RV Furnace Won’t Stay Lit: Troubleshooting and Repair Guide

The RV furnace won’t stay lit can be frustrating and unsafe for travelers. This guide explains common causes, step-by-step troubleshooting, safety checks, and repair options to restore reliable heat. It focuses on diagnosis, practical fixes, when to call a professional, and tips to prevent recurrence.

Symptom	Likely Cause	Quick Fix
Furnace lights then dies	Pilot/igniter issue, weak propane, or flame sensor	Clean sensor, check propane pressure
Clicking but no flame	Faulty igniter or control board	Inspect igniter, replace if cracked
Burner stays lit intermittently	Thermostat, vent blockage, or draft	Clear vents, test thermostat

How RV Furnaces Work And Why It Matters

An RV furnace typically runs on propane with an electric igniter and a combustion fan. The thermostat signals the control board, the igniter lights the burner, a flame sensor verifies combustion, and the blower circulates warm air. Understanding this sequence helps isolate where the problem occurs when an RV furnace won’t stay lit.

Primary Causes When An RV Furnace Won’t Stay Lit

Propane Supply Problems

Low propane tank levels, closed valves, or clogged lines can cause intermittent flame. A weak propane supply often results in the furnace lighting briefly then going out as pressure drops.

Faulty Ignition System

The igniter or pilot assembly can wear out, crack, or corrode. If the igniter fails to sustain a reliable spark or glow, the burner may light but the flame will not hold.

Dirty Or Faulty Flame Sensor

The flame sensor detects presence of a flame and signals the control board to continue gas flow. A dirty or misaligned sensor commonly causes shutdowns shortly after ignition.

Thermostat Or Control Board Issues

A malfunctioning thermostat, loose wiring, or a failing control board can send erroneous signals, causing the furnace to light briefly and then shut off.

Blocked Combustion Or Exhaust Vents

Blockages or animal nests in intake/exhaust vents create unsafe combustion conditions. Most systems include a safety switch that shuts down the furnace if airflow is restricted.

Drafts And Environmental Factors

Strong wind or negative pressure within the RV can blow out the flame. High elevation and cold lines can also change propane behavior and burner performance.

Safety Checks Before Troubleshooting

Always prioritize safety: turn off propane at the tank, ensure adequate ventilation, and disconnect power before inspecting components. If a gas smell is present, stop and ventilate the RV immediately and do not attempt ignition until the leak is located and fixed.

Step-By-Step Troubleshooting When An RV Furnace Won’t Stay Lit

1. Confirm Propane Supply And Pressure

Check tank gauge and ensure the propane valve is fully open. Swap tanks to rule out a bad regulator. If equipped, use a propane pressure gauge to verify consistent pressure under load.

2. Inspect Thermostat Settings And Wiring

Set the thermostat several degrees above ambient to call for heat. Inspect thermostat wiring for loose connections and corrosion. Replace batteries if the thermostat is battery-powered.

3. Observe The Ignition Sequence

Turn the furnace on and note behavior: is the igniter starting? Is there a visible spark or glow? Does the burner ignite then die? Document exact symptoms to narrow causes.

4. Check The Flame Sensor

Locate the flame sensor near the burner and gently clean it with a fine abrasive pad or emery cloth. Reinstall and test. A clean sensor often resolves the furnace lighting briefly then shutting off.

5. Inspect Combustion And Exhaust Vents

Visually inspect intake and exhaust pipes outside the RV for blockages, bird nests, or ice. Remove obstructions and verify vents are firmly attached and undamaged.

6. Examine The Igniter And Electrode Gap

Check for cracks, carbon buildup, or misalignment. For hot surface igniters, a cracked ceramic element requires replacement. For spark igniters, ensure electrode gaps match manufacturer specs.

7. Test Control Board And Safety Switches

Inspect for burn marks, swollen capacitors, or corrosion on the control board. Test limit switches and pressure switches for continuity with a multimeter. Replace faulty components as needed.

Common Repairs And How To Perform Them

Cleaning Or Replacing The Flame Sensor

Cleaning typically requires removing the sensor and using gentle abrasive cleaning followed by a test run. Replace if heavily corroded or damaged. This is a common, low-cost repair that often fixes the issue.

Replacing The Igniter Or Electrode

Match the replacement part to the heater model. For a hot surface igniter, disconnect power, remove the old element, and install the new part following torque and clearance specs.

Fixing Propane Flow Issues

Replace faulty regulators and check for leaks at fittings using a leak detector solution. If low tank pressure persists, service by a certified RV propane technician is recommended.

Repairing Or Replacing The Control Board

Control board replacement should follow model-specific instructions. Before replacing, check wiring harnesses and connectors. If uncomfortable with electrical work, hire a qualified RV technician.

When To Call A Professional

Consult a professional if a gas leak is suspected, the control board needs replacement, or if troubleshooting requires gas-line repair. Licensed RV technicians have tools and expertise to test propane pressure, diagnose intermittent electrical faults, and comply with safety codes.

Preventive Maintenance To Keep An RV Furnace Reliable

• Inspect vents and ducts before each season and after long storage to remove nests and debris.
• Schedule annual professional inspections focusing on burner condition, heat exchanger integrity, and gas line checks.
• Keep a spare igniter and flame sensor on hand for older RVs with hard-to-source parts.
• Operate on full tanks when possible and maintain regulators to prevent pressure-related shutdowns.
• Use carbon monoxide detectors and propane leak alarms to ensure safety while using the furnace.

Troubleshooting Checklist For Technicians And DIYers

Step	Action	Expected Result
1	Check propane level and valve	Steady fuel supply
2	Observe ignition sequence	Consistent spark/heat
3	Clean flame sensor	Flame remains lit
4	Inspect vents	Unobstructed airflow
5	Test control board	Stable control signals

Common Models And Known Issues

Furnace brands like Suburban, Dometic, and Atwood are common in U.S. RVs. Suburban models may experience thermocouple or electrode wear; Dometic units sometimes show control board failures; Atwood furnaces often face venting and regulator-related shutdowns. Always reference the model-specific service manual.

Cost Estimates And Parts To Keep On Hand

Typical part costs: igniter $30–$120, flame sensor $10–$40, control board $150–$400, regulator $40–$120. Labor for professional diagnosis and repair can vary widely but expect $100–$300 for basic repairs and $300+ for control board or regulator replacement.

Final Tips For RV Owners

Document each step during troubleshooting to help technicians if professional service is required. Keep maintenance logs, replace parts proactively for older furnaces, and test safety devices regularly. Regular inspection and simple preventive maintenance often prevent the common causes when an RV furnace won’t stay lit.