boiler to the water-to-
water heat exchanger installed on the water heater.
2. Run a 1” pex water line from the water-to-water heat exchanger on hot water
heater to the heater exchanger which is installed in the existing heating system.
3. Run a 1” pex water return line the heat exchanger which is placed into the existing
heating system to the pump at the top of the boiler.
Note: All pipe should be at least 1”. They should be 1-1/4” if the distance is greater
than 100 feet.
HINT: Label the water lines or connect them before back filling over pipe and lines
E. Electric Lines.
The size and type electric lines you install depends on distance the boiler is located from
the house and whether you choose to have the water pump on the boiler run continually or
only when the existing furnace fan runs. It is recommended that the water pump run
continually when the distance from the boiler to the house is greater than 50 feet and/or
boiler is used to heat your hot water.
1. If your boiler is less then 100 feet from your house, you may use #14 wire. If it is
greater than 100 feet, you should use #12 wire. You may certainly use #12 for the
shorter distance if you like.
2. You may use #14-2 w/ground UF Romex (under ground) wire if you choose to have the
boiler pump run continually, You will need #14-3 w/ground UF Romex wire if you want
to run the water pump only when the furnace fan runs. You, of course, would need
#12-2 or #12-3 if your boiler is greater than 100 feet from the house.
Note: The electric line and thermostat wires can be pulled through the 4” insulated flexible
pipe which contains the two lines Pex pipe.
If more than one location is to be heated, a second 4” watertight pipe will need to be
installed underground for the water lines, thermostat wire and power wire of the second
location. If the 2nd location has a furnace, you wire it as the first and no thermostat wire is
needed. Locate this pipe at the opposite side of the outdoor boiler, unless it’s running in
the same direction as the first. In that case both pipes can be on the left.

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F. Installation of Pex Pipe.
Try to keep the Pex pipe underground as it enters the house. A 5” hole in concrete
block is easily made for the I- Pex pipe. It should be sealed with a can of expanding
foam.
If the I-Pex pipe has to come above ground to come through the sill plate or attic it
should be well insulated.
G. Filling Boiler with Water.
Once your Pex Pipe is hooked up, simply turn on your fresh water valve and allow it to
fill until water runs out the overflow. After starting the pump and bleeding the heat
exchanger, top off the water again. Be sure to open the fresh water valve at least once
a week during heating season to keep the boiler topped off. Failure to do so may
result in overheating and circulating pump failure.
H. Plumbing Parts Needed.
1. The pump needs a 1” PEX CRIMP to1” MPT to screw into a flange that is supplied and
already mounted to the pump. The flange is a female 1" FPT. See the picture below to
help visualize this. It’s the brass fitting on the bottom of the pump.
2. Extra Pex fittings can be purchased from your local hardware or plumber.
The Pex Pipe connected to the bottom of the pump runs to the house and normally
runs to the heat exchanger installed in your furnace.
This will also be your supply line for your hydronic system. In either case, a brazed-
plate heat exchanger is often used between the two systems. See end of this section
for more information on hooking up a brazed-plate heat exchanger.
3. The pump comes already mounted directly to the boiler without a shut-off valve.
However, it is a good idea to install a shut-off valve above the pump so that if the
pump ever has to be changed, the water supply can be shut off so water doesn’t flow
out of the boiler during the repair.
Simply add a valve and a 1” pipe, threaded on both ends, as shown.
4. It is also a good idea to put two shut-off valves on the return lines. This helps bleed
the system of air and is a big help when troubleshooting.
Note: For larger homes, 1-¼ pipe may be best for maximum BTU output. A 1-¼ pipe can
put out up to 37% more BTUs due to higher water flow, with the same heat exchanger!
The fittings above would need to be changed to accommodate 1-¼ Pex.
HINT: Label the water lines or connect them before back filling over pipe and lines

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I. Adding Shut-off Valves.
Adding two shut-off valves on the return lines is done so that if there is a potential
problem such as a stopped up heat exchanger or pump failure, it can be diagnosed
easily by the owner, without the need for a service call.
J. Installing the Heat Exchanger in the Plenum.
Note: It is recommended that you contact your local plumbing/heating contractor to
supply and install the heat exchanger unless you have the tools and
experience required.
The heat exchanger must be installed between the furnace and the evaporator coil if
you have air conditioning. This is required since the air conditioner may freeze and
crack the heat exchange when the air conditioner is used. If you can’t place the heat
exchanger between the furnace and the evaporator coil, you must drain the heat
exchanger before using the air conditioner.
The heat exchanger must be installed so that it is airtight. No air must be able to flow
around it or out of the ductwork. Use adhesive backed foam tape (used for insulating
doors and windows) around the water coil. Use foil tape to seal off the heat exchanger
and the hole you make.
Make sure the fittings for the supply and return lines are easy to get to once the heat
exchanger is installed. There should be no splices in any of the water lines!
You should be able to find a heat exchanger to fit most popular sizes of plenums. If you
can’t, you must have your ductwork modified to accept the heat exchanger. This is best
left to a professional unless your ductwork is made up of fiberboard. In all cases wear
protective gear, gloves and glasses and a mask.
Measure the width of the heat exchanger (Dimension A in next diagram). Measure the
thickness of the heat exchanger (Dimension C).
Start by cutting a hole in the side of your ductwork the thickness of the heat exchanger
(Dimension C) and the full length of the ductwork (usually Dimension A).

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WARNING! Metal edges are very sharp! Wear protective gloves and use caution!
Slide the heat exchanger into the hole for a test fit. Ideally the tubes (D and E) should stick
out of the plenum [see diagram on previous page]. The header and tubes (F) can stick out
of the plenum as well, if necessary.
As long as the whole coil surface (B) is in the plenum, you should be good even if a little
more of the header (F and even G) sticks out.
While test fitting it, try to determine how much tape is needed around it. A different amount
(thickness) may be needed on different sides. You can purchase different thicknesses of
tape so that it will fit and seal properly.
Place foam tape around the outside of the heat exchanger to seal it off so that it fits tight
and air can’t blow by it.
The heat exchanger needs to be installed so it won’t move around. The easiest way is to
fabricate some pieces of metal into an ‘L’ shape, approx. the length of the heat exchanger
like shown above.
Install the braces as shown above. Simply put them in place, the proper width apart
(Dimension C). Drill through the duct work and your newly made ‘L’ pieces and pop rivet or
screw them into place. You will need four pieces, two each on the top and bottom.
Slide the heat exchanger carefully into the plenum to check the fit again. If all looks good,
you can seal off the ends of the heat exchanger and the hole you made in the plenum with
foil tape made for ductwork.

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K. Installing a Heat Exchanger in a Small Plenum.
You can install a heat exchanger in a plenum that is smaller than the length of the heat
exchanger, as follows. Make cuts at the top and bottom of the plenum, usually 4 inches
long (the width of the heat exchanger) as shown below.
Cut another line vertically, between the other two cuts, right in the middle as shown.
Slide the heat exchanger through the front hole to the back hole. So that it protrudes front
and back.
Ideally the core of the heat exchanger will be entirely within the plenum.
Crimp the sheet metal to the edge of the heat exchanger. This is item G in the diagram
above Using channel-lock pliers to crimp it makes a very nice professional looking
installation.
This not only forms a virtually airtight seal, but it also supports the heat exchanger as well.

Installation and Operating Instructions
NCB Built Like A Tank With Laser Precision Page 19 of 29
L. Bleeding the Heat Exchanger.
With the pump running (turn the thermostat up to 90 F so that the pump comes on),
simply close the brass valve on the return line quickly, holding it for 3-4 seconds. Then
open the valve. Repeat the procedure four times.
If you’re unsure if all the air is getting out, you can separate the two valves at the Pex
Pipe between them, after turning off both valves so that water won’t drain out.
Insert the left plastic valve and pipe in a 5-gallon bucket. Open the valve. Then simply
close the plastic valve on the return line quickly, holding it for 3-4 seconds. Then open
the valve. Repeat the procedure 4 times. That way you can see if bubbles are coming
out of the line.
M. Air Flow through Plenum.
The motors on most force air furnaces have three speeds to provide various rates of air
movement. Please consult a local furnace specialist if you want in change the air flow
of your existing furnace.
N. Connecting Power---Water Pump Powered from Furnace Fan.
A qualified electrician must wire this boiler in accordance with the National
Electrical Code.
1. You must run 12/3 w/Ground UF wire to your boiler if you want your boiler pump to run
only when your furnace blower runs. In #12/3 UF wire, there are three insulated wires:
black, red, white, plus a non-insulated ground wire. The black wire powers the blower
and outside light, and the red wire powers the water pump. The power for this red wire
comes from the power going to the fan on the existing furnace in the house.
2. The power (red or black) and neutral (white) wires may be connected to either terminal
on the water pump.
3. The back wire goes to the top terminal on the Aqua-stat switch and on to the blower
motor.
4. Ground (Bare copper wire) is attached to boiler frame and to the green ground
screw on both the pump and fan.
See the Figure 3 on next page.

Installation and Operating Instructions
NCB Built Like A Tank With Laser Precision Page 20 of 29
Figure 3. Water Pump on Boiler Comes on with Furnace Fan.