the absence of local codes or regulations, refer to current
standards of:

ANSI/NFPA 1192 Recreational Vehicles Code and ANSI/RVIA LV
Low Voltage Systems in Conversion and Recreational Vehicles

VALVE CONVERSION
1.

2.
3.

4.
5.

See drawing to check which plug to use marking is on side of
adjustment reg. plugs. Furnace come with LP plug installed and
the natural plug in the bag with the natural gas orifice. NAT or LP
is stamped on the side. The type of gas being used must match
the plug and orifice in use when installed.
Unscrew plug and remove from valve reg. tower. DO NOT
remove rod from inside the reg. tower or make any adjustments.
A. When set for LP and NAT is required:
Unscrew plug and replace the correct plug into tower for
NAT.
NAT should now be visible.
Finger tighten plug or with small wrench. DON’T over
tighten.
B. When set for NAT and LP is required:
Unscrew plug and replace plug with the correct plug into
tower for LP.
LP should now be visible.
Finger tighten plug or with small wrench. DON’T over
tighten.
This plug has been factory calibrated for this valve only. DO NOT
modify and DO NOT use plug on any other valve.
Install the correct main burner orifice per the chart.

12 VOLT DC WIRING

Label all wires before disconnecting for servicing. Wiring
errors can cause improper and dangerous operation. Verify
proper operation after servicing.

Disconnect electrical power before servicing.
Conductor Sizing – Maximum 10% Voltage Drop – (12VDC)
Table 1
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
Stranded only
10
30
Stranded only
8
40
Stranded only
6
55
Stranded only
4
75
Stranded only
2
100
Stranded only

ORIFICE REPLACEMENT
1.
2.
3.
4.

5.
6.
7.
8.

Table 2
OVERCURRENT PROTECTION
*Not More Than Seven Wires Per Harness
**Not More Than Three Wires Per Harness
AWG OR SAE
Maximum Ampacity
Conductor Size
at Conductor
(Gage)
Insulation
Temperature Rating
of 90°
20*
5
18*
7.5
16*
10
14*
17.5
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

Remove gas line from valve.
Remove burner assembly by removing 3 screws from back wall of
control box.
Remove two screws holding the burner to the manifold.
Unscrew the orifice with a 7/16” wrench or socket and replace
with the correct orifice per the chart corresponding to type of gas
required, which corresponds to the regulator plug setting.
Replace two screws holding burner to manifold.
Reinstall the burner assembly and put the three screws back into
the control wall.
Replace the gas line and check for leaks.
After converting furnace, IN PLAIN SIGHT, put “converted” sticker
(provided in you conversion packet) next to model number label.

ELECTRICAL CONNECTIONS

WARNING
INJURY OR PROPERTY DAMAGE
 Label all wires before disconnecting for service. Wiring errors can
cause improper and dangerous operation.
 Verify proper operation after serving.
 Disconnect electrical power before servicing.

7

Maximum Ampacity
at Conductor
Insulation
Temperature Rating
of: 105° C/125° C
7.5
10
15
20
25
50
70
100
120
150












5.

This furnace is designed for negative ground 12 volts DC only. DO
NOT 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 the minimum wire size show in the table above to minimize
voltage drop. Furnace must be installed so electrical components are
protected from water. To make electrical connections see attached
wiring diagram specific to furnace model.
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
component life, filtering power surges and AC spikes.
Some models are shipped with a field harness connections with 12”
wire leads. An optional field harness with a double end is available in
bulk. This harness contains 12” leads, four-pin housing, and standard
six-pin housing.
All units are supplied with a power switch which when turned off during
servicing will remove power through furnace wiring. Switch must be on
in the ON position for furnace to operate.
The direct high voltage spark ignition generates a radio frequency that
could cause interference with other microprocessor-based equipment.
Locate equipment at least five feet (5’) from furnace location. If this
distance cannot be maintained, Atwood has a kit which can be
purchased. See parts list.

Route wiring to the furnace.
Furnace
Red Wire +12 Volt DC
Black Wire -12 Volt DC
Blue Thermostat +12VDC
Blue Thermostat
1.
2.
3.

6.

.
THERMOSTAT INSTALLATION


Purchase a thermostat rated for 12 VDC or 24 VAC, Minimum 1
AMP rating.
Be sure all electrical power to the furnace is disconnected.
The thermostats are very sensitive, HANDLE WITH CARE AT
ALL TIMES.



1.
2.

3.
4.
5.

WARNING
FIRE OR EXPLOSION
Do not operate furnace while vehicle is in motion or being towed.



Field Connector
AMP 1-480704-0
Field Terminals
AMP 770020-1

1.
2.

3.

4.

CAUTION
PROPERTY DAMAGE
This furnace is designed for 120 volts AC only. DO NOT attempt to
alter furnace system or connect to 12 volts DC.

5.
6.

Route 120 volts 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.

3.
4.

During initial firing of this furnace, a burn-off of excess oils
remaining from manufacturing process may cause smoking or
fumes for 5-10 minutes.
NOTE: if furnace should lock out, the blower will go off in 3
minutes and remain off until unit is reset by reactivating the
thermostat.

STOP! Read Users Information Manual supplied with furnace.

120 VOLT AC WIRING

Furnaces are equipped with a 120 volts AC motor. All other
electrical component parts are supplied with power from a
transformer inside the furnace at 24 volts AC.

A 120 Volt model can also be supplied with a 30 inch power cord
from the factory supplied with a molded plug with ground pin.

AC units have a power switch located in the valve circuit leg only.
This switch will not remove the power from the 120 volts incoming
line. Make sure that power has been turned off before servicing.

Switch must be in the “ON” position for the furnace to operate the
valve.

1.
2.

Pick a dry area where air circulation is good.
Do not install the thermostat where there are unusual heating
conditions: such as direct sunlight, heat producing appliances
(television, radio, wall lamp, etc.) or a furnace or air conditioner
output registers.
Locate thermostat 48” to 54” above main living area floor on an
INTERIOR wall when possible
EXTERIOR wall location must have a 3/4” spacer between
thermostat and exterior wall.
Follow manufacture’s installation instructions provided with
thermostat.

OPERATING INSTRUCTIONS

Power Supply
+12 Volt DC
-12 Volts (Ground)
+12 Volts (Thermostat)
-12 Volts (Thermostat)

Wiring for thermostat using 22 minimum AWG stranded wire.
All wiring must be installed so the electrical components and
connection are protected from water.
If a unit is supplied with a connector block on the field connections
the mating parts should be used.

Furnace Connector
AMP 1-480705-0
Furnace Terminals
AMP 7708496

Connect ground wire to furnace green ground wire (after
connections are made put wire connections into furnace junction
box and replace cover).
Connect thermostat leads to the two blue furnace thermostat
leads using minimum 22-18 GA stranded wire.

7.
8.

Route wiring to left side of furnace.
Remove junction box cover (some units come with pre-wired
cords for connection directly to a 120 volts AC outlet).
Connect 120 white wire to furnace 120 white wire.
Connect 120 black wire to furnace 120 black wire.

8

Turn the manual valve (if so equipped) or the valve at the outside
LP tank to the “OFF”” position. Do not force.
Set thermostat above room temperature to begin blower
operation. A slight delay will occur before the blower comes on.
Allow blower to run for 1 minute for combustion chamber purge
cycle. If blower does not come on or stops before ignition cycle,
go to shut down and contact your dealer or a local recreational
vehicle service agency.
After 1 minute, move thermostat lever below room temperature.
Blower will remain on. Wait approximately 2 minutes for blower to
go off.
Open manual shut-off valve (if so equipped) or the valve at the
outside LP tank. Correct operation characteristics depend on the
valve being positioned fully open. Never attempt to operate with a
valve partially closed. NOTE: This furnace is equipped with a
valve shut-off switch with switch in “OFF” position. Gas will not
flow to burner nor will the furnace operate. Turn switch to “ON”
position.
Set thermostat level to desired setting. If set above room
temperature, blower will come on.
Allow 30 seconds for main burner to light after blower comes on.
This furnace is equipped with an ignition device which
automatically lights the burner. DO NOT try to light the burner by
hand.
If burner does not light, repeat Steps 1 through 7.
If after three (3) attempts with no ignition, go to shut down and
contact your dealer or a local recreational vehicle service agency.
Do not continue to cycle furnace through thermostat in an attempt
to get ignition. NOTE: If furnace should lock out, the blower will go
off in 3 minutes and remain off until unit is reset by reactivating
the thermostat.

TO SHUT DOWN
1. Set the thermostat to lowest setting, then move lever to “OFF”
position.
2. Turn manual shut off valve (if so equipped) to the “OFF” position.
Do not force.

Standard 3 tries for Ignition Controls
DIAGNOSTIC CHART
FAULT

LED INDICATION

LOCKOUT

IGNITION CONTROL DIAGNOSTIC CODES
The following charts give the diagnostic codes given by the ignition
control when faults are present.

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

A soft lockout is a condition that is timed and will make additional
attempts to correct the problem. A hard lockout requires resetting
of the thermostat or turning the power switch off, then back on.

Soft (after 1
hour)

WIRING DIAGRAMS

VALVE

LIMIT SWITCH N.C.

SAIL SWITCH
N.O.

BL

BL

3

1

2

BL

R

MOTOR

VALVE

BL

4

IGNITION CONTROL

ON/OFF SWITCHBREAKER

R

1

BK

IGNITION
CONTROL
BLO

PWR
BLO

TH
Y

R

GND

ELECTRODE

BK

SAIL SWITCH

V1
AIR

BK

COLOR

O

ORANGE

BK

BLACK

BR

BROWN

BL

BLUE

THERMOSTAT

PWR
HV

FIELD
SUPPLIED
WIRE

THERMOSTAT BL

MOTOR

- 12 VDC BK

+ 12 VDC R

+ THERMOSTAT BL

R

CODE

LIMIT SWITCH
N.C.

16 AWG 105°C THERMOPLASTIC WIRING
14 AWG 105°C THERMOPLASTIC WIRING
16/30 200°C RADIX (SIL-A-BLEND) 18 AWG WIRE
CONNECTOR NOT USED

R