A-Maize-Ing Heat NRP620-9 User manual

INSTALLATION MANUAL
MODEL NRP620-9 FURNACE
MODEL 14 BIN
899 South Prairie Lane - P.O. Box 500 Marshfield, MO 65706
PHONE [phone] FAX [phone]

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Table of Contents
SAFETY INSTRUCTIONS....................................................................................................................... 4
INSTALLATION AND LOCATION CONSIDERATIONS........................................................................... 5
Installation Configurations .............................................................................................................. 5
Required Tools .................................................................................................................................. 5
FURNACE CLEARANCES AND ACCESSIBILITY ................................................................................. 6
Combustion Air Requirements ......................................................................................................... 7
Venting.............................................................................................................................................. 8
Important Vent Installation Requirements ........................................................................................... 8
Listed Chimney ................................................................................................................................. 9
Masonry Chimney.............................................................................................................................. 9
FURNACE UNPACKING AND SET UP .................................................................................................. 12
STORAGE BIN..................................................................................................................................... 14
VIBRATOR MOUNTING INSTRUCTIONS............................................................................................ 15
THERMOSTAT WIRING ...................................................................................................................... 16
ELECTRICAL WIRING......................................................................................................................... 17
BURNER LIGHTING ............................................................................................................................ 18
OPERATION ........................................................................................................................................ 19
CLINKER BUILDUP.......................................................................................................................... 20
SUMMARY OF SETTINGS & OPERATION ........................................................................................ 20
Power Failure Considerations ........................................................................................................ 21
Storage Bin - Model 14 ................................................................................................................... 22

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SAFETY INSTRUCTIONS
ALL INFORMATION ON THIS PAGE MUST BE READ AND
UNDERSTOOD BEFORE INSTALLATION
1. Do not install or use this appliance unless the instructions in this manual are read and
understood.
2. This appliance must be installed in accordance with all local codes.
3. Installation must be performed by a qualified installer, according to federal, state, provincial
and local codes. Definition of qualified installer: any individual or firm that is engaged in and is
licensed and/or certified for installation and operation of biomass heating appliances. Who is
experienced in such work and familiar with all precautions required and has complied with all
requirements of the authority having jurisdiction.
4. Maintain adequate minimum clearances to combustible materials. (See page 6)
5. Install in an area with adequate air for combustion and ventilation - 60 cubic feet per
minute minimum.
6. Do not connect this unit to a chimney flue serving another appliance.
7. Allow the furnace to cool before servicing.
8. Disconnect all power to the unit before performing routine maintenance or service.
9. Establish a regular service and maintenance schedule for efficiency and safe operation.
10. Have a qualified service person perform tasks with which you are not familiar.
11. Caution: Children and adults should be alerted to the potential high surface temperatures of
the burner door. Keep children away!
12. Danger: Risk of fire or explosion. Do not burn gasoline, oil, garbage, or other
flammable materials not approved for this appliance.
13. Do not place clothing or other flammable material on or near this appliance.
14. 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 dispersed, they should be retained in the closed container unit until all clinkers,
embers, and ashes have thoroughly cooled.
15. Use only 20” x 20” x 1” UL approved furnace filter. (Filter included)

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INSTALLATION AND LOCATION CONSIDERATIONS
WARNING
Failure to install the A-MAIZE-ING HEAT® furnace according to the instructions in this
manual may result in death, serious injury, property damage and/or may void the
warranty.
Installation Configurations
IMPORTANT
The A-Maize-Ing Heat®furnace is for use as a primary heat source. This unit is not designed to be
installed as an add-on furnace. If you plan to use the A-Maize-Ing Heat®furnace in conjunction with
another furnace, install safety measures to prevent air back feed from one furnace to the other.
Failure to take this precaution could cause either furnace to overheat.
Required Tools
Flat-bit screwdriver 7/16” wrench
Phillips screwdriver 7/16” socket
5/16” nut driver Drill motor and ¼” drill bit
3/8” nut driver

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FURNACE CLEARANCES AND ACCESSIBILITY
Recommended distances for ease of use and serviceability:
Top 32”
Opposite side from bin 24”
Front 36”
Rear-most surface 18”
Minimum distances from a combustible surface:
Top 32”
Either side 18”
Front 30”
Rear-most surface 18”
The A-Maize-Ing Heat®furnace can be installed on a combustible floor if a non-combustible material
is placed directly under the ash removal door and chimney connector. The mat is to extend at least
16” in front of and 8” to each side of the ash removal drawer and 2” either side of the chimney
connector.
18" **
24" *
36" *
12"

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Combustion Air Requirements
Install the A-Maize-Ing Heat®furnace in a room with adequate air for combustion and ventilation -
60 cubic feet per minute minimum.
Minimum clearances for the A-Maize-Ing Heat®furnace is 32” from top of furnace to ceiling, 30”
from the front of the furnace to the wall, 18” on either side and 18” from the back of the furnace to
the wall.
The A-Maize-Ing Heat®furnace is for use as a primary heat source. The A-Maize-Ing Heat®furnace
should be installed with the metal hot air plenum connected to metal hot air duct work and metal
cold air return plenum joined to return air system. This unit is not designed to be installed as an
add-on furnace. If you plan to use the A-Maize-Ing Heat®furnace in conjunction with another
furnace, install safety measures to prevent air back feed from one furnace to the other. Failure to
take this precaution could cause either furnace to overheat.
**IMPORTANT**
Maintain the 14” x 14” (196 sq. in.) hot air and return air connections to your existing duct work.
Reduction in size of these connections can restrict air movement over and through the heat
exchanger, resulting in overheating and operational problems with the furnace.

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Venting
WARNING
Failure to provide correct chimney venting can lead to an increase in carbon monoxide
and combustion gases into the building resulting in death, serious injury, and/or
property damage.
Connect the A-Maize-Ing Heat®furnace to a lined masonry chimney acceptable to the authority
having jurisdiction. USA installation may also use a residential type Class A and building heating
appliance chimney. Canadian installation may also use a 6” (minimum) metal flue pipe using sheet
metal screws. Do not connect the A-Maize-Ing Heat®furnace to any chimney flue servicing any
other heating appliance, as recommended by the Nation Fire Prevention Association. All chimney
connections must meet the approval of the local building inspector and fire marshal and conform to
all local, state, provincial and national codes.
Venting may be provided using a lined masonry chimney, or a class “A” listed chimney. The chimney
serves two purposes:
1. Provide “draft” to the furnace for the continuous supply of fresh air into the appliance making
proper combustion possible.
2. Exhaust smoke and combustion gases resulting from the burning biomass fuel.
Important Vent Installation Requirements
The minimum distance between the top of the furnace and a combustible ceiling surface must
be 32”.
The connection from the chimney to the furnace must be made with a 6” black pipe.
The minimum distance between the connection pipe and a combustible wall surface must be
18”.
Do not use more than two elbows in the connection between the furnace and the chimney.
Horizontal elements of the connection pipe should have a minimum rise of ¼” per foot of run
to allow condensation to flow back into the furnace.

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Listed Chimney
A listed chimney must be rated for solid fuel burning appliance, comply with NFPA Standard 211, and
all applicable building codes. Consult a qualified furnace installer and/or the local building inspector
to be sure the chimney and connections comply.
Masonry Chimney
An existing lined masonry chimney must be clean and inspected. All connections to the chimney
must comply with NFPA Standard 211 and all applicable building codes. Consult a local building
inspector and/or a qualified furnace installer to be sure the chimney and connections are safe and
compliant.
**IMPORTANT**
The following procedure for measuring and setting the proper chimney draft is probably the most
important installation procedure to follow for the proper operation of the A-Maize-Ing Heat®furnace.
The A-Maize-Ing Heat®furnace requires 0.02-0.04 inches water column draft (chimney draft) on low
fire, to assure proper operation. Low fire mode is when the thermostat is satisfied and fuel is not
being augered into the burner. When the chimney draft is too high, burner fire may go out. If the
chimney draft is too low, smoke may back up in the furnace and storage bin, causing a possible
hazard.
The supplied barometric regulator should be installed in the flue (as per the enclosed instructions) to
properly regulate 0.02-0.04 inches water column draft. The counter weight setting on the barometric
regulator regulates this setting. (See “ADJUSTING THE CONTROL” instructions on page 10.)
The chimney draft should never exceed 0.04 inches water column. On extremely tall chimneys or on
chimneys larger than 6” diameter, it may be necessary to install a second barometric regulator or to
reduce the outlet opening on the chimney to approximately 28 square inches or both to maintain the
required 0.02-0.04 inches water column draft.

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FURNACE UNPACKING AND SET UP
Your furnace was shipped from the factory with a “FURNACE PACKAGE” packing list. That document
includes the part number and serial number. Locate that list and check the contents of the
packaging to ensure all items were delivered. The items you will have are in the list below.
A: FURNACE
B: HOPPER
C: HOPPER LID
D: HOPPER LEGS AND CROSS BEAMS
E: HIGH FIRE TIMER (SET @ 15 SEC. ON AND 15 SEC. OFF) LOW FIRE TIMER (SET 2 MIN. ON 6
MIN. OFF)
F: DRAFT CONTROL W/COLLAR
G: FURNACE PARTS BAG—INCLUDES (wooden handles x 4, orange wire nuts x 3, ¼” x ½” self-
tapping screw x 3, connecting tube x 1 and owner’s manual)
H: HOPPER HARDWARE BAG-INCLUDES ( 5/16” X ½” hex head cap screws x 16 and 5/16” hex
nuts x 16)
I: BURNPOT AUGER
J: BIN AUGER
K: FILTER (already installed)
L: POKER
M: HOSE CLAMP
N: VIBRATOR
1. After removal of shipping materials, remove the furnace from the pallet by removing the three
shipping screws securing the furnace to the pallet. One (1) screw is accessible by removing the
filter door. The remaining two (2) are removed from under the pallet.
2. Remove auger motor assembly and Furnace Assembly Package from the combustion chamber.
3. Insert burner auger assembly into burner auger tube and secure assembly with self-tapping bolt
using hole provided in burner auger tube. (See Figure 1 on page 13).
4. Remove cover from auger motor. Fasten flex conduit extending from the electrical box to
furnace auger motor housing using conduit lock nut. (See Figure 1 on page 13.)
See Storage Bin: Step 4 on page 14 to set up for wiring procedures.
5. Slide wooden handles on door handle, door safety handle, and heat exchanger scraper rod.

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STORAGE BIN
1. After removal of shipping container, position storage bin, on storage bin base, at desired angle
for installation. For bolt together - fabricated metal hopper stand, see page 22.
2. Install auger assembly by sliding auger boot (with clamp) under bin outlet; align elbow on bin
auger tube directly over furnace fuel inlet. Tighten auger boot clamp securely. It is advisable
to install two sheet metal screws through the clamp, auger boot, and into the hopper bin
outlet to ensure a permanent connection. Install fuel delivery coupler between bin auger tube
and furnace fuel inlet.
3. Fasten flex conduit extending from storage bin auger assembly to furnace auger motor
housing using conduit lock nut.
4. Connect one black auger motor lead to the two orange wires with wire nut connector.
Connect the other black auger motor lead to the two white wires using wire nut connector.
(See Figure 1 on page 13.)

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VIBRATOR MOUNTING INSTRUCTIONS
1. Drill two 3/16” mounting holes 2 inches apart in the center of the long angle of the hopper
bin. (See figure 1)
2. Mount vibrator to the hopper using the holes drilled. Open face of J box facing away from
hopper body. (See figure 2)
3. Secure the vibrator to the hopper with fender washers and lock nuts on the inside of the
hopper. (See figure 3)
4. Connect the flex conduit to the bin auger motor housing.
5. Connect the vibrator red wire to the red wire in the auger motor housing and the white
vibrator wire to the black and two white wires in the hopper feed auger motor housing.
Figure 1 Figure 2
Figure 3

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THERMOSTAT WIRING
Connect thermostat wires to “R” and “G” terminals located on the relay, mounted on the furnace
control box.
Note: There is also a “C” terminal on the relay. Positively identify these terminals before connecting
the thermostat wire. Connecting a thermostat wire to the “C” terminal will permanently
damage the relay.
The location of the thermostat has an important effect on the operation of your furnace. Be sure to
follow the instructions included with your thermostat.

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ELECTRICAL WIRING
WARNING
For your personal safety, turn off electrical power at service entrance before making any
electrical connections.
All electrical work must conform to your local codes and ordinances or with the National Electrical
Code. If you are not familiar with wiring and codes in general, have a competent electrician do this
job.
Make connections to the furnace junction box from a dedicated 120VAC, 15 amp fused circuit; black
to black, white to white and ground to ground terminal located inside junction box. Solder and tape,
or use wire nuts on all connections.

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BURNER LIGHTING
NOTE: If the burner has been used, all leftover ash and clinkers must be thoroughly
removed from the burner pot before following the lighting instructions.
**IMPORTANT**
On the initial lighting of the furnace, add approximately 2-3 cups of biomass fuel to the hopper. As
the fuel feeds into the auger, add only small amounts until the fire is established and the feeding
system is working properly. This procedure should be followed at the beginning of each heating
season. This procedure should also be followed if the hopper is allowed to empty and the resulting
sticky smoke film coats the hopper feed auger. Powdered graphite may also be added to lubricate the
auger, but is not recommended with the clear acrylic feed tube.
CAUTION
Biomass stalks, excess cob, fines, dirt, etc. may cause the augers to plug resulting in excessive wear
and possible auger motor failure. Burning treated seed corn is not suggested because of excessive
clinker build up and problems with fire extinguishing, caused by the treatment used on the corn.
1. Add dry, (15% or below moisture) clean USDA #3 or better corn, wood pellets, or other
biomass fuel to holding bin. (See IMPORTANT and CAUTION above)
2. Turn on the electric power to the furnace.
3. Turn thermostat to highest setting.
4. Fill burner pot with biomass fuel to the lower set of air holes located on the inside of the
burner.
5. Liberally fill burner pot to the top with kindling wood and paper, light paper and close the
door.
NOTE: Gelled fire starter may be used as a substitute.
6. Two to five minutes after lighting the furnace, depress toggle switch to start position. This will
activate the combustion blower only. Continue to depress switch to start position for
approximately three to five minutes until the auger motors are activated. (Fuel will not begin
to auger until furnace has reached operating temperature and auger motors are activated.)
7. Turn switch to “ON” position.
8. Set wall thermostat to temperature desired.
9. It may be necessary to add kindling wood a couple of times before the fuel is completely
ignited.

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OPERATION
After the fire has been established in the burner pot and operating temperature has been reached
(See burner lighting pg. 18) you need only to set the thermostat to the desired temperature. The
thermostat will turn the furnace bin auger motors and combustion blower, on and off, to sustain the
desired temperature.
A typical furnace cycle would be:
1. Thermostat activate fuel feed system, feeding the burner pot with fuel. (HIGH FIRE)
2. Heat builds up in the furnace activating the fan switch, which in turn starts the furnace
blower.*
3. When the thermostat setting is satisfied, the thermostat will shut off the fuel feed
system.
4. The furnace timer will activate, augering a specified amount of fuel to sustain burner
fire. (LOW FIRE) Timer is factory set at two (2) minutes “ON”and six (6) minutes
“OFF”. (This is a suggested setting - actual setting can be varied with user experience
and fuel used.)
5. Furnace blower will continue to run until heat is removed from furnace.
*NOTE: The furnace blower has three (3) speeds. Low (red wire-#3), Medium (blue wire-#2) &
High (black wire-#1). All units are shipped from the factory on the Medium speed. Blower
speed may be changed by accessing the 4 in. x 4 in. electrical junction box on the side of the
furnace. Change blower speeds by disconnecting the yellow furnace wire from the current
speed wire and reconnecting it to the desired speed wire. Disconnected lead must be insulated
using the wire nut removed from desired speed wire.

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CLINKER BUILDUP
The A-Maize-Ing Heat®furnace feeds biomass fuel into the bottom of the burner, therefore creating
the most efficient fuel consumption. The residual ash and clinkers are then spilled over the top of the
burner ring, falling into the ash pan below. This process essentially cleans the burner chamber.
CAUTION
If the furnace is installed in an unsuitable application, causing the furnace to run on high fire for
extended amounts of time, or if certain varieties of wood pellets are burned, clinkers can form
resulting in furnace inefficiency and possible fire outage.
The clinkers that stick to the side of the firepot must be loosened with a furnace poker (provided)
and removed manually with furnace tongs or the clinkers could render the furnace inoperative.
SUMMARY OF SETTINGS & OPERATION
HIGH FIRE
Adjustment of the opening on the combustion blower inlet controls fuel air mixture on high fire. This
opening should be adjusted during the high fire mode of operation to obtain an intense flame that
consumes the fuel at the same rate it is augered in.
The variable Btu timer relay controls the auger drive rate. It comes set from the factory at 15
seconds “ON” (red indicator) and 15 seconds “OFF” (green indicator). Allow the furnace to run for 4
hours, then evaluate if adjustment is necessary.
LOW FIRE
Adjustment of the chimney draft controls the rate of burn on the low fire mode of operation. Chimney
draft must remain below 0.04 inches water column and constant. The use of a second automatic
barometric damper may be necessary on some installations to insure the precise draft control. A
setting of 0.02 - 0.03 is ideal.
In most installations, the counter weight on the automatic barometric dampers should be set on the
minimum setting. Adjusting the on and off cycle time settings on the low fire timer controls the
amount of fuel fed to the firepot during the low fire mode of operation. The initial setting of this low
fire timer is 6 minutes “OFF” (green indicator) and 2 minutes “ON” (red indicator). After
approximately 24 hours of operation, a layer of ashes and clinkers form in the combustion area. After
this layer of ash and clinkers form, the “OFF”time can be increased to reduce the amount of fuel
consumed during this “low fire” mode of operation. Further adjustment can be made with user
experience.