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SF-20FQ • SF-25FQ • SF-30FQ • SF-35FQ • SF-42FQ
The design of the furnace has been listed for installation in recreational vehicles only. In order for the furnace to operate in conformity with generally
accepted safety regulations, the installation instructions must be followed. Failure to comply with the installation instructions will void the warranty
on the furnace and any responsibility on the part of Suburban Manufacturing Company.
The furnace was inspected before it left the factory. If any parts are found to be damaged, do not install the furnace. Immediately contact the
transportation company and file a claim.

FOR YOUR SAFETY

WHAT TO DO IF YOU SMELL GAS:

Extinguish any open flame.
Evacuate all persons from the vehicle.
Shut off the gas supply at the gas container
or source.
Do not touch any electrical switch, or use
any phone or radio in the vehicle.
Do not start the vehicle's engine or electric
generator.
Contact the nearest gas supplier or
qualified service technician for repairs.
If you cannot reach a gas supplier or
qualified service technician, contact the
nearest fire department.
Do not turn on the gas supply until the gas
leak(s) has been repaired.
This book contains instructions covering the operation and
maintenance of your furnace.
INSTALLER: LEAVE THIS MANUAL WITH THE APPLIANCE.
CONSUMER: RETAIN THIS MANUAL FOR FUTURE REFERENCE.
Should you require further information, contact your dealer or
nearest Suburban Service Center.
FOR YOUR SAFETY
DO NOT STORE OR USE GASOLINE OR OTHER
FLAMMABLE VAPORS AND LIQUIDS IN THE
VICINITY OF THIS OR ANY OTHER APPLIANCE.
WARNING!
Improper installation, adjustment, alteration,
service or maintenance can cause property damage, personal
injury or loss of life. Refer to the installation instructions and/
or owners manual provided with this appliance. Installation
and service must be performed by a qualified installer, service
agency or the gas supplier.
WARNING!
Be sure the furnace and all ignition systems
are "OFF" during any type of refueling and while vehicle is in
motion or being towed.
Part Number 205170
01-06-2015
SUBURBAN GAS FURNACES
INSTALLATION INSTRUCTIONS FOR
AIRXCEL, INC. - SUBURBAN DIVISION

INSTALLATION INSTRUCTIONS

WARNING!
Installation of this appliance must be made in accordance with the written
instructions provided in this manual. No agent, representative or employee of Suburban or
other person has the authority to change, modify or waive any provision of the instructions
contained in this manual.
THESE FURNACES ARE DESIGNED AND INSTALLED IN SUCH A MANNER
AS TO BE REMOVABLE ONLY FROM WITHIN LIVING AREA OF THE
RECREATIONAL VEHICLE.
IF UNIT IS TO BE INSTALLED VERTICALLY, YOU MUST USE KIT #520965
(INSTALLATION INSTRUCTIONS ARE ENCLOSED IN KIT).
CAUTION: If possible, do not install the furnace to where the vent can be
covered or obstructed when any door on the trailer is opened. If this is not
possible, then the travel of the door must be restricted in order to provide
a 6" minimum clearance between the furnace vent and any door whenever
the door is opened.
NOTE: The exhaust temperature of this furnace could discolor or warp some
materials. You should verify that the material used on the coach door, panel, or
cover will not discolor or warp from the exhaust temperature whenever any door,
panel, or cover is in the open position.
CAUTION: Due to the differences in vinyl siding, this appliance should not
be installed on vinyl siding without first consulting with the manufacturer
of the siding or cutting the siding away from the area around the appliance
vent.
CAUTION: In any installation in which the vent of this appliance can be
covered due to the construction of the RV or some special feature of the
RV such as slide out, pop-up etc. always insure that the appliance cannot
be operated by setting the thermostat to the positive "OFF" position and
shutting off all electrical and gas supply to the appliance. Never operate
furnace with vent covered.
NOTE: These furnaces must be installed and vented as described in this manual
so that the negative pressure created by the air circulating (return air) fan cannot
affect the combustion air intake or venting of any other appliance. It is imperative
that the products of combustion be properly vented to the atmosphere and that all
combustion air supplied to burner be drawn from the outside atmosphere. (See
NOTE: Do not install the furnace with the vent facing toward the forward end
of the coach. See figures 7 and 8.
IMPORTANT: If this furnace is to be connected to a common duct system also
serving a cooling unit, a manual or automatic damper is required to prevent any
cold conditioned air from circulating back into the furnace. Cold air passing over
the furnace combustion chamber during the operation of the cooling unit can result
in the formation of condensation inside the furnace combustion chamber. This
condensation may promote corrosion and premature failure of the combustion
chamber.
NOTE: These furnaces shall be installed so the electrical components are
protected from water.
These furnaces are design certified for propane/LP gas only. Do not attempt to
convert to natural gas.
Gas supply pressure for purposes of input adjustment:
Minimum - 11" W.C.*
Maximum - 13" W.C. *
(W.C.* - Water Column).
676 Broadway Street
Dayton, Tennessee 37321
423-775-2131
www.AIRXCEL.com

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Summary of Contents for Suburban SF-20FQ

  • Page 1 Failure to comply with the installation instructions will void the warranty on the furnace and any responsibility on the part of Suburban Manufacturing Company. The furnace was inspected before it left the factory. If any parts are found to be damaged, do not install the furnace. Immediately contact the transportation company and file a claim.
  • Page 2: Return Air

    WARNING! Do not alter, cut or otherwise modify the vent tubes as supplied by Suburban. NOTE: The compound used on threaded joints must be resistant to liquefied Doing so could result in inadequate intake of combustion air or improper venting of furnace petroleum (LP) gas.
  • Page 3: Installing Thermostat

    Connect Suburban advises the installer to provide the 1/8” NPT plug tap for test gauge thermostat wiring to the blue wire and blue-white striped wire (blue-white striped connection immediately upstream of the gas supply connection to the furnace wire is power to the thermostat) on right side of furnace.
  • Page 4: Electrode Adjustment

    4. Remove cabinet front (2 screws). PARTS AND SERVICE 5. Remove tie-down screw from center of unit and remove furnace from cabinet. Contact a conveniently located recommended Suburban Service Center. Describe to them the nature of your problem, make an appointment, if necessary, TO INSTALL and provide for delivery of your RV with the appliance installed.
  • Page 5 CONNECTION FURNACE CABINET GAS CONNECTION ANCHOR CABINET TO COACH FLOOR AS ILLUSTRATED (2 PLACES) FRONT Figure 1 SF-20FQ, SF-25FQ, SF-30FQ, SF-35FQ, SF-42FQ, STANDARD VENT INSTALLATION INTAKE: 1/2" MINIMUM OVERLAP X" TRAILER SKIN 1" EXHAUST: 1 1/4" MINIMUM OVERLAP FRONT GAS...
  • Page 6 OPENING FOR RETURN AIR SPACER BUMPS SPACER BUMPS OPENING FOR RETURN AIR 0" TO SPACER FURNACE MAINTAIN A 1/4" INCH CLEARANCE WHERE DUCTS PASS THROUGH A CABINET WALL. UL LISTED DUCT MATERIALS CAN BE 0" CLEARANCE. 0" TO SPACER THE TOTAL, FREE, UNOBSTRUCTED RETURN AIR OPENING TO THE FURNACE MUST NOT BE LESS THAN THE MINIMUM SPECIFIED.
  • Page 7 TO CLEAN THE CHAMBER, THE FURNACE MUST BE REMOVED F ROM THE CABINET AND THE MANIFOLD. BLOWER ASSEMBLY AND CONTROLS REMO VED LEAVING THE CHAMBER ONLY, AS SHOWN. USING COMPRESSED AIR, B LOW THROUGH THE CHAMBER, AS SHOWN BY ARROWS, TO REMOVE SOOT OR LOOS E DEBRIS. Figure 6 INCORRECT INCORRECT...
  • Page 8 This Suburban product is warranted to the original purchaser to be free from defects in material and workmanship under normal use and maintenance for a period of two years from date of purchase whether or not actual use begins on that date. It is the responsibility of the consumer/owner to establish the warranty period. Suburban does not use warranty registration cards for its standard warranty.

This manual is also suitable for:

Sf-25fqSf-30fqSf-42fqSf-35fq

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