Page 1
INSTALLATION
INSTRUCTIONS
DF Series Furnace
Models DFSAD12, DFSD12, DFSD16, DFSD20, DFMD16,
DFMD20, DFMD25, DFMD30, DFMD35, DFLD35,
DFLD40, DFLA35, DFLA40
INTRODUCTION ............................................................................. 2
IMPORTANT SAFETY INSTRUCTIONS AND DOCUMENT SYMBOLS .................................... 2
GENERAL INFORMATION ...................................................................... 4
PRE-INSTALLATION ........................................................................... 6
INSTALLATION .............................................................................. 16
TESTING ................................................................................... 24
TROUBLESHOOTING ........................................................................ 25
REPLACEMENT PARTS ........................................................................ 25
WARNING:
FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could result in serious
injury, death or property damage.
− Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
− WHAT TO DO IF YOU SMELL GAS
• 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.
− Installation and service must be performed by a qualified
installer, service agency, or the gas supplier.
Read these instructions carefully. These instructions MUST stay with this product.
Form No. 33400 09/17
©2017 Dometic Corporation
LaGrange, IN 46761
USA & CANADA
SERVICE OFFICE
Dometic Corporation
1120 North Main Street
Elkhart, IN 46514
SERVICE CENTER &
DEALER LOCATIONS
Visit:
www.eDometic.com
Page 2
INTRODUCTION
This manual is for use by an authorized service technician to install a Dometic DF Series Furnace. Should you require further
information, contact Dometic. The design of the DF Series Furnace (hereinaer referred to as “Furnace”) has been certified for
installation in a recreational vehicle (hereinaer referred to as “RV”) as an MSP Category III Furnace. Follow these instructions to
ensure the correct installation of the Furnace. Failure to install the Furnace according to these installation instructions nullifies the
Furnace warranty.
Dometic Corporation reserves the right to modify appearances and specifications without notice.
IMPORTANT SAFETY INSTRUCTIONS AND DOCUMENT SYMBOLS
This manual has safety information and instructions to help you eliminate or reduce the risk of accidents and injuries.
A. Recognize Safety Information
This is the safety alert symbol. It is used to alert you to potential physical injury hazards. Obey all safety messages that follow
this symbol to avoid possible injury or death.
B. Understand Signal Words
A signal word will identify safety messages and property damage messages, and will indicate the degree or level of hazard
seriousness.
indicates a hazardous situation that, if NOT avoided, could result in death or serious injury.
indicates a hazardous situation that, if NOT avoided, could result in minor or moderate injury.
is used to address practices NOT related to physical injury.
Indicates additional information that is not related to physical injury.
C. Supplemental Directives
Read and follow all safety information and instructions to avoid possible injury or death.
Read and understand these instructions before installation of this product.
Incorrect installation of this product can lead to serious injury or death.
The installation MUST comply with all applicable local or national codes, including the latest edition of the following standards:
U.S.A.
• ANSI/NFPA70, National Electrical Code (NEC)
• ANSI/RVIA LV, Low Voltage Systems in Conversion and
Recreational Vehicles
• ANSI/NFPA 1192, Recreational Vehicles Code
• ANSI Z223.1, NFPA 54 National Fuel Gas Code
• ANSI 1195, Park Trailers
FOR DFLA35 and DFLA40 Models Only
This Furnace is manufactured for use with Liquid Propane (LP) gas. A kit has been provided with the Furnace, so that a qualified
service technician can convert the Furnace for use with natural gas. Any conversion to natural gas must conform with local
codes, or in the absence of local codes, with the National Fuel Gas Code, ANSI Z223.1/NFPA 54 Natural Gas and Propane
Installation Code, in addition to the Standard for Recreational Vehicles NFPA1192 and CSA Z240 RV Recreational Vehicle Code.
CANADA
• CSA C22.1, Parts l & ll, Canadian Electrical Code
• CSA Z240 RV Series, Recreational Vehicles
• CAN/CGA B149, Natural Gas and Propane Installation
Code
2
Page 3
IMPORTANT SAFETY INSTRUCTIONS AND DOCUMENT SYMBOLS
D. General Safety Messages
Failure to obey the following warnings could result in property damage, serious injury, or death:
• This Furnace MUST be installed by a qualified service technician.
• Do NOT modify this Furnace in any way. Modifi cation can be extremely hazardous.
• FIRE OR EXPLOSION HAZ ARD:
• Do NOT store gasoline, oil- or gasoline-soaked rags, or other flammable vapors and liq uids, inside storage compartment(s).
• BEFORE refueling or parking near a gas oline pump, make sure ALL LP gas appliances (vented to the outside of the RV) are
shut OFF. Oth erwise, fumes from gasoline pumps could come into contact with an LP gas appliance burner flame and ignite.
• Turn OFF LP gas supply at tank.
• Use only with the type of gas approved for the Furnace. Refer to the Furnace rating plate.
• Use only Dometic replacement parts and components, which are specifically approved for use with the Furnace.
• CRITICAL INSTALLATION WARNINGS:
• Do NOT install this Furnace if any part has been underwater.
• Sheet metal edges are sharp; take care when handling or touching edges.
• Protect Furnace electrical components from water.
• Protect building materials from degrading from vent assembly gas exhaust.
• Compartment MUST be closed when operating the Furnace.
• Do NOT install screens over the intake air or exhaust vents for any reason.
• CARBON MONOXIDE HAZARD:
• This Furnace can produce carbon monoxide, which has no odor and can be life-threatening. The burner and vent assembly
system MUST be kept clean.
• Doors MUST be properly sealed and the dra cap and assemblies MUST be adjusted and sealed correctly to prevent
carbon monoxide from entering the RV.
• Do NOT allow snow or any objects to block the exhaust system of the Furnace.
• Combustion products MUST be properly vented to the atmosphere and all combustion air supplied to the burner MUST be
drawn from the outside atmosphere.
• Use only Dometic replacement parts and components, which are specifically approved for use with the Furnace.
• ELECTRICAL SHOCK HAZARD:
• Make sure AC power is dis connected from the Furnace during installation.
• Furnaces with 12 VDC connection are for low-voltage battery or direct current only. DC Furnaces are designed for negative
ground 12 VDC only. Do NOT attempt to alter the Furnace for a positive ground system or connect the Furnace directly to
120 or 240 VAC.
• Do NOT use a battery charger to supply power to DC model Furnaces, even when testing.
• Use only Dometic replacement parts and components, which are specifically approved for use with the Furnace.
3
Page 4
GENERAL INFORMATION
INCLUDED HARDWARE
(2) Mounting Bracket (2 to 3) Duct Adapter (depending on Furnace model)
Ventilation Assembly 15 Amp Breaker (DFMD35,DFLD35 & DFLD40 models only)
REQUIRED TOOLS AND MATERIALS
Manometer Gauge/U-Tube Volt-Ohm Meter (15+ amps)
Gas Leak Detector Liquid Wrenches
Safety Glasses RTV Type Sealant
Pipe Thread Sealing Compound Foil Tape (optional)
A. Model Specifications
DFSAD12, DFSD12, DFSD16, DFSD20 (Small Furnace Models)
MODELS
TYPE OF GAS
BTU INPUT
BTU OUTPUT
DUCT STATIC PRESSURE
AMPERAGE (AMPS)
WAT TS
POWER SUPPLY (VOLT DC)
MINIMUM RETURN AIR
DFSAD12 DFSD12 DFSD16 DFSD20
LP Gas LP Gas LP Gas LP Gas
12,000 12,000 16,000 18,000
9,120 9,120 12,160 13,680
0.10" WC, 0" WC front 0.10" WC 0.10" WC 0.10" WC
2.4* 3.4* 3.4* 4.8*
34 41 56 34
12 12 12 12
35 in.
2
35 in.
2
WC = Water Column; *15 Amp dedicated circuit for Furnace
DFMD16,DFMD20, DFMD25, DFMD30, DFMD35 (Medium Furnace Models)
MODELS
TYPE OF GAS
BTU INPUT
DFMD16 DFMD20 DFMD25 DFMD30 DFMD35
LP Gas LP Gas LP Gas LP Gas LP Gas
16,000 20,000 25,000 30,000 35,000
35 in.
2
35 in.
2
BTU OUTPUT
DUCT STATIC PRESSURE
AMPERAGE (AMPS)
WAT TS
POWER SUPPLY (VOLT DC)
RETURN AIR
MINIMUM RETURN AIR
12,160 15,200 19,000 22,800 25,840
0.20" WC 0.10" WC 0.10" WC 0.10" WC 0.10" WC
4.2* 4.2* 7.5* 7.5* 11.1*
50 50 90 90 132
12 12 12 12 12
2
80 in.
2
65 in.
WC = Water Column; *15 Amp dedicated circuit for Furnace
80 in.
65 in.
2
2
4
80 in.
65 in.
2
2
80 in.
65 in.
2
2
80 in.
65 in.
2
2
Page 5
GENERAL INFORMATION
DFLD35, DFLD40, DFLA35, DFLA40 (Large Furnace Models)
MODELS
TYPE OF GAS
BTU INPUT
BTU OUTPUT
DUCT STATIC PRESSURE
AMPERAGE (AMPS)
WAT TS
POWER SUPPLY
RETURN AIR
MINIMUM RETURN AIR
DFLD35 DFLD40 DFLA35 DFLA40
LP Gas LP Gas LP Gas & Natural Gas LP Gas & Natural Gas
35,000 40,000 35,000 40,000
26,600 30,400 26,600 30,400
0.10" WC 0.10" WC 0.10" WC 0.10" WC
12.5** 12.5** 2.5* 2.5*
138 138 154 154
12 VDC 12 VDC 12 VAC 12 VAC
80 in.
65 in.
2
2
80 in.
65 in.
2
2
80 in.
65 in.
WC = Water Column; *15 Amp dedicated circuit for Furnace; **20 Amp dedicated circuit for Furnace
B. Model Dimensions
DFSAD12, DFSD12, DFSD16, DFSD20 (Small Furnace Models)
COMPONENT WIDTH HEIGHT DEPTH WEIGHT
2
2
80 in.
65 in.
2
2
Casing 12" 7" 20"
Small Vent 4-7/16" 4-7/16" 1-1/16"
Door 14-3/4" 9-3/4" 1/2"
Interior Grill 8-1/2" 12-1/2" 1/2"
Trim Ring 14-1/8" 10-1/8" 1/8"
DFMD16,DFMD20, DFMD25, DFMD30, DFMD35 (Medium Furnace Models)
COMPONENT WIDTH HEIGHT DEPTH WEIGHT
Casing 16-1/2" 7" 20"
STD Door 19-1/16" 9-1/2" 7/16"
Flush Door 20-5/8" 11" 7/32"
Small Vent 4-7/16" 4-7/16" 1-1/16"
DFLD35, DFLD40, DFLA35, DFLA40 (Large Furnace Models)
COMPONENT WIDTH HEIGHT DEPTH WEIGHT
Casing 16-1/2" 9" 20"
Furnace 21 lbs.
Boxed 24 lbs.
Furnace 26 lbs.
Boxed 29 lbs.
Door 19-1/4" 9-1/4" 1/4"
Recess Bezel 20-9/16" 11-1/2" 3/8"
Small Vent 4-7/16" 4-7/16" 1-1/16"
Furnace 39 lbs.
Boxed 46 lbs.
5
Page 6
PRE-INSTALLATION
A. Identifying The Furnace Location
Failure to obey the following warnings could result in property damage, serious injury, or death:
• Install the Furnace only in a location and position specified in these instructions.
• Provide adequate combustion and ventilation air to the Furnace space, as specified in these instructions.
• Combustion products must be discharged outdoors. Connect this Furnace to an approved vent system only, as specified in
these instructions.
• As specified in these instructions, always install the Furnace to operate within the Furnace’s intended temperature-rise
range, with a duct system that has an external static pressure within the allowable range. Refer to the furnace rating plate.
• Do NOT install the Furnace near tilt-out rooms, slide-outs, and doors (refer to local codes for clearances), in an area where
wires, pipes, or other objects will interfere with the installation or operation of the Furnace, or in an area that is less than 12"
above a water heater (unless a heat shield is installed above the water heater).
• Do NOT install the Furnace directly on combustible flooring that restricts return air. Examples of combustible flooring
include carpet, tile, so material (like vinyl), or other combustible materials other than wood flooring.
• Do NOT install the Furnace where clearance to combustibles cannot be maintained. Excessive exposure to contaminated
combustion air will result in safety and performance-related problems.
The Furnace must be accessible for repairs.
Determining The Installation Type And Clearances Required
• Locate the Furnace near the midpoint of the RV, at least 3' from the gas service regulator, for a single-Furnace application. The
Furnace must be installed through an exterior wall. Spacing of 1/4" to ducting, within 3' of Furnace, must be provided unless
UL-listed, wire-bound, vinyl ducts are used. All ducting material used must be rated for continuous use at a minimum of 200 °F.
• Determine if you are using a horizontal or vertical installation.
• Horizontal Installation: locate the Furnace so that the gas line is at the top or rear of the Furnace.
• Vertical Installation: the Furnace top becomes the right side of the Furnace. Locate the Furnace so that the vent is at the
floor and the gas line is at the right or rear side.
• Identify the clearances required between the Furnace and the building materials surrounding the Furnace to allow for proper
airflow. Use the “Minimum Clearance To Combustibles” and the “Proper Return-Air Inlet Clearance” sections as guidelines.
Minimum Clearance To Combustibles
The minimum clearances allowed between the surface of the Furnace and combustible objects (board, wall, floor, etc) are shown in
the table.
The Furnace CANNOT be enclosed completely using these minimum dimensions.
CLEARANCE TO COMBUSTIBLES* To p Sides Rear
SM. & MED. VERTICAL/HORIZONTAL 1/2" 1/2" 1/2" 0"
Bottom
(To Screw Heads)
LG. VERTICAL/HORIZONTAL 1/2" 1" 1/2" 0"
*Combustibles are carpet, vinyl, tile, plywood, or similar building materials.
6
Page 7
PRE-INSTALLATION
Proper Return-Air Inlet Clearance
When a furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space
containing the furnace, the return air shall also be handled by duct(s) sealed to the furnace casing and terminating outside the space
containing the furnace. Failure to do so could result in property damage, serious injury, or death.
Furnaces MUST have at least the Minimum Return Air detailed in section “A. Model Specifications” on page 4 and
page 5.
FIG.1
If one wall is close
to the Return-Air
Inlet, there MUST
be at least 2"
clearance from the
TOP or Inlet SIDE.
FIG.2
If 2 or more walls are
close to the Return-Air
Inlet, there MUST be at
least 3" clearance from
the TOP and Inlet SIDE.
Vertical Wall
(Either Side
Of Furnace)
2"
(Vertical Installation)
(Vertical Installation)
3"
3"
2"
Horizontal Wall
3"
Horizontal Wall
Vertical Wall
Vertical Wall
Horizontal Wall
2"
2"
(Horizontal installation)
Horizontal Wall
3"
Vertical Wall
3"
(Horizontal Installation)
7
Page 8
PRE-INSTALLATION
B. Determining A Door Installation Option And Cutout Sizing
• Determine whether the RV has a standard door, flush door, or small vent configuration.
• Cut an opening through the side wall to fit the door installation option.
Standard Door Installations
FIG.1
17.00
to
12.50"
to
12.63"
Small Standard
Door Cutout
7.25"
to
7.38"
17.00
to
17.13"
Medium Standard
Door Cutout
7.25"
to
7.38"
17.13"
Large Standard
Door Cutout
9.25"
to
9.38"
FloorFloor
Flush Door Installations
FIG.2
15.00
to
15.13"
Small Flush
Door Cutout
Floor Floor
10.00"
to
10.13"
19.75
to
19.88
Medium Flush
Door Cutout
10.00"
to
10.13"
19.75
to
19.88"
Large Flush
Door Cutout
12.00"
to
12.13"
1.375"1.375"1.375"
R 0.50" to 0.63"
R 0.50" to 0.63"
R 0.50" to 0.63"
Small Vent Installations
FIG.3
(RV Wall Panel)
Wall Hole
Floor (Furnace Bottom)
• There is NO door cutout on the outside of the RV for the small vent installation. The cutout is a hole in the side of the RV used to
vent the Furnace outside of the RV.
Access must be provided directly in front of the Furnace on the inside of the RV, for removal of the Furnace during servicing.
2-1/8"
3-1/2"
1-3/4"
8
Page 9
PRE-INSTALLATION
C. Ducting
Failure to obey the following warnings could result in property damage, serious injury, or death:
• Do NOT install floor registers within 24" of return-air openings.
• Do NOT use undersized ducting, which can cause high-temperature limiting.
• Do NOT use oversized ducting, which can cause inadequate air flow from the registers. When hard ducting is 1-1/2" in
depth, additional flex ducts may be needed to maintain air flow requirements.
• Hard ducting MUST be sealed to the Furnace and the floor.
• Spacing of 1/4" to ducting, within 3' of the Furnace, must be provided unless UL-listed, wire-bound, vinyl ducts are used.
All ducting material used must be rated for continuous use at a minimum of 200 °F.
• Floor registers must NOT be installed directly below the thermostat.
Setting Up The Return-Air Pathways
Keep all return-air passages clear to allow the Furnace to function properly. Make sure the total return-air opening size(s) meet
the clearance requirements specified in “A. Model Specifications” on page 4 and page 5. Do NOT block the return
airflow path with ducting.
FIG.1
RV Wall
Return-Air Vent
Identifying Duct Locations
FIG.1
Duct 1
FIG.3
Duct 2
Duct 8
Duct 9
Duct 3
Duct 4
Duct 5
(Medium and Large Furnace)
Duct 2
Duct 4
Duct 2
Duct 1
Furnace
Duct 9
Duct 8
Duct 7
Front Discharge
Duct 3
Duct 4
Duct 6
Duct 5
FIG.2
Vertical
Discharge
Bottom
Discharge
(Small Furnace)
Duct 3
Duct 1
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Page 10
PRE-INSTALLATION
Air Discharge Configuration Examples
The following figures offer a visual representation of the detailed discharge requirements outlined in the “Air Discharge
Requirements” tables on page 11 and page 12. These examples show vertical and horizontal installations, using different
Furnace models and ducting options.
FIG.1
Register
(Top View)
Hard Ducting
Medium or
Large Furnace
Register
• Horizontal Furnace – Bottom exit into hard ducting
FIG.3
Medium or Large
Furnace Only
Register
(Top View)
Hard Ducting
4" Flex
Ducting
Register
FIG.2
Register
(Top View)
Hard Ducting
Medium or
Large Furnace
Register
• Vertical Furnace – Bottom exit into hard ducting
FIG.4
Duct 4
Duct 3
Duct 5
(Top View) (Top View)
Small, Medium,
or Large Furnace
(Vertical Mount)
4" Flex Ducting 4" Flex Ducting
Duct 5
Duct 4
Small, Medium, or
Large Furnace
(Horizontal Mount)
Duct 3
• 4" flex ducts into hard ducting
For medium and large Furnaces: ducts 8 and 9 are used for
additional ducting only, and are not used to calculate the
required discharge area shown at the bottom of page 11.
FIG.5
Small
Furnace
Only
5" Flex
Ducting
(Top View)
Interior Grill
Cabinet Cutout
Location
• 5" ducting over 12" long must have an additional 4" duct
added to the system.
To aid in the removal of the Furnace through the grill
cutout for servicing, when using a front interior grill, orient
the grill to the direction of the Furnace: horizontal if the
Furnace is horizontal, vertical if the Furnace is vertical.
• Make sure to use at least the minimum number of 4" flex
ducts required for your model size. See “Air Discharge
Requirements” on page 11 and page 12.
10
Page 11
PRE-INSTALLATION
Air Discharge Requirements
DFL40
DISCHARGE
REQ.
LARGE
DFL35
DISCHARGE
REQ.
DFM35
DISCHARGE
REQ.
DFM30
DISCHARGE
REQ.
DFM25
MEDIUM
DISCHARGE
REQ.
DFM20
DISCHARGE
REQ.
HORIZONTAL BOTTOM
EXIT INTO HARD
FLOOR DUCT
220 175 165 215 N/A
4" x 10" Bottom exit
PLUS 1- 4" flex duct
(for hard ducting
under 2.5" deep).
Duct 6 or 7 is recommended.
200 175 165 215 N/A
4" x 10" Bottom exit PLUS 1-
Duct 6 or 7 is recommended.
4" flex duct
(for hard ducting
under 2.5" deep).
HORIZONTAL BOTTOM
EXIT INTO HARD
FLOOR DUCT
225 155 155 285 N/A
4" x 10" Bottom exit PLUS
1- 4" flex duct
(for hard ducting
under 2.5" deep).
Duct 6 or 7 is recommended.
210 150 155 220 N/A
4" x 10" Bottom exit PLUS 1-
Duct 6 or 7 is recommended.
4" flex duct
(for hard ducting
under 2.5" deep).
175 160 160 190 N/A
4" x 10" Bottom exit
(40 in.2).
135 85 115 132 N/A
4" x 10" Bottom exit
(40 in.
2
).
VERTICAL
BOTTOM EXIT
INTO HARD
FLOOR DUCT
5" x 9-3/4" Bottom
exit does not require
additional ducts.
5" x 9-3/4" Bottom
exit does not require
additional ducts.
VERTICAL
BOTTOM EXIT
INTO HARD
FLOOR DUCT
5" x 9-3/4" Bottom
exit does not require
additional ducts.
5" x 9-3/4" Bottom
exit does not require
additional ducts.
5" x 9-3/4" Bottom
exit does not require
additional ducts.
5" x 9-3/4" Bottom
exit does not require
additional ducts.
HORIZONTAL OR
VERTICAL – USE DUCTS
3, 4 & 5 INTO HARD
FLOOR DUCT
Minimum CFM
Horizontal or vertical.
Use ducts 3, 4, and 5.
Minimum CFM
Horizontal or vertical.
Use ducts 3, 4, and 5.
HORIZONTAL OR
VERTICAL – USE DUCTS
3, 4 & 5 INTO HARD
FLOOR DUCT
Minimum CFM
Horizontal or vertical.
Use ducts 3, 4, and 5.
Minimum CFM
Horizontal or vertical.
Use ducts 3, 4 and 5.
Minimum CFM
Horizontal or vertical.
Use ducts 3, 4 and 5.
Minimum CFM
Horizontal or vertical.
Use any two ducts:
3, 4 or 5.
4" FLEX DUCTS
Three ducts
MINIMUM.
Four ducts
recommended.
Three ducts
MINIMUM.
Four ducts
recommended.
4" FLEX DUCTS
Four ducts
MINIMUM.
Three ducts
MINIMUM.
Three ducts
MINIMUM.
Two ducts
MINIMUM.
5" FRONT EXIT
FLEX DUCTS
N/A
N/A
5" FRONT EXIT
FLEX DUCTS
N/A
N/A
N/A
N/A
DFM16
DISCHARGE
REQ.
135 85 115 132 N/A
4" x 10" Bottom exit
(40 in.
2
).
5" x 9-3/4" Bottom
exit does not require
additional ducts.
Minimum CFM
Horizontal or vertical
Use any two ducts:
3, 4 or 5.
11
Two ducts
MINIMUM.
N/A
Page 12
PRE-INSTALLATION
DFS20
DISCHARGE
DFS16
DISCHARGE
SMALL
DFS12
DISCHARGE
DFSA12
(LOW AMP)
DISCHARGE
REQ.
REQ.
REQ.
REQ.
HORIZONTAL OR VERTICAL USE
(DUCTS 3, 4, & 5) OR BOTTOM
EXIT INTO HARD FLOOR DUCT
N/A
N/A
N/A
N/A
N/A
N/A
N/A N/A
N/A N/A One 5" front duct ONLY
4" FLEX DUCTS
Minimum CFM
130 92
Two 4" flex ducts –
one each from the left and right side, based
on horizontal or vertical mounting.
Minimum CFM
110 82
Two 4" flex ducts –
one each from the left and right side, based
on horizontal or vertical mounting.
Minimum CFM
90 80
Two 4" flex ducts –
one each from the left and right side, based
on horizontal or vertical mounting.
Minimum CFM
5" FRONT EXIT
FLEX DUCTS
One 5" OR two 4" ducts
(5" can be reduced to 4"
if necessary)
One 5" OR two 4" ducts
(5" can be reduced to 4"
if necessary)
One 5" OR two 4" ducts
(5" can be reduced to 4"
if necessary)
60
Air flow: shown in cubic feet-per-minute, taken with a cold system (Cold CFM).
Registers: 4" x 10" floor registers flow air better than 4" Round Plastic registers. Using 4" Round registers may require additional
ducting.
Required Discharge
MODELS REQUIRED DISCHARGE AREA
2
2
SMALL
MEDIUM
LARGE
DFSA12 Front Grill or 15 in.
DFS (12, 16, & 20) 24 in.
DFM (16 & 20) 24 in.2 with 4" flex
DFM (25 & 30) 36 in.
DFM35 48 in.
DFM (30 & 35) Horizontal Bottom 48 in.
2
DFM (16, 20, & 25) Horizontal Bottom 40 in.
DFM Vertical Bottom 48 in.
DFL (35 & 40) 36 in.2 with 4" flex
DFL (35 & 40) Horizontal Bottom 48 in.
2
DFL (35 & 40) Vertical Bottom 48 in.
2
with 4" flex
2
with 4" flex
(Bottom + 4" duct)
2
(Bottom only)
2
(Bottom only)
(Bottom + 4" duct)
2
(Bottom only)
12
Page 13
PRE-INSTALLATION
Installing The Floor Discharge System
Read BEFORE proceeding:
• Each 4" duct opening provides 12 in.2 of discharge area. For each closeable register, provide an extra 12 in.2 of
noncloseable duct discharge area. Make sure that all clearances and temperature requirements are met and the seal is
airtight.
• Ducting into dead-air space with no return air, such as holding tank areas, does not count toward achieving minimum
discharge requirements.
• 2" ducts exiting into the return-air space count as part of the minimum discharge area and minimum CFM.
• As applicable, the medium and large Furnace can be installed as a bottom-discharge system in either a horizontal or
vertical position.
STEP1
Horizontal
Bottom
Discharge
Plenum
Plenum
Vertical
Bottom
Discharge
• Cut the opening for the floor discharge system in the floor of the RV.
• Standard Door: see “Standard Door Floor Discharge Installations” on page 14.
• Flush Door: see “Flush Door Floor Discharge Installations” on page 14.
• Small Vent: see “Small Vent Floor Discharge Installations” on page 14.
• Remove the bottom discharge plate or side.
• Fasten the plenum plate bend tabs over the floor cutout.
• Place the gasket on the plenum around the floor opening.
Plenum plates and gaskets are available for purchase through Dometic. If not using a Dometic gasket and plenum plate, seal the
Furnace to the hard ducting system using an approved foil tape, or use a gasket that has a 300° F minimum temperature rating
and a UL94-V0 rating.
Vertical Mount Furnace: Kit 30205
Horizontal Mount Furnace: Kit 30261
13
Page 14
PRE-INSTALLATION
Standard Door Floor Discharge Installations
The dotted lines around the knockouts in the figures represent the floor-hole position.
FIG.1
Large Door
Vertical Install
(Top View)
5" 5" 10"
RV Wall
2.2"
9.75" 9.75"
9.5"
Flush Door Floor Discharge Installations
FIG.2
Large Door
Vertical Install
3.5"5" 5" 10"
9.75" 9.75"
9.8"
Medium Door
Vertical Install
Medium Door
Vertical Install
1.2" 3.5"
Medium & Large
Door Horizontal
Install
9.5"
RV Wall RV Wall
2.6" 4.9"
Medium & Large
Door Horizontal
Install
9.8"
4"
15.1"
4"
15.4"
(Top View)
RV Wall
Small Vent Floor Discharge Installations
FIG.3
Vertical Install
(Top View)
0.1" 5" 5"
9.75" 9.75"
Large Door
RV Wall
0.9"
Medium Door
Vertical Install
RV Wall RV Wall
Medium & Large
Door Horizontal
Install
9.6"9.6"
RV Wall
RV Wall
1.5"10"
4"
15.2"
14
Page 15
PRE-INSTALLATION
Installing The Duct Adapters
STEP1
Knockout Location
• Remove the knockout plates from the desired outlets.
• Cover all unused knockouts.
If a knockout is removed accidentally, cover plates are
available for purchase through Dometic.
Cover Plate: 31361
D. Installing the Furnace
• Proceed to the appropriate installation section to install the Furnace:
• Standard Door: See “A. Installing The Furnace Using A Standard Door Option” on page 16.
• Flush Door: See “B. Installing The Furnace Using A Flush Door Option” on page 17.
• Small Vent: See “C. Installing The Furnace Using The Small Vent Option” on page 18.
STEP2
Knockout Location
Duct Adapter
Ducting
• Install the duct adapters (provided) by inserting the flange
over the casing hole and turning the duct adapter 90° to
lock the tab into the casing slot.
• Securely attach ducting to the duct adapter. If using screws
to secure the ducting, do not use screws longer than 1/2".
15
Page 16
INSTALLATION
A. Installing The Furnace Using A Standard Door Option
STEP1
The standard door option requires that the rectangular
Sealant
(Or Butyl Tape)
Bezel
hole cut into the wall for the door opening has sharply cut
corners to match the Furnace. The Furnace must be able to
slide freely through the opening.
• Place the Furnace through the cutout approximately 1"–2"
from the wall.
• Apply RTV sealant or butyl tape to the entire back flange of
the bezel.
STEP2
Bezel
RV Wall
• Place the bezel over the tabs and flush with the front edge
of the casing. Be sure the edge of the bezel marked "TOP"
faces the top of the casing. Bend the casing tabs over the
bezel.
• Push the Furnace and bezel against the side wall. Secure
using six #6 or #8-18 Pan Head Type A screws (not
provided) placed through the bent tabs, bezel, and into
the RV wall.
• Place six more screws (three per side) to the le and right
side of the bezel. The bezel MUST fit tightly against the
wall. Remove excess sealant.
Do NOT deform the bezel during placement. The bezel
must fit tightly to maintain an airtight seal.
STEP3
Electrical Connection
Gas
Connection
• Connect the electrical wiring. Refer to “H. Connecting The
Electrical” on page 22.
• Connect the gas line to the valve. Refer to “F. Connecting
The Gas” on page 20.
STEP4
Mounting
Bracket
RV Wall
Bezel
Door
Vent
Assembly
• Align the door with the bezel.
• Secure the door using four #6-19x1/2" thread-forming
screws for plastic (not provided). Place the screws through
the door and into the bezel bosses.
• Insert the vent assembly (provided) through the hole in
the door, making sure the vent assembly goes into the
chamber tube. Make sure the vent assembly is aligned with
the Dometic text at the TOP.
• Secure the vent assembly to the door using four stainless
steel exhaust screws (provided with the door).
• To secure the Furnace to the floor of the RV, proceed to
“D. Installing The Mounting Brackets” on page 19.
16
Page 17
INSTALLATION
B. Installing The Furnace Using A Flush Door Option
STEP1
Flush-mounted door systems require the Furnace to be
Electrical Connection
Gas
Connection
installed on a 1" high platform, so the door cutout is level
with the floor surface. Otherwise, the side wall must be
routed out across the bottom to the depth of the bezel, to
create a pocket area. The flush door option requires 1/2"
radius corners.
• Place the Furnace through the cutout.
• Connect the electrical wiring. Refer to “H. Connecting The
Electrical” on page 22.
• Connect the gas line to the valve. Refer to “F. Connecting
The Gas” on page 20.
STEP2
Flush Mounting Brackets
Recessed Side
Wall Cutout
Furnace
RV Wall
• Use three screws (not included) on each side of the Furnace
to secure the flush mounting brackets to the wall. Leave
5/16" of space from the bracket to the outside of the wall.
• Apply RTV sealant or butyl tape to the back of the bezel
and the back of the flanges on the recess pan, where it will
overlap with the wall.
• Pull the front edge of the Furnace out of the wall
approximately 2".
STEP3
Flush Mounting
Bracket
RV Wall
Recess Pan
Recessed
Side Wall
Cutout
Bezel
• Slide the recess pan over the Furnace and place the bezel
on the six mounting tabs.
• Push the recess pan and bezel forward until the six casing
tabs move through the slots in the bezel.
• Bend the casing tabs to the outside of the bezel.
• Align the top three holes on the bezel with the holes in the
recess pan, then place six (three on the top and three on
the bottom) #6 or #8 x1/2" Pan Head Type AB screws, or
self-drilling screws, (not provided) into the top and bottom
holes on the bezel. Tighten the screws to attach the bezel
to the recess pan.
• Secure the Furnace using six (three per side) #6 or #8 x1/2"
Pan Head Type AB screws, or self-drilling screws, (not
provided) placed through the bezel, the recess pan, and
into the flush mounting brackets. Remove excess sealant.
Do NOT deform the bezel during placement. The bezel
must fit tightly to maintain an airtight seal.
STEP4
RV Wall
Bezel
Door
Vent
Assembly
• Secure the door using four #6-19x3/8" thread-forming
screws for plastic (not provided). The door should be flush
with the RV wall.
• Insert the vent assembly (provided) through the hole in the
door, making sure the vent assembly goes into the chamber
tube with the Dometic text aligned at the TOP.
• Secure the vent assembly to the door using four stainless
steel exhaust screws (provided with the door).
• To secure the Furnace to the floor of the RV, proceed to
“D. Installing The Mounting Brackets” on page 19.
17
Page 18
INSTALLATION
C. Installing The Furnace Using The Small Vent Option
Failure to obey this warning could result in property damage, serious injury, or death:
• Do NOT install vents where projection or door openings come within 6" of the vent opening. The RV door, panel, or cover material
may discolor, warp, or burn from the exhaust temperature.
• CARBON MONOXIDE HAZARD:
• Properly seal the vent assembly to prevent carbon monoxide from entering the RV. Do NOT vent exhaust air or draw
combustion air from the living area or an enclosed porch.
• Do NOT vent the Furnace with a venting system serving another appliance.
Access must be provided directly in front of the Furnace on the inside of the RV for removal of the Furnace during servicing.
STEP1
3-1/2"
Vent
Panel
Wall Hole
Wall Hole
RV Wall
• Locate the Furnace exhaust vent cutout location.
• Drill a 3-1/2" dia. hole through the wall for intake/exhaust.
The maximum exterior wall thickness is 2-1/2". Do NOT
exceed maximum wall thickness. Purchase an optional vent
kit to extend the vent to a 3" wall thickness, if necessary.
STEP2
Sealant
Vent
Panel
Vent Extension
RV Wall
Vent Assembly
Water Dam
• Apply butyl tape or RTV sealant to the back flange of the
vent extension before securing to the wall.
• Hold the vent extension with the printed “THIS SIDE UP”
text at the top, and the water dam at the bottom.
• Push the vent extension into the wall until it slides onto the
vent panel.
• Align the vent assembly (provided) over the vent extension
so that the Dometic text is at the TOP.
• Push the vent assembly into the chamber tube and secure
using four stainless steel exhaust screws (not provided).
Overlap the vent tube over the chamber tube by a
minimum of 1-1/2" for proper venting of exhaust fumes.
• Connect the electrical wiring. Refer to “H. Connecting The
Electrical” on page 22.
• Connect the gas line to the valve. Refer to “F. Connecting
The Gas” on page 20.
• Push the Furnace vent panel against the RV wall.
The Furnace vent panel MUST be pushed against the RV
wall before installing the mounting brackets.
• Proceed to “D. Installing The Mounting Brackets” on page 19.
18
Page 19
INSTALLATION
D. Installing The Mounting Brackets
STEP1
Mounting
Bracket
.
• Make sure the mounting surface on the RV is flat and the
Furnace is positioned evenly (front-to-back, side-to-side).
• Fasten the two mounting brackets (provided) to the casing
by placing the brackets over any two of the three holes
at the rear of the Furnace. Secure using two #8-18x1/2"
screws (provided).
• Secure the Furnace mounting brackets to the RV using
screws (not provided).
Mounting brackets can be attached to the Furnace casing
by removing an existing casing screw, ONLY with prior
approval from Dometic. When securing the Furnace, it
MUST be accessible and easily removed for service.
E. Running the Ductwork
STEP1
Not Recommended
• Stretch out all of the ducts and run them directly to the
outlets. Keep the number of angles to a minimum and
avoid sharp bends, deep sags, or crushed ducts, as shown.
• Attach and secure the 4" flexible duct to the adapter(s).
STEP2
RV Wall
Ducting
• Run duct(s) to the desired location(s) within the RV.
• Secure the ducting to the register(s).
If the burner cycles ON and OFF at the high-temperature
limit, it may be due to a restriction or bend in the ductwork.
Add extra ducting to correct this condition.
• Adjust the Furnace to the proper temperature rise aer
installation of the Furnace and ducting is complete. The
Furnace is tested to the temperature rise specified on the
rating plate.
• If checking the temperature rise is not possible, measure the airflow
at each register. Airflow should meet or exceed the measurements
in the “Air Discharge Requirements” on page 11.
• Adjust the ducting installation to obtain an airflow rate total
from all living area vents (in CFM) of the Furnace, as specified
in the “Air Discharge Requirements” on page 11.
• If readings are below the table values, improve the airflow
by adding ducts or reducing/eliminating system restrictions.
Reference the “Air Discharge Configuration Examples” on
page 10 for guidance.
19
Heat Register
Page 20
INSTALLATION
F. Connecting The Gas
FIRE OR EXPLOSION HAZ ARD. Failure to obey the following warnings could result in property damage, serious injury,
or death:
• Install gas connections in compliance with the applicable supplemental directives listed in this manual. Refer to
“C. Supplemental Directives” on page 2.
• NEVER use an open flame to check for gas leaks. Use a commercially available soap solution made specifically for the
detection of leaks to check all connections, as specified in these instructions.
• Should the gas supply fail to shut off or if overheating occurs, shut off the gas valve to the Furnace before shutting off the
electrical supply.
• Do NOT put sealing compound on flare fittings.
FIG.1
Extended
Manifold
Grommet
Plug
(Rear)
Gas Connection
An extended manifold is used in this example; however,
the use of tubing or other variations to connect the gas is
acceptable.
• Treat all male pipe threads, other than flare fittings, with a
sealing compound resistant to a chemical reaction with LP
gas.
• Remove the grommet plug from the Furnace and install on
the gas line.
• Insert the gas line through the hole in the top of the casing.
• Connect the gas line to the fitting located on the valve. If
the Furnace is supplied with an extended manifold,
connect the gas line at the rear of the Furnace.
• Reinstall the grommet plug on the casing, as it is a required
air seal. DO NOT CUT.
• Use two wrenches to hold the valve and flare nut, and
tighten the flare nut over the gas line.
• Torque the fitting to 20–22 . lbs. Do NOT twist the valve
out of position when tightening the gas line.
For DFLA35 and DFLA40 models only, a gas conversion kit
is included with your Furnace. To convert the Furnace gas
type, proceed to “G. Converting The Furnace Gas Type” on
page 21.
LP Gas Pressure Test
Read BEFORE proceeding:
• Test all piping systems BEFORE connecting the
Furnace.
• Disconnect the Furnace and any individual shut-off
valves from the gas supply piping system when
pressure testing the system at pressures of more than
1/2" PSI.
• If local codes allow the use of a flexible gas appliance
connector, do NOT use a connector which has
previously serviced another gas appliance.
• For gas conversions only, a 1/8" NPT plug is provided
upstream of the gas connections for checking the gas
pressure.
• Perform an air pressure test on the piping system. The test
must maintain an air pressure of a least 6" of mercury or
3 PSI for at least 10 minutes.
• Adjust the piping system to maintain the minimum gas
supply pressure listed on the rating plate, when all
appliances are in operation.
• Test gas connections for leakage with a commercially
available soap solution made specifically for the detection
of leaks.
20
Page 21
INSTALLATION
G. Converting The Furnace Gas Type
This section applies to DFLA35 and DFLA40 models only. These models are set up for LP gas at the factory, but can be
converted to natural gas. A natural gas conversion kit is included.
Any conversion to natural gas must conform with local codes, or in the absence of local codes, with the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 Natural Gas and Propane Installation Code, in addition to the Standard for Recreational Vehicles
NFPA1192 and CSA Z240 RV Recreational Vehicle Code.
Changing The Adjustment Regulator Caps
Read the following BEFORE proceeding:
• The convertible valve is set for a pressure setting of
3.5" for natural gas (NAT) and 10.5" for LP gas. These
settings are not adjustable.
• Do NOT modify the adjustment regulator caps or use
them with any other valve.
FIG.1
Nat Cap
LP Cap
• Unscrew the adjustment regulator cap and remove from
the valve regulator tower. Do NOT remove the rod from
inside the regulator tower or perform any adjustments.
• Place the NAT or LP cap appropriate for the conversion
onto the valve regulator tower.
• Tighten the adjustment regulator cap by hand or use
a small wrench. Do NOT overtighten the adjustment
regulator cap.
• Install the main burner orifice. Refer to the “Conversion
Specifications Table” for information specific to LP or NAT
conversion.
Conversion Specifications Table
GAS
TYPE
BTU/HR
LINE
PRESSURE
REGULATOR
CAP SETTING
Valve
Regulator
Tower
DRILL
SIZE
Replacing The Orifice
Read the following BEFORE proceeding:
• Each Furnace is supplied with two main burner orifices.
One is installed on the manifold and the other is
attached to the blower housing cover.
• The type of gas in use must match the adjustment
regulator cap and orifice installed in the Furnace.
FIG.2
Gas Connection
• Disconnect the gas line from the valve.
• Remove the three screws holding the burner assembly to
the back wall of the control box.
• Remove the two screws holding the burner to the manifold.
• Unscrew the orifice using a 7/16" wrench or socket.
• Use the “Conversion Specifications Table” to select the
correct orifice needed for the gas type.
• Install the new orifice.
• Reverse steps 1–3 to reinstall the burner, burner assembly,
and the gas line.
• Test gas connections for leakage with a commercially
available soap solution made specifically for the detection
of leaks.
• Place the "converted" sticker (provided) in a visible
location, next to the model number label.
Burner
Assembly
Orifice
Propane
(LP)
Natural
(NAT)
Propane
(LP)
Natural
(NAT)
40,000
40,000
35,000
35,000
11" WC
7" WC
11" WC
7" WC
10.5" WC
3.5" WC
10.5" WC
3.5" WC
WC = Water Column
49P
#30
#51
#30
21
Page 22
INSTALLATION
H. Connecting The Electrical
Failure to obey the following warnings could result in property damage, serious injury, or death:
• ELECTRICAL SHOCK HAZARD:
• The Furnace must be electrically grounded in accordance with local codes, or in the absence of local codes, with the National
Electrical Code, ANSI/NFPA 70, and/or the Canadian Electrical Code, CSA C22.1, Part 1, if an external electrical source is utilized.
• The Furnace MUST be installed so that electrical components are protected from water and other installation debris.
• If the Furnace model is designed for negative ground 12 VDC only, do NOT attempt to alter Furnace for a positive ground
system or connect a 12 VDC Furnace to 120 VAC or 240 VAC. Furnaces with 12 VDC connection are for low-voltage battery
or direct current only.
• Do NOT "Hi Pot" the Furnace unless the electronic ignition system (circuit board) has been disconnected.
• Do NOT use a battery charger to supply power to a DC model Furnace even when testing.
• Do NOT use 120 VAC current with VDC models. Do NOT use 12 VDC current with 120 VAC models.
• The direct high voltage spark ignition of the Furnace generates a radio frequency that may cause interference with other
microprocessor-based equipment. Locate any equipment at least five feet from the Furnace location.
Overcurrent Protection (No Wire Bundling Restrictions)
WIRE SIZE AMPACITY WIRE TYPE
20 3 Stranded Only
18 6 Stranded Only
16 8 Stranded Only
14 15 Stranded Only
12 20
10 30
8 40
6 55
4 75
2 100
Stranded Only
Stranded Only
Stranded Only
Stranded Only
Stranded Only
Stranded Only
Wiring Information
• To route wiring to the Furnace refer to the “Wiring
Diagrams” on page 23.
• Use the smallest wire size shown in the table to minimize
voltage drop.
• If power is supplied from a converter that is equipped with
a charging port, wire the converter to the Furnace at the
same time as the battery.
• If a Furnace is supplied with a connector block on the field
connections, use the mating parts.
• All Furnaces have a power switch to turn the Furnace off for
servicing. Confirm the switch is in the ON position.
Additional Information For VAC Wiring Only
• Furnaces equipped with 120 VAC motors use power from a
24 VAC transformer inside the Furnace to power electrical
component parts.
• The power switch for VAC Furnaces is located in the valve
circuit leg only.
• Use a minimum of 18 GA wire to route 120 VAC and
thermostat leads to wires located on the le side of the
control box.
Overcurrent Protection
AWG OR SAE
CONDUCTOR
SIZE
20* 5 7. 5
18* 7.5 10
16* 10 15
14* 17.5 20
MAXIMUM AMPACITY
AT CONDUCTOR
INSULATION
TEMPERATURE
RATING OF 90°
12* 22.5
10** 40
8** 55
6** 75
4** 95
2** 130
1** 150 -
1/0** 170 -
2/0** 195 -
3/0** 225 -
4/0** 260 -
* Not more than seven wires per harness; **Not more than three
wires per harness
A 15-amp circuit breaker is provided with the DFMD35,
DFLD35, and DFLD40 Furnace models. Install the breaker
inside the main fuse panel in place of a normal fuse for the
RV. Place the circuit breaker in the “Furnace Only Circuit”.
22
MAXIMUM AMPACITY
AT CONDUCTOR
INSULATION
TEMPERATURE
RATING OF
105 °C/ 125 °C
25
50
70
100
120
150
Page 23
INSTALLATION
Wiring Diagrams
FIG.1
Limit Switch N.C.
Breaker
On/Off Switch-
– 12 VDC
Red + 12 VDC
Blue + Thermostat
Black
Blue
Valve
Blue
Red
Black
Motor
Thermostat
Blue
(12 VDC)
Red
Blue
Red
Black
Black
Blue
Black
Red
Red
Sail Switch
N.O.
Ignition
Control
Electrode
PWR
BLO
FIG.2
Sail Switch
Limit Switch N.C.
Thermostat
5
1
Switch/Breaker
(12 VDC)
2
12 Volts DC
Motor
Ignition
Control
BLO
TH
V1
AIR
PWR
HV
Valve
3
4
1
2
GND
Electrode
4
FIG.3
Red
Blue
Thermostat
Blue
Limit Switch N.C.
Blue
Valve
White
Motor
Ground
120VAC Hot
Thermostat
120VAC Neutral
Blue
Black
White
Green
On/Off
Switch
Red
Green
Transformer
Brown White
Capacitor
Blue
4-Pin
Gnd
(120 VAC)
Blue
Green
Sail Switch
Ignition
Control
1
Yellow
Green
N.O.
IND
L1
R
24V
Electrode
Black
Black
FIG.4
Green
White
Black
GND
Ignition
Control
PS TH R L1V1IND24V
Limit Switch
Sail Switch
Thermostat
(120 VAC)
HV
Motor
Capacitor
3
Electrode
Power
Switch
Transformer
12
324
1
Valve
23
Page 24
INSTALLATION
I. Installing The Thermostat
Do NOT install the thermostat where there are other heating loads, such as direct sunlight, heat-producing
appliances (television, radio, wall lamp, etc.) Furnace, or air conditioner output registers. Failure to follow these instructions could
result in serious injury or death.
Read BEFORE proceeding:
• Wire the thermostat using 22 AWG minimum stranded wire.
• Purchase a thermostat rated for 12 VDC or 24 VAC, Minimum 1 AMP rating.
• Disconnect all electrical power to the Furnace.
• Locate a dry area away from the heat registers with good air circulation for the thermostat installation.
• Place the thermostat 48"– 54" above the main living area floor on an INTERIOR wall, when possible.
• Use a 3/4" spacer between the thermostat and wall, for proper room air sensing when placing on an EXTERIOR wall.
• Follow manufacturer’s installation instructions provided with the thermostat.
TESTING
A. Testing The Furnace
Do NOT operate the Furnace while the vehicle is in motion or being towed.
FIG.1
(Small Vent Models)
Testing The Operation
1. Turn the manual valve (if equipped) or the valve at the outside LP tank to the OFF position. Do NOT force.
This Furnace is equipped with a power switch. Gas will not flow to the burner, and the Furnace will not operate with the power
switch in the OFF position.
2. Turn the power switch to the ON position.
This Furnace is equipped with an ignition device which automatically lights the burner. Do NOT light the burner by hand.
3. Set the thermostat above room temperature to begin blower operation. A slight delay will occur before the blower begins
running.
4. Allow the blower to run for 15 seconds to complete the combustion chamber purge cycle.
• If the blower does not come on or stops before the ignition cycle, shut down the Furnace and contact your dealer or a local
RV service agency.
5. Move the thermostat lever below room temperature.
6. Wait approximately 90 seconds for the blower to stop running.
7. Open the manual shut off valve (if equipped) or the valve at the LP tank. Correct Furnace operation depends on the valve being
fully open. Never attempt to operate with a valve partially closed.
8. Turn the shut off switch to the ON position.
9. Set the thermostat lever to the desired setting. If set above room temperature, the blower begins running.
10. Allow 15 seconds for the main burner to light aer the blower begins running.
• If the burner does not light, confirm the gas is ON and repeat steps by resetting the thermostat to purge any air in the gas system.
• If aer three attempts there is no ignition, shut down the Furnace and contact your dealer or a local recreational vehicle
service agency. Do NOT continue to cycle the Furnace through the thermostat in an attempt to get ignition.
Shutting Down The Furnace
1. Set the thermostat to the lowest setting, then turn to the OFF position.
2. Turn the manual shut off valve at the LP tank (if equipped) to the OFF position. Do NOT force the valve.
3. At the exterior access panel, turn the valve shut-off switch to the OFF position.
Power
Switch
24
FIG.2
(Door Models)
*Power
Switch
*Switch is located behind door
Page 25
DIAGNOSTICS
A. Ignition Control Diagnostic Codes
• The following chart gives the diagnostic codes given by the ignition control when faults are present. An LED light, located in the
middle of the control board, will flash the codes indicated in the diagnostic chart. There is a standard of three tries for ignition
controls.
• A "so lockout" is a condition that is timed and will make additional attempts to correct the problem.
• A "hard lockout" requires resetting the thermostat or turning the power switch off, and then back on.
DIAGNOSTIC CHART
FAULT LED INDICATION LOCKOUT
Internal Circuit Board Failure Steady On, No Flashing Hard
Limit Switch/Airflow Problems 1 Flash With 3-Second Pause Soft
Flame Sense Fault 2 Flashes With 3-Second Pause Hard
Ignition Lockout Fault 3 Flashes With 3-Second Pause Soft (1 hour retry)
TROUBLESHOOTING
ISSUE SOLUTION
Furnace will not light – Blower does not
turn on.
Furnace will not light – Blower does turn on. 1. Air is in the propane line. Purge the air by turning on other appliances (like a cooktop) that
Furnace shuts off before it reaches the desired
temperature.
1. Check the main fuse panel for a blown fuse.
2. The Furnace-installed breaker switch may be tripped or OFF – Contact a trained RV
service provider.
3. The 12 VDC power is low; check the RV system voltage.
4. The Furnace may be in lockout. Reset the Furnace by switching the thermostat to OFF
for 10 seconds, then switch the thermostat to ON. If air is in the propane line, repeat this
process up to three times.
5. Check the intake and vents to make sure they are not blocked or obstructed.
are further downstream from the propane tanks.
2. The thermostat is not set to Heat or a high enough temperature. Adjust the thermostat.
1. Check to make sure all the vents are open and not covered.
2. Check the air intake to make sure it is not blocked or obstructed.
REPLACEMENT PARTS
ELECTRICAL SHOCK, FIRE, EXPLOSION AND/OR CARBON MONOXIDE HAZARD. Use only Dometic replacement
parts and components, which are specifically approved for use with the Furnace. Failure to obey this warning could result in
dangerous operation, property damage, serious injury, or death:
• For replacement part information, see the DF Series Furnace Parts List. For the most current information, visit
www.eDometic.com.
25
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