Rv Furnace Won’t Ignite: Troubleshooting and Common Fixes

The RV furnace won’t ignite is a common problem that leaves owners cold and inconvenienced. This article explains likely causes, step-by-step diagnostics, and practical solutions to get heat back quickly. It focuses on safety, tools, and when to call a professional.

Symptom	Possible Cause	Quick Fix
Furnace Attempts To Start But No Flame	Igniter Or Thermocouple Issue	Inspect/Replace Igniter; Clean Thermocouple
Blower Runs But No Ignition	Fuel Supply Or Gas Valve Problem	Check LP Tank, Lines, And Valve
Clicking Without Ignition	Control Board Or Safety Switch Fault	Test Control Board And Door Switches
No Power To Furnace	Blown Fuse, Tripped Breaker, Or Wiring	Check Fuses, Wiring, And Battery Voltage

How RV Furnaces Ignite: A Quick Overview

Understanding how the RV furnace ignites helps isolate problems effectively. Most RV furnaces use propane (LP) and an electronic ignition system that includes a thermostat, control board, igniter or pilot assembly, gas valve, blower motor, and safety sensors.

The typical ignition sequence: thermostat calls for heat, control board powers the igniter or opens pilot circuit, gas valve opens, flame is sensed by a thermocouple or flame sensor, and the blower starts after a short delay.

Common Causes When An RV Furnace Won’t Ignite

1. Fuel Supply Problems

Propane supply issues are a top cause. Low tank pressure, closed tank valve, empty cylinder, or a kinked/blocked line prevents gas flow. An automatic changeover regulator on twin tanks can also fail or be set incorrectly.

2. Igniter Or Pilot Failure

Modern furnaces use a hot surface igniter or spark igniter to light the burner. A cracked, worn, or carbon-fouled igniter will prevent ignition. Pilot assemblies can become clogged by debris or soot.

3. Faulty Thermocouple Or Flame Sensor

The thermocouple/ flame sensor confirms a flame is established. If it is dirty, misaligned, or failed, the control board will shut gas flow off, so the furnace won’t stay lit.

4. Electrical And Control Board Issues

Low battery voltage, blown fuses, bad wiring, or a defective control board prevent the ignition sequence. Some furnaces require 12V systems to start; weak batteries or poor connections will stop ignition attempts.

5. Safety Switches And Limit Switches

Door switches, high-limit switches, and roll-out or overheat sensors will block ignition if they detect unsafe conditions or are faulty. These switches can fail due to wear, heat exposure, or corrosion.

Tools And Safety Precautions Before Troubleshooting

Safety first. Turn off gas and power when inspecting components unless testing live sequences requires controlled checks. Work in a ventilated area and keep a multipurpose fire extinguisher nearby.

• Tools: multimeter, manifold gauge or gas leak detector, nut drivers, wire brush, replacement igniter/thermocouple, propane tank gauge.
• Safety: always turn LP tanks off before service, disconnect battery negative for electrical work, and use soapy water to check leaks.

Step-By-Step Troubleshooting Guide

Check Power And Controls

Verify the RV furnace has 12V power. Measure battery voltage at the furnace; it should be at least 11.5–12V under load. Inspect the furnace fuse and replace if blown.

Test the thermostat and control settings. Confirm the furnace switch is on and thermostat is set above ambient temperature. Reset the circuit breaker if applicable.

Verify Propane Supply And Valves

Confirm LP tanks have fuel and the tank valve is open. If equipped with two tanks, ensure the changeover regulator is functioning. Check for closed inline shutoff valves between the tank and furnace.

Use a leak detector or soapy water on fittings and regulators. Smells of propane or visible leaks require immediate shutdown and professional service.

Listen And Observe The Ignition Cycle

Turn the thermostat up to call for heat and listen. Typical signs: a click as the igniter engages, a whoosh of gas, or multiple attempts. If there is clicking but no ignition, the control board is trying but gas or flame sensing is failing.

Test And Inspect The Igniter

Locate the igniter and inspect visually. Spark igniters produce a visible arc; hot surface igniters glow red. Replace cracked or non-glowing igniters. Use the manufacturer’s replacement part for compatibility.

Clean Or Replace The Thermocouple/Flame Sensor

Remove the thermocouple or flame sensor and clean gently with steel wool or emery cloth to remove soot. Reposition the sensor so it sits in the flame path. Replace if cleaning does not restore operation.

Check The Gas Valve And Pressure

Measure gas pressure if tools are available; incorrect pressure indicates regulator or valve issues. If the valve clicks open but no gas flow occurs, internal valve failure or blockage may be present and requires replacement.

Inspect Safety And Limit Switches

Locate door, high-limit, and roll-out switches. Bypass testing can help isolate faults but should be temporary and done carefully. Replace any switch that fails continuity checks or visibly appears damaged.

Common Repair And Replacement Strategies

Replacing The Igniter

Replacement is often straightforward: remove access panels, unplug the igniter, unfasten mounting screws, and swap in the new unit. Match the part number for fit and positioning. Test ignition sequence after replacement.

Replacing The Thermocouple Or Flame Sensor

Thermocouples are inexpensive and commonly replaced after a few years. Ensure proper seating near the burner flame. Verify the sensor’s lead wires are secure and corrosion-free.

Repairing Or Replacing The Gas Valve

Gas valve repair is more complex and may require certified service. If the valve is stuck or leaking, replace with an OEM or approved replacement. Never modify valves outside manufacturer guidance.

Addressing Electrical Issues And Control Boards

Replace fuses and correct wiring faults as needed. If the control board shows burned traces or components, replacement is usually the practical fix. Note error codes or LED blink patterns for diagnostics per the furnace manual.

When To Call A Professional

Contact a qualified RV technician or licensed propane service when: propane leaks are present, gas valve or regulator replacement is needed, electrical faults persist after basic checks, or combustion-related sensors require recalibration.

Do not attempt major gas-valve, regulator, or sealed-combustion repairs without certification. Safety risks include carbon monoxide poisoning and fire.

Preventive Maintenance To Avoid Future Ignition Failures

• Run the furnace briefly before cold seasons to verify operation.
• Inspect and clean the burner area, igniter, and flame sensor annually.
• Keep LP tanks properly filled and test regulators periodically.
• Maintain battery health and secure wiring connections.
• Replace aging components on schedule—igniters, thermocouples, and filters.

Troubleshooting Checklist And Quick Fixes

Problem	Quick Actions
No Power	Check fuse, battery voltage, wiring connections
Clicks But No Flame	Inspect igniter; test gas flow and valve
Flame Lights Then Dies	Clean/replace thermocouple or flame sensor
Intermittent Ignition	Check loose connections, low battery, dirty components

Safety Tips And Carbon Monoxide Awareness

Always install an RV-rated carbon monoxide (CO) detector and test it regularly. A furnace that ignites irregularly or produces incomplete combustion raises the risk of CO buildup.

If occupants experience headaches, nausea, or dizziness while the furnace is operating, stop the furnace, ventilate the RV, and seek professional inspection immediately.

Manufacturer Resources And Parts

Refer to the furnace manufacturer’s manual for model-specific diagnostics, error codes, and replacement part numbers. Common RV furnace brands include Suburban, Atwood/Truma, and Dometic—each provides service manuals and parts lists online.

Using OEM parts ensures compatibility and preserves safety certifications. After-market parts may fit but verify quality and approvals before installation.

Key Takeaways For RV Furnace Ignition Problems

Systematic diagnosis — start with power and propane, then move to ignition components and sensors. Many issues are resolved by cleaning, replacing small parts, or restoring power and fuel flow. For gas-valve or combustion concerns, prioritize safety and professional service.

Following routine maintenance and addressing small faults early reduces the chance the RV furnace won’t ignite during a trip.