Atwood Mobile Products Model 8940 - Manual (Page 4)

4
120 VOLT AC MODELS
Route 120 volt AC and thermostat leads to wires located on the left
side of control box using a minimum of 18 GA wire. The furnace must
be installed so electrical components are protected from water. To
make electrical connections see
WIRING DIAGRAM FIG 12
1. Route wiring to left side of furnace.
2. Remove junction box cover.
3. Connect 120 white wire to furnace 120 white wire.
4. Connect 120 black wire to furnace 120 black wire.
5. Connect ground wire to furnace green ground wire.
After field hookups have been made, put wire connections into
furnace junction box and replace cover.
6. Connect thermostat leads to the two blue furnace thermostat leads.
NOTE : Furnace is equipped with a 120 volt AC motor. All other
electrical component parts are supplied with power from a trans-
former inside the furnace at 24 volts AC.
NOTE : A 120 volt model can also be supplied with a 30 inch
power cord attached from the factory supplied with a molded plug
with ground pin.
NOTE : DC units are supplied with a power switch
which when turned OFF for servicing will remove power through the
furnace wiring. Switch must be in ON position for furnace to operate.
See
FIG 1-D. AC units power switch is in valve circuit only.
POWER SUPPLY
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.
THERMOSTAT INSTALLATION
The thermostat is very sensitive. HANDLE WITH CARE AT ALL TIMES .
Locate thermostat 48˝ to 54˝ above floor on an INTERIOR wall away from
areas of abnormal heat or cold. EXTERIOR wall location must have a 3/4˝
spacer between thermostat and exterior wall.
Follow manufacturer’s installation instructions provided with thermo-
stat. When a thermostat is not supplied use a thermostat rated for 12
VDC or 24 VAC minimum lamp.
DOOR INSTALLATION
HORIZONTAL & VERTICAL
( FIG . 6-8A)
ƽ
WARNING
CARBON MONOXIDE POISONING
• Properly seal door to prevent carbon monoxide from entering coach.
1. Secure mounting brackets ( FIG 6) to wood framing on each side of
furnace opening 5/16˝ from bracket face to exterior wall of coach.
2. Before installing recessed bezel/door assembly remove rain shield
( FIG 9-A). Vertical Units Rain Shield not required and not returnable.
3. Slide furnace in cavity. DO NOT have tabs protrude outside exterior
wall until door is ready to be installed.
4. Pull furnace forward until mounting tabs protrude through exterior
wall. The edge of control box is flush with coach’s outer skin.
5. The door bezel ( FIG 7-8A) and recess pan must fit tightly, to prevent
water leakage.
NOTE : The furnace must always be installed level (front to back, side to
side) to prevent water intrusion into the interior.
6. To prevent moisture from entering inside of coach, apply RTV type
sealant to following areas:
HORIZONTAL & VERTICAL INSTALLATION
• entire mounting surface of door bezel, caulking must be tight
against inner flange of bezel.
• bending tabs over, fill tabs slots with caulking, securing with screws.
VERTICAL INSTALLATION - YOU MUST CAULK -
• around red gas inlet plug (slide plate and casing bottom intersect).
• around back of slide plate where it joins metal casing.
• around gas line where it enters gal inlet plug.
• along welded joints of two bottom corners of casing.
7. 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, making sure bezel is tight against casing and cutting
into RTV sealant on bezel.
• fill tab slots with caulking after bending tabs over and securing
with screws.
8. Bend tabs flush with door bezel, aligning holes in tabs with slots in
door bezel.
9. Install 12 mounting screws. DO NOT deform bezel.
10. Remove excess sealant from around door bezel and visually
inspect the door bezel to make sure it is completely sealed.
11. Secure mounting legs to floor for horizontal installation. Seal
around slide plate, gas plug and joint between control box right
side and back wall.
12. Fasten door ( FIG 6-8A) with fasteners provided.
RAIN SHIELD INSTALLATION HORIZONTAL & VERTICAL ( FIG . 9)
HORIZONTAL
Install rain shield after recessed bezel and door bezel are in place.
The rain shield must be in place to prevent water leakage on horizon-
tal units.
1. Insert rain shield on a 45˚ angle into right side of control box
making certain rear portion of rain shield is positioned under heat-
ing element exhaust tube
FIG . 9-A.
2. Lower left side of rain shield and position into place FIG 9-2.
3. Secure rain shield with one #8 x 1/2˝ screw into combustion
blower scroll FIG 9-B.
VERTICAL - Rain Shield not required on vertical unit and it’s not a
returnable part.
DRAFT CAP ASSEMBLY ( FIG . 10)
ƽ
WARNING
CARBON MONOXIDE POISONING
• Properly adjust draft cap to prevent carbon monoxide from
entering the coach.
With wing nut 10-C loose on draft cap assembly, close door 10-A and
adjust draft cap 10-D. The draft cap assembly must be pulled out tight
against door screen 10-B. Open door 10-A and tighten wing nut 10-C.
CONVERTIBLE GAS CONTROL FIG 5
LC MODEL UNITS come equipped with a convertible gas control. Each
unit is supplied with two main burner orifices. One will be in place, the
other will be attached to blower housing cover. Each orifice will be
clearly marked with a drill size as shown below.
GAS TYPE BTU / HR LINE PRESSURE VALVE REGULATOR DRILL SIZE
PROPANE ( LP ) 40,000 11˝ W.C. 10.5˝ W.C. 49P
NATURAL ( NAT ) 40,000 7˝ W.C. 3.5˝ W.C. 30N
PROPANE ( LP ) 35,000 11˝ W.C. 10.5˝ W.C. 51P
NATURAL ( NAT ) 35,000 7˝ W.C. 3.5˝ W.C. 32N
The pressure settings of the convertible valve are set for natural gas
NAT 3.5˝ W.C. or LP 10.5˝ W.C. and are not adjustable. Use Loctite
®
#RC609 on orifice threads when installing a new orifice. 1/8˝ NPT plug
is provided upstream of gas connections for checking gas pressure.
VALVE CONVERSION ( FIG . 5)
1. Check exposed section on side of adjustment plug to determine
whether it is set for natural or propane. NAT is stamped on one end
and LP is stamped on the other end of plug. The types of gas in use
will be showing right side up.
2. Unscrew plug and remove from valve tower. DO NOT remove rod from
tower or make any adjustments.