The Atwood furnace fault codes article helps RV owners and technicians identify and resolve common errors in Atwood/ Suburban RV furnaces. It explains LED blink patterns, error meanings, likely causes, step-by-step diagnostics, basic fixes, maintenance tips, and when to call a professional. Understanding fault codes speeds repairs and improves safety.
| Fault Code | Blinks | Common Meaning | Suggested Action |
|---|---|---|---|
| Normal Operation | Steady LED | Ignition and run OK | No action |
| No Power | LED Off | No 12V supply or blown fuse | Check battery/fuse/wiring |
| Open Flame Sensor | 3 Blinks | Open or faulty flame sensor | Inspect/replace sensor |
| Thermostat Circuit | 1 Blink | Thermostat or control issue | Test/replace thermostat |
| High Limit | 2 Blinks | Overheat or fan failure | Check airflow and fan |
How Atwood Furnaces Work
Atwood furnaces, commonly used in RVs and caravans, use propane and 12V electrical systems to provide forced-air heat. A thermostat calls for heat, the control board initiates a blower pre-purge, opens the gas valve, and an igniter lights the burner. The flame sensor confirms combustion, and the blower continues to deliver warm air. Safety switches, limit sensors, and the control board monitor conditions and display faults via an LED or blink code.
Reading And Interpreting Atwood Fault Codes
Atwood furnaces use LED blink sequences to indicate specific faults. The control board typically blinks a status LED in repeating groups; the number of blinks and the pattern correspond to a code. Count blinks within a pause cycle and confirm with the furnace manual for the exact model. Some units also show continuous LED for normal run and off for no power.
Common Fault Codes And What They Mean
This section lists common Atwood fault codes, likely causes, and practical first-step actions. Codes can vary by model; always consult the model-specific manual for exact definitions.
LED Off — No Power
Meaning: The control board receives no 12V input or a major fuse is blown. Likely Causes: Dead battery, blown inline fuse, loose connectors, or a faulty power switch. Action: Check battery voltage, inspect fuses and replace as needed, test wiring for continuity and secure connectors, and ensure the furnace switch is on.
1 Blink — Thermostat Circuit Or Low Voltage
Meaning: The thermostat call or control input is not being detected or voltage dropped below acceptable threshold. Likely Causes: Faulty thermostat, loose wiring, corroded terminals, or low battery voltage. Action: Verify thermostat is set above room temperature, test thermostat wiring with a multimeter, clean/replace connectors, and confirm battery/charger health.
2 Blinks — High Limit Or Safety Cutoff
Meaning: The furnace exceeded temperature limits or a safety sensor tripped. Likely Causes: Blocked return or supply vents, failed blower motor, dirty heat exchanger, or defective limit switch. Action: Turn off furnace, inspect and clear vents, check blower operation, clean or replace filters and vents, and test limit switch continuity.
3 Blinks — Flame Sensor Or Open Circuit
Meaning: The flame sensor did not detect a flame or the sensor circuit is open. Likely Causes: Faulty flame rod, oxidized sensor surface, burner misalignment, or wiring break. Action: Inspect flame sensor for buildup or corrosion, clean gently with fine emery cloth, verify sensor position relative to flame, and replace if open or damaged.
4 Blinks — Ignition Failure
Meaning: The igniter failed to light the burner within the expected time. Likely Causes: Weak gas pressure, clogged burner ports, failed igniter, or gas valve issue. Action: Check propane supply and regulator, inspect burner for debris, test igniter continuity, and verify gas valve function and wiring.
5 Blinks — Limit Thermostat Open
Meaning: The limit thermostat indicates an open circuit, often due to overheat or a faulty sensor. Likely Causes: Limit switch failure, wiring fault, or consistent overheating from restricted airflow. Action: Confirm airflow, test limit switch continuity, inspect wiring, and replace the limit thermostat if faulty.
Step-By-Step Diagnostic Process
Follow this logical sequence when troubleshooting fault codes to isolate electrical, fuel, and mechanical problems efficiently.
- Verify Power: Check battery voltage (12V), fuses, and connections to the furnace control board.
- Recreate Fault: Turn on thermostat and watch LED blink pattern to capture exact code.
- Inspect Airflow: Examine vents, intake, and exhaust for blockages and ensure blower runs during startup sequence.
- Check Gas Supply: Confirm propane tank valve, regulator output, and that other appliances receive gas.
- Test Ignition And Flame Sensor: Observe igniter operation, listen for clicking, and use a multimeter to test continuity where applicable.
- Swap Components: If possible, test suspect parts (thermostat, thermistor, flame sensor) with known-good units or bench test to confirm failure.
Tools And Parts Commonly Needed
Technicians and DIYers should have basic tools and replacement parts to diagnose and repair Atwood furnaces quickly. Essential tools include a multimeter, insulated screwdrivers, needle-nose pliers, and a small wire brush.
- Replacement Flame Sensor Rods
- Igniters and Igniter Wires
- Inline Fuses And Fuse Holders
- Limit Thermostats And Temperature Sensors
- Replacement Control Board (for failing electronics)
Safety Precautions And Best Practices
Working on propane appliances and 12V systems requires care. Always shut off propane and disconnect battery power before opening access panels. Ventilate the area when testing burners. Use soapy water to check for gas leaks at fittings rather than a flame. Wear safety glasses and follow the vehicle manufacturer’s safety guidance.
Maintenance Tips To Prevent Fault Codes
Regular preventive maintenance reduces fault occurrences and extends furnace life. Schedule inspections before cold-season use and after long storage periods. Keep the furnace area clean and dry to avoid corrosion and electrical shorts.
- Clean Burner Ports And Flame Sensor Annually
- Inspect And Replace Worn Wiring Or Connectors
- Ensure Vent And Flue Paths Are Clear Of Debris
- Test Blower Motor And Lubricate If Manufacturer Allows
- Replace Aging Control Boards Promptly If Recurrent Faults Occur
When To Call A Professional
Some faults require expert diagnosis or gas-system licensing. Call a certified RV technician if the problem involves persistent gas leaks, complex control board failures, or intermittent faults that resist basic diagnostics. Never ignore a propane odor or recurring safety cutoff codes.
Model Differences And Where To Find Exact Codes
Atwood and Suburban furnace models share similar fault logic but use model-specific blink code definitions. Always consult the furnace model’s installation or service manual for exact code tables and wiring diagrams. Manufacturer websites and authorized RV service centers provide downloadable manuals and part diagrams.
Troubleshooting Example Scenarios
Scenario A — Furnace Won’t Start, LED Off
Check DC power: measure battery voltage, inspect inline fuse and supply harness. Confirm shore power converter charging if battery is low. Replace blown fuse, secure loose connections, or charge/replace battery.
Scenario B — Furnace Ignites Then Shuts Off With 3 Blinks
3 blinks indicate flame sensor issues. Clean the sensor, ensure proper alignment to the flame, and replace if the open-circuit persists. Also verify burner flame pattern is correct to contact the sensor reliably.
Scenario C — Furnace Runs Intermittently, 2 Blinks Occur During Operation
2 blinks point to a high-limit or fan failure. Test blower operation under call for heat, inspect for obstructed airflow, and test the limit switch for continuity. Replace failed blower motors or switches as needed.
Replacement Parts And Cost Considerations
Parts costs vary: flame sensors and fuses are inexpensive, while control boards and blower motors are pricier. Labor costs at RV shops add up, so DIY repairs save money when within the skillset. Ensure OEM or compatible parts rated for Atwood/ Suburban systems to maintain safety and reliability.
| Part | Typical Price Range | Difficulty |
|---|---|---|
| Flame Sensor | $10–$40 | Low |
| Igniter | $15–$60 | Medium |
| Blower Motor | $50–$200 | Medium–High |
| Control Board | $100–$300 | High |
Documentation And Resources
Manufacturer manuals, RV forums, and official service bulletins are valuable resources. Use serial and model numbers from the furnace rating plate to locate the correct manual. Certified RV technician networks and parts suppliers can confirm compatibility and provide wiring diagrams for complex repairs.
Key Takeaways For RV Owners
Monitor LED blink patterns carefully and document sequences for technicians. Perform simple checks first: power, fuses, battery, and airflow. Regular cleaning and inspection of burners and sensors prevent many faults. For gas-related or electrical concerns beyond basic checks, seek professional service to ensure safety and compliance.