The pilot light on an RV furnace is a small, continuously burning flame that ignites the main burner when heat is required. Understanding how to light, diagnose, and maintain the pilot light helps keep the furnace reliable, extends component life, and ensures safe operation while traveling or camping.
| Topic | Quick Notes |
|---|---|
| Purpose | Pilot ignites main burner; critical for furnace startup |
| Common Causes Of Failure | Clogged orifice, thermocouple failure, low propane, draft, faulty gas valve |
| Basic Steps | Turn off gas, set control to pilot, ignite with match or piezo, hold until stable |
| Safety Tips | Ventilate, smell for gas, leak test after work, turn off propane supply before repairs |
How An RV Furnace Pilot Light Works
The pilot light is a small constant flame fed by propane from the RV’s supply. When the thermostat calls for heat, the pilot flame ignites the main burner through a gas valve, allowing higher-volume combustion for heating. Most modern RV furnaces use a pilot assembly that also includes a thermocouple or flame sensor to confirm pilot presence and allow the gas valve to remain open.
Key Components: pilot orifice, pilot tube, thermocouple or flame sensor, gas control valve, igniter (if equipped), and wiring to thermostat or propane system.
Preparing To Light The Pilot Light
Before any attempt to light the pilot, ensure the RV is parked level and in a well-ventilated area. Turn off any open flames and avoid lighting the pilot in enclosed spaces with poor ventilation. Confirm propane tank valves are open and the propane system has adequate pressure.
Check the furnace access panel and owner’s manual for the pilot location and specific lighting procedure. Most units have a control knob labeled OFF/PILOT/ON, and some models provide a piezo igniter or an electronic igniter switch.
Step-By-Step: How To Light An RV Furnace Pilot Light
Follow the manufacturer’s instructions when available. The general process is:
- Turn the furnace switch and thermostat to OFF.
- Locate and open the furnace service panel or access door.
- Turn the gas control knob to OFF and wait 5 minutes to clear any accumulated gas.
- Set the knob to PILOT and depress it to start gas flow to the pilot orifice.
- While holding the gas knob in, use the pilot igniter button or a long-reach lighter/match to ignite the pilot.
- Keep the knob depressed for 30–60 seconds after ignition to warm the thermocouple.
- Release the knob; if the pilot stays lit, set the control to ON and replace the access panel.
Tip: If the pilot does not stay lit after several attempts, do not repeatedly flood the area with gas. Stop and inspect for problems.
Troubleshooting Common Pilot Light Problems
Pilot light failures are common and usually traceable to a few recurring causes. A systematic approach saves time and prevents unnecessary parts replacement.
1. No Gas Flow
Check that propane tanks are turned on and regulators are delivering pressure. Confirm other gas appliances in the RV work. If there is zero gas flow, inspect tank valves, regulator, and supply lines. A frozen or faulty automatic changeover regulator can interrupt flow.
2. Pilot Ignites But Won’t Stay Lit
This condition often indicates a weak thermocouple or dirty pilot orifice. The thermocouple measures the pilot flame and signals the gas valve to remain open. Thermocouples wear out and should be replaced if they fail to hold the valve open after a warm-up period.
3. Weak Or Unsteady Pilot Flame
A small, yellow, or flickering flame suggests a clogged pilot orifice or draft affecting the pilot tube. Cleaning the orifice with compressed air or a fine wire may restore a strong blue flame. Check for nearby vents or drafts that disturb the flame.
4. Clicking Or Rapid Ignition Without Flame Detection
Electronic igniters that click but fail to light or detect the flame could have wiring issues, grounding problems, or a faulty flame sensor. Inspect wiring connections and grounding points for corrosion or loose terminals.
Maintenance Procedures To Keep The Pilot Reliable
Regular maintenance prevents pilot light problems and extends furnace life. Perform visual inspections and simple cleaning at least once per heating season or before long trips.
- Inspect pilot assembly for corrosion and soot; clean with compressed air.
- Replace the thermocouple every few years or when it fails to hold the pilot.
- Check the pilot orifice for clogs and clean using the recommended method in the manual.
- Examine furnace vents and flue for obstructions, nests, or rust.
- Test the propane system for leaks using a soap solution after any service.
Safety Precautions When Working With The Pilot Light
Working on the pilot light involves gas and an open flame, so prioritize safety. If a strong propane smell is present, avoid ignition sources and ventilate the area until the odor clears. Use a gas detector or soapy water to find leaks instead of a naked flame.
Always: turn off the propane source before making repairs, wear eye protection, and follow the furnace manufacturer’s warning labels. When in doubt, call a certified RV technician or propane professional.
When To Replace Parts Versus Call A Professional
Some tasks are suitable for owners with mechanical skill: cleaning the pilot orifice, replacing a thermocouple, or changing a furnace filter. More complex issues—gas valve replacement, sealed combustion systems, or persistent leaks—require licensed technicians.
Replaceable By Owners: thermocouple, pilot orifice cleaning, access panel inspections. Call A Pro For: gas control valve replacement, sealed combustion diagnostics, combustion or carbon monoxide concerns, and certified leak repairs.
How To Diagnose A Faulty Thermocouple
The thermocouple generates a small millivolt signal when heated by the pilot. A quick test is to observe pilot behavior: if it lights but goes out when the knob is released, the thermocouple is likely weak.
For more precision, a multimeter can measure the thermocouple’s output; a healthy unit usually produces 20–30 mV when heated. Replace the thermocouple if readings are significantly lower or if visual inspection shows corrosion, kinks, or damage.
Preventing Drafts And Flame Disturbance
Drafts from open vents, windows, or external wind can blow out a pilot. Ensure the furnace access panel seals properly and check external vents for windshields or baffles. In cold weather, gusts near the exterior vent may be reduced with a wind deflector designed for the furnace model.
Important: Never block intake or exhaust vents; doing so can cause unsafe combustion and carbon monoxide buildup.
Checklist Before Winter Or Extended Trips
Perform these checks to minimize the chance of pilot issues while traveling:
- Inspect and clean the pilot assembly and burner area.
- Test the propane system and ensure tanks are full and regulators function.
- Replace the thermocouple if older than three to five years or showing wear.
- Run the furnace through a complete cycle to verify pilot ignition and main burner operation.
- Install a working carbon monoxide detector near sleeping areas and test batteries.
Common Manufacturer Variations And Notes
Manufacturers like Suburban, Atwood, Truma, and Dometic have variations in pilot assembly design and lighting procedures. Always consult the specific furnace manual for torque values, part numbers, and model-specific safety instructions.
Some newer furnaces use electronic ignition systems without a standing pilot; this article focuses on standing-pilot designs that remain common in many RVs.
Frequently Asked Questions (FAQ)
Why Does The Pilot Light Smell Like Gas?
A rotten-egg or strong propane odor before lighting indicates a gas buildup from repeated unsuccessful ignition attempts or a leak. Ventilate the area and stop attempts until the source is found. If leaks are suspected, close the tank valve and contact a professional.
How Long Should The Pilot Stay Lit Before Releasing The Knob?
Hold the control knob depressed for about 30–60 seconds, or as specified by the furnace manual, to allow the thermocouple to heat adequately and signal the gas valve to remain open.
Is It Safe To Light The Pilot With A Match?
Yes, if the area is ventilated and the user takes care to follow the correct procedure. Use a long-reach lighter or match to keep hands away from the assembly. If there is a strong gas odor, do not light the pilot.
Can Low Tank Pressure Cause Pilot Problems?
Yes, low propane pressure from nearly empty tanks, faulty regulators, or blocked lines can cause a weak or nonexistent pilot flame. Check tank levels and perform pressure checks if necessary.
Useful Parts And Tools For DIY Pilot Maintenance
Keeping certain tools and spare parts on hand makes owner-performed maintenance easier: thermocouple replacements, replacement pilot orifice kits, screwdrivers, a multimeter, compressed air, a long-reach lighter, leak detection solution, and a soft wire brush.
Note: Use parts designed for the specific furnace model to ensure proper fit and safe operation.
Resources And Where To Find Reliable Help
Owner manuals, manufacturer support pages, and RV forums provide model-specific guidance. For certified service, search for RVIA-certified technicians or local propane appliance specialists who are familiar with mobile systems and DOT-regulated components.
Manufacturers’ customer service and authorized dealers can provide OEM parts and wiring diagrams when needed.
Additional Safety: Carbon Monoxide And Ventilation
An improperly burning pilot or restricted venting can increase carbon monoxide risk. Install and regularly test carbon monoxide detectors and ensure furnace vents are free from blockage and animal nests. If a detector alarms, evacuate and seek fresh air immediately.
Action: If repeated combustion irregularities occur, avoid using the furnace until inspected by a professional to prevent CO hazards.
Summary: Practical Steps For A Reliable RV Pilot Light
Maintain the pilot assembly, replace aging thermocouples, clean orifices, and verify propane pressure before trips. Follow safe lighting procedures, avoid working with gas in confined spaces, and seek professional help for complex gas valve or combustion issues. Routine attention keeps the furnace dependable and reduces the risk of roadside heating failures.