Rv Furnace Clicking but Not Lighting

The RV furnace Clicking But Not Lighting is a common, fixable problem that leaves campers cold and frustrated. This article explains the most likely causes, step-by-step diagnostic checks, safe troubleshooting techniques, replacement part guidance, cost expectations, and when to call a professional to restore reliable heat. Safety-first tips and maintenance steps are included to reduce recurrence.

Symptom	Likely Cause	Quick Fix
Clicking, No Flame	Thermocouple/Flame Sensor Fault	Clean/Replace Flame Sensor
Rapid Clicking	Weak Battery / Low Voltage	Charge/Replace Battery
Single Click Then Silence	Gas Valve Not Opening / Obstructed Orifice	Check Gas Supply / Valve
Clicking With Burner Glow But No Flame	Dirty Or Clogged Burner	Clean Burner Ports

How RV Furnaces Ignite: Basic Components And Operation

RV furnaces commonly use either a standing pilot, intermittent pilot (spark ignition), or direct electronic ignition. Key components include the thermostat, control board or millivolt system, igniter or pilot assembly, gas valve, flame sensor or thermocouple, blower motor, and wiring. Understanding these parts helps narrow down why the unit clicks but the flame fails to light.

Common Causes For Clicking But No Ignition

Several typical issues produce the clicking sound without ignition. Igniter/pilot failure occurs when the spark or pilot does not light. Flame sensor or thermocouple problems prevent the control system from detecting flame. Gas supply or valve issues stop fuel flow. Electrical problems such as low voltage, bad wiring, or a failing control board can interrupt the ignition sequence. Finally, dirty burners or clogged orifices prevent proper combustion even if the gas flows and sparks are present.

Safety Precautions Before Troubleshooting

Always prioritize safety. Turn off LP gas at the supply tank or cylinder and the furnace gas valve before opening panels. Disconnect 12V power when inspecting wiring. Work in a well-ventilated area and avoid open flames if gas is suspected. Wear gloves and eye protection. If there is a strong smell of gas, leave the RV and call the gas supplier or emergency services—do not attempt repairs.

Step-By-Step Diagnostic Checklist

Follow an organized sequence to find the fault efficiently and safely.

1. Check Battery Voltage: Low batteries often cause clicking without ignition. Measure system voltage with a multimeter; 12.2V or lower can cause erratic ignition. Recharge or replace the battery as needed.

2. Verify Propane Supply: Ensure the tank or cylinder has gas, the valve is open, and the regulator is functioning. Swap tanks if suspecting an empty cylinder.

3. Listen To Ignition Behavior: Rapid repeated clicks suggest a weak spark or control board retry cycle. A single click followed by silence typically indicates gas valve failure or blocked gas flow.

4. Inspect For Error Codes: Many modern furnaces have LED indicators or diagnostic codes. Consult the furnace manual for code meanings before further troubleshooting.

5. Check The Thermostat: Ensure the thermostat calls for heat and that wires are properly connected. A faulty thermostat can trigger the igniter without opening the gas valve.

6. Examine The Flame Sensor / Thermocouple: A dirty or corroded flame sensor may not detect a flame, causing the unit to click and shut off. Clean or replace the sensor as indicated by the manual.

7. Inspect Igniter And Pilot Assembly: For spark ignition, confirm the igniter produces a visible spark. For standing pilot systems, ensure the pilot lights and stays lit.

8. Check Gas Valve And Orifice: If there is spark but no flame, the gas valve may not open or the orifice may be clogged. Verify gas flow from the valve outlet and clean or replace obstructed components.

9. Look For Blocked Air/Burner Ports: Spider webs, debris, and soot can clog burner ports and airways. Clean with compressed air and a soft brush.

How To Test Specific Components

Testing Battery And Electrical Supply

Use a multimeter set to DC voltage to measure battery output at the furnace 12V input. With furnace attempting to ignite, voltage should remain above 11.5V. Test voltage drop across wiring during start cycles to reveal bad connectors or thin wires.

Testing The Igniter/Spark

Visually confirm a strong, consistent spark at the pilot electrode during ignition attempts. If no spark appears, check the igniter wiring and coil. Replacement igniters are inexpensive and usually straightforward to swap.

Testing The Thermocouple Or Flame Sensor

Thermocouples generate a small millivolt signal; inspect for corrosion and proper contact with the pilot flame. Flame sensors in electronic systems can be cleaned with emery cloth to remove carbon buildup. Replace if cleaning doesn’t restore reliable detection.

Testing The Gas Valve

Confirm that the gas valve receives the control signal and that gas exits the valve. Use a manometer or smell test in a well-ventilated area with caution. If the valve clicks electrically but no gas emits, the valve may be seized or failed and should be replaced by a qualified technician.

Cleaning And Maintenance Steps That Often Fix The Issue

Many ignition failures result from dirt, corrosion, or insect nests. Routine cleaning typically involves removing the burner assembly, vacuuming debris, brushing burner ports, and cleaning the flame sensor with a non-abrasive pad. Replace air filters and clear intake/exhaust vents to maintain airflow and combustion stability.

Parts Replacement Guide And Compatibility

Common replacement parts include igniters, pilot assemblies, thermocouples, flame sensors, gas valves, control boards, and blower motors. Always use OEM or compatible parts specified for the furnace model (brands like Suburban, Atwood, Dometic). Verify part numbers in the furnace manual or on the original component before ordering.

Tools And Supplies Needed For DIY Repairs

• Multimeter for voltage and continuity checks
• Philips and flat-head screwdrivers
• Socket set for panel and mounting screws
• Needle-nose pliers for connectors
• Soft brushes, compressed air, and emery cloth for cleaning
• Replacement igniter, thermocouple, or flame sensor as required
• Propane leak detector solution or soapy water for gas leak checks

When To Call A Professional

Professional service is recommended when a gas valve or control board requires replacement, when diagnostic checks indicate gas leakage, or when electrical wiring issues are complex. If the repair requires tools or certifications for gas systems, a certified RV technician or licensed propane technician should perform the work. Safety and code compliance are critical when handling fuel systems.

Estimated Costs For Common Repairs

Cost varies by unit and region. Typical price ranges: igniter/pilot assembly $30–$120, thermocouple/flame sensor $15–$75, gas valve $120–$400, control board $150–$500, professional service call $100–$200 plus labor. Parts and labor for complex repairs can reach $600–$1,000 for older or rare models.

Preventive Maintenance To Avoid Future Clicking Issues

Annual furnace service before winter travel reduces failures. Recommended steps: clean burners and sensors, inspect wiring and connectors, test battery health, check exhaust and intake vents, verify thermostat operation, and cycle the furnace to ensure ignition. Keep insect screens on vents and store RVs with sealed vents to prevent nests.

Troubleshooting Table: Symptom To Likely Fix

Symptom	Immediate Check	Possible Fix
Clicks Rapidly, No Flame	Battery Voltage	Recharge/Replace Battery
Click, Gas Smell, No Flame	Gas Valve/Orifice	Shut Off Gas, Call Technician
Clicks, Spark Visible, No Flame	Clogged Orifice/Burner	Clean Or Replace Orifice
Click, Pilot Lights Then Goes Out	Thermocouple/Flame Sensor	Clean/Replace Sensor

Frequently Asked Questions

Why Does The Furnace Click But Stop After One Or Two Attempts?

Most units have a built-in safety retry sequence; if ignition fails after a few attempts the system locks out and requires reset. This behavior prevents gas buildup and indicates a persistent ignition or gas flow problem that needs inspection.

Can Low Propane Pressure Cause Clicking Without Lighting?

Yes. Low pressure from near-empty tanks, faulty regulators, or obstructed lines reduces flow below the ignition threshold. Replacing or swapping tanks and checking regulators often resolves the issue.

Is It Safe To Keep Trying To Start The Furnace If It Keeps Clicking?

No. Repeated starts can flood the combustion chamber with propane if the valve is partially stuck. Allow time between attempts, ventilate the area, and investigate causes rather than continually pressing the thermostat.

Resources And Manuals

Manufacturer manuals (Suburban, Atwood, Dometic) contain wiring diagrams, part numbers, and diagnostic codes. RV forums and YouTube repair channels provide model-specific walkthroughs. For gas safety, consult the National Propane Gas Association and local licensed RV technicians for code guidance.

Final Practical Checklist For Campers

• Before departure: Test furnace operation and clean accessible components.
• Carry spares: Keep a replacement igniter, thermocouple/flame sensor, and basic tools in the RV.
• Monitor battery health: Maintain battery charge with solar or shore power to ensure reliable ignition.
• Know when to stop: If gas odor or persistent faults appear, shut gas off and seek professional help.