Manual-backed troubleshooting
Atwood RV Furnace Troubleshooting: Start With the Series
This guide covers Dometic Hydro Flame AFS, AFM, and AFL furnaces governed by Literature 31973. If the label shows another Atwood or Hydro Flame series, use that furnace’s exact manual rather than applying a cross-series repair procedure.
Safety first
Leave immediately if you smell propane, a propane or carbon monoxide alarm sounds, you see smoke or soot, or you smell ammonia. Do not operate switches, appliances, fans, phones, or other ignition sources. From a safe location, call 911, the fire department, or your propane supplier. Do not return until a qualified professional says it is safe.
Things you can try first
These checks use normal controls and owner-accessible areas. Stop immediately when a listed stop condition occurs.
Confirm AFS, AFM, or AFL and Literature 31973
Use RV records or already-visible rating information to confirm both the furnace series and applicable manual revision. Stop if either differs from this page.
Source
Source: Printed page 1, title and series scope; rating-label references in manual
Record the normal thermostat response once
From inside the RV, record whether the furnace responds, warm air develops, ignition appears delayed, or operation cycles erratically. Do not repeat unsafe or abnormal operation to refine the observation.
Source
Source: Printed pages 2-3, operating and shutdown guidance
Check only already-visible airflow openings
When the furnace is off and cool, move loose household items covering an owner-visible warm-air or return-air opening. Look from a safe distance for a door, slide-out, snow, stored item, soot, or another visible exterior-vent obstruction. Do not touch the vent, insert tools, remove parts, alter ducting, or add a screen.
Source
Source: Printed pages 1-2 and 4, venting airflow and soot warnings
Check your manual first
Only continue when your exact installed equipment and its documentation make this owner-accessible action clear.
Let the exact manual set the boundary
Use only normal controls and visible owner actions your manual specifically names. If it asks for service access, a component, or a procedure not shown there, leave it for a technician.
When this needs a technician
Do not open the furnace to inspect combustion, ignition, controls, wiring, or safety devices.
The furnace responds normally to the thermostat
Stop and route to serviceUse the normal controls described in the applicable manual and keep warm-air registers and return-air openings unobstructed. This page does not add a generic ignition sequence or part-diagnosis procedure.
Source: Literature Number 31973, Revision A, 3/13/19
Ignition is delayed or the furnace cycles erratically
Stop and route to serviceDometic directs the owner to shut the furnace down and call a service agency. Do not continue operating it to isolate a switch, sensor, burner, valve, motor, board, or wiring fault.
Source: Literature Number 31973, Revision A, 3/13/19
Soot appears at the exterior vent
Stop and route to serviceThe manual identifies soot as a visual warning that the furnace is operating unsafely and directs immediate shutdown and qualified service. Use the emergency gate when soot, smoke, odor, or an alarm creates a potential emergency.
Source: Literature Number 31973, Revision A, 3/13/19
The vent is covered or obstructed
Stop and route to serviceDo not operate the furnace with its vent covered. Dometic also warns against installing a screen over the intake or exhaust vent because restriction can cause unsafe operation.
Source: Literature Number 31973, Revision A, 3/13/19
The label shows another hydro flame or Atwood series
Stop and route to serviceDo not use this AFS/AFM/AFL page. Obtain the exact applicable owner manual and route internal diagnosis to qualified service.
Source: Literature Number 31973, Revision A, 3/13/19
Time to call a tech
Stopping here protects the RV and gives the technician a clearer starting point.
Propane odor, an alarm, smoke, or soot occurs.
Follow the emergency gate. Keep the RV and furnace out of operation until qualified professionals clear them.
Ignition is delayed or furnace operation cycles erratically.
Keep the furnace out of operation and contact a Dometic dealer or qualified service agency with the recorded model and symptom.
The furnace is not an AFS, AFM, or AFL series under Literature 31973, or internal access would be required.
Stop using this page. Obtain the exact owner manual or qualified service; this source does not support another series.
Before you call for service
Make a clear service brief
Record these details without removing a furnace panel or repeating abnormal operation.
- Complete furnace series model and serial number
- Confirmation that Literature 31973 Revision A applies
- RV make model and year
- Thermostat type and requested setting
- Whether warm air developed
- Whether ignition was delayed or cycling was erratic
- Whether a visible opening was covered
- Any odor alarm smoke or soot
Quick reference
Common questions
Can I use this page for an Atwood 8500-series furnace?
No. This page is limited to Dometic hydro flame AFS, AFM, and AFL furnaces governed by Literature 31973, Revision A. Obtain the exact 8500-series manual before using any model-specific guidance.
Can I clean the sail switch or igniter on an AFS, AFM, or AFL furnace?
Not from this owner guide. Dometic assigns repair and preventive maintenance to qualified service and says never to attempt furnace repair yourself.
Should I add an insect screen over the furnace vent?
No. Literature 31973 warns not to install screens over the intake or exhaust vents because restriction can cause unsafe furnace operation.
Primary documentation
Sources and revision record
hydro flame Furnace Models Series AFS, AFM, AFL User's Information Manual
Literature Number 31973, Revision A, 3/13/19
Reviewed: August 7, 2026
Relevant sections: Printed pages 1-4: safety, operation, visible venting and airflow, soot, erratic cycling, delayed ignition, and qualified-service boundary
Revision note: Third-pass minimal revision: restores the legacy search intent and direct opening while retaining the exact AFS/AFM/AFL manual-family boundary.
Sources last reviewed: August 7, 2026