8. If X - Y is less than 21”, then an opening 9 5/8” x 9 3/8” must be cut through
the inner wall only. DO NOT CUT THROUGH COACH SKIN. (See Figure
2.) Next, locate the center line of the exhaust and intake tube. Cut two 2 1/4”
diameter holes through the outer skin as shown in Figure 4.
NOTE: Whenever the furnace cabinet is installed through the outside wall, the
return air louvers on the furnace cabinet must not be blocked. The maximum
projection of the furnace cabinet into the wall is 2 1/2”. (See Figure 2.)
NOTE: Furnace cabinet approved for 0” clearance to combustible materials rear
2 1/2” of furnace cabinet.
9. If X - Y is 21” or greater, two methods may be used to install the furnace.
a. Cut a 4” x 7 1/2” opening through combustible wall as shown in Figure 3.
DO NOT CUT THROUGH TRAILER SKIN. Next, locate the center line of
the exhaust and intake tube. Cut two 2 1/4” diameter holes through trailer
skin. (See Figure 4.)
b. If you do not wish to cut the 4” x 7 1/2” opening, locate the center line of
the exhaust and intake tube as shown in Figure 4. Next, cut two 2 3/4”
diameter holes through trailer skin and also the combustible wall of the
trailer as illustrated in Figure 6. Care must be taken when locating the
center line of the exhaust and intake tube as well as when cutting the holes
in order to assure a 3/8” clearance around the exhaust and intake tube to
combustible materials.
10. Refer to the chart in Figure 1 and select the range for which the ‘X’ dimension
falls. The intake tube length directly to the left of the selected range is
the length required. NOTE: The 7 3/4” length exhaust tube assembly will
accommodate all approved installation depths - only the intake tube must be
ordered when needed. Under no circumstances should the standard 5” intake
tube be cut or altered to adapt to the 21” - 23 1/4” range.
11. Secure furnace to the oor using the two holes provided in furnace cabinet.
(See Figure 2 or Figure 3.)
12. NOTE: OPTIONAL DISCHARGE DUCT ADAPTER -The cabinet has a 4”
diameter knockout on the left side of cabinet. (See Figure 6A.) A 4” diameter
connector can be attached to this location to provide a warm air discharge
duct. (Not to exceed 10” in length.)
CONNECTING GAS SUPPLY
A 3/8” are connection is provided on the right side of the furnace for the gas supply
connection to the furnace.
Connect the gas supply to the furnace at the manifold, following the suggestions
outlined below. It will be necessary to hold the are tting on the furnace manifold
when connecting or loosening gas lines.
NOTE: Be sure all male joints have been treated with a sealing compound
resistant to the action of liqueed petroleum (LP) gas.
In order to maintain a check on gas supply pressure to the furnace. Suburban
advises the installer to provide a 1/8” NPT plug tap for test gauge connection
immediately upstream of the gas supply connection to the furnace.
NOTE: The appliance must be disconnected from the gas supply piping system
during any pressure testing of that system at test pressure in excess of 1/2 PSIG.
The appliance must be isolated from the gas supply piping during any pressure
testing of the gas supply piping system at test pressure equal to or less than 1/2 PSIG.
WARNING! All joints must be checked for leaks. Do not use open ame to check for
leaks! Use a soap and water solution.
CONNECTING ELECTRICAL SUPPLY
CAUTION: These furnaces are designed for a negative ground 12 volt
D.C. system only. Do not attempt to alter the furnace for a positive ground
system or connect the furnace directly to 115 volts A.C. Damage to furnace
component parts will occur. Connect only to a protected circuit fused for
not more than 7.5 amps.
Be sure all wiring to the furnace is of heavy enough gauge to keep the voltage
drop through it to a minimum and to provide enough power for start-up surge. No.
12 gauge wire is recommended.
If any of the original wire that is supplied with the appliance must be replaced, it
must be replaced with Type 105° C or its equivalent.
Connect the power supply to the red and yellow wires on the right side of the
furnace. The wires are color coded, red for positive (+) and yellow for negative
(-). This polarity must be observed so the furnace motor will run with the proper
direction of rotation to insure correct air delivery. (See wiring diagram.)
If the furnace power supply is to be from a convertor, we recommend that the
convertor system used to power the furnace be wired in parallel with the battery.
This will serve two purposes:
1. Provide a constant voltage supply to the furnace.
2. Filter any A.C. spikes or volt surges.
NOTE: Furnace models NT-16SEQ AND NT-20SEQ are equipped with an electric
ignitor device that has an energy consumption of.1 amps at 12 volts D.C.
CONNECTING THERMOSTAT
The thermostat used with this unit must have NO voltage output to return leg when
there is not a call for heat or in the “OFF” setting.
Locate the room thermostat approximately 4-1/2 feet above the oor on an inside
bulkhead where it is not affected by heat from any source except room air. Connect
thermostat wiring to the blue wire and blue-white striped wire (blue-white striped
wire is power to the thermostat) on right side of furnace. (See wiring diagram.) If
your furnace is equipped with a thermostat that has an adjustable anticipator, the
anticipator should be set at .7 amps. If you desire longer heating cycles, adjust
the anticipator to a higher setting. If you desire shorter heating cycles, adjust the
anticipator to a lower setting. Adjustments to the anticipator setting should be
made in .5 amp increments.
INSTALLING VENT ASSEMBLY
The vent outlet must be installed so it is in the same atmospheric pressure zone
as the combustion air intake. The exhaust and intake tubes must be installed
from the outside, pass through the RV skin and slide onto the furnace exhaust
and intake.
WARNING! Do not alter the vent assembly supplied with this furnace. Any modications
will result in improper installation which could cause unsafe furnace operation. Never
operate furnace with vent covered.
CAUTION! Combustion air must not be drawn from the living area. All air for
combustion must be drawn from the outside atmosphere. All exhaust gases
must be vented to the outside atmosphere - never inside the RV. Therefore,
it is essential to insure that the vent cap and tube assemblies are properly
installed.
1. Apply caulking to RV skin behind vent cap as shown in Figure 6. Apply
caulking generously around perimeter of vent cap and across center as
shown.
2. Insert intake tube through RV skin and slide it onto the furnace intake (See
Figure 1.) Minimum tube overlap of 1/2” is required.
3. Insert vent cap exhaust tube through RV skin and slide it onto the furnace
exhaust (See Figure 1.) Minimum tube overlap of 1 1/4” is required.
4. Attach vent cap assembly to outer skin of RV with the six (6) screws provided.
Do not install vent assembly upside down. The word “Suburban” must be right
side up.
Due to high temperatures, the unit should be located out of trafc and
away from furniture and draperies.
Children and adults should be alerted to the hazards of high surface
temperatures and should stay away to avoid burns or clothing ignition.
Young children should be carefully supervised when they are in the same
room as the unit.
Clothing or other ammable material should not be placed on or near
the unit.
Any safety screen or guard removed for servicing the unit must be
replaced prior to operating the unit.
The area around the unit must be kept clear from combustible materials,
gasoline and other ammable vapors and liquids.
Installation and repairs should be done by a qualied service person. The
unit should be inspected before use and at least annually by a qualied
service person. More frequent cleaning may be required due to excessive
lint from carpeting, bedding material, etc. It is imperative that control
compartments, burners, and circulating air passageways of the unit be
kept clean.
PARTS AND SERVICE
Contact a conveniently located recommended Suburban Service Center.
Describe to them the nature of your problem, make an appointment, if necessary,
and provide for delivery of your RV with the appliance installed.
To obtain information on locating a local service agency, contact:
AIRXCEL, Inc., - Suburban Division
Customer Service Department
676 Broadway Street
Dayton, TN 37321
(423) 775-2131 Ext. 7101
www.Airxcel.com
VENT TUBE (INTAKE) SEE CHART
MOUNTING SURFACE
VENT TUBE (EXHAUST) 8" X 2" O.D.
2" O.D. X 2 3/4" SPECIAL
2" O.D. X 5" *STANDARD
2' O.D. X 7 1/4" SPECIAL
INTAKE TUBE LENGTH ONLY
STANDARD TUBE FURNISHED WITH FURNACE.
THE SPECIAL TUBES, IF NEEDED, MUST
PART NO.
NEVER INSTALL VENT TUBES
ON INTAKE & 1 1/4" ON EXHAUST
WITH LESS THAN 1/2" OVERLAP
X050708
X050711
X050712
1 1/4" MIN. OVERLAP
"X"
"X" DIMENSION
25 1/2" TO 27 3/4"
21" TO 23 1/4"
23 1/4" TO 25 1/2"
TRAILOR SKIN
2 1/4"
VENT CAP
1/2" MIN. OVERLAP
DIA.
2 1/4"
Y"
7 1/2" DIA.
21" OF INTAKE TUBE
ON EXHAUST
Figure 1
2
