Atwood AFMD16, Technical Installation Manual

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7

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
WARNING
FIRE OR EXPLOSION
Do not operate furnace while vehicle is in motion or being towed.

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 .
1. Turn the manual valve (if so equipped) or the valve at the outside
LP tank to the “OFF”” position DO NOT force. 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.
2. 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 go to shut down and contact your dealer or a
local recreational vehicle service agency.
3. After 1 minute, the blower may not be running at this time, move
thermostat lever below room temperature. Wait approximately 2
minutes for blower to go off.
4. 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. Turn shut-off switch to “ON” position.
5. Set thermostat lever to desired setting. If set above room
temperature, blower will come on.
6. 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.
7. If burner does not light, repeat Steps 1 through 5.
8. 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.
TO SHUT DOWN
1. Set the thermostat to lowest setting, move lever to “OFF” position.
2. Turn manual shut off valve (if so equipped) to the “OFF” position.
Do not force.
SYSTEM CHECKS
WARNING
FIRE OR EXPLOSION
Never check for leaks with an open flame. Turn on the gas and apply
soapy water to all joints to see if bubbles are formed.
PROPANE GAS PRESSURE TEST
The furnace and any individual shut-off valve must be disconnected from
gas supply piping system during any pressure testing of system at test
pressures of more than 1/2” PSI.
Before furnace is connected, piping systems must be tested to be leak
free. The test must maintain air pressure of a least 6” of mercury or 3”
PSI for at least 10 minutes.
The entire piping system must be maintained within a range of 10 to 14”
WC when all appliances are in operation. Test gas connections for
leakage with a leak test solution.
IGNITION CONTROL DIAGNOSTIC CODES
The following charts give the diagnostic codes given by the ignition
control when faults are present.

A soft lockout is a condition that is timed and will make additional
attempts to correct the problem. A hard lookout requires resetting of
the thermostat or turning the power switch off, then back on.
STANDARD 3 TRIES FOR IGNITION CONTROLS
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