This furnace is designed for negative ground 12 volts DC only.
attempt to alter furnace for a positive ground system or connect the
furnace directly to 120 volts AC. Damage to furnace components will
occur and warranty will be voided.
Use a minimum of 18 GA wire to minimize voltage drop. Furnace must
be installed so electrical components are protected from water. To
make electrical connections see wiring diagram
1. Route wiring to left side of furnace.
2. Connect red wire to positive side of power supply.
3. Connect yellow wire to grounded side of power supply.
4. Connect blue wire marked positive thermostat to + side wire of ther-
mostat using 22-18 GA stranded wire.
5. Connect other blue wire to other thermostat lead using minimum
22-18 GA stranded wire.
For best furnace performance when power supply is from a converter
equipped with a charging port, wire converter to furnace parallel with
battery. This provides consistent voltage to furnace, increasing compo-
nent life, filtering power surges and AC spikes.
Each model with door is shipped with a standard field harness connec-
tion with 12˝ wire leads. An optional field harness with a double end is
available in bulk FIG 15 #55. This harness contains 12˝ leads, a four
pin housing, and standard six pin housing
: All units are supplied with a power switch which when turned off
or servicing will remove power through furnace wiring. Switch
must be in ON position for furnace to operate
Atwood Mobile Products highly recommends the use of an electronic
(solid state) converter with clean, clear power output. This will assure
the life of the electronic controls and motor life could be extended as
much as 500% beyond typical linear converter applications.
The thermostat is very sensitive.
Locate thermostat 48˝ to 54˝ above floor on an
areas of abnormal heat or cold.
spacer between thermostat and exterior wall.
Follow manufacturer's installation instructions provided with thermo-
stat. When thermostat is not supplied, use a thermostat rated for 12
VDC or 24 VDC minimum 1 AMP.
CARBON MONOXIDE POISONING
Properly seal door to prevent carbon monoxide from entering coach.
or with optional
1. Pull furnace forward until mounting tabs protrude through exterior
wall. The edge of control box is flush with coach's outer skin, (
- with gas connection on bottom).
2. The door bezel must fit tightly, to prevent water leakage.
: The furnace must always be installed level (front to back, side
to side) to prevent water intrusion into the interior.
3. To prevent moisture from entering inside of coach, apply RTV type
sealant to the following areas:
entire mounting surface of door bezel, making sure caulking is tight
against inner flange of bezel.
fill tab slots with caulking after bending tabs over, securing with screws.
- YOU MUST CALK -
around red gas inlet plug (slide plate and casing bottom intersect).
around back slide plate where it joins metal casing.
HANDLE WITH CARE AT ALL TIMES
wall away from
wall location must have a 3/4˝
9) may be used alone
around gas line where it enters gas inlet plug.
along welded joints of two bottom corners of casing.
4. The inlet plug and slide plate must be in closed position and bezel
flange inside of casing. Insert six mounting tabs through slots pro-
vided in bezel, bezel must be tight against casing and cutting into
RTV sealant on bezel.
5. Bend tabs flush with door bezel, aligning holes in tabs with slots in
6. Install 12 mounting screws.
7. Remove excess sealant from around door bezel and visually inspect
door bezel to make sure it is completely sealed.
8. Secure mounting legs on the back of the unit to floor for horizontal
installation. For vertical installation secure legs to a vertical member
that is attached to floor. Seal around slide plate, gas plug and joint
between control box right side and back wall.
1. Position and secure mounting brackets to door framing on each side of
opening, allowing 5/16˝ from end of bracket face to outside of coach.
2. Pull furnace forward until edge of control box is flush with recess
pan, with mounting tabs protruding through exterior wall.
3. Insert recess bezel and door bezel until furnace tabs go through
notches on door bezel. RTV type sealant must be applied to entire
back flange of both parts creating a water tight seal. Secure to
4. Fasten recess bezel and door bezel to brackets with three screws on
each side. Do not deform recess bezel or door bezel.
5. Bend tabs over and secure with six screws. Fill tab slots with RTV
type sealant after installing furnace.
DRAFT CAP ASSEMBLY
CARBON MONOXIDE POISONING
Properly adjust draft cap to prevent carbon monoxide from enter-
With wing nut 12-C loose on draft cap assembly, close door 12-A and
adjust draft cap 12-D. The draft cap assembly must be pulled out tight
gainst door screen 12-B. Open door 12-A and tighten wing nut 12-C.
OPTIONAL FURNACE INSTALLATION
RECESSED FURNACE -
Only intake and exhaust portion of furnace is viewed from exterior of
coach when furnace is installed.
Furnace must be removable for service.
All 65 in
return air should be taken from interior of coach.
Areas to be sealed.
Coach access door butting against furnace pan cover.
Bottom edge of cut out section in metal pan cover.
Draft cap assemblies to be maintained tight against the coach
outside compartment doors where intake screens will be mounted.
INSTALLATION OF DRAFT CAP ASSEMBLY
. Draft Cap assembly must over lap 1.25˝ inside
1. Remove four (4) outside tabs located on control box. Leave two (2)
center tabs to mount door. Bend these two center tabs toward inside
of control box area 90˚, as close to control box as possible, to main-
tain a good seal. Install two fastening clips provided.
2. Install furnace in coach as close to outer compartment door as pos-
sible. Furnace must maintain a pressure seal against gasket on
screen to prevent flue products and water leakage from entering
interior of coach.
3. Connect gas line to right side of furnace. Tighten gas fitting using
two wrenches. Attach electrical wiring to left side of furnace. Attach
red wire to positive connection and yellow wire to negative. Attach
two blue wires to the thermostat wires.
DO NOT PULL COMPLETELY OUT OF