Atwood Rv Furnace Troubleshooting Guide

The following guide helps diagnose and fix common Atwood RV furnace problems, covering safety checks, diagnostics, and step-by-step repairs. It focuses on practical troubleshooting for the Atwood/Dometic line of RV furnaces and highlights electrical, propane, thermostat, and ignition issues. Always follow safety precautions when working with gas and electrical systems.

Symptom	Common Cause	Quick Fix
Furnace Won’t Start	Faulty thermostat, blown fuse, bad thermostat wiring	Check fuses, batteries, and thermostat wiring
Igniter Clicks But No Flame	Clogged pilot, bad gas valve, low propane pressure	Clean pilot, test gas valve, check tank and regulator
Furnace Starts Then Shuts Off	Overheat switch, blocked vent, failed limit switch	Clear vents, inspect heat exchanger and limit switch
Blower Runs But No Heat	Burner won’t light, dirty burner, weak propane flow	Inspect burner assembly, clean or replace parts, check propane

How Atwood RV Furnaces Work

Atwood furnaces are forced-air appliances using a combustion chamber and blower to distribute heat through ductwork. They rely on a thermostat, control board or gas valve, igniter or pilot assembly, and safety switches such as a limit/overheat switch and flame sensor.

Understanding these components helps isolate failures: electrical controls manage operation, fuel delivery supplies propane, and airflow carries heat into living spaces.

Safety First: Before Troubleshooting

Disconnect power and propane when performing inspections beyond basic checks. Work in a well-ventilated area and keep a fire extinguisher nearby. If unsure about gas line or control board interventions, consult a certified RV technician.

Tip: Turn off propane at the tank and open a window to vent any smell of gas before starting repairs.

Initial Checks And Basic Troubleshooting Steps

Begin with simple checks that resolve many issues quickly. These steps save time and help avoid unnecessary part replacements.

• Verify 12V Power: Check battery voltage and fuse for the furnace circuit. Low voltage can cause control failures.
• Check Thermostat Settings: Ensure the thermostat is set to heat and above room temperature. Replace dead thermostat batteries if present.
• Inspect Fuses And Breakers: Locate the inline fuse or furnace fuse on the RV panel and replace if blown. Reset breakers if tripped.
• Smell For Gas: If gas odor is present, shut off propane and address leaks before further testing.

Common Symptoms And Troubleshooting Procedures

Furnace Won’t Start Or No Response

If the furnace shows no control lights or the blower never activates, this points to an electrical issue.

• Check Battery Voltage: Measure at battery and furnace terminals. 12V under 11.5V may cause failures.
• Inspect Fuses: Replace the furnace inline fuse (commonly 20A) and any PCB-mounted fuse.
• Verify Wiring To Thermostat: Loose or reversed wires can prevent operation. Confirm proper connections per furnace wiring diagram.
• Test The Switch Or Control Board: If power is present but the control board shows no activity, the board may be defective.

Igniter Clicks But No Flame Or Weak Flame

Clicking without ignition often indicates fuel delivery or pilot issues. Diagnosis requires checking the pilot, gas valve, and propane source.

• Check Propane Supply: Verify tank valve is open and propane is flowing. Inspect the regulator; a frozen or faulty regulator reduces pressure.
• Clean Pilot Orifices: Debris in pilot jets can prevent ignition. Remove and gently clean orifices with compressed air.
• Test Gas Valve Operation: Use a multimeter to confirm the gas valve coil receives voltage during start sequence. If coil energizes but no gas, replace the valve.
• Inspect Flame Sensor: A dirty sensor can fail to detect flame, causing shutoff. Clean with a soft cloth.

Furnace Lights Then Shuts Off Quickly

Short burners often result from flame sensing issues, heat exchanger overheating, or poor airflow causing limit switch activation.

• Check For Blocked Vents: Exterior intake or exhaust blocked by debris triggers safety shutdowns. Clear vent screens and obstructions.
• Inspect Limit Switch: The overheat or limit switch opens if the heat exchanger gets too hot. Replace if faulty after confirming airflow is clear.
• Clean Burner Assembly: Soot or buildup causes uneven combustion and shutdown. Remove burner tray and clean thoroughly.
• Ensure Sufficient Airflow: Dirty blower motor or cabin filters reduce airflow and trigger safety cutouts.

Blower Runs But No Heat

When the blower runs but no flame is present, the ignition sequence is failing. This narrows focus to ignition components and fuel flow.

• Confirm Igniter Function: Some Atwood models use hot surface igniters or spark igniters. Observe for ignition after the pre-purge cycle.
• Check Gas Pressure: Low tank pressure or an underperforming regulator produces no flame. Try with another propane source if available.
• Examine Burner And Manifold: Corrosion or debris can block gas ports. Disassemble and clean the burner manifold carefully.

Diagnosing Electrical Components

Electrical tests require a multimeter and knowledge of expected voltages and resistances. Follow manufacturer wiring diagrams when available.

• Test Continuity Of Thermostat Wiring: Verify continuity between thermostat terminals and furnace control.
• Measure Voltage At Gas Valve: Expect 12V during ignition command. If absent, trace back to the control board.
• Check Blower Motor And Capacitor: Measure motor resistance and inspect capacitor for bulges or leakage.
• Inspect Control Board For Visible Damage: Burnt traces, bulging capacitors, or corroded connectors indicate replacement.

Cleaning And Routine Maintenance

Routine cleaning prevents many Atwood furnace problems. Regular maintenance improves safety and reliability.

• Clean Exterior Vents Annually: Remove leaves, insects, and debris from intake and exhaust vents.
• Vacuum Furnace Interior: Remove accumulated dust around blower, heat exchanger, and burner area.
• Replace Filters And Screens: If the furnace has cabin air filters, replace or clean them on schedule.
• Inspect Heat Exchanger For Cracks: Cracks can cause carbon monoxide leaks. If suspected, discontinue use and have a professional inspect.

When To Replace Parts

Knowing when to repair versus replace saves time and ensures safety. Replace components that repeatedly fail or show wear beyond simple repair.

• Replace Igniter If Cracked Or Nonfunctional: Hot surface igniters degrade with time and should be replaced rather than repaired.
• Replace Gas Valve On Leak Or No Flow: A failing valve that does not regulate fuel safely requires replacement.
• Replace Control Board For Erratic Behavior: If diagnostics show inconsistent outputs or burnt components, a new board restores reliable control.
• Replace Blower Motor If Noisy Or Overheating: Bearings wear out and motors that overheat are best replaced.

Testing For Carbon Monoxide And Safety Devices

Combustion appliances can produce hazardous gases when malfunctioning. Regular checks of detectors and ventilation systems are essential.

• Install And Test CO Detectors: Place detectors near sleeping areas. Test monthly and replace batteries regularly.
• Check Seals And Flues: Ensure all seals between furnace and ducts are intact to prevent exhaust leaks.
• Perform A Combustion Analysis If Suspected Leak: Hire a professional to measure CO and combustion efficiency when problems arise.

Model-Specific Notes And Resources

Atwood models and successor Dometic-branded units share many parts but vary in layout and control boards. Reference the model and serial number when ordering parts or following service manuals.

• Consult The Owner’s Manual: Manuals include wiring diagrams, part numbers, and troubleshooting flows specific to model.
• Use Manufacturer Technical Bulletins: These often address common failure modes and updated repair procedures.
• Source OEM Parts For Critical Components: Gas valves, control boards, and igniters should be OEM or approved equivalents for safety.

Step-By-Step Common Repair Examples

Replacing A Blown Inline Fuse

Locate the inline fuse near the furnace or in the RV panel. Use the amperage rating on the old fuse. Replace with the same rating. After replacement, test the furnace operation; repeated blows indicate short circuit requiring further diagnosis.

Cleaning A Clogged Pilot Or Burner

Turn off propane and power. Remove access panel, locate pilot jet and burner tray, and use compressed air to clear debris. Reassemble and restore power. If ignition remains weak, replace the pilot assembly.

Replacing The Limit Switch

Disconnect power. Access the furnace control compartment and locate the limit/overheat switch near the heat exchanger. Replace with matching part and reconnect wiring precisely. Restore power and test operation, monitoring for proper airflow and temperature.

When To Call A Professional

Complex gas valve replacements, cracked heat exchangers, suspected carbon monoxide leaks, and persistent electrical faults should be handled by certified RV technicians. Professional service ensures compliance with safety standards and proper diagnostic equipment use.

Warning: Any repair involving gas fittings or combustion chamber integrity warrants professional inspection if the technician is not fully confident.

Frequently Asked Questions (FAQ)

Why Does The Furnace Smell Like Gas After Trying To Start?

A lingering gas smell can be from multiple ignition attempts with unburned propane. Turn off the propane, ventilate the RV, and visually inspect for leaks. Use soapy water on fittings to find bubbles, or call a professional.

How Often Should An Atwood Furnace Be Serviced?

Annual inspection and cleaning before winter use is recommended. Heavy-use RVs or dusty environments may require more frequent service.

Can A Weak Battery Cause Furnace Problems?

Yes. Many furnaces require a stable 12V supply. A weak battery can prevent ignition, cause control resets, or reduce gas valve operation.

Parts And Tools Checklist For DIY Repairs

• Multimeter for voltage and continuity checks
• Inline fuse replacements matching amperage
• Replacement igniter, limit switch, and gas valve (model-specific)
• Compressed air, soft brushes, and approved cleaners
• Socket set, screwdrivers, and wire connectors
• Owner’s manual and schematic for the specific Atwood model

Additional Resources And References

Use manufacturer manuals, RV forums, and certified service centers for specific procedures and part numbers. OEM schematics and service bulletins provide model-specific troubleshooting flows and are invaluable for accurate repairs.

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